Affiliation:
1. School of Materials Science and Engineering, Chongqing University of Arts and Sciences, Chongqing 402160, China
2. School of Physics and Materials Science, Guangzhou University, Guangzhou 510006, China
Abstract
In this work, we investigated the effects of different acceptors (IT−4F and PC71BM) on the charge dynamics in PM6-based solar cells. The correlation between different acceptors and the performance of organic solar cells was studied by atomic force microscope, steady-state absorption spectrum, transient absorption spectrum, and electrical measurements. Optical absorption exhibited that IT−4F has strong absorption in the near-infrared region for the active layer. Transient absorption measurements showed that different acceptors (IT−4F and PC71BM) had a significant influence on the behaviors of PM6 excitons and charge dynamics. That is, the exciton dissociation rate and delocalized polaron transport in the PM6:IT−4F active layer were significantly faster than that in the PM6:PC71BM active layer. The lifetime of localized polaron in the PM6:PC71BM active layer was longer than that in the PM6:IT−4F active layer. Conversely, the lifetime of delocalized polaron in the PM6:IT−4F active layer was longer than that in the PM6:PC71BM active layer. Electrical measurement analysis indicated that lower bimolecular recombination, higher charge transport, and charge collection ability were shown in the PM6:IT−4F device compared with the PM6:PC71BM device. Therefore, PM6:IT−4F solar cells achieved a higher power conversion efficiency (12.82%) than PM6:PC71BM solar cells (8.78%).
Funder
National Natural Science Foundation of China
Major Cultivation Project of Chongqing University of Arts and Sciences
Genera Program of Chongqing Natural Science Foundation
Science and Technology Research Program of the Chongqing Municipal Education Commission
General Program of Yongchuan Natural Science Foundation
Guangdong Basic and Applied Basic Research Foundation
Scientific Research Projects of Guangzhou University
Subject
Radiology, Nuclear Medicine and imaging,Instrumentation,Atomic and Molecular Physics, and Optics