Ultrafast spectroscopy reveals singlet fission, ionization and excimer formation in perylene film

Abstract 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 ava...

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Autores principales:	Wenjun Ni, Licheng Sun, Gagik G. Gurzadyan
Formato:	article
Lenguaje:	EN
Publicado:	Nature Portfolio 2021
Materias:	Medicine R Science Q
Acceso en línea:	https://doaj.org/article/8341d022801d432d87ca6989f792a858
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spelling	oai:doaj.org-article:8341d022801d432d87ca6989f792a8582021-12-02T15:54:13ZUltrafast spectroscopy reveals singlet fission, ionization and excimer formation in perylene film10.1038/s41598-021-83791-z2045-2322https://doaj.org/article/8341d022801d432d87ca6989f792a8582021-03-01T00:00:00Zhttps://doi.org/10.1038/s41598-021-83791-zhttps://doaj.org/toc/2045-2322Abstract 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 λex = 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.Wenjun NiLicheng SunGagik G. GurzadyanNature PortfolioarticleMedicineRScienceQENScientific Reports, Vol 11, Iss 1, Pp 1-10 (2021)
institution	DOAJ
collection	DOAJ
language	EN
topic	Medicine R Science Q
spellingShingle	Medicine R Science Q Wenjun Ni Licheng Sun Gagik G. Gurzadyan Ultrafast spectroscopy reveals singlet fission, ionization and excimer formation in perylene film
description	Abstract 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 λex = 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.
format	article
author	Wenjun Ni Licheng Sun Gagik G. Gurzadyan
author_facet	Wenjun Ni Licheng Sun Gagik G. Gurzadyan
author_sort	Wenjun Ni
title	Ultrafast spectroscopy reveals singlet fission, ionization and excimer formation in perylene film
title_short	Ultrafast spectroscopy reveals singlet fission, ionization and excimer formation in perylene film
title_full	Ultrafast spectroscopy reveals singlet fission, ionization and excimer formation in perylene film
title_fullStr	Ultrafast spectroscopy reveals singlet fission, ionization and excimer formation in perylene film
title_full_unstemmed	Ultrafast spectroscopy reveals singlet fission, ionization and excimer formation in perylene film
title_sort	ultrafast spectroscopy reveals singlet fission, ionization and excimer formation in perylene film
publisher	Nature Portfolio
publishDate	2021
url	https://doaj.org/article/8341d022801d432d87ca6989f792a858
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_version_	1718385458516328448

Ultrafast spectroscopy reveals singlet fission, ionization and excimer formation in perylene film

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