PVSAT 2024
10–12 April 2024
Technology and Innovation Centre (TIC),
University of Strathclyde, Glasgow, UK

iop.org

Programme
Wednesday 10 April 2024
10:30am
Time

Registration and Welcome Refreshments
Talk

Speaker

TasmiatRahmanGeorge11am
Welcome
Koutsourakis
Strathclyde
hostSession 1 Chair: Tasmiat Rahman
Invited
11:15am
Aruna Ivaturi
SpeakerDavid
11:45amContributed
Keeble12:00pm

Contributed

Dan Lamb

Title

Affiliation

Conference Chair

University ofSouthampton

Programme Chair

NPL

Strathclyde Intro

University ofStrathclyde

TBC
Detection of vacancy-related point
defects in antimony selenide
CdTe-based PV on ultrathin glass for
emerging large area space applications

12:15pm

Flash Poster Presentations A

12:30pm

Lunch

1:30pmPoster Session

2:45pmAfternoon Break

University ofStrathclyde
University Of
DundeeSwansea
University

Session 2 Chair: Elizabeth Gibson
3pm

InvitedSpeaker

Satoshi
Uchida3:30pmContributed

Oliver Hutter

3:45pmContributed

Matthew
Wright4pm

Contributed

4:15pmMr Yazan
J.K. Musleh

Nanoscopic observation of organometal
halide perovskite solar cells withsuperlattice
Hysteresis and Transient Behaviour inCurrent Voltage Measurements of
Antimony Selenide Solar Cells
Impact of Surface Electric Fields on Light
Soaking Enhancements in SHJ Solar
Cells
Irradiance Estimation for Vertical Bifacial
AgriPV Systems: Integrating Regression
Analysis and DecompositionTransposition Matrix in the UK Context
Afternoon Break

University ofTokyo
Northumbria
University
University Of
OxfordUniversity ofSouthampton

Session 3 Chair: Nigel Mason
Time

Talk

Speaker

Title

Affiliation

Contributed

DanielParsons

A Novel System for Performancemeasurements of Indoor Photovoltaic
Devices under Indoor Standard Testing
Conditions (ISTC)

National PhysicalLaboratory

4:45pmContributed

James
McQueen

5pm

Contributed

4:30pm5:15pmContributed

Multiphysics Modelling for the Designof >35% Efficient Perovskite-on-SiliconTandem Solar Cells
Zn(x)Mg(1-x)O buffer layer for CZTSSe
solar cells using co-sputtering
technique.
Indoor Characterisation and
Performance Analysis of Static
Hexagonal Concentrators for Building
Integrated Low Concentrating
Photovoltaic Applications

Prabeesh
Punathil
Lewis Osikibo
TamunoIbuomi

5:30pm6:30pm

University Of
OxfordNorthumbria
University
Glasgow
Caledonian
University

Welcome Reception

Thursday 11 April 2024
Session 4 Chair: Stuart Boden
Time

Talk

Speaker

9:15amInvitedSpeaker

Robert Hoye

9:45amContributed

John Murphy

10am

Contributed

ErshadParvazian

10:15amContributed

Jessica
Barichello

Title

Affiliation

Photovoltaic Materials Development:
Roadmap on Current Challenges andFuture Opportunities
Contact metallization processing
considerations for silicon
photovoltaics
Utilizing Low-Toxicity Solvents in Rollto-Roll Fabrication of Carbon
Electrode Perovskite Solar Cells

University Of
Warwick

Beneath the surface: Investigating
Perovskite Solar Cells under Water

CNR - ISM Istituto
di Struttura della
Materia

10:30am

Exhibitor Flash presentations

10:45amMorning Break

University of
OxfordSwansea
University

Session 5 Chair: George Koutsourakis
11am

InvitedSpeaker

Michael Owen
Bellini

11:30amContributed

Ram Datt

11:45amContributed

Nicholas Grant

12pm

Contributed

Fátima Santos

12:15pm

Contributed

Bethany Willis

Addressing durability and reliability
issues for commercial and precommercial PV technologies
Organic Solar Cells at Stratospheric
Condition for High Altitude Platform
Station Application
Nature of Al2O3 surface passivation
for high efficiency silicon
photovoltaics
Monolithic dye-sensitized solar cellswith copper polymer gel electrolytes
for indoor applications
Life-cycle assessment for moresustainable photovoltaics research
and manufacturing

NREL
Swansea
University
University Of
Warwick
University of Porto
Northumbria
University

12:30pm

Lunch

Session 6 Chair: Nicola Pearsall
Time

Talk

Speaker

Title

Affiliation

1:30pmInvitedSpeaker

Alona
Armstrong

TBC

Lancaster
University

2pm

Contributed

Zaid Haymoor

2:15pmContributed

Sophie Pain

2:30pmContributed

StefanNicholson

2:45pmThe use of Artificial neural network toenhance MPPT finding methodology
on Energy Harvesting chips
Hafnium oxide: A thin film passivating
dielectric with controllable etch
resistance
Unveiling the effects of electrontransport layers on all inorganic
perovskite film formation

Swansea
University
University Of
Warwick
University ofStrathclyde

Afternoon BreakSession 7 Chair: Nakita Noel
3pm

InvitedSpeakerRuy Sebastian
Bonilla3:30pmContributed

Jay Patel

3:45pmContributed

Austin Kay

4pm

Contributed

Udari
Wijesinghe

4:15pmCharged-Up Solar Cells: The Role ofInterface Electric Fields in Photovoltaic
Devices
Terrestrial And Non-Terrestrial
Environmental Effects on Perovskite
Solar Cell Performance
Realistic Performance Limits of Indoor
Photovoltaics
Intense Pulsed Light Sintering of
Antimony Selenide Thin Films

University of
OxfordKing’s College
LondonSwansea
University
Northumbria
University

Afternoon BreakSession 8 Chair: Steve Ransome
4:30pmContributed

4:45pmContributed

5pm

Contributed

5:15pm5:30pm

Contributed

7:15pm10pm

Halide Perovskites Based Indoor
Photovoltaics: Role of Interfacial
LayersUnravelling the effects of oxygen
Yixin Wang
doping on charge-carrier dynamics of
AgBiS2 solar harvester
Unlocking the Potential of Alternative
Hole Transporting Materials for SolidAmy Neild
State Dye-Sensitised Solar Cells
through Prolonged Oxidation and Light
Soaking Treatment
Revisiting the Significance of Spectral
Haoxiang
Solar Irradiance Data: Economical
Zhang
Approaches to Effective Measurement
Drinks Reception and Conference Dinner(Trades Hall, 85 Glassford Street, Glasgow, G1 1UH)

Lethy Krishnan
Jagadamma

University of St
Andrews
University Of
OxfordNewcastle
University
University ofSouthampton

Friday 12 April 2024
Session 9 Chair: Aruna Ivaturi
Time

Talk

Speaker

Title

Affiliation

9:15amInvitedSpeakerMarina Freitag

TBC

Newcastle
University

9:45amContributed

MahmoudDhimish

10am

Contributed

Yuelin Xiong

10:15amContributed

Yue Hu10:30amContributed

NicholasBurridge

10:45am

Do Minor Cracks in Solar Cells, Barely
Visible in Electroluminescence, Really
Matter?
Self-Aligned Laser Opening and Stencil
Metallisation for Silver-Free Contacts
in Silicon Solar Cells
Control crystallisation of perovskites inprintable mesoscopic solar cells
Application-Targeted Metal Grid Enhanced Transparent Electrodes for
Organic Photovoltaics

University Of
York
University Of
OxfordUniversity of
Edinburgh
Swansea
University

Morning BreakSession 10 Chair: Alex Cole
Invited
11am
Speaker

Kurt Barth

TBC

12:15pm

Hybrid satellite albedo data for bifacial
PV systems in complex landscapesand comparison with hybrid groundbased data
Understanding the Ionic Modulation of
Lucy Hart
Open-Circuit Voltage in Perovskite
Solar Cells
Characterisation of Solar Cell
Matthew WrightInterfaces using Elastic Recoil
Detection Analysis
Closing Remarks / Awards

12:30pm

Lunch (pre-packed grab and go)

1:30pmConference concludes and depart

11:30amContributed

11:45amContributed

12pm

Contributed

GeorgeKoutsourakis

Loughborough
University
National
PhysicalLaboratory
Imperial
College London
University Of
OxfordPoster Presentations
Posterboard
No.

Paper Title

Presenter

Affiliation

1

Exploring the Dynamics of Risk and Quality inSolar Photovoltaic Systems

Sharmarke
MohamedHassanUniversity Of YorkChen Cao

University of Southampton

Aryaveer Singh

University Of Dundee

Zongtai Zhang

Durham University

Abdulaziz A.
Alanazi

Prince Sattam Bin
Abdulaziz University

Yiliao Zhou

University of Southampton

Ochai Oklobia

Swansea University

Willow Herring

University of Southampton

Fahad M.
Alsahli

University of Exeter

Thomas Lynch

University of York

Ajeet Srivastav

University of Strathclyde

PraveenChandrasekar

University of Strathclyde

2
3
6
7
8
9
11

12
13
15

16

Auxetic Crystalline Silicon Solar Module with
Rotating Square Array Structure
Detection and identification of vacancyrelated point defects in perovskite halide
semiconductors
Simulating relative performance of Organicand Silicon PV in real-world conditions
Synthesis, XRD, EDX, SEM, and TEM
characterization of two sulfide
nanostructures Ni(S2COBu)3 and[Ni(S2COPn)3
Floating Photovoltaic (FPV) for climate
vulnerable river island communities
CdTe thin film absorber layers grown underCd-rich conditions by MOCVD: impact on film
surface topography and structure
Evaluating the feasibility of novel PV
technologies for powering PM2.5 sensors inindoor and outdoor applications
Influence of Thickness on the Electrical
Properties of ITO Thin Films Grown by RF
Magnetron Sputtering Technique forConcentrated Perovskite Solar Cells
Enhancing Solar Cell Longevity: Assessing
the Impact of ITO Coatings on PID ResistanceTuning the morphology and phase structureof tungsten oxides for photovoltaic
applications
Calamitic-Type Dipolar and Quadrupolar
Chromophores with Twisted Peripheral
Handle: Structure-Property Outlook as Nonfullerene Acceptors for Binary Solar Cells

Your partner for photovoltaic material properties and performance characterisation

Carrier lifetime
with DeltaFlex

TMTime Resolved 			 Photoluminescence(TRPL) from picoseconds 		
to seconds​
Fast acquisitions 			(100 MHz pulsed sources)​
Modularity and versatility

Bandgap and Quantum Yield​with Fluorolog QMTMGreatest sensitivity for low 		 photoluminescent materialsHighest straylight rejection on
the market for extremely 		 scattering materialsExtended spectral range for abroader range of applications(180 – 5500 nm)​​Eco friendly PowerArc™ sourcewith improved efficiency​and 		less power consumption
Upconversion and TRPL 		
options for greater versatility

Dynamic Fluorescence Spectroscopy
Laser 2000 works in partnership with PicoQuant to offer you
everything from individual components to full spectroscopy systems.
Speak to us to find out more.

Pulsed Lasers & LEDs

TCSPC | Metrology | Quantum• Picosecond pulsed sources• High-power and UV picosecond lasers• Nanosecond pulse shaping

Photon Counting & Timing• TCSPC and time
tagging electronics• Photon counting detectors• Software• Accessories• OEM integration

Material Science | Life Sciences

Fluorescence Spectrometers• High-end photoluminescence spectrometers- Fully automated.
- Time-resolved and steady-state operation• Compact lifetime fluorometers- Steady-state in emission and time-resolved mode
- Compact setup for fast, precise measurements

Fluorescence Microscopes

Life Sciences• Single photon counting confocal microscopes• Confocal platforms with single molecule sensitivity• Time-resolved confocal fluorescencemicroscopes with super-resolution capability• FLIM and FCS upgrade kits for laser scanning microscopes+44 (0) 1933 461 666
sales@laser2000.co.uk
photonics.laser2000.co.uk

You have the ideas, we have thetechnologies to bring them to life.

Explore G2V’s cutting-edge Class AAA
LED Solar Simulators tailored for precise
testing of Perovskite, Silicon, OPV, QDot,
CIGS, CdTe, GaAsP, Multijunction
tandems, and beyond.
G2V delivers unparalleled accuracy andreliability in solar spectrum simulation.
The pico.™ small-area solar simulator
precisely replicates terrestrial or
extraterrestrial Solar Spectra.
Harness high-precision solar simulation
with the sunbrick.™ large area LED solar
simulator. Fit for any space.

Photonic Solutions is the leading technology
supplier to the UK photonics sector.

0131 664 8122
www.photonicsolutions.co.uk

SCAN ME!

