A5027404486- Conducting polymers and applications
- Organic Electronics and Photovoltaics
- Organic Light-Emitting Diodes Research
- Perovskite Materials and Applications
- Molecular Junctions and Nanostructures
- Thin-Film Transistor Technologies
- Organic and Molecular Conductors Research
- Magnetism in coordination complexes
- Chalcogenide Semiconductor Thin Films
- Silicon and Solar Cell Technologies
- Photochemistry and Electron Transfer Studies
- Fullerene Chemistry and Applications
- Advanced Photocatalysis Techniques
- Crystallization and Solubility Studies
- Quantum Dots Synthesis And Properties
- Rare-earth and actinide compounds
- Carbon Nanotubes in Composites
- Semiconductor materials and interfaces
- Electron Spin Resonance Studies
- Advanced Thermoelectric Materials and Devices
- Graphene research and applications
- Quantum and electron transport phenomena
- Spectroscopy and Quantum Chemical Studies
- Transition Metal Oxide Nanomaterials
- Advanced Condensed Matter Physics
University of Tsukuba
2016-2025
Tsukuba University of Technology
2024
Toshiba (Japan)
2023
Kyoto University
2023
National Institute of Advanced Industrial Science and Technology
2019
Kanazawa University
2016
Materials Science & Engineering
2016
Japan Science and Technology Agency
2010-2015
Nagoya University
1999-2009
Tokyo Metropolitan University
1999-2006
This work provides an efficient way to facilitate both electron and hole extraction in the designated interfaces of perovskite solar cells. A record power conversion efficiency 23.6% for mixed Sn–Pb cell devices is realized.
An electron spin resonance (ESR) method is applied to a pentacene field-effect device investigate gate-induced hole carriers in such devices. Clear field-induced ESR signals are observed, demonstrating that all of the field-injected have S = 1/2 spins. Anisotropic due unpaired pi electrons show molecular orientation at interface The spatial extent density distribution (wave function) evaluated from linewidth, accounting for hyperfine structure, be order 10 molecules.
Electron spin resonance (ESR) spectroscopy of 2,2′,7,7′-tetrakis-(N,N-di-p-methoxyphenylamine)9,9′-spirobifluorene (spiro-OMeTAD) thin films and perovskite (CH3NH3PbI3)/spiro-OMeTAD layered are reported. Clear ESR signals (g = 2.0030) were observed by adding a dopant lithium bis(trifluoromethanesulfonyl)imide (Li-TFSI) to the spiro-OMeTAD films, which directly showed (hole) formation in Li-TFSI doping. The number spins film has increased more than two orders magnitude doping under dark...
A clear correlation between the number of accumulated holes (Nspin) in poly(3-hexylthiophene) (P3HT) and deterioration performance is observed polymer solar cells under simulated irradiation. The sites hole accumulation with deep trapping levels are formed at interfaces P3HT:[6,6]-phenyl C61-butyric acid methyl ester (PCBM) poly(3,4-ethylenedioxythiophene):poly(4-styrenesulfonate) (PEDOT:PSS) layers.
The microscopic mechanisms behind the very high mobility in rubrene single-crystal transistors achieved by interface treatments with self-assembled monolayers (SAMs) have been clarified using field-induced electron spin resonance (FI-ESR). Clearly observed FI-ESR signals exhibit extremely narrow linewidths owing to carrier mobility. precise angular dependence of $g$ values shows that crystallinity semiconductor channel is unchanged SAM treatments. trapping time charge carriers at directly...
The mechanism of light‐induced degradation in organic solar cells based on regioregular poly(3‐hexylthiophene) and indene‐C 60 bisadduct is studied by transient absorption (TA) electron spin resonance (ESR) measurements. After 45 h light exposure under simulated illumination at 100 mW cm −2 , the short‐circuit current density, open‐circuit voltage, fill factor are all degraded about 20%–30% relative to initial photovoltaic parameters. For assignment limiting conversion processes cells,...
Sn-based perovskite solar cells (PSCs) have attracted attention because of their low environmental impact. Unfortunately, the readily occurring oxidation Sn2+ inhibits further improvement efficiency and stability. Ruddlesden–Popper (RP) perovskites are considered promising candidates as absorbers that improve performance stability PSCs. However, microscopic understanding performance-enhancing mechanisms remains insufficient. For this study, electron spin resonance (ESR) spectroscopy...
<title>Abstract</title> In recent years, polymer solar cells have been investigated extensively because of their cost-effectiveness and flexibility. Notably, inverted type using PTzBT((2,5-bis(3-(2-butyloctyl)thiophen-2-yl)thiazolo[5,4-d]thiazole)-alt-(2,5-bis(3-(2-hexyldecyl)thiophen-2-yl)thiazolo[5,4-d]thiazole)) gained prominence superior conversion efficiency stability, particularly with the incorporation non-fullerene acceptor ITIC...
