Precisely tuning Ge substitution for efficient solution-processed Cu2ZnSn(S, Se)4 solar cells

• 来源期刊: 中国物理B（英文版）
• 关键词: Cu2ZnSn(S,Se)4 solar cells Ge substitution bandgap
• 年，卷（期）: 2018,（1）
• 页码范围: 116-120
• 页数: 5页
• 语种: 英文
• DOI: 10.1088/1674-1056/27/1/018809

摘要

The kesterite Cu2ZnSn(S,Se)4 (CZTSSe) solar cells have yielded a prospective conversion efficiency among all thin-film photovoltaic technology. However, its further development is still hindered by the lower open-circuit voltage (Voc), and the non-ideal bandgap of the absorber is an important factor affecting this issue. The substitution of Sn with Ge provides a unique ability to engineer the bandgap of the absorber film. Herein, a simple precursor solution approach was successfully developed to fabricate Cu2Zn(SnyGe1?y)(SxSe1?x)4 (CZTGSSe) solar cells. By precisely adjusting the Ge content in a small range, the Voc and Jsc are enhanced simultaneously. Benefitting from the optimized bandgap and the maintained spike structure and light absorption, the 10％Ge/(Ge+Sn) content device with a bandgap of approximately 1.1 eV yields the highest efficiency of 9.36％. This further indicates that a precisely controlled Ge content could further improve the cell performance for efficient CZTGSSe solar cells.