Perovskite
SolarInvited Speaker Presentations
Photovoltaic materials development: Roadmap on current challenges andfuture opportunities
Prof. Robert Hoye1
1University Of Oxford, United Kingdom

Session 4: Robert Hoye (Invited Speaker) Followed by Contributed Talks,
April 11, 2024, 09:15 - 10:30
Photovoltaics (PVs) are a critical technology for curbing growing levels of anthropogenic
greenhouse gas emissions, and meeting increases in future demand for low-carbon electricity. In
order to fulfil ambitions for net-zero carbon dioxide equivalent (CO2eq) emissions worldwide, theglobal cumulative capacity of solar PVs must increase by an order of magnitude from 0.9 TWp in
2021 to 8.5 TWp by 2050 according to the International Renewable Energy Agency, which isconsidered to be a highly conservative estimate. In 2020, the Henry Royce Institute brought
together the UK PV community to discuss the critical technological and infrastructure challenges
that need to be overcome to address the vast challenges in accelerating PV deployment. In 2023,
86 individuals from >50 groups, mostly based in academic institutions, companies and national
laboratories in the UK, convened to discuss the key developments in the field as a whole,especially the progress made in the field since the earlier roadmap. In this talk, I will discuss key
points raised (Figure 1), which focus both on the challenges in improving the efficiency, stability
and levelized cost of electricity of current technologies for utility-scale PVs, as well as thefundamental questions in novel technologies that can have a significant impact on emerging
markets, such as indoor PVs, space PVs, and agrivoltaics. I discuss challenges in advanced
metrology and computational tools, as well as the growing synergies between PVs and solar fuels,and offer a perspective on the environmental sustainability of the PV industry. This talk will finish
with important current challenges, as well as future opportunities, and areas in which
communities from different parts of the PV field can learn from each other.

Charged-up solar cells: the role of interface electric fields in photovoltaic
devices
Sebastia Bonilla1
1University of Oxford, United Kingdom

Session 7: Ruy Sebastian Bonilla (Invited Speaker) Followed by Contributed Talks,
April 11, 2024, 15:00 - 16:15
In this work, we examine the relationship between interface electric fields and efficiency
enhancements via surface passivation in silicon solar cells. The historical trajectory of silicon PV
technologies reveals a consistent upward trend in efficiency improvements, bringing us closer tothe practical limit of ~28.5%. Achieving efficiencies ever nearer this limit requires superb
interface passivation with a surface recombination current J0s<5 fA/cm2. For ultimate interface
passivation, two fundamental elements are required: chemical passivation and field effect. The
first key ingredient, chemical passivation, involves addressing imperfections in the chemicalinterface, where unsaturated bonds can impede optimal performance. These imperfections
contribute to a higher minority carrier capture rate, impacting the concentration of available
photogenerated carriers. The second key ingredient, field effect, involves carrier density
modulation by applying electric fields. Contrary to conventional perceptions that these two key
ingredients operate independently, this contribution will demonstrate how they are profoundlyinterdependent. The intricate relationship between the chemistry of an interface and its impact on
the field effect, and vice versa, forms a pivotal aspect in improving solar cell interfaces. It is wellknown that interface passivation strongly depends on the polarity and strength of the electricfield. Here we show that the surface electric fields not only influence the surface carrier
population but also affect the resulting chemical interface properties post-annealing. This has
been observed in at least three interfaces crucial to Si PV technology: Ag-Si metal interfaces,
polysilicon-SiOx-Si passivating contacts, and SiO2-Si surfaces.

Nanoscopic Observation of Organometal Halide Perovskite Solar Cells
with Superlattice
Satoshi Uchida1
1University of Tokyo, Japan

Session 2: Satoshi Uchida (Invited Speaker) Followed by Contributed Talks,
April 10, 2024, 15:00 - 16:15
The micro-structural observation analysis of the perovskite layer with high resolution TEM is themost promising approach to understand the crystal structure. Recently we newly revealed that the
tetragonal and cubic phases coexist at room temperature in the conventional MAPbI3 thin film
device. Furthermore superlattices composed of these mixture of tetragonal and cubic planes
without any compositional change was also found.
Recently, there has been a surge of interest in organometal halide perovskite solar cells (PSCs).
These cells have exhibited a remarkable increase in power conversion efficiency (PCE), withcertified PCEs reaching over 26% by employing mixed organic cations and halide anions. The PCE
is significantly influenced by the photovoltaic properties of each component within the PSC.
Despite the crucial role of crystallographic information, micro-structural analysis of the perovskite
layer has not been extensively pursued.
It has been widely accepted that the organometal halide perovskite exists in distinct phases:
orthorhombic phase < 165K < tetragonal phase < 327K < cubic phase. However, our recent
observations have revealed the coexistence of tetragonal and cubic phases at room temperaturein conventional MAPbI3 thin film devices. Moreover, we have made the surprising discovery ofsuperlattices comprising a mixture of tetragonal and cubic planes without any compositional
alterations. The formation of these superlattices occurs through intrinsic structural transitions,
without the need for artificial modifications. Consequently, many phenomena related to structural
superlattices are anticipated to occur spontaneously and automatically within relevant contexts.
Organometal halide perovskites demonstrate a remarkable ability to self-adjust their microstructural configurations and self-organize buffer layers inside crystals or at hetero-interfaces byintroducing self-assembled superlattices. We believe that this report represents a pivotal
advancement, bringing PCEs of organometal halide perovskite solar cells closer to their
theoretical maximum and redefining the potential of these materials for a wide range ofapplications beyond solar cells.[1-5]References[1] T.W. Kim, S. Uchida, T. Matsushita, L. Cojocaru, R. Jono, K. Kimura, D. Matsubara, M. Shirai, K.
Ito, H. Matsumoto, T. Kondo and H. Segawa, Advanced Materials, 30(8), 2018, 1705230.
[2] T.W. Kim, M. Kim, N. Shibayama, L. Cojocaru, S. Uchida, T. Kondo and H. Segawa, Advanced
Functional Materials, 1804039 (2018).
[3] T.W. Kim, T. Matsushita, S. Uchida, T. Kondo and H. Segawa, Applied Physics Express, 11(10),101401 (2018).
[4] T.W. Kim, M. Kim, L. Cojocaru, S. Uchida and H. Segawa, ACS Energy Letters, 3, 2743–2749(2018).
[5] L. Cojocaru, T.W. Kim, S. Uchida, and H. Segawa, Chemistry Letters, 48, 26-27 (2019).

Tetragonal
phase
Cubic
phase

Fig. 1. TEM images (Hitachi HF-3300, 300KeV), a) HRTEM (×1,000K) image showing thecoexistence of the tetragonal and cubic nano domains. b) Fourier transformed diffraction
pattern (FTDP) at small area (6.5nm×6.5nm) for cubic C[101] zone axis and c) tetragonal
T[111] zone axis.

Oral Contributed Presentations
Hybrid satellite albedo data for bifacial PV systems in complex
landscapes and comparison with hybrid ground based data
Dr James Blakesley1, Dr George Koutsourakis1, Mr Daniel Parsons1, Dr Natalie Mica2, Suhas
Balasubramanyam2, Mark Russell2
1National Physical Laboratory, United Kingdom, 2RINA Tech UK Ltd, United Kingdom

Session 10: Kurt Barth (Invited Speaker) Followed by Contributed Talks,
April 12, 2024, 11:00 - 12:15
Bifacial photovoltaic (PV) systems can absorb light from both their front and their rear side, hence
they are able to harvest the light reflected from the ground. For this reason, ground albedo is a
critical parameter in estimating the expected performance of bifacial PV systems. It is importantthat albedo data are available at the planning and design stage of a PV system, when site data
might not be available, but when confidence in expected yield directly affects investment value.
Such albedo data should be accurate and relevant, with known uncertainties, in order to increase
confidence in yield modelling at the design phase.
This work investigates the challenges of different albedo data sources and proposes solutions
towards more reliable datasets. Satellite sources, such as the NASA Moderate Resolution Imaging
Spectrometer (MODIS) products, provide data that can be used to model effective albedo
anywhere in the world [1]. Nevertheless, there are numerous sources of error that can add
uncertainty in bifacial gain, reducing confidence and increasing financial risk. Especially forsmaller potential sites located in varied landscapes, the scaling error caused by the low spatial
resolution of MODIS data can be large [2]. By analysing case studies in complex landscapes, weinvestigate the accuracy of different albedo measurement approaches. Monitoring stations withreference PV cells and pyranometers were deployed to validate satellite data. Since these sites
are much smaller than a MODIS pixel, we have evaluated alternative approaches, among which anovel method of combining MODIS data with higher resolution satellite data (Sentinel 2 data).
This combined satellite data method offers a practical solution with good agreement with groundbased station data, showing great promise for remote estimation of effective albedo for bifacial
PV systems in complex landscapes.

Unravelling the effects of oxygen doping on charge-carrier dynamics of
AgBiS2 solar harvester
Yixin Wang1, Yi-Teng Huang1, Dennis Friedrich2, Xiaoyu Guo1, Yuchen Fu1, Robert L.Z. Hoye1
1Inorganic Chemistry Laboratory, Department of Chemistry, University of Oxford,

United Kingdom, 2Institute for Solar

Fuels, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Germany

Session 8: Contributed Talks, April 11, 2024, 16:30 - 17:30
I-V-VI₂ ternary chalcogenides are receiving broad research interest due to their low toxicity andabundance nature, fuelled by the high power conversion efficiency (PCE) and excellent stability of
AgBiS₂. [1,2] Due to the high absorption coefficient, a thinner layer of AgBiS₂ is required for solar
cell devices, which mitigates possible charge-carrier recombination and is beneficial for carriercollection. Whereas, carrier-phonon coupling leads to carrier localization, limiting carriers’
mobilities and lifetimes. [3,4]In this work, it is discovered that synthesizing AgBiS₂ nanocrystal (NC) under low vacuum andambient conditions could give better optoelectronic properties of AgBiS₂ NC. This is attributed tothe doped oxygen content that passivates the defects in NC samples. X-ray photoelectron
spectroscopy (XPS) is employed to measure oxygen content and optical-pump terahertz-probe(OPTP) as well as photoluminescent (PL) are measured to extract the carrier dynamics.
The PL peak at 880 nm is recognized as the bandgap, which becomes more intense withincreasing oxygen content. This reveals that the oxygen content can introduce additional densityof state (DOS) near the conduction band minimum (CBM). Besides, the OPTP results suggest thatwith an increasing extent of oxygen doping, a slower localization rate of charge carriers isobserved. This is interpreted as oxygen doping can passivate dangling bonds in the surface of NC
by forming bonds to saturate the dangling bonds, avoiding carriers being trapped in defects.
In conclusion, we verify that oxygen doping can alleviate charge-carrier localization in AgBiS₂. This
demonstrates the potential of utilizing oxygen doping to enhance the optoelectronic performanceof AgBiS₂ NC. This insightful work opens further research in the field of passivation strategies for
AgBiS₂ material.

Self-Aligned Laser Opening and Stencil Metallisation for Silver-Free
Contacts in Silicon Solar Cells
Yuelin Xiong1, Ruidong Zhou1, Anastasia Soeriyadi1, Zongtao Liu1, Soumyajit Maitra1, Jingyan
Chen1, Yifu Shi1, John O’Sulllivan1, Pietro Altermatt2, Ruy Sebastian Bonilla1
1Department of Materials, University Of Oxford, United Kingdom, 2Trina Solar, State Key Laboratory for Photovoltaic

Science and Technology (SKL PVST), China

Session 9: Marina Freitag (Invited Speaker) Followed by Contributed Talks,
April 12, 2024, 09:15 - 10:45
In 2020, silver accounted for 10.3% of the global supply, used extensively in PV components
generating 135 GW. To meet the 2030 target of 3 TW PV production, sustainable and costeffective metallisation approaches should be developed [1]. Moreover, the ongoing trend toward
smaller finger widths for reducing the shadowing effect and material usage underscores the needfor precise alignment between metal deposition and dielectric openings. In this work, we explore
the possibility of a novel self-aligned process with a sustainable metal. We fabricate and placestainless steel stencil masks on the top surface of silicon solar cell precursors, enabling laser
ablation defined by the stencil mask opening. Finally, thermal evaporation is used to deposit
aluminium through the shadow mask without mechanical realignment. We laser raster
perpendicular to the stencil finger openings, enabling point contact with precise contact area
definition.
We successfully demonstrate 25 μm wide metal fingers via thermally evaporated aluminium
directly deposited onto laser-patterned point contacts of 20 μm*17 μm size. This self-aligned
process is demonstrated on textured silicon passivated with 75 nm silicon nitride. Optical andelectron microscopy analysis shows that the UV picosecond laser ablation damage is limited, andsufficient alignment is achieved. Line resistivity of 15.74 Ω/cm and contact resistivity of <10mΩ·cm2 show the current-carrying capabilities of the contacts, in agreement with themicrostructural characterisation. PL analysis demonstrates that the passivation quality is
minimally affected by the laser opening of the dielectric layer. Complete devices bearing the
stencil self-aligned contacts on the front surface are characterised electrically, showing thefeasibility of developing functional cells with the proposed metallisation method. This novel
approach can potentially replace non-sustainable silver as front and back contacts for bifacialsolar cells since other metal pastes and deposition methods can be easily integrated into a metal
stencil mask process.

