Emerging Binary Chalcogenide Light Absorbers: Material Specific Promises and Challenges

In the quest for higher efficiency and lower cost solar energy conversion devices, new light absorber materials are being intensively researched. With their attractive optical and electrical properties, metal chalcogenide materials have emerged as promising candidates for these next-generation light absorbers. In this review, we survey studies on chalcogenide light absorbers having a simple binary composition, namely, Cu2S, SnS, GeSe, WSe2, Sb2S3, and Sb2Se3. Each material has its own unique strengths and weaknesses in terms of cost, abundance, optoelectronic properties, secondary phase formation, anisotropic carrier transport, and defect properties. After critical consideration of the unique properties, we scrutinize recently developed strategies for overcoming the material specific challenges while presenting future perspectives on each material.