Solar photovoltaic technology stands at the forefront of the renewable energy revolution, driving the quest for cleaner and more sustainable power sources. Among the countless materials under exploration are two-dimensional (2D) systems─particularly niobium-based monolayers─which have captivated researchers with their remarkable potential. In this work, we harness first-principles calculations to unveil the rich tapestry of electronic, excitonic, optical, transport, and thermoelectric properties exhibited by the Nb3TeBr7 monolayer. Our computational results confirm the dynamic and mechanical stability of this intriguing material. Through detailed electronic structure analyses using PBE, PBE-SOC, and HSE06 functionals, we uncover a direct HSE06 band gap of 1.56 eV, with electronic states near the Fermi level predominantly arising from Nb atoms. The optical response of the monolayer reveals pronounced anisotropy, as captured by both the Independent Particle Approximation (IPA) and Bethe–Salpeter Equation (BSE) approaches. Estimates of power conversion efficiency (PCE) based on the Shockley–Queisser limit and the spectroscopic-limited maximum efficiency (SLME) indicate PCE values up to 30.40% at the IPA level and 27.40% at the BSE level for the monolayer. For simulated electron doping (via increased Fermi energy) at selected temperatures, the figure of merit (ZT) reaches about 0.1. Simulated hole doping (via lowered Fermi energy) yields ZT values of about 0.05. Although these ZT values are modest, their stability across a range of temperatures suggests that targeted doping with impurities might improve thermoelectric performance.
Marques et al. (Fri,) studied this question.