PbTiO3 as Electron‐Selective Layer for High‐Efficiency Perovskite Solar Cells: Enhanced Electron Extraction via Tunable Ferroelectric Polarization |
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Authors: | Ming‐Zi Wang Hong‐Jian Feng Chong‐Xin Qian Jiawei He Jiangshan Feng Yong‐Hua Cao Kang Yang Zun‐Yi Deng Zhou Yang Xi Yao Jianping Zhou Shengzhong Liu Xiao Cheng Zeng |
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Affiliation: | Ming‐Zi Wang,Hong‐Jian Feng,Chong‐Xin Qian,Jiawei He,Jiangshan Feng,Yong‐Hua Cao,Kang Yang,Zun‐Yi Deng,Zhou Yang,Xi Yao,Jianping Zhou,Shengzhong (Frank) Liu,Xiao Cheng Zeng |
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Abstract: | PbTiO3 (PTO) is explored as a versatile and tunable electron‐selective layer (ESL) for perovskite solar cells. To demonstrate effectiveness of PTO for electron–hole separation and charge transfer, perovskite solar cells are designed and fabricated in the laboratory with the PTO as the ESL. The cells achieve a power conversion efficiency (PCE) of ≈12.28% upon preliminary optimization. It is found that the PTO ferroelectric layer can not only increase the PCE, but also tune the photocurrent via tuning PTO's ferroelectric polarization. Moreover, to understand the physical mechanism underlying the carrier transport by the ferroelectric polarization, the electronic structure of PTO/CH3NH3PbI3 heterostructure is computed using the first‐principles methods, for which the triplet state is used to simulate charge transfer in the heterostructure. It is shown that the synergistic effect of type II band alignment and the specific ferroelectric polarization direction provide the effective extraction of electrons from the light absorber, while minimize recombination of photogenerated electron–hole pairs. Overall, the ferroelectric PTO is a promising and tunable ESL for optimizing electron transport in the perovskite solar cells. The design offers a different strategy for altering direction of carrier transport in solar cells. |
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Keywords: | electron‐selective layers ferroelectric tuning PbTiO3 perovskite solar cells |
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