Query: Laminated fabrication of polymeric photovoltaic diodes

Candidate papers:

abstract: Photoexcited electron transfer between donor and acceptor molecular semiconductors provides a method of efficient charge generation following photoabsorption, which can be exploited in photovoltaic diodes. But efficient charge separation and transport to collection electrodes is problematic, because the absorbed photons must be close to the donor acceptor heterojunction, while at the same time good connectivity of the donor and acceptor materials to their respective electrodes is required. Mixtures of acceptor and donor semiconducting polymers, (or macromolecules) can provide phase separated structures which go some way to meeting this requirement, providing high photoconductive efficiencies. Here we describe two layer polymer diodes, fabricated by a lamination technique followed by controlled annealing. The resulting structures provide good connectivity to the collection electrodes, and we achieve a short circuit photovoltaic quantum efficiency of up to 29% at optimum wavelength, and an overall power conversion efficiency of 1.9% under a simulated solar spectrum. Given the convenience of polymer processing, these results indicate a promising avenue towards practical applications for such devices.
author_names: Magnus Granstrom

Klaus Petritsch

Ana Claudia Arias

Andrea Lux

Mats R Andersson

Richard H Friend
title: Laminated fabrication of polymeric photovoltaic diodes
venue: Nature
year: 1998

abstract: This study presents the slot die coating process of two layers of organic materials for the fabrication of organic light emitting diodes (OLEDs) Poly(3,4 ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) which is commonly used in OLEDs and in organic photovoltaic devices as the hole injection layer (HIL) has been deposited via slot die coating. Uniform films of PEDOT:PSS were obtained after optimizing the slot die processing parameters: substrate temperature, coating speed, and ink flow rate. The film quality was examined using optical microscopy, profilometry, and atomic force microscopy. Further, poly(9,9 dioctylfluorene) (F8) and poly(9,9 dioctylfluorene alt benzothiadiazole) (F8BT) a well know polymer blend F8:F8BT, which is used as an emissive layer in OLEDs, has been slot die coated. The optoelectronic properties of the slot die coated F8:F8BT films were examined by means of photoluminescence (PL) and electroluminescence (EL) studies. The fabricated OLEDs, consisting of slot die coated PEDOT:PSS and F8:F8BT films, were characterized to record the brightness and current efficiency.
author_names: Amruth C

Marco Colella

Jonathan L W Griffin

James William Kingsley

Nicholas W Scarratt

Beata Luszczynska

Jacek Ulanski
title: Slot Die Coating of Double Polymer Layers for the Fabrication of Organic Light Emitting Diodes
venue: Micromachines
year: 2019

abstract: Abstract The hierarchical micro /nanotextures adorning the petal surfaces of certain flower species exhibit outstanding sunlight harvesting properties, which can be exploited for photovoltaic (PV) applications via a direct replication approach into polymeric cover layers. This route has been so far hampered by the restricted size of the original bio template and by the limited number of replication cycles when a polymeric mold is used. Here, we therefore introduce an upscaling strategy allowing the fabrication of mechanically stable, temperature resistant and large area nickel mold inserts which can be employed for hot embossing lithography, and ultimately for the mass production of bioreplicated films that improve light management in PV modules. As a proof of concept, we laminate the thus produced textured foils, here corresponding to rose petal replicas, onto glass encapsulated copper indium gallium diselenide (CIGS) solar modules with a surface of 100 cm2. We demonstrate an increase of the power output of 5.4% with respect to a device with an uncoated glass cover layer (measured in outdoor operating conditions) This improvement is notably attributed to the excellent light in coupling properties of the replicated texture at high oblique incidence angles.
author_names: Benjamin Fritz

Ruben Hunig

Markus Guttmann

Marc Schneider

K M Samaun Reza

Oliver Salomon

Philip L Jackson

Michael Powalla

Uli Lemmer

Guillaume Gomard
title: Upscaling the fabrication routine of bioreplicated rose petal light harvesting layers for photovoltaic modules
year: 2020

abstract: Organometal halide perovskite light emitting diodes (LEDs) with laminated carbon nanotube (CNT) electrodes are reported. The LEDs have an indium tin oxide (ITO) bottom electrode, a screen printed methylammonium lead tribromide (MAPbBr3)/polymer composite thin film as the emissive layer, and laminated CNT as the top electrode. The devices can be turned on at 2.2 V, reaching a brightness of 4,960 cd m 2 and a current efficiency of 1.54 cd A 1 at 6.9 V. The greatly simplified fabrication process in this work can potentially lead to the scalable manufacturing of large size and low cost LED panels in the future.
author_names: Xin Shan

