Abstract
Hybrid organic-inorganic perovskites, such as methylammonium lead tri-iodide (MAPbI3), are interesting candidates for efficient absorber materials in next-generation solar cells, partly due to an unusual combination of low exciton-binding energy and strong optical absorption. Excitonic effects in this material have been subject to debate both for experiment and theory, indicating a need for better understanding of the screening mechanisms that act upon the electron-hole interaction. Here, we use cutting-edge first-principles theoretical spectroscopy, based on density-functional and many-body perturbation theory, to study atomic geometries, electronic structure, and optical properties of three MAPbI3 polymorphs and find good agreement with earlier results and experiment. We then study the influence of free electrons on the electron-hole interaction and show that this explains consistently smaller exciton-binding energies, compared to those in the material without free electrons. Interestingly, we also find that the absorption line shape strongly resembles that of the spectrum without free electrons up to high free-electron concentrations. We explain this unexpected behavior by formation of Mahan excitons that dominate the absorption edge, making MAPbI3 robust against free-electron-induced changes observed in other semiconductors.
| Original language | English (US) |
|---|---|
| Article number | 035205 |
| Journal | Physical Review B |
| Volume | 100 |
| Issue number | 3 |
| DOIs | |
| State | Published - Jul 19 2019 |
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ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics
Cite this
Free-electron effects on the optical absorption of the hybrid perovskite CH3NH3PbI3 from first principles. / Leveillee, Joshua; Schleife, André.
In: Physical Review B, Vol. 100, No. 3, 035205, 19.07.2019.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Free-electron effects on the optical absorption of the hybrid perovskite CH3NH3PbI3 from first principles
AU - Leveillee, Joshua
AU - Schleife, André
PY - 2019/7/19
Y1 - 2019/7/19
N2 - Hybrid organic-inorganic perovskites, such as methylammonium lead tri-iodide (MAPbI3), are interesting candidates for efficient absorber materials in next-generation solar cells, partly due to an unusual combination of low exciton-binding energy and strong optical absorption. Excitonic effects in this material have been subject to debate both for experiment and theory, indicating a need for better understanding of the screening mechanisms that act upon the electron-hole interaction. Here, we use cutting-edge first-principles theoretical spectroscopy, based on density-functional and many-body perturbation theory, to study atomic geometries, electronic structure, and optical properties of three MAPbI3 polymorphs and find good agreement with earlier results and experiment. We then study the influence of free electrons on the electron-hole interaction and show that this explains consistently smaller exciton-binding energies, compared to those in the material without free electrons. Interestingly, we also find that the absorption line shape strongly resembles that of the spectrum without free electrons up to high free-electron concentrations. We explain this unexpected behavior by formation of Mahan excitons that dominate the absorption edge, making MAPbI3 robust against free-electron-induced changes observed in other semiconductors.
AB - Hybrid organic-inorganic perovskites, such as methylammonium lead tri-iodide (MAPbI3), are interesting candidates for efficient absorber materials in next-generation solar cells, partly due to an unusual combination of low exciton-binding energy and strong optical absorption. Excitonic effects in this material have been subject to debate both for experiment and theory, indicating a need for better understanding of the screening mechanisms that act upon the electron-hole interaction. Here, we use cutting-edge first-principles theoretical spectroscopy, based on density-functional and many-body perturbation theory, to study atomic geometries, electronic structure, and optical properties of three MAPbI3 polymorphs and find good agreement with earlier results and experiment. We then study the influence of free electrons on the electron-hole interaction and show that this explains consistently smaller exciton-binding energies, compared to those in the material without free electrons. Interestingly, we also find that the absorption line shape strongly resembles that of the spectrum without free electrons up to high free-electron concentrations. We explain this unexpected behavior by formation of Mahan excitons that dominate the absorption edge, making MAPbI3 robust against free-electron-induced changes observed in other semiconductors.
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U2 - 10.1103/PhysRevB.100.035205
DO - 10.1103/PhysRevB.100.035205
M3 - Article
AN - SCOPUS:85073650133
VL - 100
JO - Physical Review B
JF - Physical Review B
SN - 2469-9950
IS - 3
M1 - 035205
ER -