Probing the Spatial Heterogeneity of Carrier Relaxation Dynamics in CH3NH3PbI3 Perovskite Thin Films with Femtosecond Time-Resolved Nonlinear Optical Microscopy

被引：12

作者：

Yu, Jin ^{[1
]}

Li, Zhongguo ^{[2
]}

Liao, Yuheng ^{[3
]}

Kolodziej, Charles ^{[2
]}

Kuyuldar, Seher ^{[2
]}

Warren, Warren S. ^{[1
]}

Burda, Clemens ^{[2
]}

Fischer, Martin C. ^{[1
]}

机构：

[1] Duke Univ, Dept Chem, Durham, NC 27708 USA

[2] Case Western Reserve Univ, Dept Chem, Cleveland, OH 44106 USA

[3] Duke Univ, Dept Phys, Durham, NC 27708 USA

来源：

ADVANCED OPTICAL MATERIALS | 2019年 / 7卷 / 22期

基金：

中国国家自然科学基金; 美国国家科学基金会;

关键词：

fluorescence lifetime imaging microscopy; perovskite thin films; pump-probe microscopy; transient absorption; GRAIN-BOUNDARIES; CHARGE-CARRIERS; METHYLAMMONIUM; TRANSPORT;

D O I：

10.1002/adom.201901185

中图分类号：

T [工业技术];

学科分类号：

08 ;

摘要：

The spatial heterogeneity of carrier dynamics in polycrystalline metal halide perovskite (MHP) thin films has a strong influence on photovoltaic device performance; however, the underlying cause is not yet clearly understood. Here, the sub-micrometer scale mapping of charge carrier dynamics in CH3NH3PbI3 thin films using time-resolved nonlinear optical microscopy, specifically transient absorption microscopy (TAM) with sub-picosecond (ps) and time-resolved photoluminescence (PL) microscopy with nanosecond temporal resolution is reported. To study the influence of physical morphology on charge carrier dynamics, MHP thin films having granular- and fibrous structures are investigated. On both types of films, spatial regions with short-lived transient gain signals (fast nonradiative relaxation within approximate to 1 ps) typically show slower charge recombination via radiative relaxation, which is attributed to the presence of additional energy states near the band edge. In addition, fibrous films show longer PL lifetimes. Interestingly, the functional contrast shown in TAM images exhibits fundamental differences from the structural contrast shown in scanning electron microscopy images, implying that the variation of trap density in the bulk contributes to the observed spatial heterogeneity in carrier dynamics.

引用

页数：6

共 45 条

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