Single-Component Organic Solar Cells Based on Intramolecular Charge Transfer Photoabsorption

• Main Authors: Ken-ichi Nakayama, Tatsuya Okura, Yuki Okuda, Jun Matsui, Akito Masuhara, Tsukasa Yoshida, Matthew Schuette White, Cigdem Yumusak, Phillip Stadler, Markus Scharber, Niyazi Serdar Sariciftci
• Format: Article
• Language: English
• Published: MDPI AG 2021-03-01
• Series: Materials
• Subjects: organic solar cell; intramolecular charge transfer; photon energy loss; exciton binding energy
• Online Access: https://www.mdpi.com/1996-1944/14/5/1200

Conjugated donor–acceptor molecules with intramolecular charge transfer absorption are employed for single-component organic solar cells. Among the five types of donor–acceptor molecules, the strong push–pull structure of DTDCPB resulted in solar cells with high <i>J</i>_SC, an internal quantum efficiency exceeding 20%, and high <i>V</i>_OC exceeding 1 V with little photon energy loss around 0.7 eV. The exciton binding energy (EBE), which is a key factor in enhancing the photocurrent in the single-component device, was determined by quantum chemical calculation. The relationship between the photoexcited state and the device performance suggests that the strong internal charge transfer is effective for reducing the EBE. Furthermore, molecular packing in the film is shown to influence photogeneration in the film bulk.