bluuebunny/crossref_metadata_2025_split huggingface dataset:
(Invited) Charge Carrier Dynamics of Inorganic Perovskite Quantum Dots Showing Water Treatment Effect of Photoluminescence Efficiency
Authors: Furube Akihiro , Mori Koki , Chen Shih-Hsuan , Chen Liang-Yih 
Published: May 2020

All-inorganic perovskite CsPbX3 (X = Cl, Br, I) quantum dots (QDs) exhibit a high photoluminescence quantum yield, and is attracting attention due to the increasing demand for optoelectronic devices such as solar cells and light-emitting diodes (LEDs). In this study, we prepared a solution of CsPbBr3 QD synthesized by hot injection method and performed femtosecond transient absorption spectroscopy. In particular, we investigated the change in transient absorption during the process of improving luminous efficiency by water treatment.
To study the luminescence increment mechanism, a two-layer structure of oleylamine (OAm) aqueous solution (in the lower part) and CsPbBr3 QD hexane solution (in the upper part) was made, and transient absorption measurement under 400 nm excitation was performed for 8 hours.
As time passed, the OAm and/or water molecules moved up to the upper QD surface, and the increase in the photoluminescence occurred. Previous experiments have shown that the emission quantum yield increases from about 30% to about 70%. In the measurement of transient absorption, transient bleaching was confirmed to grow little by little 2 hours after the preparation of the two-layer structure. The bleaching reached its maximum amplitude after 3 or 4 hours, and gradually decreased till 8 hours. Since the bleaching intensity is proportional to the number of excitons generated, it was found that the excitation efficiency was increased by the water treatment. Ultrafast exciton quenching probably by the QD surface seems to be the main reason of the low emission quantum yield before the water treatment.
Donor-Acceptor-Donor-Type Cyclopenta[2,1-b;3,4-b’]Dithiophene Derivatives As a New Class of Hole Transporting Materials for Highly Efficient and Stable Perovskite Solar Cells
Authors: Abate Seid Yimer , Lin Yan-Duo , Chung Hsin-Cheng , Liau Kang-Ling , Chow Tahsin J. , Sun Shih-Sheng , Tao Yu-Tai 
Published: May 2020

Three new donor-acceptor-donor-type (D-A-D) hole-transporting materials (HTMs), YC-1–YC-3, based on 4-dicyanomethylene-4H-cyclopenta[2,1-b;3,4-b’]dithiophene (DiCN-CPDT) core structure endowed with two arylamino-based units as peripheral groups were designed, synthesized and applied in perovskite solar cells (PSCs). Hole mobility, steady-state photoluminescence, thin-film surface morphology on top of perovskite layer, and photovoltaic performances for the YC series were systematically investigated and compared with that of Spiro-OMeTAD. It was found that YC-1 exhibited more efficient hole transport and extraction characteristics at the perovskite/HTM interface. Meanwhile, the film of YC-1 showed a homogeneous and dense capping layer coverage on perovskite layer without any pinholes, leading to the improvement of the fill factor and open circuit voltage. PSC device based on YC-1 as HTM exhibited a high power conversion efficiency (PCE) of 18.03%, which is comparable to that of the device based on the benchmark Spiro-OMeTAD (18.14%),1 and also a better long-term stability, with 85% of the initial efficiency retained after 500 hours storage under the condition of 30% relative humidity, presumably due to the hydrophobic nature of the material. This work demonstrates that the dicyanomethylene-CPDT-based derivatives are promising HTMs for efficient and stable PSCs.
Y. S. Lin, S. Y. Abate, K. W. Lai, C. W. Chu, Y. D. Lin, Y. T. Tao, & S. S Sun, ACS Appl. Mater. Interfaces,
2018,
10, 41439.

Figure 1
(Invited) Ultrafast Solar Energy Conversion with Earth-Abundant Complexes
Authors: Chabera Pavel , Lindh Linnea , Rosemann Nils , Warnmark Kenneth , Yartsev Arkady , Sundstrom Villy , Persson Petter 
Published: May 2020