Do Minor Cracks in Solar Cells, Barely Visible in Electroluminescence,
Really Matter?
Dr Mahmoud Dhimish1
1University Of York, United Kingdom

Session 9: Marina Freitag (Invited Speaker) Followed by Contributed Talks,
April 12, 2024, 09:15 - 10:45
In the realm of solar panel technology, short cracks near the busbar tips are a common yet often
overlooked issue. These minuscule fractures are challenging to detect; they require highly
optimised electroluminescence (EL) camera systems with superior resolution and specific focus
adjustments [1]. Consequently, many of these short cracks remain unnoticed during standard EL
testing in both manufacturing and field environments. Even when identified, the industry's current
acceptance criteria tend to be lenient regarding these defects. This raises a critical question:
Should there be a higher level of concern regarding these seemingly minor imperfections?
In this presentation, I will address a critical concern in the field of solar panel technology bypresenting evidence from our latest research. Our study focuses on the progression of small
cracks in various PV module technologies. We specifically examine modules that exhibit theseminor cracks, tracking their development as we apply increasing mechanical loads on the panel
fronts. This research, conducted in collaboration with Above Surveying Ltd (UK) and Brightspot
Automation (USA), aims to provide a deeper understanding of how these cracks affect solar panel
performance and durability. We have found that almost all short cracks evolve into longer ordendritic forms. Interestingly, cells without pre-existing short cracks rarely develop new cracks
under stress. However, when a previously intact cell does crack under high load, the result isoften dramatic shattering.

Hysteresis and Transient Behaviour in Current Voltage Measurements of
Antimony Selenide Solar Cells
Dr Oliver Hutter1
1Northumbria University, United Kingdom

Session 2: Satoshi Uchida (Invited Speaker) Followed by Contributed Talks,
April 10, 2024, 15:00 - 16:15
Antimony selenide (Sb2Se3) is a promising light-absorber used in low-cost, non-toxic, earthabundant thin-film solar cells with rapidly rising efficiency values. Many n-type metal oxides havebeen investigated as buffer layers in Sb2Se3 solar cell architectures and among them, titaniumoxide (TiO2) is most commonly used. The current density−voltage measurement of Sb2Se3 solar
cells in FTO/TiO2/Sb2Se3/P3HT/Au configuration shows a hysteresis-like distortion that depends
on the voltage scan direction, scan rate, scan range, and voltage bias conditions prior tomeasurement. The presence of hysteresis can significantly influence the photovoltaic propertiesof devices, which can overestimate or underestimate the accurate power conversion efficiency ofsolar cells. The fabricated solar cells show normal hysteresis where the forward scan result
exhibits lower performance than the reverse scan under certain circumstances. We identify thisphenomenon to be caused by charge carrier accumulation which may be because the capacitive
charge is quickly discharged through charge separation. In addition, the accumulation of oxygen
vacancies at the TiO2/ Sb2Se3interface can reduce charge extraction, and at the same time,
significantly accelerate the charge recombination at the interface, which also leads tounfavourable hysteresis. However, the hysteretic effects are not observed in devices utilizing
alternative buffer layers like ZnO and SnO2, suggesting that the buffer absorber interfaces have asignificant effect on transients in Sb2Se3 absorber devices. Therefore, further improvements of
Sb2Se3 solar cells are essential through careful surface engineering of existing TiO2 or through a
judicious choice of alternative interfacial layers.

Contact metallization processing considerations for silicon photovoltaics
Dr Edris Khorani1, Dr Sophie Pain1, Dr Tim Niewelt1,2, Dr Nicholas Grant1, Professor John Murphy1
1University of Warwick, United Kingdom, 2Fraunhofer Institute for Solar Energy Systems ISE, Germany

Session 4: Robert Hoye (Invited Speaker) Followed by Contributed Talks,
April 11, 2024, 09:15 - 10:30
The rapid growth of the c-Si photovoltaic (PV) industry over recent years has led to major
technological advancements that have in-turn led to improvements in cell performance. From theAl back-surface field architecture to passivated emitter and rear cell (PERC) and now to the tunneloxide passivated contact (TOPCon) cell, one of the ongoing primary concerns has been alleviating
the electrical losses in the contacting regions. To reach the theoretical power conversion
efficiency limit of 29.4 %, the existing electrical losses from the contact architectures andfabrication methods in-use must be mitigated, e.g., reaching the same level or even exceeding theperformance of electron-selective contacts with the hole-selective counterpart for TOPCon. One
aspect to consider is the metallization process used for contact formation. Two widely used
options are electron beam (e-beam) and thermal evaporation.
In this work, we explore the difference in electrical performance when using e-beam and thermal
evaporation for Al contact metallization. We examine 100 nm symmetrical Al₂O₃ passivation on ptype Si (Cz, Ga-doped, 5 Ωcm, <100>, 120 µm thick) specimen before and after 100 nm Al
metallization and find that the e-beam method is unsuitable due to the detrimental radiation
effects from the e-beam source. A similar procedure is performed using thermal evaporation,
where we find that the degradation in passivation is negligible until the Al₂O₃ passivation layers
are less than 5 nm in thickness. We also conduct superacid re-passivation to determine whether
the defect-induced damage in both the e-beam and thermal evaporation specimens is surface orbulk related. We investigate the defects induced by these processes further via deep-leveltransient spectroscopy (DLTS). Additionally, the consequential effects on contact resistivity as wellas enhancements via ‘Alnealing’ (i.e., hydrogenation effects) are also presented.

Hafnium oxide: A thin film passivating dielectric with controllable etch
resistance
Dr Sophie Pain1, Dr Ailish Wratten1, Dr Edris Khorani1, Ms Anup Yadav1, Dr Tim Niewelt1,2,3, Mr
Brendan Healy1, Dr Marc Walker4, Dr David Walker4, Dr Nicholas Grant1, Professor John Murphy1
1School of Engineering, University Of Warwick, United Kingdom, 2Fraunhofer Institute for Solar Energy Systems ISE,

Germany, 3Institute for Sustainable Systems Engineering, University of Freiburg, United Kingdom, 4Department of
Physics, University of Warwick, United Kingdom

Session 6: Alona Armstrong (Invited Speaker) Followed by Contributed Talks,
April 11, 2024, 13:30 - 14:45
Engineering the properties of dielectric nanoscale thin films according to desired applications will
enable the next generation of photovoltaics. First, excellent surface passivation is required to givelong effective charge carrier lifetimes for high-efficiency solar cells. Second, cell manufacturing
often requires selective thin film removal, hence controllable etch resistance can be useful. Third,
passivating contacts - now needed for state-of-the-art devices - need to be selective for efficient
hole/electron extraction and this can be enabled by tuneable fixed charge polarity.
Atomic layer deposition (ALD), based on sequential self-terminating reactions, is one means togrow ultra-thin passivation layers, and offers a large degree of control over film growth conditions,and subsequent properties. It is scalable and Al₂O₃ grown by ALD is used in ~30% of solar cells
produced today. Recent studies have identified HfOx as a potential ALD-grown alternative. 10-20
nm HfOx films achieve surface recombination velocities (SRVs) 10 cm/s possible (c.f. <1 cm/s for
ALD Al₂O₃).
In this contribution, we will demonstrate the flexibility offered by hafnium oxide and summarise
recent improvements in passivation. We utilise carrier lifetime measurements, Kelvin probe
analysis, corona charging, atomic force microscopy, X-ray diffraction and X-ray photoelectron
spectroscopy to characterise properties of HfOx nanolayers. Careful selection of growth conditions
and post-deposition processing allows the etch resistance to be controlled. Furthermore,
literature reports of ALD-grown HfOx suggest both negative and positive charges are possible,
depending on growth conditions. Via Kelvin probe and corona charge analysis, we determine thatcharge polarity is not influenced by growth co-reactant or post-deposition processing, with the roleof the hafnia precursor yet to be determined. Recent work has also improved passivation qualities
achievable (with SRVs now competitive with Al₂O₃) and suggested that HfOx has the potential toprovide multiple routes towards passivating contacts.

Intense Pulsed Light Sintering of Antimony Selenide Thin Films
Miss Udari Wijesinghe1
1Northumbria University, United Kingdom

Session 7: Ruy Sebastian Bonilla (Invited Speaker) Followed by Contributed Talks,
April 11, 2024, 15:00 - 16:15
Antimony selenide (Sb₂Se₃) has emerged as a promising photoelectric material owing to its
excellent material properties. Post-deposition annealing treatments have been carried out toimprove the degree of crystallinity and optical properties. However, these thermal annealing
treatments typically require 60 minutes or more of thermal annealing at high temperatures (>300°C), severely limiting the throughput and substrate choice. For the first time, we report a low
thermal budget annealing technique using a photonic curer to produce crystalline Sb₂Se₃ thinfilms starting with amorphous Sb₂Se₃. Photonic curing can heat Sb₂Se₃ thin film to several
hundred degrees over a short time while maintaining the substrate at a low temperature. Here,the effect of photonic curing conditions on the conversion of amorphous Sb₂Se₃ to obtain
crystalized Sb₂Se₃ using a single pulse was analyzed. For a given radiant exposure, short pulse
length pluses (<1 ms) cause damage to Sb₂Se₃ films due to the higher power delivered by theshorter pulse, resulting in higher temperatures at the Sb₂Se₃ layer and thermal expansion of the
top surface of the underneath layer. Longer pulses (>5 ms) allow heat transfer to the substrateduring the light pulse, limiting the temperature reached at the sample surface and resulting in a
crystallized Sb₂Se₃ layer with no or minimum surface damage. Similarly, for a constant pulse
length, an increase in the radiant exposure eventually damages the Sb₂Se₃ due to increased
power delivery and higher surface temperatures of the sample. Therefore, increasing the pulse
length or decreasing the radiant exposure can avoid damage caused to the Sb₂Se₃ layer. Hence,
photonic curing shows the capability of sintering Sb₂Se₃ thin films and creating crystalline films
without sacrificing surface coverage. This opens up new opportunities in the manufacturability of
Sb₂Se₃ solar cells by eliminating the rate-limiting annealing step.

Zn(x)Mg(1-x)O buffer layer for CZTSSe solar cells using co-sputtering
technique.
Dr Prabeesh Punathil1, Dr Giray Kartopu, Dr. Pietro Maiello, Prof Vincent Barrioz, Prof. Neil S
Beattie, Prof. Guillaume Zoppi
1Northumbria University, United Kingdom

Session 3: Contributed Talks, April 10, 2024, 16:30 - 17:30
Kesterite solar cells based on Cu2ZnSn(S,Se)4 (CZTSSe) absorbers have recently demonstrating
efficiency >14% after a decade long period of stagnation. While a clear Voc deficit remains, afurther boost in efficiency can be generated by maximizing the optical properties of the structure
and providing better band alignment with the window layer. Furthermore, the most common ntype partner layer, cadmium sulfide (CdS), is toxic and deposited using chemical bath methods
producing large amount of waste, thereby reducing the sustainable nature of kesterite solar cells.
Here we explore alternative buffer other buffer layers that can be used to maintain the non-toxic
nature of CZTSSe solar cell without a compromise in energy conversion efficiency.
In this work, MgxZn1-xO is used as a replacement for the CdS buffer layer. The MgxZn1-xO is oneof the most favorable candidates for replacing the CdS because it has a higher tunable band gap
as compared to CdS and the Conduction Band Offset (CBO) can be tuned to a more optimal value
through modification of the Zn/Mg ratio. Due to its wider bandgap, MgxZn1-xO also shows ahigher optical transmission than that of CdS thus increasing output current of the device. In thisstudy, MgxZn1-xO thin films were deposited by co-sputtering of ZnO and MgO targets and their
physical properties were studied by changing the doping ratios. Different x = Zn/Mg ratio films
were obtained by changing the MgO (0 to 100 W) and ZnO (30 to 80 W) sputtering power ratio.
The bandgap of the films varied from 3.21 eV to 4.46 eV as x increases from 0 to 0.66. CZTSSe
photovoltaic devices with MgxZn1-xO buffer layers of varied properties were fabricated andcompared with reference devices made using a CdS buffer layer. The performance of completed
devices will be discussed insight of the information collected.

