Charge transfer processes via tandem modification of efficient non-fullerene acceptors for organic solar cells. (1st January 2022)

• Record Type: Journal Article
• Authors: Zang, Zifu; Wang, Qungui; Song, Peng; Ma, Fengcai; Li, Yuanzuo
• Is Part Of: Solar energy. Volume 231(2022)
• Page Start: 503
• Page End: 515
• Publication Date: 2022-01-01
• Subjects: Solar cells -- Non-fullerene acceptors (NFAs) -- Electronic mobility -- Donor/Acceptor (D/A) compounds; Solar energy -- Periodicals; Solar engines -- Periodicals; 621.47
• DOI: 10.1016/j.solener.2021.11.078
• Languages: English
• ISSNs: 0038-092X

Abstract

Graphical abstract: Highlights: The chlorination and π-extension at terminal groups can tune the energy levels and absorption ranges, leading to high JSC . Using different method, the electronic rates, mobility and D/A charge separation/recombination rates have been calculated. The macroscopic characterization of VOC, VLOSS, and JSC has been roughly estimated. Abstract: High-efficiency non-fullerene acceptors (NFAs) have extensive applications in organic solar cells (OSCs) instead of fullerene-based acceptors. Herein, the dithienothiophen[3.2-b]-pyrrolo-benzothiadiazole (BDP), chlorinated BDP-2Cl, BDP-4Cl and designed BDPN-4Cl have been investigated. One performed the density functional theory (DFT) and time-dependent density functional theory (TD-DFT) to study their optimized structures, frontier molecular orbitals (FMOs) and other photoelectric parameters, which showed that designed BDPN-4Cl displayed narrower band gaps, smaller reorganization energy, larger electrophilic index and wider absorption spectrum than prototypical NFAs, and it had a greater ratio of charge separation rate/charge recombination rate ( KCS / KCR ) for heterojunction. It was also found that the designed BDPN-4Cl exhibited the largest electron transport ability, which was conducive to the interfacial process. Structure modification at the end positions of NFAs, such as the π-extension at the end-capping, showed a synergistic effect on performance. Furthermore, one also estimated the ideal performance ( VOC, VLOSS, JSC ) of all the compounds to reveal the influence of halogen atomic substitution and π-extension at the end-capping on performance. The present investigation suggests viable strategies for further designing NFAs in OSCs.