25-30 August 2019
Henry Ford Building
Europe/Berlin timezone

Tuning Spin Dynamics in Crystalline Tetracene

26 Aug 2019, 11:30
25m
Lecture Hall D (Henry Ford Building)

Lecture Hall D

Henry Ford Building

Talk EPR development and applications EPR

Speaker

Dr Naitik A. Panjwani (Berlin Joint EPR Lab, Fachbereich Physik, Freie Universität Berlin, D-14195, Berlin, Germany)

Description

Tetracene is an archetypal material undergoing singlet fission—the generation of a pair of triplet excitons from one singlet exciton. Here, using time-resolved electron spin resonance, we show how the spin dynamics in tetracene crystals are influenced by temperature and morphology. Upon cooling from 300 to 200 K, we observe a switch between singlet fission and intersystem crossing generated triplets, manifesting as an inversion in transient spin polarization. We extract a spin dephasing time of approximately 40 ns for fission-generated triplets at room temperature, nearly 100 times shorter than the dephasing time that we measure for triplets localized on isolated tetracene molecules. These results highlight the importance of morphology and thermal activation in singlet fission systems. In addition, we present recent findings on single crystal tetracene studied using optically detected magnetic resonance, where additional features in the spectrum are observed.

We acknowledge support from DFG SPP-1601 (BI 464/10-2, BE 5126/1-2) and the Nanoscale project within the excellence initiative of the Freie Universität Berlin. The work at Nanjing University is supported by the National Natural Science Foundation of China (21873047). We thank L. R. Weiss for insightful discussions.

Primary authors

Dr Naitik A. Panjwani (Berlin Joint EPR Lab, Fachbereich Physik, Freie Universität Berlin, D-14195, Berlin, Germany) Dr Sam L. Bayliss (Berlin Joint EPR Lab, Fachbereich Physik, Freie Universität Berlin, D-14195, Berlin, Germany) Dr Felix Kraffert (Berlin Joint EPR Lab, Fachbereich Physik, Freie Universität Berlin, D-14195, Berlin, Germany) Rui Wang (National Laboratory of Solid State Microstructures, School of Physics, Nanjing University, Nanjing 210093, China ) Chunfeng Zhang (National Laboratory of Solid State Microstructures, School of Physics, Nanjing University, Nanjing 210093, China; Synergetic Innovation Center in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China) Prof. Robert Bittl (Berlin Joint EPR Lab, Fachbereich Physik, Freie Universität Berlin, D-14195, Berlin, Germany) Prof. Jan Behrends (Berlin Joint EPR Lab, Fachbereich Physik, Freie Universität Berlin, D-14195, Berlin, Germany)

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