The electronic structure, optical, and thermoelectric properties of novel BiPbCh (Ch = Se, Te) materials: insights from first-principles study.

Ternary chalcogenides have attracted much interest because of their potential for use in sustainable energy applications due to their tunable electronic, optical, and transport characteristics. This work examined the structural, electronic, optoelectronic, and thermoelectric properties of novel BiPbSe and BiPbTe chalcogenides through density functional theory. The predicted energy gap values measured with the TB-mBJ and PBE-GGA are 1.12 and 0.71 eV for BiPbSe and 1.08 and 0.82 eV for BiPbTe respectively. Both materials behave as semiconductors and have direct energy gaps, which makes them attractive for solar energy applications. COHP study illustrates that strong Bi-chalcogen bonding characterizes the valence band, whereas antibonding states prevail above the Fermi level in both BiPbSe and BiPbTe. Their promise as absorber materials in photovoltaic devices is highlighted by optical investigations that show considerable absorption in the visible and infrared ranges, high dielectric constants, and higher photoconversion performance. The Seebeck coefficient, lattice thermal conductivity, and electrical conductivity were employed to assess thermoelectric features. These ternary materials are suitable for integrated solar energy collecting and conversion systems because of their outstanding optical absorption and thermoelectric potential. The structure-property interactions of these materials are explained by this study, opening the door for testing and more optimization for improved energy devices.