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Band Dispersion and Hole Effective Mass of Methylammonium Lead Iodide Perovskite
Author(s) -
Yang JinPeng,
Meissner Matthias,
Yamaguchi Takuma,
Zhang XiuYun,
Ueba Takahiro,
Cheng LiWen,
Ideta Shinichiro,
Tanaka Kiyohisa,
Zeng XiangHua,
Ueno Nobuo,
Kera Satoshi
Publication year - 2018
Publication title -
solar rrl
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.544
H-Index - 37
ISSN - 2367-198X
DOI - 10.1002/solr.201800132
Subject(s) - tetragonal crystal system , iodide , effective mass (spring–mass system) , perovskite (structure) , electronic band structure , x ray photoelectron spectroscopy , materials science , semiconductor , crystal structure , valence (chemistry) , analytical chemistry (journal) , chemistry , crystallography , condensed matter physics , inorganic chemistry , optoelectronics , physics , nuclear magnetic resonance , quantum mechanics , organic chemistry , chromatography
Solar cells incorporating organic–inorganic perovskites, especially methylammonium lead iodide (CH 3 NH 3 PbI 3 ), have recently shown remarkable performances and therefore attracted wide interest. For understanding the origin of the high performance, the effective charge carrier masses of CH 3 NH 3 PbI 3 are critical. However, reliable experimental data on its electronic band structure, which determines the effective mass, is yet to be provided. Here, the electronic structure of CH 3 NH 3 PbI 3 single crystals is studied by using angle‐resolved photoelectron spectroscopy on cleaved crystal surfaces after characterizing the surface structure by low‐energy electron diffraction. Coexisting cubic and tetragonal phases of CH 3 NH 3 PbI 3 are found in diffraction patterns. Moreover, a clear band dispersion of the top valence band is observed along directions parallel to different high‐symmetry points of the cubic structure, in consistence with theoretical calculations. Based on these values, the effective hole mass is then estimated to be 0.24(±0.10) m 0 around the M point and 0.35(±0.15) m 0 around the X point, which are significantly lower than in organic semiconductors. These results reveal the physical origin of the high performance of solar cells incorporating perovskite materials compared to pure organic semiconductors.