Size-dependent phase transition in methylammonium lead iodide perovskite microplate crystals.
Methylammonium lead iodide perovskite has attracted considerable recent interest for solution processable solar cells and other optoelectronic applications. The orthorhombic-to-tetragonal phase transition in perovskite can significantly alter its optical, electrical properties and impact the corresponding applications. Here, we report a systematic investigation of the size-dependent orthorhombic-to-tetragonal phase transition using a combined temperature-dependent optical, electrical transport and transmission electron microscopy study. Our studies of individual perovskite microplates with variable thicknesses demonstrate that the phase transition temperature decreases with reducing microplate thickness. The sudden decrease of mobility around phase transition temperature and the presence of hysteresis loops in the temperature-dependent mobility confirm that the orthorhombic-to-tetragonal phase transition is a first-order phase transition. Our findings offer significant fundamental insight on the temperature- and size-dependent structural, optical and charge transport properties of perovskite materials, and can greatly impact future exploration of novel electronic and optoelectronic devices from these materials.
Department of Chemistry and Biochemistry, University of California, 607 Charles E. Young Drive East, Los Angeles, California 90095, USA.
Dehui
D
Li
Department of Chemistry and Biochemistry, University of California, 607 Charles E. Young Drive East, Los Angeles, California 90095, USA.|California Nanosystems Institute, University of California, Los Angeles, California 90095, USA.
Gongming
G
Wang
Department of Materials Science and Engineering, University of California, Los Angeles, California 90095, USA.
Hung-Chieh
HC
Cheng
Department of Chemistry and Biochemistry, University of California, 607 Charles E. Young Drive East, Los Angeles, California 90095, USA.
Chih-Yen
CY
Chen
Department of Materials Science and Engineering, University of California, Los Angeles, California 90095, USA.
Hao
H
Wu
Department of Materials Science and Engineering, University of California, Los Angeles, California 90095, USA.
Yuan
Y
Liu
California Nanosystems Institute, University of California, Los Angeles, California 90095, USA.|Department of Materials Science and Engineering, University of California, Los Angeles, California 90095, USA.
Yu
Y
Huang
Department of Chemistry and Biochemistry, University of California, 607 Charles E. Young Drive East, Los Angeles, California 90095, USA.|California Nanosystems Institute, University of California, Los Angeles, California 90095, USA.
Xiangfeng
X
Duan