Advances in visible and ultraviolet self-powered photodetectors: exploring 2D materials and Janus heterostructures

This review summarizes recent progress in self-powered photodetectors (SPPDs) operating in the visible and ultraviolet spectral ranges, with a particular focus on devices based on two-dimensional materials and Janus heterostructures. The work discusses the operating principles of self-powered photodetection, including the photovoltaic effect and built-in electric fields enabling bias-free operation. Various material systems are examined, including graphene, transition metal dichalcogenides, MXenes, black phosphorus, perovskites, and Janus structures. The review further highlights device architectures such as Schottky junctions, p–n junctions, heterostructures, and flexible substrates, along with their fabrication strategies and transfer techniques. Key performance metrics including responsivity, detectivity, quantum efficiency, and response time are analyzed to evaluate device performance. The work provides a comprehensive overview of the challenges and opportunities for next-generation low-power optoelectronic devices based on advanced 2D materials and hybrid heterostructures.