Materials of the International Seminar of the Institute of Spectroscopy of the Russian Academy of Sciences (ISAN), dedicated to the anniversary of Professor M.N. Popova
Spectroscopy of condensed state

Transmission spectra of singe crystals of MAPbI$_3$ hybrid perovskites near the edge of fundamental absorption

V. E. Anikeeva^ab, K. N. Boldyrev^ab, O. I. Semenova^c, M. N. Popova<sup>a

a</sup> Institute of Spectroscopy, Russian Academy of Sciences, 108840 Troitsk, Moscow, Russia
^b National Research University Higher School of Economics, 101000 Moscow, Russia
^c Rzhanov Institute of Semiconductor Physics, Siberian Branch of Russian Academy of Sciences, 630090 Novosibirsk, Russia

Abstract: The paper presents the transmission spectra of hybrid perovskite MAPbI$_3$ single crystals near the fundamental absorption edge in a wide temperature range. The absorption coefficient $\alpha$ of the single crystal samples is estimated at a temperature $T$ = 150 K for the light with a photon energy $E$ = 1.6 eV and at $T$ = 40 K for $E$ = 1.8 eV. The obtained values turned out to be several orders of magnitude smaller than the values of $\alpha$ for thin-film samples known from the literature. A sharp shift of the fundamental absorption edge by $\sim$ 100 meV was observed at a temperature $T_1$ =160 K of the structural phase transition from the tetragonal to the orthorhombic phase. The temperature hysteresis of the shift of the fundamental absorption edge near $T_1$ was recorded, which is characteristic of a first-order phase transition.

Keywords: hybrid organometallic perovskites, MAPbI$_3$ single crystal, optical spectroscopy, fundamental absorption.

Received: 22.07.2021
Revised: 22.07.2021
Accepted: 05.08.2021

DOI: 10.21883/OS.2022.01.51898.21-21

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