Characterisation of Solar Cell Interfaces using Elastic Recoil Detection
Analysis
Matthew Wright1, Dr Matthew Sharpe2, Callum McAleese2, Yan Wang1, Yifu Shi1, Sebastian
Bonilla1
1University of Oxford, United Kingdom, 2Surrey Ion Beam Centre, University of Surrey, United Kingdom

Session 10: Kurt Barth (Invited Speaker) Followed by Contributed Talks,
April 12, 2024, 11:00 - 12:15
The passivation of crystalline silicon (c-Si) surfaces with hydrogen (H) is critical in achieving therecently observed record cell efficiencies [1]. In addition, surface-related degradation inpassivating contact structures has been attributed to an accumulation of hydrogen at the c-Si /SiOx interface [2]. Therefore, it is critical to analyse the distribution of hydrogen throughout thepassivating structure following firing, particularly near the c-Si / SiOx interface. The hydrogen
distribution is typically measured using a SIMS depth profile [3]. However, this can be inaccurate
as the remnant H background gas in the chamber can distort the measured H concentration andprimary ion bombardment can cause an apparent shift in the detected H species, skewing themeasured distribution. In our previous work (presented at PVSAT-17), we introduced time-of-flightelastic recoil detection analysis (ToF-ERDA) as an alternative characterisation approach tomeasure the distribution of H in TOPCon structures. This proved a promising way to distinguishbetween deuterium (D) and H profiles, however, the ability to resolve the interface was limited
due to two reasons: i) The surface of the silicon was thus quite rough, ii) the sample stack was >100 nm thick, meaning the interface was deep in the sample. In this work, we aim to overcome
these experimental issues by fabricating simple dielectric passivating layers onto flat siliconsurfaces.
We perform ToF-ERDA measurements on both SiNx and Al2O3 passivation stacks. These results
show a clearer ability to resolve the interface between the c-Si and passivation layers, further
presenting ToF-ERDA as a useful tool for solar cell analysis.

Impact of Surface Electric Fields on Light Soaking Enhancements in SHJ
Solar Cells
Matthew Wright1, Donghao Liu1, Dr Audrey Morisset2, Prof Franz-Josef Haug2, Prof Sebastian
Bonilla1
1University of Oxford, United Kingdom, 2Ecole Polytechnique Fédérale de Lausanne, Switzerland

Session 2: Satoshi Uchida (Invited Speaker) Followed by Contributed Talks,
April 10, 2024, 15:00 - 16:15
The current silicon solar cell world record efficiency of 26.81% was achieved with a siliconheterojunction (SHJ) device architecture. Light-soaking SHJ solar cells has been to shownto increase the efficiency, due to improved VOC and FF. In fact, the world record cell
received a light soaking process under 60 sun illumination to boost efficiency. Although it isa well demonstrated phenomenon, the exact mechanism leading to light soaking improvements isstill under investigation. The current hypothesis is that hydrogen migrates to the a-S(i) / c-Si
interface under light-soaking, when in the presence of doped layers, which improves the surface
passivation. The aim of this work is to investigate this hypothesis by applying surface electricfields to SHJ lifetime samples during light soaking, to assess the impact on the observed
enhancements. Surface electric fields were applied to SHJ lifetime precursors using corona
charging. a sample subjected to negative surface corona charge during light soaking. When
negative charge was applied to the surface, almost no lifetime enhancement is seen, thus the
charge suppresses the changes seen due to light soaking. Applying positive surface charge leads
to a far greater enhancement, the lifetime increases from 11.9 ms to 15.1 ms. These results
indicate two key findings, i) surface electric fields can modulate light soaking enhancements in
SHJ samples and ii) the direction of the field impacts this modulation. These results could provide
evidence to strengthen the hypothesis that efficiency gains are related to the migration ofhydrogen ions through the a-Si to passivate defects at the interface.

Nature of Al2O3 surface passivation for high efficiency silicon
photovoltaics
Dr Nicholas Grant1, Dr Sophie Pain1, Dr Edris Khorani1, Dr Richard Jefferies1, Dr Ailish Wratten1,
Dr Shona McNab2, Dr David Walker3, Dr Yisong Han3, Prof Richard Beanland3, Dr Ruy Bonilla2,
Prof John Murphy1
1School of Engineering, University of Warwick, United Kingdom, 2Department of Materials, University of Oxford, United

Kingdom, 3Department of Physics, University of Warwick, United Kingdom

Session 5: Michael Owen Bellini (Invited Speaker) Followed by Contributed Talks,
April 11, 2024, 11:00 - 12:30
The re-emergence of aluminium oxide (Al₂O₃) in 2006 has enabled high levels of surface
passivation to be achieved on the rear side of PERC solar cells, owing to the high levels ofnegative charge and good chemical passivation properties of the film. With the recent
introduction of passivating contact structures, Al₂O₃ passivation is now being utilised on the front
surface of TOPCon solar cells which use n-type substrates. As such, Al₂O₃ is playing an everincreasing role in mitigating surface recombination on either the front or rear surface. However,as the efficiency continues to rise, front side surface passivation is becoming every more sensitive
to recombination at the Si-Al₂O₃ interface, meaning efforts to understand this interface and thus
develop solutions to mitigate interface defects could have very large impact.
In this work, we subject atomic layer deposited Al₂O₃ coated silicon samples to annealing
temperatures of 350–600°C and show how recombination at the silicon-Al₂O₃ interface can beinhibited to maximise its passivation potential for silicon based solar cells (e.g. TOPCon). We
subject Al₂O₃ passivated samples to corona charging in order to separate chemical from fieldeffect passivation contributions as a function of annealing temperature. For films thicker than 2.5
nm, we achieve an interface defect density of 3×10¹⁰ /eVcm² and a fixed charge density of~5×10¹² q/cm², which collectively yield a surface recombination velocity of 0.75 cm/s whenannealed at 450°C. By examining the Si-Al₂O₃ interface by transmission electron microscopy andenergy dispersive x-ray spectroscopy, we show that in the as-deposited state, a relatively thick
SiO₂ layer of ~5 nm is present between the Al₂O₃ film and silicon surface, however post annealingat temperatures ≥350°C, Al from the Al₂O₃ layer diffuses into the SiO₂ and forms an alloy,
whereby the oxide layer reduces in thickness to <2 nm with a composition of SixAlyO₂.

Detection of vacancy-related point defects in antimony selenide
Professor David Keeble1, Dr Julia Wiktor, Dr Theo Hobson, Dr Marcel Dickmann, Dr Werner Egger,
Dr Jon Major, Professor Ken Durose
1University Of Dundee, United Kingdom

Session 1: Aruna Ivaturi (Invited Speaker) Followed by Contributed Talks,
April 10, 2024, 11:15 - 12:15
Antimony selenide (Sb2Se3) is photovoltaic material with an optimal bandgap and a high opticalabsorption coefficient comprising of earth abundant elements. Solar cell power conversion
efficiencies initially increased markedly but more recently the rate of increase has slowed. Thereis a large open circuit voltage deficit which is consistent with the presence of detrimental
concentrations of point defects.
Vacancy defects are a centrally important class of point defect. Positron annihilation spectroscopy(PAS) methods have specific sensitivity to neutral or negatively charged vacancy-related defects.
Positrons trap at missing atom defects. An implanted positron eventually annihilates with anelectron resulting in two annihilation photons. The lifetime of the positron state increases for
positrons localized at vacancy defects compared to that for the delocalized perfect lattice state.
Two component density functional theory (TC-DFT) enables the lifetimes of these states to be
calculated (Fig. 1).
The possible ground state configurations monovacancy defects in Sb2Se3 have been recently
determined by DFT. It was reported that both the Se and Sb vacancies, due to negative-U
behaviour, are amphoteric with midgap charge transition levels from positive states to negative
charge states for Fermi level positions higher in the gap.
Here we report positron lifetime measurements on crystal and closed-space sublimated film
Sb2Se3 samples exhibiting p-type, intrinsic, and n-type conductivity. No positron trapping tomonovacancy defects was observed for p-type. Trapping to positron states localized at vacancy
defects with lifetimes consistent with the TC-DFT calculated monovacancy values was observedfor intrinsic and n-type samples. Evidence of trapping to larger divacancy defects was also
observed.

Multiphysics Modelling for the Design of >35% Efficient Perovskite-onSilicon Tandem Solar Cells
Mr James McQueen1, Mr Darshit Trevadia1, Professor Sebastian Bonilla1
1Department of Materials, University of Oxford, United Kingdom

Session 3: Contributed Talks, April 10, 2024, 16:30 - 17:30
Computational modelling and simulation of tandem solar cells have emerged as crucial tools inenabling and maintaining rapid performance improvements at every level. In this work, wedevelop advanced device models, verifying them to produce highly accurate analysis and designof perovskite-on-silicon devices. The resulting finite element simulation is used to establish theguidelines and materials targets for practically achievable tandem solar cells, with significantly
reduced research and development overheads compared to extensive experimental work.
Current state-of-the-art tandem simulations must employ a multiphysics approach, including
advanced optics with ray tracing and the Transfer Matrix Method (TMM). They also require
coupling standard drift-diffusion modelling with ion migration in perovskites to account for the
recent physical understanding of degradation and ionic charge effects. Such complexity, however,can make the models less accessible for wider investigation. A user-friendly device model
grounded in all the essential underlying physics is developed in this work, and used to inform thepractical limits for device design, including surface recombination velocity and parasitic
resistances at contacts. Hence, a roadmap is established for achieving maximum tandem device
efficiency, contributing to existing work.
We focus on perovskite-on-TOPCon device models in SCAPS, a popular solar cell simulation
software for its low barrier to entry and overall versatility. We extend the modelling in SCAPS tobring it in line with the state-of-the-art literature work, thus developing an accessible tandem
device simulation which includes the TMM and an ion migration model in the perovskite cell. The
completed simulation is finally used to suggest targets for key experimental device parameters,
including SRV and contact resistivity effects, whilst also uniquely shedding light on the effect of
spatial bandgap variation through the perovskite layer. The materials and devices selected for thisinvestigation are chosen to remain closely aligned with industrial development of TOPCon solar
cells.

Life-cycle assessment for more sustainable photovoltaics research andmanufacturing
Miss Bethany Willis1, Mr Michael Jones1, Dr Stephen Campbell1, Dr Giray Kartopu1, Dr Prabeesh
Punathil1, Dr Wai Ming Cheung1, Dr Elliot Woolley2, Dr Lewis C. R. Jones2, Dr Vincent Barrioz1, Dr
Guillaume Zoppi1, Dr Yongtao Qu1, Prof Neil S. Beattie1
1Northumbria University, United Kingdom, 2Loughborough University, United Kingdom

Session 5: Michael Owen Bellini (Invited Speaker) Followed by Contributed Talks,
April 11, 2024, 11:00 - 12:30
Photovoltaics (PV), like other renewable electricity sources, for electricity generation has beenlabelled as “sustainable” for decades throughout markets and research. Although the definition ofsustainable is well understood it is often difficult to compare technologies from a sustainable
point of view due to the lack of quantitative data.
Life-cycle assessment (LCA) is an environmental evaluation tool which provides quantitative data
regarding the environmental impact through the impact on humans, ecosystems and natural
resources – thus the sustainability of a product. From analysis of emissions and materials flows,
the environmental impact of the entire life-cycle of a product can be measured from the mining of
its raw materials, use, disposal and ideally, recycling, in a “cradle-to-cradle” flow. LCA can be
conducted on any product at any stage in its development from its design and prototype to thefinal commercial version making it a valuable tool to explore new possibilities in sustainability
research.
Here, a research grade, lab-scale manufacturing process involving the synthesis of Cu2ZnSnS4(CZTS) nanoparticles used for the absorber layer of inorganic thin film solar cells is investigated.
Guided by an LCA, the fabrication of the CZTS nanoparticles is adapted to demonstrate moresustainable synthesis without loss of the eventual PV performance. In addition to this, an LCA iscarried out on commercial silicon passivated emitter rear contact (PERC) cells identifying“hotspots” in the manufacturing process and cell fabrication stages to suggest where
improvements in its sustainability can be improved. Both studies demonstrate how LCA canimprove new and existing PV technologies and inform ecodesign of more sustainable PV products.

