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PbTiO 3 as Electron‐Selective Layer for High‐Efficiency Perovskite Solar Cells: Enhanced Electron Extraction via Tunable Ferroelectric Polarization
Author(s) -
Wang MingZi,
Feng HongJian,
Qian ChongXin,
He Jiawei,
Feng Jiangshan,
Cao YongHua,
Yang Kang,
Deng ZunYi,
Yang Zhou,
Yao Xi,
Zhou Jianping,
Liu Shengzhong Frank,
Zeng Xiao Cheng
Publication year - 2019
Publication title -
advanced functional materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.069
H-Index - 322
eISSN - 1616-3028
pISSN - 1616-301X
DOI - 10.1002/adfm.201806427
Subject(s) - ferroelectricity , materials science , photocurrent , heterojunction , optoelectronics , perovskite (structure) , polarization (electrochemistry) , electron , energy conversion efficiency , charge carrier , chemistry , dielectric , physics , crystallography , quantum mechanics
PbTiO 3 (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/CH 3 NH 3 PbI 3 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.