Improved performance in organic solar cells using aluminum-doped cathode-modifying layer

• Published in: Applied physics. A, Materials science & processing Vol. 127; no. 8
• Main Authors: Guan, Xi, Feng, Shang, Liu, Wenxing, Wang, Yufei, Qin, Dashan
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.08.2021; Springer Nature B.V
• Subjects: Aluminum; Applied physics; Cathodes; Characterization and Evaluation of Materials; Circuits; Commercialization; Condensed Matter Physics; Electron mobility; Electrons; Energy conversion efficiency; Machines; Manufacturing; Materials science; Nanotechnology; Optical and Electronic Materials; Photovoltaic cells; Physics; Physics and Astronomy; Processes; Short circuit currents; Solar cells; Surfaces and Interfaces; Thermal stability; Thin Films; Al-doped BCP; Cost effectiveness; Organic solar cells; Cathode-modifying layers
• ISSN: 0947-8396; 1432-0630
• DOI: 10.1007/s00339-021-04735-y

Organic solar cells (OSCs) have been developed using aluminum-doped bathocuproine (BCP:Al) as cathode-modifying layer. Although BCP:Al thin film shows decreased electron mobility than neat BCP thin film, the former is advantageous over the latter in the following two aspects. Firstly, BCP:Al has more gap states, offering more efficient electron injection and extraction at the interface with electron acceptor, thereby contributing to the increase in fill factor. Secondly, BCP:Al increases the optical absorption of device, contributing to the increase in short-circuit current density. As a result, the OSC based on BCP:Al shows improved power conversion efficiency than that based on neat BCP. Moreover, the former device presents increased thermal stability than the latter, mostly because doped Al clusters can inhibit the aggregation tendency of BCP molecules. We provide a novel insight to fabricate cost-effective cathode-modifying layers, useful for pushing forward the commercialization of OSCs.