Singlet exciton fission (SF) is a spin-allowed process whereby two triplet excitons are created from one singlet exciton. This phenomenon can offset UV photon energy losses and enhance the overall efficiency in photovoltaic devices. For this purpose, it requires photostable commercially available SF materials. Excited state dynamics in pure perylene film, ease of commercial production, is studied by time-resolved fluorescence and femtosecond transient absorption techniques under different photoexcitation energies. In film, polycrystalline regions contain perylene in H-type aggregate form. SF takes place from higher excited states of these aggregates in ultrafast time scale < 30 fs, reaching a triplet formation quantum yield of 108%. Moreover, at λ = 450 nm singlet fission was detected as a result of two-quantum absorption. Other competing relaxation channels are excimer (1 ps) and dimer radical cation formation (< 30 fs). Excimer radiatively relaxes within 19 ns and radical cation recombines in 3.2 ns. Besides, exciton self-trapping by crystal lattice distortions occurs within hundreds of picosecond. Our results highlight potential of simple-fabricated perylene films with similar properties as high-cost single crystal in SF based photovoltaic applications.
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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7933242 | PMC |
http://dx.doi.org/10.1038/s41598-021-83791-z | DOI Listing |
Chemistry
January 2025
Yamaguchi University, Department of Chemistry, 753-8512, Yamaguchi, JAPAN.
We report herein the synthesis of an unprecedented isomer of perylene, dicyclohepta[cd,fg]-as-indacene bearing two phenyl groups (1-Ph) by the nickel-mediated intramolecular homocoupling of a 4,4'-biazulene derivative (2). The X-ray crystallographic analysis and theoretical calculations revealed that 1-Ph adopts a unique helically twisted geometry although the local aromaticity of azulene moieties was preserved. The double covalent linkage of the two azulene skeletons imparts significant orbital interaction, which affords near-infrared (NIR) absorption (up to 1720 nm) and remarkable redox behaviors despite its closed-shell electronic structure.
View Article and Find Full Text PDFACS Appl Electron Mater
December 2024
James Watt School of Engineering, University of Glasgow, G12 8QQ Glasgow, Scotland, U.K.
Electronics based on natural or degradable materials are a key requirement for next-generation devices, where sustainability, biodegradability, and resource efficiency are essential. In this context, optimizing the molecular chemical structure of organic semiconductor compounds (OSCs) used as active layers is crucial for enhancing the efficiency of these devices, making them competitive with conventional electronics. In this work, honey-gated organic field-effect transistors (HGOFETs) were fabricated using four different perylene derivative films as OSCs, and the impact of the chemical structure of these perylene derivatives on the performance of HGOFETs was investigated.
View Article and Find Full Text PDFChem Sci
December 2024
Key Laboratory of Rubber-plastics of Ministry of Education/Shandong Provincial, Key Laboratory of Rubber-plastics, School of Polymer Science & Engineering, Qingdao University of Science & Technology Qingdao China
The internal rotation of triplet-generating molecules is detrimental to room temperature phosphorescence (RTP) radiation, and this rotation is usually mitigated by doping into rigid microenvironments. The chemical locking of internal rotation units in advance should be an effective strategy but is rarely studied in comparison. Herein, a triplet-generating molecule with two rotatable phenyls (DIA) was designed, synthesized, and then cyclized using two types of bonding bridges.
View Article and Find Full Text PDFAdv Mater
January 2025
College of Food Science and Engineering, Northwest A&F University, Yangling, 712100, China.
Wettability is important for photodynamic film sterilization since higher wettability enhances the capture of bacteria in contact with photosensitizers. Herein, a small number of violet phosphorus quantum dots (VPQDs) are anchored into hypericin bacterial cellulose films (VP/Hy-BC films) to improve wettability, reducing the water contact angle from 56.8° to 33.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
January 2025
State Key Laboratory of Chemical Resource Engineering, College of Materials Science and Engineering, Beijing University of Chemical Technology, Beijing, 100029, P. R. China.
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