Irradiance Estimation for Vertical Bifacial AgriPV Systems: Integrating
Regression Analysis and Decomposition-Transposition Matrix in the UK
Context
Mr Yazan J.K. Musleh1, Dr Stuart A. Boden1, Dr Tasmiat Rahman1
1University Of Southampton, United Kingdom

Session 2: Satoshi Uchida (Invited Speaker) Followed by Contributed Talks,
April 10, 2024, 15:00 - 16:15
Agricultural Photovoltaics (AgriPV), is a key technology for sustainable development, particularly
targeting the Food-Energy-Water Nexus [1]. This method allows the dual use of land for farming
and photovoltaic (PV) power generation. Despite its potential, accurate assessment of irradiancegains and Land Equivalent Ratios (LER) in the UK faces hurdles. An obstacle is the lack ofavailability of stations measuring irradiance components. Costs and maintenance issues impede
thorough data collection. Measurements like Diffuse-Horizontal-Irradiance (DHI) and especially
Photosynthetically-Active-Radiation (PAR) and its diffuse component (dPAR) are rarely recorded. In
the UK, only 1 site actively measures PAR and dPAR, and 3 sites offer open-source data on
Global-Horizontal-Irradiance (GHI) and DHI. Analysis of 104 decomposition models was conducted
to derive DHI from GHI. The Engerer2h [2] model demonstrated a consistent Mean-Bias-Deviation(MBD) of 0.07% across datasets and locations as per Fig1. Additionally, 105 mathematicalregression models were used to estimate PAR, employing a methodology that quantifies
irradiance in the 400-to-700 nm range. The Xia3 [3] model yielded an MBD of -0.30% concerning
PAR databases classified under the Köppen-Geiger “Cfb” category, encompassing 12 stations.
Future work will focus on validating transposition models, utilizing Engerer2h, by comparing topyranometer readings gathered at the University of Southampton’s Outdoor-Testing-Facility in
Chilbolton. Following this, techniques will be employed to calculate the back-of-array (BOA)
irradiance, quantifying the irradiance impacting the rear side. The Xia3 model, in combination withEngerer2h, will be employed to estimate dPAR, validated against data from Auchencorth Moss.
Ultimately, the research will quantify the irradiance on both panel sides, PAR in unshaded areas
and dPAR in shaded regions caused by vertical systems (see Fig 2). Thus, this research will
evaluate and quantify different UK sites for LER assessment. This approach will provide deeper
insights into AgriPV's potential in the UK, underlining its significance in sustainable land
management.

A Novel System for Performance measurements of Indoor Photovoltaic
Devices under Indoor Standard Testing Conditions (ISTC)
Daniel Parsons1, Dr George Koutsourakis1, Dr James Blakesley1
1National Physical Laboratory, United Kingdom

Session 3: Contributed Talks, April 10, 2024, 16:30 - 17:30
There has been a lack of specified measurement conditions for indoor photovoltaic (IPV) devices
until the recently published in the IEC TS 62607-7-2:2023 standards In this work, we present thefirst reported system for IPV characterisation which is compliant with this newly released
standard. The system uses digital light processing (DLP) to deliver a spectrally invariant lightsource and has been classified for spectral coincidence, spatial uniformity and temporal stability.
The system has been used to determine the IV parameters of commercial and emerging IPVtechnologies and it will feature in national and international intercomparisons, to investigate theclarity of the IEC TS 62607-7-2:2023 standard.

Unveiling the effects of electron transport layers on all inorganic
perovskite film formation.
Mr Stefan Nicholson1,2, Dr Jochen Bruckbauer2, Dr Paul Edwards2, Dr Carol Trager-Cowan2,
Professor Robert Martin2, Dr Aruna Ivaturi1
1Smart Materials Research and Device Technology Group, Department of Pure and Applied Chemistry, University ofStrathclyde, United Kingdom, 2Semiconductor Spectroscopy and Devices Group, Department of Physics, SUPA,
University of Strathclyde, United Kingdom

Session 6: Alona Armstrong (Invited Speaker) Followed by Contributed Talks,
April 11, 2024, 13:30 - 14:45
Perovskite photovoltaics have emerged as a promising technology with combined advantages ofhigh efficiency, low materials cost, along with easy and scalable fabrication. The choice ofelectron transport layer (ETL) is important for achieving high efficiencies. The main properties thatare considered for this choice are the band alignment, conductivity, transparency and theextraction performance. Whilst these characteristics are important, the effects of the underlying
layer on the crystallographic and emissive properties of the film should not be ignored.
In the presented study, correlative studies between cathodoluminescence (CL), electronbackscatter diffraction (EBSD) and x-ray diffraction (XRD) are presented, unveiling a resounding
impact on an all-inorganic absorber from the choice of the underlying electron transport layer.
SnO2, TiO2 and ZnO have been compared as the electron transport layers for the growth of
CsPbI2Br. The impact of the underlying ETL layer on the grain level heterogeneity within theperovskite films is explored Detailed EBSD measurements revealed Zinc oxide to be the ETL
which promoted grain growth, directs preferential orientation of the perovskite grains, and forms amore homogeneous layer. Bulk characterization by XRD confirms the observations made in EBSD,
showing that the localized grain data is replicated across the entire film surface for the CsPbI2Br
films grown on ZnO. Cathodoluminescence shows a more uniform emission with less grainboundary non-radiative recombination effects, showing improved optoelectronic properties of the
all-inorganic CsPbI2Br films grown on ZnO.
These insights into the growth of perovskites portray fundamental understanding that must be
applied when designing solar cell stacks.

Utilizing Low-Toxicity Solvents in Roll-to-Roll Fabrication of Carbon
Electrode Perovskite Solar Cells
Ershad Parvazian1, David Beynon1, Rahul Patidar1, Trystan Watson1
1SPECIFIC IKC, Faculty of Science and Engineering, Swansea University, United Kingdom

Session 4: Robert Hoye (Invited Speaker) Followed by Contributed Talks,
April 11, 2024, 09:15 - 10:30
Perovskite solar cells (PSCs) are emerging as key players in sustainable solar energy, offering highefficiency in lab settings. Yet, commercializing these cells requires overcoming the use of toxic
solvents like DMF/DMSO and Chlorobenzene/Chloroform, crucial in creating perovskite and holetransporting layers. These chemicals, while effective, pose significant health and environmental
risks, especially in large-scale manufacturing. Additionally, PSCs face stability challenges underreal-world conditions, particularly humidity, leading to performance degradation over time.
Our study introduces a transformative approach: developing roll-to-roll (R2R) coated PSCs withcarbon electrodes using low-toxicity solvents. This method aims to minimize environmental
impacts and enhance the safety and practicality of mass production. We replaced hazardous
solvents with safer alternatives: DI water for the tin oxide layer, Acetonitrile (ACN) for theperovskite layer, and Oxylene for the hole transporting layer. The carbon ink incorporates 2Methylanisole, promoting safer, more cost-effective production.
Our results are encouraging. The R2R coated PSCs with carbon electrodes not only achieved apower conversion efficiency (PCE) over 10% but also maintained 85% of this efficiency after 90
days, demonstrating improved stability. This advancement is significant, as it indicates thepotential of PSCs as durable, sustainable solar cells.
Conclusively, our research marks a crucial step in transitioning PSCs from laboratory innovations
to scalable, environmentally-friendly, and economically feasible energy solutions. By addressing
toxicity, stability, and cost challenges, we pave the way for broader adoption of PSCs in the solar
energy sector, contributing to a greener energy future.

Organic Solar Cells at Stratospheric Condition for High Altitude Platform
Station Application
Dr Ram Datt1, Dr Harrison Ka Hin Lee2, Dr Guichuan Zhang3, Prof Hin-Lap Yip4, Dr Wing Chung
Tsoi1
1Swansea University, United Kingdom, 2Department of Physics, City University of Hong Kong, China, 3School of

Semiconductor Science and Technology, South China Normal University, China, 4Department of Materials Scienceand Engineering, City University of Hong Kong, China

Session 5: Michael Owen Bellini (Invited Speaker) Followed by Contributed Talks,
April 11, 2024, 11:00 - 12:30
In summary, we have studied organic photovoltaic (OPV) for space applications. In space,particularly in a High-altitude platform station (HAPS) environment. In this study, we have selected
the PM6: Y6 and PM6: IT-4F blend systems based on OPV and studied their photovoltaic
performance under a broad range of temperatures, vacuum, and light spectrum according to
HAPS environment conditions. The PM6: Y6 device was found to perform well, and the PCE
dropped between -20 to 10 oC, which is negligible. Whereas, for PM6: IT-4F device, the PCE
dropped almost 12% at -20 oC compared to its peak value. Moreover, the device characteristics
are also measured under a broad range of temprature, including -100 to +80. The recombination
mechanism was studied under three different temperatures: 80, 20, and -100 oC. The slope(kT/q) and recombination parameter (α) have been calculated under 80, 20, and -100 oC
temperatures. This work provides an in-strength study on a benchmark OSC system PM6: Y6 andhighlights its great potential for HAPS or space applications.

Understanding the Ionic Modulation of Open-Circuit Voltage in Perovskite
Solar Cells
Lucy Hart1, Fraser Angus3, Pablo Docampo3, James Durrant2, Piers Barnes1
1Department of Physics and Centre for Processable Electronics, Imperial College London, United Kingdom,2Department of Chemistry and Centre for Processable Electronics, Imperial College London, United Kingdom, 3Schoolof Chemistry, University of Glasgow, United Kingdom

Session 10: Kurt Barth (Invited Speaker) Followed by Contributed Talks,
April 12, 2024, 11:00 - 12:15
Metal halide perovskites are a promising class of materials for use in the active layer of next
generation solar cells, with the highest performance lab-scale perovskite solar cells (PSCs)
achieving efficiencies of over 25%. Aside from their promising photovoltaic performance, thesematerials are of scientific interest due to their high densities of mobile halide vacancies whichmean they can conduct both ionic and electronic charge. Thus, when an electrical bias is applied
to a PSC, the electric field experienced by the electronic carriers is modulated by the redistributionof ionic charge in response to the same applied field. This fundamentally changes the device
physics of PSCs and has been shown to lead to extraction losses and carrier accumulation undershort-circuit conditions. However, the presence of mobile ions can also reduce recombination
currents at the perovskite/transport layer interfaces and so can lead to an increase in open-circuit
voltage (VOC).
Herein, we use device level drift-diffusion simulations to determine the conditions under which
the presence of mobile ions can increase VOC. We find that mobile ions lead to the largest
improvement in VOC in PSCs where there is both a large energetic offset to the transport layers
and where surface recombination is the dominant loss pathway. This is because, under these
conditions, it is possible to have an accumulation (depletion) of halide vacancies at the interface
between the perovskite and the electron (hole) transport layer. This distribution of mobile ions
results in smaller potential drops in the perovskite layer when compared to a device with thesame parameters, but no mobile ions, and thus reduces surface recombination currents,
increasing VOC. We then use Stabilise and Pulse measurements to experimentally verify the
results of our simulations by probing how VOC depends upon the ionic configuration in n-i-p PSCs
with varying electron transport layers.

Application-Targeted Metal Grid -Enhanced Transparent Electrodes for
Organic Photovoltaics
Nicholas Burridge1, Dr. Gregory Burwell1, Dr. Oskar Sandberg2, Dr. Ardalan Armin1, Prof. Paul
Meredith1
1CISM - Swansea University, United Kingdom, 2Abo Akademi University, Finland

Session 9: Marina Freitag (Invited Speaker) Followed by Contributed Talks,
April 12, 2024, 09:15 - 10:45
Despite recent developments in organic photovoltaic (OPV) devices at lab scales (< 1 cm²),
commercially viable OPV devices suffer performance losses at scale (> 10 cm²),[1,2] largely due
to the large series resistance exhibited by state-of-the-art monolithic transparent conducting
electrodes (m-TCEs). To reduce the series resistance of TCEs, one solution is to use the TCE in
conjunction with a metallic grid to form gridded-TCEs (g-TCEs),[3–5] which essentially divides acell into an array of smaller sub-cells.[6] Although TCE materials exhibit a trade-off between
average visible transmittance (AVT) and conductivity, the use of TCEs with metallic grids allows
the electro-optical properties of high-performance TCEs to be optimised. In this work, the scalingrelated performance barrier for OPVs is presented. The performance impact of critical grid
geometry is studied with varying light intensity for different OPV applications. At high irradiances,smaller grid critical dimensions (CD) result in improved OPV device performance and can be
combined with TCEs with high AVT. At low irradiances, the requirement for a highly conductive TCE
reduces, because of the reduced photocurrent, allowing coarser grid structures to be utilised. To
overcome the challenging surface morphology of on-plane metal grids, a method to recess
metallic grids into substrates is demonstrated through exemplary planar (± 30 nm) 5 cm² g-TCEs,
demonstrated with silver nanowires and aluminium-doped zinc oxide (AZO). The AZO g-TCEs wereshown to provide a sheet resistance of 0.5 Ω/□, with AVT greater than 77 %. These results showthat high-performance g-TCE structures are a highly versatile approach for utilising OPV in various
applications.

