Abstract
The quest for clean energy conversion has become one of the most important efforts for tackling the greenhouse effect for a sustainable environment. This involves energy-scavenging processes like photovoltaics and catalysis, which have been manifested using the solar spectrum. For high-efficiency and durable conversion processes, the search for the low-cost, stable, and environment-friendly functional materials is elusive. In the field of solar cells and catalysis, double perovskite oxides (DPOs) have emerged as potential candidates in recent years. Through compositional tuning and band gap engineering, a plethora of materials are being developed for pertinent applications in this field of energy. Oxide perovskites possess the advantage of a high carrier lifetime compared to that with halide perovskites, which can be beneficial for energy applications. In this perspective, we have presented theoretical investigations focusing on the different types of double perovskite oxides based on the composition space in a systematic manner. Corresponding electronic and optical properties are discussed along with a future outlook on the novel routes to find efficient members in this family.