Transition-metal complexes are widely used as photosensitizers and photocatalysts, and in light-emitting devices.[1] We have studied ultra-fast processes in a variety of DSSC and photocatalytic applications.[2,3] More recently we demonstrated the first iron complex [FeIII(btz)3]3+ exhibiting room temperature photoluminescence from a CT state and show that it has a 100 ps excited state CT lifetime which is unprecedented for any iron complex.[4] This was characterized as a rare low-spin FeIII
d5
complex with emission from a long-lived doublet ligand-to-metal charge transfer (2LMCT) state. Absence of intersystem crossing (ISC) in this complex avoids significant excited state energy losses as encountered in the prevailing class of d6
TM complexes of e.g. FeII and RuII. Furthermore, we have also shown [FeII(btz)3]2+ low-spin complex [5], a FeII analogue to [FeIII(btz)3]3+. It exhibits strong metal-to-ligand charge transfer (MLCT) absorption bands throughout the visible spectrum, and excitation of these bands gives rise to a 3MLCT state with a 528 ps excited state lifetime in CH3CN solution that is more than one order of magnitude longer compared to the MLCT lifetime of any previously reported FeII complex. Together, these results show that the FeII and FeIII oxidation states of the same Fe(btz)3 complex feature long lived MLCT and LMCT states, respectively. This demonstrates the versatility of iron N-heterocyclic carbene complexes as promising light-harvesters for a broad range of photophysical and photochemical applications, and on-going efforts for further improvements of the excited state dynamics of such systems will be outlined, including the very latest development of an iron compound [Fe(phtmeimb)2]+ with an excited state stable enough to emit luminescence with unprecedented 2 ns lifetime and with the ability to engage in bi-molecular electron transfer [6].

References:

1 Ponseca, C. S., Jr.; Chabera, P.; Uhlig, J.; Persson, P.; Sundstrom, V. Ultrafast Electron Dynamics in Solar Energy Conversion.
Chem Rev
2017, 117 (16), 10940.
2 H. Imahori et al, Photoinduced Charge Carrier Dynamics of Zn−Porphyrin−TiO2 Electrodes: The Key Role of Charge Recombination for Solar Cell Performance,
J. Phys. Chem. A
2011, 115, 16, 3679-3690
3 M. Yamamoto et al, Visible light-driven water oxidation with a subporphyrin sensitizer and a water oxidation catalyst,
Chem. Commun.
2016,52, 13702-13705
4 Chabera, P. et al. A low-spin Fe(III) complex with 100-ps ligand-to-metal charge transfer photoluminescence. Nature 2017, 543 (7647), 695.
5 Chabera, P. et al. Fe(II) Hexa N-Heterocyclic Carbene Complex with a 528 ps Metal-to-Ligand Charge-Transfer Excited-State Lifetime, J Phys Chem Lett 2018, 9, 459−463.
6 Kjær, K. S. et al. Luminescence and reactivity of a charge-transfer excited iron complex with nanosecond lifetime. Science 2019, 363 (6424), 249-253.

Figure caption:

Photoluminescent iron complex [6]

Figure 1
(Invited) Ordered Semiconductor Through-Hole Membranes with Controlled Geometrical Structures by Anodization Processes
Authors: Yanagishita Takashi , Masuda Hideki 
Published: May 2020

The semiconductor materials with naturally occurring self-ordered nanostructures have attracted growing interest for the preparation of functional nanodevices for energy conversion.1 To obtain the nanodevices with optimized performance, control of the geometrical structure of semiconductors is essential. For example, the fabrication of highly ordered structures of semiconductors contributes to the efficient absorption of the incident light and also enhance the charge separation in the interfaces. Anodization process of metals is an effective method for the preparation of ordered hole array structures of metal oxides. One advantageous point of this process is controllability of the geometrical structures of the obtained porous structures based on the anodization conditions.2 In addition, the naturally occurring self-ordered ordered nanoporous structures can be obtained under the appropriate anodization conditions. In our previous reports, we described that ordered nanothrough-hole membranes can also be obtained effectively by two-layer anodization process.3,4 This process allows repeated preparation of ordered through-hole membranes from a single metal substrate by repetition of the process. As an application to semiconductor through-hole membranes, ordered TiO2 through-hole membranes were obtained by two-layer anodization using an electrolyte containing fluoride ions.5 The hole period of the obtained TiO2 membranes could be controlled by changing the anodizing voltage. In the present report, preparation of various types of semiconductor through-hole membranes will be presented. For example, the preparation of ideally ordered TiO2 through-hole membranes by the combination process of two-layer anodization and pretexturing of Ti was described. The obtained TiO2 through-hole membranes with controlled geometrical structures will be applied to various types of energy conversion devices.
1. P. Roy, S. Berger, P. Schmuki, Angew. Chem. Int. Ed., 50, 2904 (2011).
2. H. Masuda and K. Fukuda, Science, 268, 1466 (1995).
3. T. Yanagishita and H. Masuda, Electrochim. Acta, 184, 80 (2015).
4. T. Yanagishita, A. Kato, T. Kondo, and H. Masuda, Jpn. J. Appl. Phys., 56, 035202 (2017).
5. T. Yanagishita, H. Inada, T. Kondo, N. T. Nguyen, P. Schmuki, and H. Masuda, J. Electrochem. Soc., 165, E763 (2018).
3D Architecture Electrode Materials for Supercapacitors
Authors: Ramadoss Ananthakumar , Arunkumar S , Swain Nilimapriyadarsini , Saravanakumar Balasubramanian , Mohanty Smita , Nayak Sanjay Kumar 
Published: May 2020

