Sustainable p-type copper selenide solar material with ultra-large absorption coefficient

• Published in: Chemical science (Cambridge) Vol. 9; no. 24; pp. 5405 - 5414
• Main Authors: Chen, Erica M, Williams, Logan, Olvera, Alan, Zhang, Cheng, Zhang, Mingfei, Shi, Guangsha, Heron, John T, Qi, Liang, Guo, L Jay, Kioupakis, Emmanouil, Poudeu, Pierre F P
• Format: Journal Article
• Language: English
• Published: England Royal Society of Chemistry 2018
• Subjects: Absorbers (materials); Absorptivity; Conduction bands; Copper selenides; Corners; Crystal structure; ENERGY STORAGE; Interstices; Low cost; MATERIALS SCIENCE; P-type semiconductors; Photovoltaic cells; Solar cells; SOLAR ENERGY; Solar energy absorbers; Thin films
• ISSN: 2041-6520; 2041-6539
• DOI: 10.1039/c8sc00873f

Earth-abundant solar absorber materials with large optical absorption coefficients in the visible enable the fabrication of low-cost high-efficiency single and multi-junction thin-film solar cells. Here, we report a new p-type semiconductor, Cu TiSe (CTSe), featuring indirect (1.15 eV) and direct (1.34 eV) band gaps in the optimal range for solar absorber materials. CTSe crystallizes in a new noncentrosymmetric cubic structure (space group 4[combining macron]3 ) in which CuSe tetrahedra share edges and corners to form octahedral anionic clusters, [Cu Se ] , which in turn share corners to build the three-dimensional framework, with Ti ions located at tetrahedral interstices within the channels. The unique crystal structure and the Ti 3d orbital character of the conduction band of CTSe give rise to near-optimal band gap values and ultra-large absorption coefficients (larger than 10 cm ) throughout the visible range, which are promising for scalable low-cost high-efficiency CTSe-based thin-film solar cells.