Morphology- and crystal packing-dependent singlet fission and photodegradation in functionalized tetracene crystals and films.

Autor:	Goldthwaite WT; Department of Physics, Oregon State University, Corvallis, Oregon 97331, USA., Lambertson E; Department of Physics, Oregon State University, Corvallis, Oregon 97331, USA., Gragg M; Department of Physics, Oregon State University, Corvallis, Oregon 97331, USA., Windemuller D; Department of Chemistry, University of Kentucky, Lexington, Kentucky 40511, USA., Anthony JE; Department of Chemistry, University of Kentucky, Lexington, Kentucky 40511, USA., Zuehlsdorff TJ; Department of Chemistry, Oregon State University, Corvallis, Oregon 97331, USA., Ostroverkhova O; Department of Physics, Oregon State University, Corvallis, Oregon 97331, USA.
Jazyk:	angličtina
Zdroj:	The Journal of chemical physics [J Chem Phys] 2024 Nov 21; Vol. 161 (19).
DOI:	10.1063/5.0234494
Abstrakt:	Singlet fission (SF) is a charge carrier multiplication process that has potential for improving the performance of (opto)electronic devices from the conversion of one singlet exciton S1 into two triplet excitons T1 via a spin-entangled triplet pair state 1(TT). This process depends highly on molecular packing and morphology, both for the generation and dissociation of 1(TT) states. Many benchmark SF materials, such as acenes, are also prone to photodegradation reactions, such as endoperoxide (EPO) formation and photodimerization, which inhibit realization of SF devices. In this paper, we compare functionalized tetracenes R-Tc with two packing motifs: "slip-stack" packing in R = TES, TMS, and tBu and "gamma" packing in R = TBDMS to determine the effects of morphology on SF as well as on photodegradation using a combination of temperature and magnetic field dependent spectroscopy, kinetic modeling, and time-dependent density functional theory. We find that both "slip-stack" and "gamma" packing support SF with high T1 yield at room temperature (up to 191% and 181%, respectively), but "slip-stack" is considerably more advantageous at low temperatures (<150 K). In addition, each packing structure has a distinct emissive relaxation pathway competitive to SF, while the states involved in the SF itself are dark. The "gamma" packing has superior photostability, both in regards to EPO formation and photodimerization. The results indicate that the trade-off between SF efficiency and photostability can be overcome with material design, emphasize the importance of considering both photophysical and photochemical properties, and inform efforts to develop optimal SF materials for (opto)electronic applications. (© 2024 Author(s). Published under an exclusive license by AIP Publishing.)
Databáze:	MEDLINE
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