Elucidating complex triplet-state dynamics in the model system isopropylthioxanthone.

Autor:	Liaros N; Department of Chemistry & Biochemistry, University of Maryland, College Park, MD 20742, USA., Gutierrez Razo SA; Department of Chemistry & Biochemistry, University of Maryland, College Park, MD 20742, USA., Thum MD; Department of Chemistry & Biochemistry, University of Maryland, College Park, MD 20742, USA., Ogden HM; Department of Chemistry & Biochemistry, University of Maryland, College Park, MD 20742, USA., Zeppuhar AN; Department of Chemistry & Biochemistry, University of Maryland, College Park, MD 20742, USA., Wolf S; Department of Chemistry & Biochemistry, University of Maryland, College Park, MD 20742, USA., Baldacchini T; Newport Corporation, 1791 Deere Avenue, Irvine, CA 92606, USA., Kelley MJ; Newport Corporation, 1791 Deere Avenue, Irvine, CA 92606, USA., Petersen JS; Department of Chemistry & Biochemistry, University of Maryland, College Park, MD 20742, USA.; imec, Kapeldreef 75, 3001 Leuven, Belgium., Falvey DE; Department of Chemistry & Biochemistry, University of Maryland, College Park, MD 20742, USA., Mullin AS; Department of Chemistry & Biochemistry, University of Maryland, College Park, MD 20742, USA., Fourkas JT; Department of Chemistry & Biochemistry, University of Maryland, College Park, MD 20742, USA.; Institute for Physical Science & Technology, University of Maryland, College Park, MD 20742, USA.; Maryland Quantum Materials Center, University of Maryland, College Park, MD 20742, USA.; Maryland NanoCenter, University of Maryland, College Park, MD 20742, USA.
Jazyk:	angličtina
Zdroj:	IScience [iScience] 2021 Dec 09; Vol. 25 (1), pp. 103600. Date of Electronic Publication: 2021 Dec 09 (Print Publication: 2022).
DOI:	10.1016/j.isci.2021.103600
Abstrakt:	We introduce techniques for probing the dynamics of triplet states. We employ these tools, along with conventional techniques, to develop a detailed understanding of a complex chemical system: a negative-tone, radical photoresist for multiphoton absorption polymerization in which isopropylthioxanthone (ITX) is the photoinitiator. This work reveals that the same color of light used for the 2-photon excitation of ITX, leading to population of the triplet manifold through intersystem crossing, also depletes this triplet population via linear absorption followed by reverse intersystem crossing (RISC). Using spectroscopic tools and kinetic modeling, we identify the reactive triplet state and a non-reactive reservoir triplet state. We present compelling evidence that the deactivation channel involves RISC from an excited triplet state to a highly vibrationally excited level of the electronic ground state. The work described here offers the enticing possibility of understanding, and ultimately controlling, the photochemistry and photophysics of a broad range of triplet processes. Competing Interests: The authors declare no competing interests. (© 2021 The Author(s).)
Databáze:	MEDLINE
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