Phase Transition Control for High Performance Ruddlesden–Popper Perovskite Solar Cells

• Published in: Advanced materials (Weinheim) Vol. 30; no. 21; pp. e1707166 - n/a
• Main Authors: Zhang, Xu, Munir, Rahim, Xu, Zhuo, Liu, Yucheng, Tsai, Hsinhan, Nie, Wanyi, Li, Jianbo, Niu, Tianqi, Smilgies, Detlef‐M., Kanatzidis, Mercouri G., Mohite, Aditya D., Zhao, Kui, Amassian, Aram, Liu, Shengzhong (Frank)
• Format: Journal Article
• Language: English
• Published: Germany Wiley Subscription Services, Inc 01.05.2018; Wiley
• Subjects: Crystal structure; Crystallization; Energy conversion efficiency; in situ diagnostics; Material Science; Materials science; Nucleation; Optoelectronic devices; Orientation; Perovskite structure; Perovskites; Phase transitions; Phases; Photovoltaic cells; Purity; Quantum wells; Ruddlesden–Popper perovskites; Solar cells; SOLAR ENERGY; solution processing; Ruddlesden-Popper perovskites; in situ diagnostics; phase transitions; solution processing; solar cells
• ISSN: 0935-9648; 1521-4095; 1521-4095
• DOI: 10.1002/adma.201707166

Ruddlesden–Popper reduced‐dimensional hybrid perovskite (RDP) semiconductors have attracted significant attention recently due to their promising stability and excellent optoelectronic properties. Here, the RDP crystallization mechanism in real time from liquid precursors to the solid film is investigated, and how the phase transition kinetics influences phase purity, quantum well orientation, and photovoltaic performance is revealed. An important template‐induced nucleation and growth of the desired (BA)2(MA)3Pb4I13 phase, which is achieved only via direct crystallization without formation of intermediate phases, is observed. As such, the thermodynamically preferred perpendicular crystal orientation and high phase purity are obtained. At low temperature, the formation of intermediate phases, including PbI2 crystals and solvate complexes, slows down intercalation of ions and increases nucleation barrier, leading to formation of multiple RDP phases and orientation randomness. These insights enable to obtain high quality (BA)2(MA)3Pb4I13 films with preferentially perpendicular quantum well orientation, high phase purity, smooth film surface, and improved optoelectronic properties. The resulting devices exhibit high power conversion efficiency of 12.17%. This work should help guide the perovskite community to better control Ruddlesden–Popper perovskite structure and further improve optoelectronic and solar cell devices. The crystallization mechanism for Ruddlesden–Popper perovskite in real time from liquid precursors to the solid film is presented. The template‐induced nucleation and growth of the (BA)2(MA)3Pb4I13 phase, which is achieved only via direct crystallization without formation of intermediate phases, helps to realize superior films with high phase purity, perpendicular quantum‐well orientation, improved optoelectronic properties, and excellent photovoltaic performance.