Investigating the Tetragonal‐to‐Orthorhombic Phase Transition of Methylammonium Lead Iodide Single Crystals by Detailed Photoluminescence Analysis

Abstract

Here, the phase‐transition from tetragonal to orthorhombic crystal structure of the halide perovskite methylammonium lead iodide single crystal is investigated. Temperature dependent photoluminescence (PL) measurements in the temperature range between 165 and 100 K show complex PL spectra where in total five different PL peaks can be identified. All observed PL features can be assigned to different optical effects from the two crystal phases using detailed PL analyses. This allows to quantify the fraction of tetragonal phase that still occurs below the phase transition temperature. It is found that at 150 K, 0.015% tetragonal phase remain, and PL signatures are observed from quantum confined tetragonal domains, suggesting their size to be about 7–15 nm down to 120 K. The tetragonal inclusions also exhibit an increased Urbach Energy, implying a high degree of structural disorder. The results first illustrate how a careful analysis of the PL can serve to deduce structural information, and second, how structural deviations in halide perovskites have a significant impact on the optoelectronic properties of this promising class of semiconductors.

Halide Perovskite Nanocrystal Emitters

“…Though the calculated absorption spectrum appeared to be similar in shape to the experimental one, the excitonic peaks showed a red shift after the phase transition from orthorhombic to tetragonal structures. Although Geng et al did not report the simulated PL, a similar corresponding red shift in the PL spectrum has been reported in the study by Schötz et al [ 45 ]…”

Structural Diversity in Layered Hybrid Perovskites, A2PbBr4 or AA′PbBr4, Templated by Small Disc-Shaped Amines

“…In such a case, we would expect a decrease of the PL signals associated to the high temperature phase, the abrupt appearance of low temperature phase PL features, also with a similar spectral width compared to the high temperature phase PL features. 49 Typically this all would happen within a relatively small temperature range. 50 The ratio between the high and low energy bands is temperature dependent, i.e.…”

Recent Advances and Perspectives on Powder‐Based Halide Perovskite Film Processing

“…[ 87 ] Thus, detailed analysis including optical modeling were applied to the measured steady‐state PL spectra of thick films to extract reliable information. [ 88,89 ] Additionally, increased crystallinity and thickness can lead to increased excited state diffusion. This reduces the charge carrier density immediately after laser excitation and increases the spatial area where the excited states are present.…”