Lead-free germanium iodide perovskite materials for photovoltaic applications

• Main Authors: Krishnamoorthy, Thirumal, Ding, Hong, Yan, Chen, Leong, Wei Lin, Baikie, Tom, Zhang, Ziyi, Sherburne, Matthew, Li, Shuzhou, Asta, Mark, Mathews, Nripan, Mhaisalkar, Subodh Gautam
• Other Authors: School of Electrical and Electronic Engineering
• Format: Article
• Language: English
• Published: 2020
• Subjects: Engineering::Materials; Perovskite; Photovoltaic Applications
• Online Access: https://hdl.handle.net/10356/142601
• Institution: Nanyang Technological University

Computational screening based on density-functional-theory calculations reveals Ge as a candidate element for replacing Pb in halide perovskite compounds suitable for light harvesting. Experimentally, three AGeI3 (A = Cs, CH3NH3 or HC(NH2)2) halide perovskite materials have been synthesized. These compounds are stable up to 150 °C, and have bandgaps correlated with the A-site cation size. CsGeI3-based solar cells display higher photocurrents, of about 6 mA cm−2, but are limited by poor film forming abilities and oxidising tendencies. The present results demonstrate the utility of combining computational screening and experimental efforts to develop lead-free halide perovskite compounds for photovoltaic applications.