Sri Ganesh R Bade

Thomas Geske

Melissa B Davis

Rachel R Smith

Zhibin Yu
title: Organometal halide perovskite light emitting diodes with laminated carbon nanotube electrodes
venue: Organic Photonics Electronics
year: 2017

abstract: Abstract This work presents post fabrication electric field and heat treatment methods developed for polymer light emitting diodes (PLEDs) which have degraded due to exposure to oxygen and water vapors during low cost fabrication performed in standard room conditions. Investigated PLEDs have structures composed of indium tin oxide (ITO) poly(3,4 ethylenedioxythiophene) poly(styrenesulfonate) (PEDOT:PSS) poly[2 methoxy 5 (2' ethyl hexyloxy) 1,4 phenylene vinylene] (MEH PPV) and aluminum (Al) Heat treatment restores the light emitting function of dysfunctional PLEDs but also causes a high turn on voltage of 10 V. Electric field treatment utilizing 1 V reduces this high turn on voltage to 3 V. This procedure also improves open circuit voltages from 5 mV to 55 mV, and short circuit currents from 0.5 nA to 5 nA when PLEDs are operated as photovoltaic cells under a light intensity of 500 mW/m2. Repeated I V sweep measurements additionally show improved stability and uniformity. The reasons for these improvements, the usage of an optimal treatment temperature of 130 degC, and the usage of treatment voltages of 0 and 1 V are discussed.
author_names: A O Sevim

Senol Mutlu
title: Post fabrication electric field and thermal treatment of polymer light emitting diodes and their photovoltaic properties
year: 2009

abstract: Materials with a combination of high electrical conductivity and optical transparency are important components of many electronic and optoelectronic devices such as liquid crystal displays, solar cells, and light emitting diodes. In this study, to fabricate a low resistance and high optical transparent electrode film for organic photovoltaic, the following steps were performed: the design and manufacture of an electroforming stamp mold, the fabrication of thermal roll imprinted (TRI) poly carbonate (PC) patterned films, the manufacture of high conductivity and low resistance Ag paste which was filled into patterned PC film using a doctor blade process and then coated with a thin film layer of conductive polymer by a spin coating process. As a result of these imprinting processes the PC films obtained a line width of 10{pm}0.5{mu}m, a channel length of 500{pm}2{mu}m, and a pattern depth of 7.34{pm}0.5{mu}m. After the Ag paste was used to fill part of the patterned film with conductive polymer coating, the following parameters were obtained: a sheet resistance of 9.65{Omega}/sq, optical transparency values were 83.69 at a wavelength of 550 nm.
title: Fabrication of Transparent Electrode Film for Organic Photovoltaic using Ag grid and Conductive Polymer
year: 2011

abstract: An effective electron injection layer (EIL) is crucial to efficient polymer light emitting diodes (PLEDs) with high work function metal as cathode. This work presents the use of water/alcohol soluble poly(vinyl alcohol) (PVA) especially doped with alkali metal salts, as a highly effective EIL to fabricate efficient multilayer PLEDs, allowing the use of stable aluminum as the cathode. Using neat PVA as EIL, the maximum brightness and maximum current efficiency of the device [ITO/PEDOT:PSS/SY/PVA/Al(90 nm) were significantly enhanced to 5518 cd/m2 and 2.64 cd/A (from 395 cd/m2 and 0.06 cd/A without the EIL) due to promoted electron injection and hole blocking. The device performance is further enhanced by doping the PVA with alkali metal salts (M2CO3 or CH3COOM; M: Na, K, Cs) and the enhancement is increased with increasing dopant concentration. Particularly, the PVA doped with 30 wt% alkali metal carbonates revealed the best performance (20214 25163 cd/m2, 5.83 6.83 cd/A) This has been attributed to improved electron injection from aluminum cathode, which has been confirmed by the corresponding increase in the open circuit voltages (Voc) obtained from photovoltaic measurements. Current results indicate that commercially available PVA are promising electron injection layer for PLEDs when doped with appropriate alkali metal salts.
author_names: Cheng Liang Wu