Realistic Performance Limits of Indoor Photovoltaics
Austin Kay1, Shimra Ahmed1, Nicholas Burridge1, Dr. Gregory Burwell1, Dr. Oskar Sandberg2,
Prof. Ardalan Armin1, Prof. Paul Meredith1
1Swansea University, United Kingdom, 2Åbo Akademi University, Finland

Session 7: Ruy Sebastian Bonilla (Invited Speaker) Followed by Contributed Talks,
April 11, 2024, 15:00 - 16:15
By recycling low-intensity, artificial light generated by LEDs and fluorescent lamps, indoor
photovoltaics (IPVs) based on next-generation semiconductor materials, like organics andperovskites, could power billions of wireless devices and sensors in the forthcoming Internet-ofThings.[1]Alongside the benefits of flexibility and solution-processibility, organic semiconductors andperovskites have tailorable optical properties, which are extremely desirable as the spectral
fingerprints of indoor light sources differ from source to source.[2] Due to the infancy of the field,
however, the performance limits of IPVs are poorly understood beyond the Shockley-Queisser
limit. These performance limits are herein defined, and the limiting effects of shunt and series
resistances, as well as radiative and non-radiative recombination, are clarified.
Following this, a methodology and computational tool are presented for extrapolating
measurements made under AM1.5 G conditions to arbitrary illumination conditions.[3] Thismethodology is applied to predict the performance of several state-of-the-art systems underillumination by LED-B4 – a light source specified in the new indoor testing standard.[4]Figure 1: Power conversion efficiencies (PCEs) simulated for state-of-the-art perovskites, organics,
and inorganics under LED-B4 light at 500 lux, then plotted against the optical gap.
References
1.
Burwell, G., O.J. Sandberg, W. Li, P. Meredith, M. Carnie, and A. Armin, Scaling
Considerations for Organic Photovoltaics for Indoor Applications. Solar RRL, 2022. 6(7): p.
2200315.
2.
Kay, A.M., M.E. Fitzsimons, G. Burwell, P. Meredith, A. Armin, and O.J. Sandberg, The
Thermodynamic Limit of Indoor Photovoltaics Based on Energetically-Disordered Molecular
Semiconductors. Solar RRL, 2023: p. 2300277.
3.
Kay, A.M. Photovoltaic Performance Simulator. 2023; Available from:https://github.com/Austin-M-Kay/Photovoltaic_Performance_Simulator.
4.
International Electrotechnical Commission, Indoor Testing Standard 62607-7-2:2023.
Available from: https://webstore.iec.ch/publication/61819.

CdTe-based PV on ultrathin glass for emerging large area space
applications
Dr Dan Lamb1, Dr Ochai Oklobia, Professor Craig Underwood, Professor Stuart Irvine
1Swansea University, United Kingdom, 2University of Surrey, United Kingdom

Session 1: Aruna Ivaturi (Invited Speaker) Followed by Contributed Talks,
April 10, 2024, 11:15 - 12:15
This paper will describe the emerging space applications that will require large area PV arrays andthe new performance drivers that could require a sea change from the ubiquitous multi-junction
III-V based PV to a low-cost, light weight single-junction solution. The paper will address some of
the challenges of direct deposition of PV material onto ultrathin glass. Discussion will be made on
the additional characterization that a PV technology must undergo when designed for space
deployment. Finally, a summary of the data and lessons learned from the CdTe payload aboard
the AlSat Nano CubeSat mission between 2016 and 2023.

Monolithic dye-sensitized solar cells with copper polymer gel electrolytes
for indoor applications
Fátima Santos1, Dzmitry Ivanou1, Adélio Mendes1
1LEPABE/ALiCE; FEUP, Portugal

Session 5: Michael Owen Bellini (Invited Speaker) Followed by Contributed Talks,
April 11, 2024, 11:00 - 12:30
Internet of Things devices have been increasing considerably in the last decade, and continuous
growth is expected for the coming ones. With power conversion efficiencies (PCEs) of 30 % underroom light, low-cost fabrication, safe materials and attractive aesthetics, dye-sensitized solar cells(DSSCs) became one of the most favorable indoor photovoltaics to cover their power needs. The
most efficient DSSCs use copper redox mediators in a volatile electrolyte; the liquid-junction
devices often suffer electrolyte leakages, compromising their long-term performance. Polymer gel
electrolytes (PGE) are a reliable alternative; their higher viscosity reduces leakage problems, while
keeping adequate ionic conductivity and diffusion of redox species. Moreover, the chargetransport limitations through the polymeric network are considerable under 1-sun illumination,
but less pronounced under low-light conditions. Therefore, PGE-DSSCs are less efficient than theliquid-junction devices under 1-sun, but present comparable or even superior performance underroom light conditions. Up to now, the highest PCEs for DSSCs using Cu-PGE are 5.0 % (AM1.5G)
and 25.5 % (1000 lx). F Santos et al. prepared Cu-PGE by adding polyethylene oxide (PEO,
average MW ~ 400 000) and poly(methylmethacrylate) (PMMA, average MW ~ 120 000) to theliquid Cu-electrolyte using 3-methoxypropionitrile (MPN) solvent, and by heating the mixture to
100 ºC for 4 h under constant stirring. These Cu-PGE were used in monolithic DSSCs (M DSSCs)
with Y123 sensitizer and a carbon counter-electrode, which delivered PCEs of 6.6 % (AM1.5G)
and 28.4 % (1000 lx), a record for DSSCs using Cu-PGE. The monolithic structure uses a single
transparent conductive oxide (TCO) substrate, reducing the material costs and making themodule’s fabrication more straightforward. The high viscosity of PGE permits cell separation by
TCO scribing after deposition techniques, allowing module encapsulation using a single sealantframe, which is more attractive for market-scale production of M-DSSCs for indoor applications.

The use of Artificial neural network to enhance MPPT finding
methodology on Energy Harvesting chips
Zaid Haymoor1, Matt Carnie, Kris Seunarine
1Swansea Univesity, United Kingdom

Session 6: Alona Armstrong (Invited Speaker) Followed by Contributed Talks,
April 11, 2024, 13:30 - 14:45
Getting the most out of indoor solar panels is crucial for better energy harvesting. Current market
chips employ a conventional yet rudimentary approach—the fractional open circuit voltage
method—to identify the MPP. Our investigation delves into the limitations of this method,
particularly in high irradiance scenarios, such as near windows and within clean rooms. A
comprehensive review of datasheets from market-leading energy harvesting chip manufacturers(e-peas, Texas Instruments, ST, and Analog Devices) revealed the prevalence of the fractional
open circuit voltage method in chip design. While this method is low complexity and powerefficient, its performance falters under intense lighting conditions. Modules, especially those withhigh series resistance, experience a flattened I-V curve and a substantial drop in fill factor,
resulting in significant deviations in the maximum power point voltage, which lowers energy
harvesting efficiency under the fractional open circuit MPPT method.
Our research aims to highlight the flaws of the standard method and proposes a solution basedon a light intensity sensor and a pre-trained neural network. The experiment started by collecting
data using our indoor low light testing box, focusing on a module from epshine across a range oflighting conditions. Using MATLAB, we developed an artificial neural network to predict the
optimal power point voltage based on lux levels only. Our experimental framework involves acomparison between the traditional fractional open circuit voltage method and our neuralnetwork-based approach. The analysis spans a spectrum of lighting intensities, revealing theefficacy and superiority of our proposed methodology in optimising indoor photovoltaic energy
harvesting.
We gathered data on light intensity, I-V curve, and the key parameters MPP and VMPP . The
dataset was divided into training and testing sets. Notably, the impact of temperature change wasomitted from our analysis, considering the controlled nature of temperature in indoor
environments.

Halide Perovskites Based Indoor Photovoltaics: Role of Interfacial Layers
Lethy Krishnan Jagadamma1, Mr Shaoyang Wang
1University of St Andrews, United Kingdom

Session 8: Contributed Talks, April 11, 2024, 16:30 - 17:30
With the explosive development of the Internet of Things (IoT) technology, indoor photovoltaics(IPVs) are becoming a promising candidate to sustainably power billions of wireless sensors forsecured and smart buildings. Among the various photovoltaics technologies available today,
halide perovskite-based IPVs are most promising for integration with IoT because of their excellent
optoelectronic properties, easy and cost-effective processability using solution1based methods
such as roll-to-roll printing, high specific power, and earth-abundance. The low intensity of theindoor light sources means the absence of beneficial light-induced trap filling of the perovskite
photoactive layer. This demands stringent defect minimisation approaches at every functional
layer to maximize the power conversion efficiency of IPVs and thereby reduce the efficiency gap(more than 20 % now) between the theoretically predicted and experimentally observed power
conversion efficiency of IPVs [1].
In this talk, I will discuss the effect of interfacial layer selection in maximizing efficiency andsuppressing the hysteresis effects under indoor lighting [2]. Our study shows that even though
under 1 Sun, different interlayers have comparable efficiencies, under indoor lighting theirperformance can be drastically different and requires separate defect passivation to maximise
the indoor light harvesting. Compared to organic-based charge transport layers, the metal oxidebased transport layers are found to be detrimental for indoor light harvesting and requireinterface engineering to suppress the charge accumulation at the buried interfaces. Thisconclusion has been arrived at by a series of systematic investigations of completed photovoltaic
devices and their partial heterostructures.
References[1] S. Wang et al, J. Phys. Mater. 6 024004 (2023)[2] A. Bulloch et al., Philos. Trans. R. Soc. A 380 20210144 (2022)

Beneath the surface: Investigating Perovskite Solar Cells under Water
Jessica Barichello1, Peyman Amiri2, Paolo Mariani2, Farshad Jafarzadeh2, Miguel Angel Molina3,
Marilena Isabella Zappia3, Luca Gabatel3, Sebastiano Bellini3, Francesco Bonaccorso3,
Francesca Brunetti2, Matthias Auf der Maur2, Aldo Di Carlo1,2, Fabio Matteocci2
1ISM-CNR, Istituto di Struttura della Materia, Italy, 2CHOSE, Centre for Hybrid Organic Solar Energy, Department ofElectronic Engineering, University of Rome, Italy, 3BeDimensional S.p.A., Italy

Session 4: Robert Hoye (Invited Speaker) Followed by Contributed Talks,
April 11, 2024, 09:15 - 10:30
In an always-connected world with an urgent need for clean energy, considering never-thinking
solutions may help address the challenges of future cities. While photovoltaic (PV) devices havetraditionally been used in rooftop and building-integrated photovoltaic applications, theirversatility extends to agrivoltaics and even space-based power generation. However, theuntapped potential of underwater (UW) PV systems remains unexplored. The Internet ofUnderwater Things (IoUT) is an emerging technology that has the potential to revolutionize theway we interact with the underwater world. IoUT devices can be used to monitor marine life,
collect data on water quality, and even control underwater infrastructure. As water depths
increase, the higher-wavelength components of sunlight are absorbed, leaving predominantly
blue-green light (400-600 nm) at depths of 50 meters and beyond (figure 1). Recent theoreticalanalyses [1] suggest that high-bandgap (2-2.2 eV) PV devices are ideal candidates for deep-UW
applications, making them suitable for powering IoUT devices [2]. Perovskite solar cells (PSCs)
stand out as a promising technology with high-power conversion efficiency, tunable bandgap, andthe unique characteristics of being colored and semi-transparent. Moreover, PSCs are lightweight,
making them ideal for deployment in remote locations. This work presents a pioneeringexperimental application of two PSCs: a high-bandgap, semi-transparent, and bifacial FaPbBr3
device, and a reference narrow-bandgap triple-cations perovskite solar cell
(Cs0.08FA0.80MA0.12Pb(I0.88Br0.12)3). Following the testing of PIB encapsulant robustness in
PSC devices, we investigated the sensitivity of the perovskite to a humid environment by testing
the three devices at depths of -1, -3, and -6 cm. Moreover, we combined experimental results withtheoretical simulations to extend the evaluation to a depth of -10 meters. Notably, all devices
exhibited enhanced PCE at a depth of -1 cm, suggesting a novel approach to floating PV systems
that leverages the increased PCE on water and the cooling benefit associated with submersion.

Indoor Characterisation and Performance Analysis of Static Hexagonal
Concentrators for Building Integrated Low Concentrating Photovoltaic
Applications
Mr Lewis Tamuno-Ibuomi1, Dr Roberto Ramirez-Iniguez1, Prof A Sheila Homles-Smith1, Dr Geraint
Bevan1
1Glasgow Caledonian University, United Kingdom

Session 3: Contributed Talks, April 10, 2024, 16:30 - 17:30
The use of optical concentrators, together with solar cells is gaining traction as a technology that
can improve the electrical performance of building integrated photovoltaic (PV) systems. These
photovoltaic cells are usually small in size, evaluated under 1 sun (1000 W/m^2) and have low
conversion efficiency. The gain of optical concentrators designed to improve their performance isless than 10 and are therefore classified as low gain concentrators. When the concentrated
photovoltaic system (concentrator and cell) is incorporated within the building envelope, it iscalled building integrated low concentrating photovoltaic (BILCPV). This technology can generateclean, affordable, and sustainable electricity within the building infrastructure. It offers acomparable alternative to fossil fuels and hence, promotes net zero and low emissions energy.
This paper discusses the indoor experimental characterisation and performance of two static,
nonimaging, 3D, novel hexagonal concentrators that were recently developed. These new familiesof solar concentrators were conceived from two independent methodologies. One is created using
the dielectric totally internally reflecting concentrator (DTIRC) approach, and it is named
rotationally asymmetrical hexagonal DTIRC (RAHDTIRC) while, the other is based on parametricequations, formulated from 3D polar coordinates, and named low concentrating hexagonal
photovoltaic (LCHPV) system. The concentrators and solar cells were tested indoors understandard test conditions of 1000 W/m^2, room temperature of 25°C and air mass of 1.5G. Fromthe indoor experiments, it was found that at normal incidence, the RAHDTIRC-PV unit can increase
the power output of the PV cell by 3.6x, while the LCHPV unit increased the cell power by 3.7x.
When compared with their optical power gains, the RAHDTIRC-PV unit was 12.4% lower, while the
LCHPV unit was only 3.9% lower. The total height of the RAHDTIRC-PV and LCHPV prototypes are
30mm and 18mm respectively, while their geometrical concentration gains are 4.58x and 4.13x
respectively.

