Electroabsorption Spectroscopy Measurements of the Exciton Binding Energy, Electron–Hole Reduced Effective Mass, and Band Gap in the Perovskite CH3NH3PbI3

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• 作者：Mark E. Ziffer ; Joseph C. Mohammed ; David S. Ginger
• 刊名：ACS Photonics
• 出版年：2016
• 出版时间：June 15, 2016
• 年：2016
• 卷：3
• 期：6
• 页码：1060-1068
• 全文大小：659K
• 年卷期：0
• ISSN：2330-4022

文摘

We use electroabsorption (EA) spectroscopy to measure the exciton binding energy (E<sub>Bsub>), electron–hole reduced effective mass (μ), and one-electron band gap (E<sub>gsub>) at the fundamental absorption edge of the hybrid organic–inorganic perovskite CH<sub>3sub>NH<sub>3sub>PbI<sub>3sub> 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 CH<sub>3sub>NH<sub>3sub>PbI<sub>3sub> follows the low-field Franz–Keldysh–Aspnes (FKA) effect. Following FKA analysis we find that μ = 0.12 ± 0.03m<sub>0sub>, E<sub>Bsub> = 7.4 meV, and E<sub>gsub> = 1.633 eV. Our results provide direct experimental evidence that at room temperature primary transitions occurring in CH<sub>3sub>NH<sub>3sub>PbI<sub>3sub> can essentially be described in terms of free carrier generation.