Temperature-Dependent Photoluminescence and Energy-Transfer Dynamics in Mn 2+ -Doped (C 4 H 9 NH 3 ) 2 PbBr 4 Two-Dimensional (2D) Layered Perovskite

Bakthavatsalam, R and Biswas, A and Chakali, M and Bangal, PR and Kore, BP and Kundu, J (2019) Temperature-Dependent Photoluminescence and Energy-Transfer Dynamics in Mn 2+ -Doped (C 4 H 9 NH 3 ) 2 PbBr 4 Two-Dimensional (2D) Layered Perovskite. In: Journal of Physical Chemistry C .

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Abstract

Reported here are the low-temperature photoluminescence (PL), energy-transfer mechanism, and exciton dynamics of Mn 2+ -doped two-dimensional (2D) perovskites that show interesting differences from their three-dimensionally doped counterpart. Dopant emission in 2D system shows increased PL intensity and shortened lifetime with increase of temperature and strong dopant emission even at low temperatures. Transient absorption (TA) spectroscopy reveals the dominant role of "hot" excitons in dictating the fast energy-transfer timescale. The operative dynamics of the generated hot excitons include filling up of existing trap states (shallow and deep) and energy-transfer channel from hot excitons to dopant states. Global analysis and target modeling of TA data provide an estimate of excitons (hot and band edge) to a dopant energy-transfer timescale of 330 ps, which is much faster than the band edge exciton lifetime (2 ns). Such fast energy-transfer timescale arises due to enhanced carrier exchange interaction resulting from higher exciton confinement, increased covalency, and involvement of hot excitons in the 2D perovskites. In stark contrast to three-dimensional systems, the high energy-transfer rate in 2D system results in high dopant emission intensity even at low temperatures. Increased intrinsic vibronic coupling at higher temperatures further supports efficient Mn 2+ sensitization that ultimately dictates the observed temperature dependence of the dopant emission (intensity, lifetime). © 2019 American Chemical Society.

Item Type:	Journal Article
Publication:	Journal of Physical Chemistry C
Publisher:	American Chemical Society
Additional Information:	Copyright for this article belongs to American Chemical Society.
Keywords:	Dynamics; Energy transfer; Perovskite; Photoluminescence; Temperature distribution, Energy transfer dynamics; Energy transfer mechanisms; High-energy transfers; Low temperature photoluminescence; Temperature dependence; Temperature dependent photoluminescences; Three dimensional systems; Two Dimensional (2 D), Excitons
Department/Centre:	Division of Chemical Sciences > Solid State & Structural Chemistry Unit
Date Deposited:	09 Apr 2019 05:20
Last Modified:	09 Apr 2019 05:20
URI:	http://eprints.iisc.ac.in/id/eprint/62041

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