First principles exploration of structural stability, optoelectronic and thermoelectric properties of BaXO3 (X = Hf, Ti, V) for solar cell applications

The structural, electronic, optical, and thermoelectric properties of BaXO3 (X = Hf, Ti, V) are explored by using the PBE-GGAapproximation based on density functional theory under the framework of WEIN2k code for optoelectronic and solar cell applications. The structural stability of all the examined compounds has been confirmed by employing the Birch-Murnaghan equation of states wherein negative ground-state energy levels for all compounds indicate their structural stability. The electronic band gap from band structure analysis and Total Density of States (TDOS) has been observed as BaVO3< BaTiO3< BaHfO3.The Partial Density of States (PDOS) elaborates that formation of conduction band (C.B) and valence band (V.B) is consequence of hybridization of O-2p and Hf-4d/Ti-3d/V-3d states along with minute contribution of Ba-6s states for BaXO3 (X = Hf, Ti, V). Comparatively, BaVO3 indicates the smallest energy band gap because Vanadium (V) has the highest electro negativity so accumulates more charges. Regarding the optical behavior, BaVO3has shown maximum absorption of electromagnetic radiation and conductivity in the ultraviolet region, which makes it a suitable candidate for optoelectronic applications.However, in our study BaTiO3 is found second best material for optoelectronic applications. The thermoelectric properties of the studied compounds have been calculated by means of the Boltztrap code. Thermoelectric parameters have unveiled BaTiO3as suitable candidate for thermoelectric applications due to its high electrical conductivity and higher power factor at/above the room temperature. Henceforth,BaTiO3 has been observed to be the best candidate for absorption layer (AL) in solar cell applications.