Mixed Ge/Pb perovskite light absorbers with an ascendant efficiency explored from theoretical view

Organic-inorganic methylammonium lead halide perovskites have recently attracted great interest emerging as promising photovoltaic materials with a high 20.8% efficiency, but lead pollution is still a problem that may hinder the development and wide spread of MAPbI 3 perovskites. To reduce the use o...

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Bibliographic Details
Published in:Physical chemistry chemical physics : PCCP 2016-06, Vol.18 (21), p.1448-14418
Main Authors: Sun, Ping-Ping, Li, Quan-Song, Feng, Shuai, Li, Ze-Sheng
Format: Article
Language:English
Subjects:
Computational efficiency
Computing time
Electronics
Lead (metal)
Mathematical analysis
Perovskites
Photovoltaic cells
Solar cells
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Summary:Organic-inorganic methylammonium lead halide perovskites have recently attracted great interest emerging as promising photovoltaic materials with a high 20.8% efficiency, but lead pollution is still a problem that may hinder the development and wide spread of MAPbI 3 perovskites. To reduce the use of lead, we investigated the structures, electronic and optical properties of mixed MAGe x Pb (1− x ) I 3 theoretically by using density functional theory methods at different calculation levels. Results show that the mixed Ge/Pb perovskites exhibit a monotonic decrease evolution in band energy to push the band gap deeper in the near-infrared region and have a red shift optical absorption with an increased proportion of Ge. The results also indicate that lattice distortion and spin-orbit coupling (SOC) strength play important roles in the band gap behavior of MAGe x Pb (1− x ) I 3 by affecting the bandwidths of CBM and VBM. The calculations for short circuit current density, open circuit voltage, and theoretical power conversion efficiency suggest that mixed Ge/Pb perovskite solar cells (PSCs) with efficiency over 22% are superior to MAPbI 3 and MAGeI 3 . And notably, MAGe 0.75 Pb 0.25 I 3 is a promising harmless material for solar cells absorber with the highest theoretical efficiency of 24.24%. These findings are expected to be helpful for further rational design of nontoxic light absorption layer for high-performance PSCs. MAGe 0.75 Pb 0.25 I 3 with the highest theoretical efficiency of 24.24% is superior to MAPbI 3 , which can become the best candidate.
ISSN:1463-9076
1463-9084
DOI:10.1039/c6cp02105k