The optoelectronic properties of lead halide perovskites strongly depend on their underlying crystal symmetries and dynamics, sometimes exhibiting a dual photoluminescence (PL) emission via Rashba-like effects. Here we exploit spin- and temperature-dependent PL to study single-crystal APbBr3 (A = Cs and methylammonium; CH3NH3) and evaluate the peak energy, intensity, and line width evolutions of their dual emission. Both perovskites exhibit temperature trends governed by two temperature regimes - above and below approximately 100 K - which impose different carrier scattering and radiative recombination dynamics. With increasing temperature, high-energy optical phonons activate near 100 K to drive energy splitting of the dual bands and induce line width broadening via electron-phonon coupling, with a stronger coupling constant inferred for carriers recombining by the spin-split indirect bands, compared to the direct ones. We find that the unusual thermal evolutions of all-inorganic and hybrid bulk lead bromide perovskites are comparable, suggesting A-site independence and the dominance of dynamic effects, and are best understood within a framework that accounts for Rashba-like effects.
Bibliographical noteFunding Information:
The authors acknowledge financial support from the Research Foundation-Flanders (FWO, Grant Nos. 12Y7218N, G.0197.11, 12Y6418N, and 12O3719N postdoctoral fellowship to J.A.S., H.Y., M.K., and E.D.), KU Leuven Research Fund (C14/15/053), the Flemish government through long term structural funding Methusalem (CASAS2, Meth/15/04), the Hercules foundation (HER/11/14), and the Belgian Federal Science Policy Office (IAP-VII/05). The research leading to these results has received funding from the European Research Council under the European Union’s Seventh Framework Programme (FP/2007-2013)/ERC Grant Agreement (Grant No. 307523). B.M. acknowledges support from the Winton Programme for the Physics of Sustainability and from Robinson College, Cambridge, and the Cambridge Philosophical Society for a Henslow Research Fellowship. B.W. acknowledges support from the National Natural Science Foundation of China (NFSC) (Grant No. 51802331), Guangdong Provincial Key Laboratory of Optical Information Materials and Technology (Grant No. 2017B030301007), and the 111 Project. T.K. acknowledges support from the Impuls- und Vernetzungsfonds der Helmholtz Gemeinschaft via the project PEROSEED. We are grateful to the UK Materials and Molecular Modelling Hub for computational resources, which is partially funded by EPSRC (EP/P020194/1). T.C.S. and D.G. acknowledge the support from the Ministry of Education AcRF Tier 2 Grant MOE2016-T2-1-034 and MOE2017-T2-1-001 and from the Singapore National Research Foundation Investigatorship NRF-NRFI-2018-04. We would also like to express our sincere thanks to Prof. Chao Zhang for his helpful discussions.
Copyright © 2019 American Chemical Society.
All Science Journal Classification (ASJC) codes
- Chemistry (miscellaneous)
- Renewable Energy, Sustainability and the Environment
- Fuel Technology
- Energy Engineering and Power Technology
- Materials Chemistry