Reply to the ‘Comment on “Air-stable double halide perovskite Cs ₂ CuBiBr ₆ : synthesis and memristor application”’ by L. Xiao, J. Guo, G. Tang and Z. Xiao, <i>Phys. Chem. Chem. Phys.</i> , 2025, <b>27</b> , DOI: 10.1039/D5CP001

This article addresses the comments from Xiao <i>et al.</i> on our work titled "Air-stable double halide perovskite Cs₂CuBiBr₆: synthesis and memristor application" published in <i>Physical Chemistry Chemical Physics</i> (<i>Phys. Chem. Chem. Phys.</i>, 2025, <b>27</b>, 3150). The authors mentioned some inconsistencies, which have been addressed in this letter. (1) We have successfully synthesized the double halide perovskite Cs₂CuBiBr₆ more than a hundred times under ambient conditions and continue to explore this material for its properties and further applications. We have presented XRD data and matched the data with simulated peaks. (2) The stoichiometric composition of our material is also presented from the energy dispersive X-ray spectroscopy (EDS), which shows good agreement with the expected value. (3) The bandgap of the materials was measured using scanning tunnelling spectroscopy (STS), which is a very sophisticated technique used to estimate the bandgap of the material. The bandgap was calculated using the HSE06 functional with a HF value of 0.5. (4) We have also studied the thermodynamic stability using density functional theory (DFT).