Open AccessElectroabsorption Spectroscopy Measurements of the Exciton Binding Energy, Electron–Hole Reduced Effective Mass, and Band Gap in the Perovskite CH3NH3PbI3
Author(s) -
Mark E. Ziffer,
Joseph C. Mohammed,
David S. Ginger
Publication year - 2016
Publication title -
acs photonics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.735
H-Index - 89
ISSN - 2330-4022
DOI - 10.1021/acsphotonics.6b00139
Subject(s) - exciton , perovskite (structure) , effective mass (spring–mass system) , band gap , tetragonal crystal system , absorption edge , spectroscopy , materials science , binding energy , absorption spectroscopy , electron , absorption (acoustics) , direct and indirect band gaps , molecular physics , atomic physics , condensed matter physics , optoelectronics , physics , phase (matter) , chemistry , optics , crystallography , quantum mechanics , composite material
We use electroabsorption (EA) spectroscopy to measure the exciton binding energy (EB), electron–hole reduced effective mass (μ), and one-electron band gap (Eg) at the fundamental absorption edge of the hybrid organic–inorganic perovskite CH3NH3PbI3 in its tetragonal phase at 300 K. By studying the second-harmonic EA spectra at the fundamental absorption edge we establish that the room-temperature EA response in CH3NH3PbI3 follows the low-field Franz–Keldysh–Aspnes (FKA) effect. Following FKA analysis we find that μ = 0.12 ± 0.03m0, EB = 7.4 meV, and Eg = 1.633 eV. Our results provide direct experimental evidence that at room temperature primary transitions occurring in CH3NH3PbI3 can essentially be described in terms of free carrier generation.
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