Cheng Yi Lin

Yun Chen
title: Fabrication of efficient polymer light emitting diodes using water/alcohol soluble poly(vinyl alcohol) doped with alkali metal salts as electron injection layer
venue: Journal of Materials Science
year: 2016

abstract: Abstract Non traditional photovoltaic (PV) modules, such as solar shingles, facades and skins, are expected to increase in market share as the solar industry matures and moves to fill building integrated photovoltaics niches. The advent of building integration and the application of photovoltaics to multiple surfaces come with fabrication challenges and inherent geometrical, optical and thermal constraints. In this paper, we investigate the curved lamination process and the integration of a dichroic polymeric film within the laminate for the particular case of a large scale optical collector called a "PVMirror" PVMirror is a concentrating solar power (CSP)/PV hybrid design that combines the high efficiency of PV and storage capability of CSP using a dichroic film. The film does not degrade upon lamination and exhibits good adhesion to encapsulants. Multiple lamination approaches, such as tuning the thickness of the encapsulant, are shown to significantly reduce the impact of the lamination process on the shape error of PVMirror modules, which could also be applied to the fabrication of other non traditional PV modules.
author_names: Xiaodong Meng

Kathryn C Fisher

Lennon O Reinhart

Wyatt S Taylor

Michael E Stuckelberger

Zachary C Holman

Mariana I Bertoni
title: Optical characterization of curved silicon PV modules with dichroic polymeric films
venue: Solar Energy Materials and Solar Cells
year: 2019

abstract: Recent work on solar cells based on interpenetrating polymer networks and solid state dye sensitized devices shows that efficient solar energy conversion is possible using organic materials. Further, it has been demonstrated that the performance of photovoltaic devices based on small molecules can be effectively enhanced by doping the organic material with electron accepting molecules. But as inorganic solar cells show much higher efficiencies, well above 15 per cent, the practical utility of organic based cells will require their fabrication by lower cost techniques, ideally on flexible substrates. Here we demonstrate efficiency enhancement by molecular doping in Schottky type photovoltaic diodes based on pentacene an organic semiconductor that has received much attention as a promising material for organic thin film transistors, but relatively little attention for use in photovoltaic devices. The incorporation of the dopant improves the internal quantum efficiency by more than five orders of magnitude and yields an external energy conversion efficiency as high as 2.4 per cent for a standard solar spectrum. Thin film devices based on doped pentacene therefore appear promising for the production of efficient 'plastic' solar cells.
author_names: Jan Hendrik Schon

Christian Kloc

Ernst Bucher

Bertram J Batlogg
title: Efficient organic photovoltaic diodes based on doped pentacene
venue: Nature
year: 2000

abstract: Poly(p phenylene vinylene) (PPV) is a family of conjugated polymers that have been used in a variety of fields, including light emitting diodes, light emitting transistors, photovoltaic cells, and sensors. PPV is generally synthesized by a Wittig or a Knoevenagel condensation reaction. Owing to its poor solubility, it has been difficult to utilize PPV in solutionbased manufacturing processes. To overcome this issue, alkoxysubstituted PPVs, such as poly[2 methoxy 5 (2 ethylhexyloxy) 1,4 phenylenevinylene] (MEH PPV) (Scheme I) have been developed. The long alkyl substituents enhance the solubility in common organic solvents. In addition, there have been numerous attempts to tune the emission wavelength of PPV for display applications. Depending on the substituents and steric hindrance, the fluorescence of PPV can be tuned from blue to red. Many efforts have been devoted to fabricate patterned PPV images on solid substrates. For instance, Dirk and coworkers reported the patterning of PPV using a photolabile xanthate group. PPV patterns were produced by elimination of xanthate groups upon exposure to UV light. In addition, patterns can be fabricated by employing photolithography, micromoldingin capillaries (MIMIC) and array spotting techniques. Among the various patterning methods, the photolithographic approach has been considered as the most reliable due to its high scalability and resolution. Conventional photolithographic methods generally utilize precursor PPVs that are converted to PPVs by UV irradiation. Polydiacetylenes (PDAs) discovered by Wegner in 1969, are optically and structurally unique conjugated polymers. When 254 nm UV light is irradiated on self assembled diacetylene (DA) monomers, 1,4 addition polymerization occurs to form a colored (typically blue) PDA. Polydiacetylene (PDA) shows a color transition (typically blue to red) and exhibits self fluorescence when exposed to external stimuli. In addition, the solubility of PDA in common organic solvents is drastically decreased after polymerization. We hypothesized that, if a thin film of PPV containing DA moieties (PPV DA) is UV irradiated with a photomask, photoinduced PDA formation should occur in the UV exposed area (Figure 1) Subsequent development of the film in an organic solvent should remove any organic solvent soluble (UV unirradiated) part, leaving patterned PPV images behind.
author_names: Sumin Park

Seongho Jeon

Tae Geun Kim

Jong-Man Kim
title: A side chain crosslinking approach for the fabrication of conjugated polymer patterns
venue: Macromolecular Research
year: 2016