Issue 23, 2017

The Rashba effect and indirect electron–hole recombination in hybrid organic–inorganic perovskites

Abstract

Slow electron–hole recombination, characterized by the bimolecular coefficient k2 in hybrid organic–inorganic perovskites (HOIPs), is a key to their outstanding photovoltaic performance. The measured k2 in HOIPs strongly deviates from k2T−3/2 (T is the temperature) in typical direct-gap semiconductors. Here we show that the observed temperature dependence can be quantitatively accounted for by phonon-assisted recombination of electrons and holes located at the band extrema, which become indirect due to the Rashba effect. Polar optical phonons are most effective in facilitating this indirect recombination. The variation in k2 in HOIPs among different studies in the literature can be attributed to different Rashba strengths in their samples. Our results indicate that the confluence of the Rashba effect and polar coupling transform HOIPs into a unique indirect semiconductor that can accommodate both strong optical absorption and slow carrier dynamics.

Graphical abstract: The Rashba effect and indirect electron–hole recombination in hybrid organic–inorganic perovskites

Supplementary files

Article information

Article type
Communication
Submitted
19 Apr. 2017
Accepted
22 Maijs 2017
First published
22 Maijs 2017

Phys. Chem. Chem. Phys., 2017,19, 14907-14912

The Rashba effect and indirect electron–hole recombination in hybrid organic–inorganic perovskites

Z. Yu, Phys. Chem. Chem. Phys., 2017, 19, 14907 DOI: 10.1039/C7CP02568H

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