Terrestrial And Non-Terrestrial Environmental Effects on Perovskite Solar
Cell Performance
Dr Jay Patel1
1King's College London, United Kingdom

Session 7: Ruy Sebastian Bonilla (Invited Speaker) Followed by Contributed Talks,
April 11, 2024, 15:00 - 16:15
Metal halide perovskite-based photovoltaics are emerging as a promising alternative toconventional silicon-based photovoltaics for both terrestrial and space applications. As we
progress towards the commercialization of perovskite-based photovoltaic technology, several
critical questions must be addressed:
1)
The impact of shading on the panels
2)
The influence of daily temperature fluctuations and varying climatic conditions
3)
The effects of high vacuum and the Air Mass 0 solar spectrum in space
In this presentation, I will discuss experimental findings that shed light on the chemical andphysical processes affected when these solar cells operate in diverse environments. Firstly, I will
explore the consequences of partial shading on the panels, as caused by typical weather events
such as cloud cover or snow [1,2]. This includes examining both reversible and irreversible
degradation processes. Secondly, the presentation will cover how the performance of singlejunction and multijunction perovskite-based photovoltaics is altered by changes in operating
temperature, along with the resulting energy yield variations in different geographic locations [3].
Lastly, the behavior of perovskite solar cells under space conditions will be discussed, focusing on
various encapsulation techniques and their impact on device durability [4].
References[1] L Bertoluzzi, L., J.B Patel et al Adv. Energy Mater. 2021, 11, 2002614.
[2] I.E Gould, J.B Patel et al 2021 IEEE 48th Photovoltaic Specialists Conference, pp. 1365-1367[3] T Moot*, J.B Patel* et al., ACS Energy Lett. 2021, 6, 5, 2038–2047[4] K.T. VanSant, A.R. Kirmani, J.B. Patel et al ACS Appl. Energy Mater. 2023, 6, 20, 10319–
10326

Unlocking the Potential of Alternative Hole Transporting Materials for
Solid-State Dye-Sensitised Solar Cells through Prolonged Oxidation andLight Soaking Treatment
Amy Neild1, Benjamin Vella2, Miriam Fsadni1, Pablo Docampo2, Elizabeth Gibson1
1Newcastle University, United Kingdom, 2University of Glasgow, United Kingdom

Session 8: Contributed Talks, April 11, 2024, 16:30 - 17:30
Aromatic amides serve as promising hole transporting materials (HTMs) due to their facile
synthesis via condensation chemistry. TPABT is an example of an amide-based small moleculethat exhibits high conductivity values (~10-5 S cm-1 upon the addition of standard ionic additives)at an estimated cost of only $5/g, reaching power conversion efficiencies of ~15% whenemployed as a HTM in perovskite solar cells. In this work, utilisation of TPABT as a HTM in solidstate dye-sensitised solar cells highlighted that extended aging compared with the common
benchmark HTM Spiro-OMeTAD was essential for dye regeneration to allow for oxidation of TPABT.
This emphasises the different oxidation pathways for alternative HTMs, which for TPABT is
ascribed to the closer molecular packing. Initially, 2 day old TPABT devices exhibited significant
hysteresis with a poor power conversion efficiency of 0.19%. However, after performing a lightsoaking treatment on 3-month-aged devices the power conversion efficiency improved from
0.33% to 1.48% and hysteresis was no longer observed. This raises the question, should we bereassessing devices that initially underperformed while utilising alternative HTMs? Furthermore,should we adopt a different approach in analysing materials when optimising the concentration of
additives?

Control crystallisation of perovskites in printable mesoscopic solar cells
Yue Hu1
1University of Edinburgh, United Kingdom

Session 9: Marina Freitag (Invited Speaker) Followed by Contributed Talks,
April 12, 2024, 09:15 - 10:45
Perovskite solar cells (PSCs) have attracted intensive attention due to their ever-increasing power
conversion efficiency (PCE), low-cost materials constituents, and simple solution fabrication
process. In printable mesoscopic PSCs, the perovskite is deposited on a triple-layer scaffold,made of screen printed mesoporous TiO2 layer, ZrO2 spacer layer and carbon electrode; suchdevices use carbon electrodes to replace the noble metal back contacts and do not require ahole-conducting layer.
Controlling the crystallization of organic–inorganic hybrid perovskite is of vital importance toachieve high performing perovskite solar cells. The growth mechanism of perovskites has been
intensively studied in devices with planar structures and traditional structures. However, for the
printable mesoscopic perovskite solar cells, it is difficult to study the crystallization mechanism of
perovskite owing to the complicated mesoporous structure. In this talk, I am going to share thedevelopment of the printable mesoscopic PSCs and how we manage to control the crystallization
in mesopores.

Revisiting the Significance of Spectral Solar Irradiance Data: Economical
Approaches to Effective Measurement
Haoxiang Zhang1, Dr Stuart Boden1, Dr Tasmiat Rahman1
1University Of Southampton, United Kingdom

Session 8: Contributed Talks, April 11, 2024, 16:30 - 17:30
This study introduces a cost-effective spectroradiometer built for PV related spectral irradiancemeasurement. Spectral irradiance has a significant impact on analysing the performance of PV
systems for both cell levels and system levels, including effective spectral irradiance from acertain spectral response, spectral albedo for bifacial PV, module temperature, tracking
strategies, etc.
However, the measurement instrument, spectroradiometers are notably costly, which leads to ascarcity of available measured spectral data and consequent research, particularly in regions withtemperate climates, such as the United Kingdom. The spectroradiometer built in this work uses
USB2000+ spectrometer from ocean optics, with cosine correctors attached to the optical fibres.
A raspberry pi 5 is used as a controller and a data logger. The low cost of the prototype
spectroradiometer will help make spectral data more accessible and facilitate further research inthese areas.
A breakdown of the system components and functions is shown in Figure 1. In terms of accuracy,
the absolute irradiance measurement is calibrated by a radiometrically calibrated light source HL3P-CAL-INT from ocean optics. A comparison between measured spectra and reference spectra of
HL-3P-CAL-INT is shown in Figure 2a, and measured spectra of solar simulator ABET Sun3000 isshown in Figure 2b.
The maximum number of connected spectrometers is not limited. As shown in Figure 3, potential
applications include albedometer, spectral POA measurement, spectral BOA measurement andspectral GHI measurement. The study presents an analysis of the spectral irradiance data, alongwith a comprehensive evaluation of the reliability and accuracy of the prototype
spectroradiometers.

Poster Presentations
Exploring the Dynamics of Risk and Quality in Solar Photovoltaic Systems
Mr Sharmarke Mohamed Hassan1, Dr. Mahmoud Dhimish1
1University Of York, United Kingdom

Flash Poster Presentations A, April 10, 2024, 12:15 - 12:30
The study presents an in-depth analysis of solar photovoltaic (PV) systems' performance,
encompassing a dataset of 85 ground-mounted installations spread across the entire United
Kingdom, as depicted in the map provided (Figure 1(a)). The geographical spread of the locations,highlighted in red on the map, was deliberately chosen to represent the wide variety of climaticand operational challenges that solar installations encounter throughout the UK. By evaluating
85,000 modules—equivalent to 5,592,000 solar cells—with a service life ranging from 6 to 9
years, the research offers a comprehensive perspective on the health and efficiency of PV
systems in differing environments. Electroluminescence (EL) imaging [1,2] conducted at night
served as the primary method for identifying microcracks and latent defects, with initial findings
exposing a range of defect types. The study’s extensive scope and methodical approach,integrating EL image analysis with the geographic distribution of PV systems, provides valuable
insights into the factors that influence the durability and performance of solar installations acrossdiverse UK locations.
In this poster, we will delve into a comprehensive analysis of various defect types observed in theexamined PV systems, as showcased in Figure 1(b). The figure illustrates a range of defects suchas line cracks, corrosion, complex cracks, edge ribbon cracks, and potential-induced degradation(PID), each of which can significantly impact the performance and longevity of PV modules.
Through meticulous EL imaging, our study categories these imperfections and evaluates theirprevalence and severity. We will discuss the implications of these findings, including the probablecauses and the potential effects on the overall efficiency of PV modules. Our analysis aims to
inform maintenance strategies and guide improvements in PV module design to mitigate such
defects, thereby enhancing the durability and reliability of solar energy systems.

Synthesis, XRD, EDX, SEM, and TEM characterization of two sulfide
nanostructures Ni(S2COBu)3 and [Ni(S2COPn)3
Abdulaziz A. Alanazi1
1Prince Sattam Bin Abdulaziz University, Saudi Arabia

Flash Poster Presentations A, April 10, 2024, 12:15 - 12:30
Nickel sulfides are well known for their various properties and applications, including their use as
modified thin films for photocatalytic applications [1,2]. Herein, we report the synthesis of two
stable and pure nickel sulfides nanostructures Ni(S2COBu)3 and Ni(S2COPn)3 from K(S2COBu)]
Potassium butyl xanthate and [K(S2COPn)] Potassium pentyl xanthate single metal xanthate
precursors using the melting method at two different temperatures 400 and 500°C. The obtained
nanoparticles were characterized using powder X-ray diffraction (Figure), energy-dispersive X-ray
spectroscopy (EDX), scanning electron microscopy (SEM), and transmission electron microscopy(TEM) techniques. The results disclosed that the size of the nanoparticles increases with theincrease of the alkyl chain length of the xanthate ligand and the melting temperature. Further, theincrease in temperature is accompanied by the appearance of a distinctive β NiS phase. In
continuity of this work, the synthesized nanostructures will be further assisted for theirphotocatalytic applications.

Enhancing Solar Cell Longevity: Assessing the Impact of ITO Coatings on
PID Resistance
Mr Thomas Lynch1, Dr Mahmoud Dhimish1, Professor Keith McKenna1
1University of York, United Kingdom

Flash Poster Presentations A, April 10, 2024, 12:15 - 12:30
The use of photovoltaic (PV) cells is critical in the sustainable generation of electricity. However,the performance of PV cells can decline over time due to Potential Induced Degradation (PID), a
phenomenon where the power output of a module decreases significantly during exposure tocertain conditions such as high voltage, temperature, and humidity.
Indium Tin Oxide (ITO) is commonly applied as a transparent conductive oxide layer in various
electronic devices, including solar cells. Its role in mitigating PID effects has been a subject of
research, with the aim to enhance the durability and lifespan of solar cells. This study examines
the effectiveness of ITO coatings in reducing power output loss due to PID in solar cells.

Influence of Thickness on the Electrical Properties of ITO Thin Films
Grown by RF Magnetron Sputtering Technique for Concentrated
Perovskite Solar Cells
Fahad Alsahli1,2, Hessa I. Alabdan1,3, Shubhranshu Bhandari1, Tapas K. Mallick1
1Environment and Sustainability Institute, University of Exeter, United Kingdom, 2Physics Department, College of

Science, University of Hafr Al Batin, Saudi Arabia, 3College of Science and Humanities – Jubail, Imam Abdulrahman
Bin Faisal University, Saudi Arabia

Flash Poster Presentations A, April 10, 2024, 12:15 - 12:30
Recent development on tandem silicon/perovskite solar cell becoming popular to overcome highefficiency limit. Increasing light flux is enable further to enhance its efficiency though low
concentrated optical integration, while Indium tin oxide (ITO) has become a crucial material in thefields of photovoltaics and nanotechnology due to its great electrical properties and exceptional
chemical stability. This study provides a thorough analysis of growing ITO thin films with various
thicknesses to indicate the impact of thickness on electrical properties for low concentration
optical device for perovskite solar cells. ITO has been prepared by RF magnetron sputtering using
Argon gas only with no alteration of temperature followed by annealing in a tube furnace underinert conditions. An investigation of the influence of thickness on the electrical properties of thefilms was conducted using a four-point probe. We have found that the best thickness for ITO withrespect to electrical performance is 75 nm. This work has led us to acquire excellent ITO thin films
for the applications of perovskites solar cells.

