Charge-carrier photogeneration and extraction dynamics of polymer solar cells probed by a transient photocurrent nearby the regime of the space charge-limited current  

作　　者：Boa Jin Hyunmin Park Yang Liu Leijing Liu Jongdeok An Wenjing Tian Chan Im 

机构地区：[1]Department of Chemistry,Konkuk University,Seoul 05029,Republic of Korea [2]State Key Laboratory of Supramolecular Structure and Materials,College of Chemistry,Jilin University,Changchun 130012,China

出　　处：《Frontiers of Chemical Science and Engineering》2021年第1期164-179,共16页化学科学与工程前沿（英文版）

基　　金：This study was supported by the projects of National Research Foundation of Korea(Project No.:NRF-2018R1D1A1B07048843,Ministry of Education and NRF-2018K2A9A2A06023902,Ministry of Science and ICT)in addition to the program for Changbaishan Scholars of Jilin Province,China.

摘　　要：To understand the complex behaviors of photogenerated charge carriers within polymer-based bulk-heterojunction-type solar cells,the charge-carrier photogeneration and extraction dynamics are simultaneously estimated using a transient photocurrent technique under various external-bias voltages,and a wide range of excitation intensities are analyzed.For this purpose,conventional devices with 80 nm thick active layers consisting of a blend of representative P3HT and PTB7 electron-donating polymers and proper electron-accepting fullerene derivatives were used.After the correction for the saturation behavior at a high excitation-intensity range nearby the regime of the space charge-limited current,the incident-photon-density-dependent maximum photocurrent densities at the initial peaks are discussed as the proportional measures of the charge-carrier-photogeneration facility.By comparing the total number of the extracted charge carriers to the total number of the incident photons and the number of the initially photogenerated charge carriers,the external quantum efficiencies as well as the extraction quantum efficiencies of the charge-carrier collection during a laser-pulse-induced transient photocurrent process were obtained.Subsequently,the charge-carrier concentration-dependent mobility values were obtained,and they are discussed in consideration of the additional influences of the charge-carrier losses from the device during the charge-carrier extraction that also affects the photocurrent-trace shape.

关 键 词：charge-carrier photogeneration transient photocurrent polymer solar cells charge-carrier extraction space charge-limited current 

分 类 号：TM914.4[电气工程—电力电子与电力传动]