Improvement in spectral range of Sb 2 Se 3 absorption layer on Bi addition

Abstract Antimony selenide ( Sb 2 Se 3 ) is a versatile material used in solar cells. The alteration in the physical properties of Sb 2 Se 3 alloys on Bi addition has been analysed. ( Sb 2 Se 3 ) 100 -x Bi x ( x = 0, 0.2, 0.4, 0.6, 0.8, 1.0, and 1.2) system has been studied to examine the structural alterations by computing physical parameters. The increase in parameters, i.e., average coordination number 〈 Z 〉, total number of constraints per atoms ( N c ), and crosslinking density ( D cl ) reflect an increase in rigidity of the Sb 2 Se 3 on Bi incorporation. The computed band gap decreases on Bi addition, from 1.095 eV to 1.079 eV, indicating an approximate increase in absorption wavelength from 1132.42 nm to 1149.21 nm. An increase in rigidity reflects reduction in defect states decreasing the recombination rate within absorption layer. There are variations in cohesive energy, electronegativity, and average single-bond energy. The study reveals that this composition can be utilized to develop novel solar absorber layer materials.