Effect of Nd substitution on electronic, thermoelectric, and optical response of WO3

Abstract

The properties of Nd-doped WO3 thin films are studied to assess their suitability for photovoltaic and optoelectronic applications. The simulations on pristine and Nd-doped WO3 were performed using Tran Blaha modified Becke-Johnson approximation to explore the various properties, whereas the spin coating technique was employed to synthesize thin films. X-ray diffraction analysis revealed the crystalline cubic structure in all synthesized thin films. The morphology contains uniform rod-like features and the width of these were enhanced in doped composition. The projected density of states demonstrated the major prominent contributions of W-d in conduction and O-p in the valence band while Nd-f orbital plays a major contribution in doped compositions. Thermoelectric parameters were found to change significantly with Nd incorporation in WO3. The highest refractive index and real epsilon values were recorded at the higher energy regimes approximately 2.96 and 8.61, respectively, for compositions containing maximum dopant content. The optical conductivity and absorption coefficient showed an enhanced trend in doped composition which is considered favourable for improved optoelectronic and photovoltaic applications. The experimental band gap of WO3 was calculated as 2.03 eV and found to decrease with increment of Nd doping concentration.