Energy is the prime source of life. The escalated consumption of fossil fuel has created the major problem of energy crisis, which demands the ample production and storage of renewable energy. In connection to this, the energy storage systems (EES) have been proved as secured solution to this setback. In fact, EES are contributing major character in the sector of portable electronic device, aerospace, electric vehicles, smart grids etc. Various energy storage systems like lithium ion batteries (LIBs), fuel cells, supercapacitors (SCs), hybrid devices etc. are being designed and developed by the researchers in the field of energy storage device. LIBs has their intrinsic advantage of high energy density whereas supercapacitors have the merit of high power density with good cyclic stability. As a matter of the fact, a sustainable energy storage device critically claims both optimized energy density along with power density. Supercapacitors due to its high power density, long cycling stability and fast charge/discharge property are considered as one of the most promising energy storage devices. The major bottleneck of SCs is its low energy density in comparison to batteries. Moreover, the energy density is dependent on the value of applied potential window and specific capacitance of the used electrode material. Hence, consistent efforts have been made towards finding high performance electrode materials for SCs. One of the strategies proposed to enhance the energy storage capacity of SCs is the construction of highly porous three-dimensional (3D) architecture electrodes with high surface area in a limited footprint area (Ramadoss et al., 2016; Ramadoss et al., 2017; Kwak et al., 2017). The construction of 3D compact architecture will help to shorten the diffusion path for fast transport of ions/electrons, increase the electrical conductivity, utilization of plentiful active materials in a small area for energy storage, which promotes fast kinetics and excellent electrochemical performance. Based on that, extensive efforts have been devoted to developing 3D electrodes for supercapacitors (Figure 1), and substantial progress and development have been achieved.

References:

1. Ramadoss, A., Kang, K. N., Ahn, H. J., Kim, S. I., Ryu, S. T., and Jang, J. H. (2016). “Realization of high performance flexible wire supercapacitors based on 3-dimensional NiCo2O4/Ni fibers,” Journal of Materials Chemistry A 4(13): 4718-4727.
2. Ramadoss, A., Yoon, K. Y., Kwak, M. J., Kim, S. I., Ryu, S. T., and Jang, J. H. (2017). “Fully flexible, lightweight, high performance all-solid-state supercapacitor based on 3-dimensional-graphene/graphite-paper,” Journal of Power Source 337: 159-165.
3. Kwak, M. J., Ramadoss, A., Yoon, K. Y., Park, J., Thiyagarajan, P., and Jang, J. H. (2017). “Single-step synthesis of N-doped three-dimensional graphitic foams for high performance supercapacitors,” ACS Sustainable Chemistry & Engineering 5(8): 6950-6957.

Figure 1
Computational Modeling of Boron Subphthalocyanines and Subnaphthalocyanines to Justify Their Development and to Predict and Confirm Their Electrochemical and Physical Properties
Authors: Bender Timothy P , Holst Devon 
Published: May 2020

For some time, our group has been focused on the molecular design, synthesis and application of derivatives of boron subphthalocyanines (BsubPcs) and subnaphthalocyanines (BsubNcs), which are macrocyclic molecules with a chelated central boron atom. Our focal point has been and continues to be equally balanced between the basic and applied chemistry of BsubPcs/BsubNcs and their application as light absorbing and electronic conducting materials in organic photovoltaics (OPVs)/organic solar cells. Electrochemical properties being critical to this application. For OPVs, we selected a preferred approach to the development of BsubPcs/BsubNcs whereby their molecular design and their synthesis is justified through a development cycle which includes data accumulation of their basic physical chemistry properties, their immediate integration into OPVs and their stability evaluation when applied into OPVs/organic solar cells. Based on data acquisition, we then cycle back to consider alternative molecular designs of BsubPcs/BsubNcs. Recently we have re-Integrated into this cycle our computational modeling methodology which is used to screen potential BsubPcs/BsubNcs for their application in OPVs/organic solar cells and other organic electronic devices.
For this presentation I will begin by outlining how we have re-adopted our past computational model to help develop these materials. I will start by showing how we calibrate several levels of computational modeling relative to firm experimental data. I will highlight how a low level and high level computational model can be calibrated and the difference between them. I will then move onto several examples of how we have developed BsubPcs/BsubNcs for application in OPVs and other organic electronic devices utilizing this method.
An example I will show is that we have recently identified a pathway to BsubPcs whereby all carbons are bio-sourced. In order to justify their synthesis with the desired OPV application, I will highlight how the computational model justified the time and resource commitment to their synthesis and development. I will also show how the computational calibration model did accurately predict their relevant properties, the prediction being a level of justification for their development.
I will outline several other BsubPc/BsubNc macrocycle structures that where either justified by the computational model to be developed or where not justified. I will also highlight to the community progress in avoiding bay-position halogenation of the BsubNc macrocycles during their formation.
Additional co-authors/investigators will be identified during this presentation.

