Halide perovskites have attracted great interest as active layers in optoelectronic devices. Among perovskites with diverse compositions, α-FAPbI_(3) is of utmost importance with great optoelectronic properties and a...Halide perovskites have attracted great interest as active layers in optoelectronic devices. Among perovskites with diverse compositions, α-FAPbI_(3) is of utmost importance with great optoelectronic properties and a decent bandgap of 1.48 eV.However, the α-phase suffers an irreversible transition to the photo-inactive δ-phase, whereas the δ-phase is usually regarded as useless phase with poor optoelectronic properties. Therefore, it is commonly accepted that the thermodynamic stable δ-FAPbI_(3) greatly limits the application of FAPbI_(3). Every coin has two sides, although the δ-phase is difficult to apply as photoelectrical active layers, it is possible to combine δ-FAPbI_(3) with α-FAPbI_(3) to realize functional applications. Firstly, this review analyzes the cause of the contrasting properties between α-and δ-FAPbI_(3), where the stronger electron-phonon coupling in 1D hexagonal δ-FAPbI_(3) restricts its internal carrier and phonon transport. Secondly, the factors affecting the phase transitions and strategies to control phase transition between α-and δ-FAPbI_(3) are presented. Finally, some functional applications of δ-FAPbI_(3) in combination with α-FAPbI_(3) are given according to previous reports. By and large, we hope to introduce δ-FAPbI_(3) from another perspective and give some insights into its unique properties, hopefully providing new strategies for the subsequent advances to FAPbI_(3).展开更多
基金supported by the National Natural Science Foundation of China (Nos. T2322003, 52172146)the Fundamental Research Funds for the Central Universities (No. 2242024K40017)Shuangchuang Talent of Jiangsu Province (No. JSSCRC2021506)。
文摘Halide perovskites have attracted great interest as active layers in optoelectronic devices. Among perovskites with diverse compositions, α-FAPbI_(3) is of utmost importance with great optoelectronic properties and a decent bandgap of 1.48 eV.However, the α-phase suffers an irreversible transition to the photo-inactive δ-phase, whereas the δ-phase is usually regarded as useless phase with poor optoelectronic properties. Therefore, it is commonly accepted that the thermodynamic stable δ-FAPbI_(3) greatly limits the application of FAPbI_(3). Every coin has two sides, although the δ-phase is difficult to apply as photoelectrical active layers, it is possible to combine δ-FAPbI_(3) with α-FAPbI_(3) to realize functional applications. Firstly, this review analyzes the cause of the contrasting properties between α-and δ-FAPbI_(3), where the stronger electron-phonon coupling in 1D hexagonal δ-FAPbI_(3) restricts its internal carrier and phonon transport. Secondly, the factors affecting the phase transitions and strategies to control phase transition between α-and δ-FAPbI_(3) are presented. Finally, some functional applications of δ-FAPbI_(3) in combination with α-FAPbI_(3) are given according to previous reports. By and large, we hope to introduce δ-FAPbI_(3) from another perspective and give some insights into its unique properties, hopefully providing new strategies for the subsequent advances to FAPbI_(3).
