Vacancy ordered Cs<inf>2</inf>SnX<inf>6</inf> (X = Cl, Br, I) double perovskites as an absorber and antiferromagnetic NiO with GO as a hole transport layer for highly efficient heterojunction solar cell application

This article investigates the vacancy ordered Cs2SnX6 (X = Cl, Br, I) double perovskites (VODP) using jTB-mBJ XC potentials and conclusively noticed that jTB-mBJ's refined parameters are transferable to VODPs for accurate prediction of material properties. The article presents a comparative analysis of CsMX3 perovskites. Further, a mixed Mott-Hubbard and charge-transfer state for antiferromagnetic NiO is predicted with an agreeable 4.15 eV band gap using TB-mBJ XC potential. VODP Cs2SnI6 as an absorber is integrated with NiO and graphene oxide (GO) as an effective HTM and interlayer, respectively, in an inverted configuration, showing 27.07 % photoconversion efficiency under optimal device parameters. The impact of various materials’ parameters is also investigated to understand the correlation between materials parameters and photovoltaic (PV) performance. Thus, the present study may bring a new dimension to VODP-based photovoltaic materials and devices.