Figure 1
DFT Investigation of Porphyrin Aggregates
Authors: Sabuzi Federica , Stefanelli Manuela , Monti Donato , Conte Valeria , Galloni Pierluca 
Published: May 2020

Owing the attractive potential applications of porphyrin assemblies in photocatalysis, sensors and material science, nowadays studies concerning porphyrin aggregation are largely diffused. These chromophores can organize in elaborated architectures by an assorted set of non-covalent interactions (i.e. π–π stacking, H-bonding, metal coordination, hydrophobic effect, and electrostatic forces) between the tetrapyrrolic macrocycles, mostly in J-or H-aggregated species, where the aromatic platforms are stacked side by side and face to face, respectively. UV-vis spectroscopy allows the identification of the porphyrin arrangement within the aggregates, through the modified spectral features of the porphyrin monomer following the interaction among the porphyrin units. Despite plenty of experimental investigations dealing with the self-organization of porphyrin both in solution and at the solid state, computational studies are still limited.
In this communication, a computational examination of the different porphyrin aggregation approaches will be presented, taking into account the amphiphilic [5-{4-(3-trimethylammonium)propyloxyphenyl}-10,15,20-triphenylporphyrin] chloride, whose aggregation behavior has been previously experimentally investigated. In particular, the definition of appropriate functionals to study and characterize porphyrin aggregates, to get more insights on the kind of the interactions responsible for the formation of the specific noncovalent systems (J-, H-, T- or cation-π aggregates) experimentally observed will be proposed.
Fig. Calculated structures of J-type (left) and cation-π (right) dimers of [5-{4-(3-trimethylammonium)propyloxyphenyl}-10,15,20-triphenylporphyrin] chloride.

Figure 1
Using the Electrode Potential to Orient Single Molecules in Nanoscale Electrical Junctions
Authors: Borguet Eric 
Published: May 2020

Charge transport through and between molecules is central to important processes in nature. Studying the conductivity of single molecules can contribute to a better understanding of charge transport, and also help to develop building blocks of molecular electronics, light harvesting devices, etc. We measure the conductivity of molecules using the Scanning Tunneling Microscope break-junction (STM-BJ) method that utilizes repeatedly formed circuits where one or a few molecules are trapped between two electrodes, at least one of which has nanoscale dimensions. The statistical analysis of thousands of measurements yields the conductance of single molecules.
One particular interest is the role of the molecule-electrode contact and orientation in charge transport. In the simplest analysis this contact can present a substantial barrier to charge injection, which can have important consequences in devices such as dye sensitized semiconductor nanoparticle solar cells. Our most recent developments include controlling the orientation of the molecule in the junction using the electrode potential so that we can measure conductance along different molecular axes, accessing elements of the anisotropy of the molecular conductance tensor. Specifically, when the molecule is oriented flat, with the molecular plane parallel to the electrode surface, charge transport is measured perpendicular to the molecular plane. This approach can be applied to molecules that do not have suitable molecular anchoring groups for traditional STM-BJ measurements, and allows us to determine the importance of anchoring groups in charge transport in molecular junctions.
Electron-Triggered Metamorphism in Porphyrin-Based Self-Assembled Supramolecular Polymers
Authors: Chowdhury Shagor , Kahlfuss Christophe , Dumont Elise , Saint-Aman Eric , Demets Grégoire Jean-François , Ramos Ana Paula , Frath Denis , Chevallier Floris , Bucher Christophe 
Published: May 2020

