中国科学院福建物构所孙志华团队报道了二维钙钛矿铁电体中异常光伏效应的巨极化灵敏度。相关研究成果发表在2023年7月18日出版的《美国化学会杂志》。

极化灵敏度在光电检测中显示出巨大的潜力，铁电反常光伏（APV）效应有望显著提高极化灵敏度。然而，由于光激发载流子的漏电流引起的严重极化疲劳，探索新的APV活性铁电体具有挑战性。

研究人员首次报道了由混合有机阳离子(HA)2(EA)2Pb3Br10 （1，其中HA+为正己基铵，EA+为乙基铵）合金化组装的二维杂化钙钛矿铁电体中的强APV效应，该铁电体具有大的自发极化～3.8μC/cm²和高的居里温度～378K。它的铁电性使其具有强的APV效应，带隙以上的光电压高达7.4V，超过了它的带隙（～2.7eV）。最引人注目的是，基于对偏振光角度的依赖性，这种强大的APV效应以～25的巨大电流比提供了最高水平的偏振灵敏度，远远超过了其他2D单相材料。

该研究为APV活性铁电体的探索提供了线索，并启发了其未来的高性能光电器件应用。

附：英文原文

Title: Giant Polarization Sensitivity via the Anomalous Photovoltaic Effect in a Two-Dimensional Perovskite Ferroelectric

Author: Yi Liu, Wuqian Guo, Lina Hua, Xi Zeng, Tian Yang, Qingshun Fan, Yu Ma, Changhao Gao, Zhihua Sun, Junhua Luo

Issue&Volume: July 18, 2023

Abstract: Polarization sensitivity, which shows great potential in photoelectric detection, is expected to be significantly improved by the ferroelectric anomalous photovoltaic (APV) effect. However, it is challenging to explore new APV-active ferroelectrics due to severe polarization fatigue induced by the leakage current of photoexcited carriers. For the first time, we report a strong APV effect in a 2D hybrid perovskite ferroelectric assembled by alloying mixed organic cations, (HA)2(EA)2Pb3Br10 (1, where HA+ is n-hexylammonium and EA+ is ethylammonium), which has a large spontaneous polarization ～3.8 μC/cm2 and high a Curie temperature ～378 K. Its ferroelectricity allows a strong APV effect with an above-bandgap photovoltage up to 7.4 V, which exceeds its bandgap (～2.7 eV). Most strikingly, based on the dependence on polarized-light angle, this strong APV effect renders the highest level of polarization sensitivity with a giant current ratio of ～25, far beyond other 2D single-phase materials. This study sheds light on the exploration of APV-active ferroelectrics and inspires their future high-performance optoelectronic device applications.

DOI: 10.1021/jacs.3c05020

Source: https://pubs.acs.org/doi/10.1021/jacs.3c05020