Detection and identification of vacancy-related point defects inperovskite halide semiconductors
Mr Aryaveer Singh1, Dr Julia Wiktor, Dr Mingze Li, Dr Maciej Liedke, Mr Zhifang Shi, Professor
Jinsong Huang, Professor David Keeble
1University Of Dundee, United Kingdom

Flash Poster Presentations A, April 10, 2024, 12:15 - 12:30
The intensive development of metal halide perovskite solar cells is driven by the unprecedentedly
rapid increase in cell efficiency values. While this success has been in part attributed to defecttolerance and reports of modest defect densities. Nevertheless, there has been a refocusing ofefforts to identify and quantify point defects in these materials.
Vacancy defects are a centrally important class of point defect. Positron annihilation spectroscopy(PAS) methods have specific sensitivity to neutral or negatively charged vacancy-related defects.
Positrons trap at missing atom defects. An implanted positron eventually annihilates with anelectron resulting in two annihilation photons. The lifetime of the positron state increases for
positrons localized at vacancy defects compared to that for the delocalized perfect lattice state.
Two component density functional theory (TC-DFT) enables the lifetimes of these states to be
calculated.
Previous positron lifetime studies of crystal and thin MAPbI3 measured values consistent withpositrons localized at B-site, Pb, vacancies. The spectrum exhibited close to saturation trapping tothis positron state. Here we extend these studies and report measurements on other perovskite
halides, including MAPbBr3 and FAPbBr3 to investigate the effects of changing anion and the Asite cation. Measurements included depth-profiling variable energy positron annihilation lifetime
measurements were performed using the mono-energetic positron source beamline at theHelmholtz–Zentrum Dresden–Rossendorf.
The positron lifetimes in MAPbBr3 were measured to be shorter in MAPbI3. Positron lifetime
spectra were measures that yielded a dominant lifetime component consistent with the TC-DFT
value for positron trapping to Pb vacancy defects.

Auxetic Crystalline Silicon Solar Module with Rotating Square Array
Structure
Chen Cao1, Tasmiat Rahman, Stuart Boden
1University of Southampton, United Kingdom

Flash Poster Presentations A, April 10, 2024, 12:15 - 12:30
This work combines an elastomer substrate with a planar rotating-square auxetic structure andthe concept of dividing c-Si PERC solar cells into small tiles and restructuring them into an array to
produce a lightweight, flexible and stretchable solar module as shown in Figure 1. Due to thenegative Poisson's ratio of the auxetic structure, bi-directional expansion with uniaxial stretchingis achieved, allowing the area coverage and so interception of light by the solar cell tiles to be
adjusted. Output voltage and current can be tailored according to the combination of series orparallel connections between tiles in the design. Potential applications include BIPV (e.g. partiallyshaded windows), AgriPV (e.g. greenhouse roofs), portable PV devices and indoor PV.
The prototype modules are designed with 20×20mm and 31.75×31.75mm square tiles,
determined by the number of busbars on the original solar cell. Extensive current-voltage (I-V)
characterization of the individual solar cells/tiles under AM1.5 illumination (see Figure 2(a)),
reveals slight performance degradation due to the saw damage and un-passivated edges
however, good power conversion efficiencies are retained. Tensile testing has been carried out on
the polyurethane material (Clear Flex 50, Smooth-on) cast into the configurations used for theflexible array (see Figure 2(b)). At a strain of approximately 29%, the tiles reach their maximum
rotation angle of 45°, at which the module transmittance area is 28 cm2.
Analysis of the electrical, optical and mechanical properties of the auxetic array prototype withfully encapsulated and interconnected solar cell tiles will be presented.

Evaluating the feasibility of novel PV technologies for powering PM2.5
sensors in indoor and outdoor applications
Miss Willow Herring1, Dr Tasmiat Rahman1
1University Of Southampton, Southampton, United Kingdom
Flash Poster Presentations A, April 10, 2024, 12:15 - 12:30
Solar power presents an ideal solution for powering low cost particulate matter sensor nodes inan IoT application where mains power is not a feasible solution, however the different
environments such a sensor could be used in stand to benefit different cell topologies. This
research characterises the power demands of some of the most popular particulate mattersensors on the market, with a focus towards using novel PV technologies to power them. We
discovered that most of the sensors under test at 4.5v consumed between 60 and 80mA mean,
with standard deviations varying between 2.4 and 31mA.

Floating Photovoltaic (FPV) for climate vulnerable river island
communities
YILIAO ZHOU1, Dr Sunny Chaudhary1, Dr Craig Hutton2, Dr Tasmiat Rahman1
1Sustainable Electronic Technologies, School of Electronics & Computer Science, Universityof Southampton, United
Kingdom, 2School of Geography & Environmental Science, University of Southampton , United Kingdom

Flash Poster Presentations A, April 10, 2024, 12:15 - 12:30
There are arguably no more vulnerable communities in Bangladesh than the agricultural andfishing communities of the populated and land-limited river island chars. A key consequence of
this remoteness is poor access to clean, affordable, and reliable energy. In this study, a workshop
with char communities in Northern Bangladesh explored annual energy consumption variations
linked to different livelihoods. Our goal was to assess gender-specific energy demands, bothpresent and future. We suggested a Hybrid Renewable Energy System (HREs), focusing on FPV
and Wind energy, and optimized its design using HOMER PRO. A detailed FPV analysis was
conducted using PVSyst. The study also examined the social and environmental impacts of FPV,
considering local energy needs and the HREs load profile.
Based on the load profile acquired at the workshop, significant diesel usage is noted in irrigation.
Peak demand occurs from January to March. Addressing these fluctuating needs, the optimal ecotechnical approach recommended is a hybrid system combining photovoltaic (PV), diesel, andbattery components. The proposed PV facility has a 64.6kW capacity, with wind power excluded
due to inadequate local wind resources. When contrasted with entirely diesel-powered
alternatives, the optimized Hybrid HREs are expected to decrease annual CO2 emissions by 115
tons. Simulations in PVsyst revealed that optimizing six parameters, as illustrated in Figure 1, led
to a reduction in the Levelized Cost of Energy (LCOE) from $0.1058/kWh to $0.0774/kWh. Basedon the sensitivity check result presented in Figure 1, albedo and degradation were identified as
crucial factors in this optimization process. Post-installation of HREs, surplus energy production
during post-irrigation periods holds the potential to support the local sewing industry, contributing
to the alleviation of gender-based livelihood inequalities. Additionally, a considerable proportion ofsolar power in the energy mix is expected to mitigate the greenhouse effect, local pollution, andsmoke damage.

CdTe thin film absorber layers grown under Cd-rich conditions by MOCVD:
impact on film surface topography and structure
Dr Ochai Oklobia1, Professor Stuart J. C. Irvine1, Dr Tom Dunlop2, Dr Dan Lamb1
1Swansea University, Oxide and Chalcogenide Facility, Centre for Integrative Semiconductor Materials (CISM), Facultyof Science and Engineering, United Kingdom, 2Swansea University, SPECIFIC IKC, Faculty of Science and Engineering,
Swansea, United Kingdom

Flash Poster Presentations A, April 10, 2024, 12:15 - 12:30
Cd-rich composition growth combined with group-V element doping is a promising approach for
producing CdTe absorber, with increased p-type doping for high efficiency CdTe solar cells [1].
This development was significant to achieving of As doped CdSeTe solar cell record efficiency of
22.3%, recently reported by First Solar Inc. [2]. In a previous study, high quality CdTe absorberlayers from in-situ Cd-rich metal organic chemical vapour deposition (MOCVD) growth werereported, demonstrating impressive increase and control in the incorporation of As dopants, witha corresponding enhancement in device VOC [3].
In this study, the impact of Cd-rich growth conditions on the surface morphologies and structuralproperties of CdTe absorber layers fabricated by MOCVD are investigated. Atomic force
microscopic (AFM) surface topography measurements, using non-saturated growth conditions,revealed a much rougher surface compared to a Cd-rich grown CdTe sample. The RMS roughness
was noted to be reduced by a factor of 2.6 with Cd-rich growth. The Cd precursor partial pressure(pDMCd)was kept constant at 3.11 × 10-4 atm and the Te precursor partial pressure (pDIPTe)
decreased to yield a range of pDMCd:pDIPTe ratios from 2:1 to 5:1. The resulting CdTe film
surface roughness was found to increase at higher the pDMCd:pDIPTe ratios. CdTe absorberlayers fabricated using pDMCd:pDIPTe ratios of 2:1 and 3:1, having a comparatively smoothersurface presented intense interference fringes in their transmittance spectra. This was absent insamples (pDMCd:pDIPTe = 4:1 and 5:1) with rougher surface morphologies, accompanied withincreased absorption in the long wavelength region. XRD characterization of these layers revealed
that the crystal quality improved under Cd-rich growth conditions. The crystallographic andtopological analysis in this work will provide further insights into the structural mechanism in CdTe
absorber layers for increased PCE with Cd-rich growth conditions.

Simulating relative performance of Organic and Silicon PV in real-world
conditions
Zongtai Zhang1, Roderick Mackenzie1, Christopher Groves1
1Department of Engineering, Durham University, United Kingdom

Flash Poster Presentations A, April 10, 2024, 12:15 - 12:30
To understand the electrical behaviour of Organic photovoltaics (OPVs), the most common
equivalent electrical circuit used to model OPVs is the one-diode model (ODM). Our study
introduces a modified De Soto ODM for predicting the power output of OPVs in real-world
conditions. By applying this model to historical weather data including temperature and irradiancefrom London in the UK, we provide time-resolved power output predictions for OPVs. These
predictions are then analysed in the context of the UK's dynamic power pricing and carbon
emissions data. Our findings highlight the significance of considering non-standard atmosphericconditions (non-AM1.5) in evaluating OPV performance. Furthermore, we establish a correlation
between climate/seasonal variations and CO2 emissions in the electrical grid. This analysis
underscores the potential impact of renewable energy sources like OPVs in achieving Net Zerogoals and provides a comparative yield analysis with conventional silicon panels.

Tuning the morphology and phase structure of tungsten oxides forphotovoltaic applications
Suresh Bandi1, Ajeet Srivastav2,3
1Malaviya National Institute of Technology, India, 2Visvesvaraya National Institute of Technology, India, 3University Of

Strathclyde, United Kingdom

Flash Poster Presentations A, April 10, 2024, 12:15 - 12:30
In this work, we report the synthesis of three different classes of tungsten oxides taking tungsten
powder as a sole precursor by optimizing the experimental conditions. The combined effects ofhigh energy ball milling and change in furnace atmosphere (air and H2O vapor) during heat
treatments are key for phase, morphology, and structure tuning. The heat treatment of
nanocrystalline tungsten in the open atmosphere results in nanocrystalline WO3 with alteredbandgap. Heat treatment of tungsten powder in water vapor atmosphere resulted in W18O49
nanowires. Whereas nanocrystalline cubic H0.5WO3 can be formed by adopting similar
experimental techniques by simply replacing the precursor with nanocrystalline tungsten. Theseoxides can be used as charge transport materials for designing more stable and efficient solar
cell devices owing to their phase, morphology, and oxygen deficient structure.

Calamitic-Type Dipolar and Quadrupolar Chromophores with Twisted
Peripheral Handle: Structure-Property Outlook as Non-fullerene Acceptors
for Binary Solar Cells
Dr. Praveen Chandrasekar1
1University of Strathclyde, United Kingdom, 2CSIR-Central Electrochemical Research Institute, India

Flash Poster Presentations A, April 10, 2024, 12:15 - 12:30
Owing to their unique optoelectronic and structural characteristics, tetracyanobutadiene (TCBD)
based active layer materials have gained momentum in organic solar cells (OSCs).[1-5] In thepresent contribution,[3] symmetrical and unsymmetrical π-molecules possessing TCBD as πtwisted end group on carbazole/fluorene backbone were synthesized as non-fullerene acceptors(NFAs). Structural correlation of these chromophores on optoelectronic, electrochemical andphysicochemical properties revealed better acceptor properties for symmetrical molecules
compared to their unsymmetrical counterparts. High molar absorptivity, deep HOMO–LUMOs andother complementary functional properties are some of the associated factors for their better
acceptor character. In a binary solar cell configuration blended with a standard P3HT donor,
quadrupolar-type symmetrical chromophores displayed higher power conversion efficiencies
compared to dipolar-type unsymmetrical analogues. In particular, the carbazole-based
symmetrical chromophore with an efficiency of 5.37% emerged as the best candidate with further
enhancement to 6.30% upon additive processing (Figure 1). The dependence of processing inaugmenting photo-induced current was attributed to the better nanoscale morphology,
crystallinity, and electron mobility of the active layer. In terms of efficiency, it is the third highest
for any TCBD-based NFA material. Overall, this work validates the impact of a non-planar TCBD
auxiliary positioned within a calamitic-type π-backbone in realizing alternative NFAs. From afundamental perspective, our initial results are promising and further fine-tuning of molecular
structure could possibly enhance the cell efficiency.

PVSAT 2024
10–12 April 2024
Technology and Innovation Centre (TIC),
University of Strathclyde, Glasgow, UK
Registered Charity no. 293851 (England & Wales)
and SCO40092 (Scotland).