Temperature Dependence of the Urbach Energy in Lead Iodide Perovskites

by Martin Ledinský, Tereza Schönfeldová, Jakub Holovsky, Erkan Aydin, Zdeňka Hájková, Neda Neykova, Antonín Fejfar, Stefaan De Wolf, Lucie Landová
Article Year: 2019

Bibliography

Ledinsky, M., Schönfeldová, T., Holovsky, J., Aydin, E., Hájková, Z., Landová, L., Neykova, N., Fejfar, A., and De Wolf, S., "Temperature Dependence of the Urbach Energy in Lead Iodide Perovskites" The Journal of Physical Chemistry Letters 2019 10 (6), 1368-1373​.

Abstract

​To gain insight in the properties of photovoltaic and light-emitting materials, detailed information about their optical absorption spectra is essential. Here, we elucidate the temperature dependence of such spectra for methylammonium lead iodide (CH3NH3PbI3), with specific attention for its sub bandgap absorption edge (often referred to as Urbach energy). Based on these data, firstly, we find clear further evidence for the universality of the correlation between the Urbach energy and open-circuit voltage losses of solar cells. Secondly, we find that for CH3NH3PbI3 the static, temperature-independent, contribution of the Urbach energy is 3.8 ± 0.7 meV, which is smaller than that of crystalline silicon (Si), gallium arsenide (GaAs), indium phosphide (InP) or gallium nitride (GaN), underlining the remarkable optoelectronic properties of perovskites.

Keywords

Perovskites CH3NH3Pbl3 Urbach Energy temperature dependence Urbach Focus