Manipulating the D:A interfacial energetics and intermolecular packing for 19.2% efficiency organic photovoltaics. Issue 6 (12th May 2022)

• Record Type: Journal Article
• Authors: He, Chengliang; Pan, Youwen; Ouyang, Yanni; Shen, Qing; Gao, Yuan; Yan, Kangrong; Fang, Jin; Chen, Yiyao; Ma, Chang-Qi; Min, Jie; Zhang, Chunfeng; Zuo, Lijian; Chen, Hongzheng
• Is Part Of: Energy & environmental science. Volume 15:Issue 6(2022)
• Page Start: 2537
• Page End: 2544
• Publication Date: 2022-05-12
• Subjects: Energy conversion -- Periodicals; Fuel switching -- Periodicals; Environmental sciences -- Periodicals; Environmental chemistry -- Periodicals; 333.79
• DOI: 10.1039/d2ee00595f
• Languages: English
• ISSNs: 1754-5692

Abstract

Abstract : A novel electron acceptor, BTP-H2, demonstrates a high efficiency of 18.5% with a high V oc of 0.932 V. It also enables the ternary device to yield an efficiency of 19.2%, ranking the highest among single-junction organic photovoltaics. Abstract : Manipulating the donor:acceptor (D:A) energetics, e.g., the highest occupied molecular orbital (HOMO) offset, is the key to balancing the charge separation and charge recombination for high-performance organic solar cells (OSCs). Herein, we designed and synthesized a non-fullerene electron acceptor, i.e., BTP-H2, which shows strong intermolecular interaction and near-zero HOMO offset when pairing with polymer donor PM6. Transient absorption spectroscopies unveil that BTP-H2 exhibits a long-lived intra-moiety charge-separation state, which contributes to efficient hole transfer or charge generation, irrespective of the small HOMO offset. In addition, the small energetic offset reduces the non-radiative loss for a high open-circuit voltage ( V oc ). As a result, we demonstrate high-performance OSCs with the best power conversion efficiency (PCE) of 18.5%, a high V oc of 0.932 V and a peak photon-to-electron response of ∼ 90%. Furthermore, ternary OSCs comprising PM6:BTP-H2:L8-BO exhibit a champion PCE of 19.2% (certified value of 18.8%) due to the improved balance between charge generation and charge recombination, and this represents the best among PCEs of single-junction OSCs.