Stimuli-responsive self-assembled molecular materials are currently subject to intense research activity. This growing interest stems largely from the myriad of exciting applications envisioned for dynamic supramolecular assemblies, also known as dynamers, in materials science, sensing, catalysis and electronics. Enormous technologic interests are for instance at stake in being able to devise molecular objects that could respond to external stimuli by changes in structure and function. These particular properties can lead to applications in various domains as (i) in molecular electronics, (ii) in analytic science, with switchable hosts allowing the controlled binding/release of pollutants or drugs, (iii) in materials science with the development of adaptive supramolecular polymers.
Our group has been focusing over the past few years on the development of tailor-made redox-controllable molecular and supramolecular systems involving electrogenerated pi-radicals as key responsive and/or assembling elements [1, 2]. In this lecture, we will focus on the physico-chemical properties of a series of porphyrin-based molecular tectons whose self-assembly can be controlled with optical or electrical stimulus. The dynamic properties of these stimuli-responsive molecular architectures and molecular materials will mainly be discussed on the basis of electrochemical, spectroelectrochemical and ESR experiments supported by quantum chemical calculations [3-6].

References :

[1] C. Kahlfuss, E. Saint-Aman, C. Bucher (2016). Redox-controlled intramolecular motions triggered by π-dimerization and πmerization processes In T. Nishinaga (Ed.), Organic Redox Systems: Synthesis, Properties, and Applications (pp. 39). New-York: John Wiley and sons.
[2] H. D. Correia, S. Chowdhury, A. P. Ramos, L. Guy, G. J.-F. Demets, C. Bucher, Polymer International
68, 572 (2019).
[3] S. Chowdhury, Y. Nassar, L. Guy, D. Frath, F. Chevallier, E. Dumont, A. P. Ramos, G. J.-F. Demets, C. Bucher, Electrochimica Acta
316, 79 (2019).
[4] C. Kahlfuss, S. Denis-Quanquin, N. Calin, E. Dumont, M. Garavelli, G. Royal, S. Cobo, E. Saint-Aman, C. Bucher, Journal of the American Chemical Society
138, 15234−15242 (2016).
[5] C. Kahlfuss, T. Gibaud, S. Denis-Quanquin, S. Chowdhury, G. Royal, F. Chevallier, E. Saint-Aman, C. Bucher, Chemistry - A European Journal
24, 13009 (2018).
[6] C. Kahlfuss, R. Gruber, E. Dumont, G. Royal, F. Chevallier, E. Saint-Aman, C. Bucher, Chemistry - A European Journal
25, 1573 (2019).

Figure 1
Site Isolation of Catalytically Active Mn(III)-Porphyrin into Porous Materials
Authors: Lee Suk Joong , Yoon Jong Ho 
Published: May 2020

Porous materials (PMs) including porous coordination polymers (PCPs), metal–organic frameworks (MOFs), porous organic polymers (POPs), and polymers with intrinsic microporosity (PIMs), have received much attention and they often show novel and/or enhanced performances in wide range of applications such as catalysis, separation, gas storage, drug delivery, biosensing, and imaging. Although they can be successfully obtained by controlling the growth conditions, their fabrication is still a major challenge because of lack of information regarding the crucial factors for the precise control of particles during the synthesis. Furthermore, the translation of building blocks into well-defined structures, whose properties and functions are regulated in the building block level, still remains very challenging. In this regard, metalloporphyrins would be good building blocks for the construction of such functional materials witnessed by a wide range of molecular architectures, such as molecular boxes, self-assembled arrays, CPs and MOFs with various applications. Particularly, Mn(III)- and Fe(III)-containing metalloporphyrins are often used to fabricate various functional molecular architectures and to mimic the extraordinary behavior of enzymes in both homogeneous and heterogeneous catalytic systems.In the case of homogeneous catalysis, these materials have frequent trouble with fast catalytic degradation because of µ-oxo dimer formation or ligand oxidation. To avoid the catalyst degradation, the heterogenization of homogeneous catalysts, such as immobilization and/or site-isolation of homogeneous catalysts using supporters are widely used alternative strategies. In this regard, I like to present the preparations and heterogeneous catalytic uses of Mn(III)–porphyrin in various porous materials (PMs).
References
1. D. Y. Shin, J. H. Yoon, S. H. Kim, H. Baik, S. J. Lee,*
Catal. Sci. Technol. 2018, 8, 6306-6310.
2. J. Yi, H. Y. Jeong, D. Y. Shin, C. Kim, S. J. Lee,*
ChemCatChem 2018, 10, 3974-3977.
3. J. Yi, H. M. Ahn, J. H. Yoon, C. Kim, S. J. Lee,*
New J. Chem., 2018, 42, 14067-14070.