Comment on “Phase transitions, screening and dielectric response of CsPbBr3” by Š. Svirskas, S. Balčiūnas, M. Šimėnas, G. Usevičius, M. Kinka, M. Velička, D. Kubicki, M. E. Castillo, A. Karabanov, V. V. Shvartsman, M. R. Soares, V. Šablinskas, A. N. Salak, D. C. Lupascu and J. Banys, J. Mater. Chem. A, 2020, 8, 14015

Abstract

All-inorganic lead halide perovskites have gained a renewed scientific interest due to the outstanding optoelectronic properties unveiled recently, and the related prospects for efficient optical devices. In one of the most recent papers, Svirskas et al. (J. Mater. Chem. A, 2020, 8, 14015) reported on a new phase transition in CsPbBr₃. In this comment we show that the claims regarding the new intriguing properties of this material are not supported by convincing experimental data. In particular, a detailed analysis of the results presented in the paper revealed a misinterpretation of the experimental data, as well as substantial inconsistencies between the calorimetric, dielectric, and dilatometric studies. Apparently, this contradicts the existence of a new phase transition in CsPbBr₃. We also provide new experimental evidence confirming that the crystal structure is stable below room temperature, at least up to 95 K.