Thin film solar cell with 8.4% power conversion efficiency using an earth‐abundant Cu 2 ZnSnS 4 absorber

• Published in: Progress in photovoltaics Vol. 21; no. 1; pp. 72 - 76
• Main Authors: Shin, Byungha, Gunawan, Oki, Zhu, Yu, Bojarczuk, Nestor A., Chey, S. Jay, Guha, Supratik
• Format: Journal Article
• Language: English
• Published: 01-01-2013
• ISSN: 1062-7995; 1099-159X
• DOI: 10.1002/pip.1174

Using vacuum process, we fabricated Cu
2
ZnSnS
4
solar cells with 8.4% efficiency, a number independently certified by an external, accredited laboratory. This is the highest efficiency reported for pure sulfide Cu
2
ZnSnS
4
prepared by any method. Consistent with literature, the optimal composition is Cu‐poor and Zn‐rich despite the precipitation of secondary phases (e.g., ZnS). Despite a very thin absorber thickness (~600 nm), a reasonably good short‐circuit current was obtained. Time‐resolved photoluminescence measurements suggest a minority carrier‐diffusion length on the order of several hundreds of nanometers and relatively good collection of photo‐carriers across the entire absorber thickness. Copyright © 2011 John Wiley & Sons, Ltd.