Abstract Microscopic characterization of charge carriers in solar cells is useful for high‐performance cell fabrication because the formation and accumulation charges greatly affect device performance. Electron spin resonance (ESR) suitable such it can directly observe with spins these cells. In this work, ESR method applied to organic thin‐film investigate devices. Heterojunction indium tin oxide (ITO)/poly(3,4‐ethylenedioxythiophene):poly(4‐styrenesulfonate) (PEDOT:PSS)/pentacene/C 60...
Abstract Perovskite solar cells are attractive because of their remarkably improved power conversion efficiency. In view application, however, it is important not only to increase the efficiency, but also elucidate deterioration mechanism. Here, we show operando direct observation spin states in using electron resonance, thereby investigating operation and mechanisms from a microscopic viewpoint. By simultaneous measurements cell characteristics hole transport material spiro-OMeTAD...
Abstract Ternary polymer solar cells based on a thiazolothiazole-based donor (PTzBT) and fullerene acceptor (PC 61 BM) have attracted attention because they show high efficiency stability by addition of non-fullerene (ITIC). However, the performance improvement mechanism is not completely elucidated. Here, we due to less charge accumulation in PTzBT with ITIC using operando electron spin resonance from microscopic viewpoint. We observed two correlations between device number spins ( N )...
We report electron spin resonance (ESR) studies on field-induced charge carriers in regioregular poly(3-hexylthiophene) (RR-P3HT) and poly(3-octylthiophene) (RR-P3OT) for metal–insulator–semiconductor (MIS) diode structures with Al 2 O 3 as an insulating layer. The ESR signals ( g ∼2.002) were clearly observed; their intensities monotonically increased the absolute value of gate bias accumulation mode a saturation behavior at higher voltages. consistent those photogenerated positive polarons...
The mechanism of light-soaking phenomenon in inverted-type organic solar cells (IOSCs) with a structure indium-tin-oxide/TiOx/P3HT:PCBM/Au was studied by electron spin resonance (ESR) spectroscopy. Charge accumulation the cell during UV-light irradiation observed using ESR, which clearly correlated phenomenon. origin charge is clarified as holes that are deeply trapped at p-type P3HT polymer-chain ends bromine after hole transfer from band excitation TiOx layer. considered to be...
This study investigates the effects of reducing treatment by 1,4-bis(trimethylsilyl)-2,3,5,6-tetramethyl-1,4-dihydropyrazine (TM-DHP) additives on band bending in perovskite surface near poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) hole-selective contacts tin-based-perovskite solar cells. We took electron spin resonance (ESR) spectroscopy measurements PEDOT:PSS/tin stacks dark and under one-sun illumination. The findings indicate that downward is formed tin layer...
Using electron spin resonance (ESR) spectroscopy, we investigated the effects of addition tin (Sn) powder to perovskite layers on band bending at surface near poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) hole-transport in solar cells (PSCs) involving formamidinium (FA)-methylammonium (MA)-mixed-cation I-Br-mixed-halide perovskites. We performed dark ESR spectroscopy measurements a PEDOT:PSS/FA
Using electron spin resonance (ESR), we clarified the origin of efficiency degradation polymer solar cells containing a lithium-fluoride (LiF) buffer layer created by thermal annealing process after deposition an Al electrode (post-annealing). The device structure was indium-tin-oxide/ poly(3,4-ethylenedioxythiophene):poly(4-styrenesulfonate)/poly(3-hexylthiophene):phenyl-C61-butyric acid methyl ester (P3HT:PCBM)/LiF/Al. Three samples consisting quartz/P3HT:PCBM/LiF/Al, quartz/P3HT:PCBM/Al,...
Polymer solar cells are one of the promising energy sources because easy solution-processable production with large area at a low cost without toxicity. Among polymer materials, donor–acceptor conjugated copolymer PTB7 has been extensively studied typical high-performance cells. Here, we show operando direct observation charge accumulation in PTB7:PC71BM blend from microscopic viewpoint using electron spin resonance spectroscopy. The ambipolar charges PTB7-based is directly observed for...
The performance of organic solar cells has been remarkably improved recently, where the cell structures are important for achieving high efficiency and stability. formation accumulation long-lived charges in critical stability cells; however, their relations with have not yet clarified from a microscopic viewpoint. Here, we report mechanism inverted polymer fullerene compared to conventional even though same photoactive layers utilized. We directly observe these electron spin resonance at...
Organic–inorganic hybrid perovskite solar cells have attracted much attention as important next-generation cells. Their cell performance is known to change during operation, but the root cause of instability remains unclear. This report describes an investigation using electron spin resonance (ESR) evaluate improvement mechanism for open-circuit voltage, VOC, inverted at initial stage device operation. The ESR study revealed transfer interface from layer hole-transport not only under dark...