Comment on “Photodetection and scintillation characterizations of novel lead-bismuth double perovskite halides” by F. Maddalena, M. D. Birowosuto, C. Dang et al., J. Mater. Chem. C, 2022, 10, 11266

Abstract

This Comment re-examines the synthesis of Cs4PbBi2X12 (X = Br, I) double perovskites reported by Maddalena et al. (J. Mater. Chem. C, 2022, 10, 11266). Thermodynamic calculations reveal strongly negative decomposition energies, favoring decomposition into products involving Cs3Bi2X9. Experimental X-ray diffraction patterns mismatch simulated trigonal Cs4PbBi2X12 structures but align with Cs3Bi2X9 phases. Optical bandgaps further coincide with decomposition products Cs3Bi2X9. Combined evidence indicates the synthesized materials are phase mixtures, not pure double perovskites.