Research

Tuning nonradiative recombination via cation substitution in inorganic antiperovskite nitrides- By Prof. Saswata Bhattacharya

Inorganic antiperovskite nitrides have recently emerged as promising materials for photovoltaic applications, yet their nonradiative recombination dynamics remain largely unexplored. Here, we examine the influence of X-site cation substitution on the nonradiative electron-hole recombination in X3⁢NSb (X =Ca, Sr, and Ba). Ca- and Sr-based compounds adopt a cubic phase, whereas Ba stabilizes in a hexagonal structure, introducing pronounced symmetry-driven effects. To separate symmetry effects from cation chemistry, we also examine the hexagonal polymorph of Sr3⁢NSb (Sr3⁢NSbhexa). Substituting Ca with Sr narrows the band gap, suppresses octahedral and band-edge fluctuations, reduces nonadiabatic (NA) coupling by ∼54%, and extends carrier lifetimes by a factor of 2.5. In Sr3⁢NSbhexa, the combination of larger band gap and enhanced band gap fluctuations—leading to faster dephasing—further slows down recombination by 41%. In contrast, in Ba3⁢NSbhexa, enhanced NA coupling accelerates recombination relative to Sr3⁢NSbhexa. Overall, recombination lifetimes are dictated by the interplay between band gap, NA coupling strength, and decoherence time, with Sr3⁢NSbhexa exhibiting the longest lifetime. These findings highlight the coupled influence of cation chemistry and crystal symmetry in tailoring carrier dynamics for high-performance antiperovskite-based optoelectronics materials.

Link :  https://doi.org/10.1103/lky4-k5yp, 4 February 2026

Contact Details

Saswata Bhattacharya
Department of Physics,
saswata@physics.iitd.ac.in