Abstract
The electronic structure and related optical properties of an emerging thin-film photovoltaic material CH3NH3PbBr3 are studied. A block-shaped α-phase CH3NH3PbBr3 single crystal with the natural <100> surface is synthesized solvothermally. The room-temperature dielectric function ε = ε1 + iε2 spectrum of CH3NH3PbBr3 is determined by spectroscopic ellipsometry from 0.73 to 6.45 eV. Data are modeled with a series of Tauc-Lorentz oscillators, which show the absorption edge with a strong excitonic transition at ∼2.3 eV and several above-bandgap optical structures associated with the electronic interband transitions. The energy band structure and ε data of CH3NH3PbBr3 for the CH3NH3+ molecules oriented in the <111> and <100> directions are obtained from first-principles calculations. The overall shape of ε data shows a qualitatively good agreement with experimental results. Electronic origins of major optical structures are discussed.
Original language | American English |
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Pages (from-to) | 4304-4308 |
Number of pages | 5 |
Journal | Journal of Physical Chemistry Letters |
Volume | 6 |
Issue number | 21 |
DOIs | |
State | Published - 13 Oct 2015 |
Bibliographical note
Publisher Copyright:© 2015 American Chemical Society.
NREL Publication Number
- NREL/JA-5J00-65045
Keywords
- density functional theory calculations
- electronic structure
- optical property
- perovskite solar cell
- spectroscopic ellipsometry