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光照下金属卤化物钙钛矿介电常数的时间分辨变化
作者:小柯机器人 发布时间:2020/11/17 12:59:22

光照下金属卤化物钙钛矿介电常数的时间分辨变化,这一成果由美国俄勒冈州立大学John G. Labram和Chong Fang研究小组经过不懈努力而取得。 2020年11月13日,国际知名学术期刊《美国化学会志》发表了这一成果。

在这篇报告中,该团队利用频率相关的时间分辨微波电导率(TRMC)来研究在光照射下,一系列MHPs的εr值是如何随时间变化的。飞秒瞬态吸收和受激拉曼光谱法对载流子和极化率进行了进一步的表征。该课题组人员发现εr的变化与光生载流子密度大致成正比,但衰减的时间常数比电导率短,表明电荷载流子的存在并不能决定极化。

据悉,尽管金属卤化物钙钛矿(MHPs)具有出色的太阳能吸收剂性能,但其基本性能仍然未知。特别是他们的极性是一个密集研究的领域,同时其相对介电常数(εr)是一个广泛用于量化在不同时间尺度下的极化性的参数。

附:英文原文

Title: Time-Resolved Changes in Dielectric Constant of Metal Halide Perovskites under Illumination

Author: Min Ji Hong, Liangdong Zhu, Cheng Chen, Longteng Tang, Yen-Hung Lin, Wen Li, Rose Johnson, Shirsopratim Chattopadhyay, Henry J. Snaith, Chong Fang, John G. Labram

Issue&Volume: November 13, 2020

Abstract: Despite their impressive performance as a solar absorber, much remains unknown on the fundamental properties of metal halide perovskites (MHPs). Their polar nature in particular is an intense area of study, and the relative permittivity (εr) is a parameter widely used to quantify polarization over a range of different time scales. In this report, we have exploited frequency-dependent time-resolved microwave conductivity (TRMC) to study how εr values of a range of MHPs change as a function of time, upon optical illumination. Further characterization of charge carriers and polarizability are conducted by femtosecond transient absorption and stimulated Raman spectroscopy. We find that changes in εr are roughly proportional to photogenerated carrier density but decay with a shorter time constant than conductance, suggesting that the presence of charge carriers alone does not determine polarization.

DOI: 10.1021/jacs.0c07307

Source: https://pubs.acs.org/doi/10.1021/jacs.0c07307

 

期刊信息

JACS:《美国化学会志》,创刊于1879年。隶属于美国化学会,最新IF:14.612
官方网址:https://pubs.acs.org/journal/jacsat
投稿链接:https://acsparagonplus.acs.org/psweb/loginForm?code=1000