Effects of Mixed Halogenation on the Performance of Nonfullerene Acceptors in All‐Small Molecule Organic Solar Cells

Abstract

Mixed halogen substitution on the end groups of organic photovoltaic materials has been proven to be an effective way to generate materials with enhanced performance. A systematic comparison of the mixed halogen atom types can provide comprehensive information on this strategy; however, this is usually limited by the lack of a facile synthesis route. Herein, a new class of end groups featuring mixed halogenation, easily obtained via two steps with excellent yields, is reported. The new end groups are applied in synthesizing acceptor materials, and their performance is compared in organic solar cell devices. Combined with the small molecule donor BTR‐Cl, the best‐performing acceptor BTP‐FCl‐FCl achieves a power conversion efficiency of 15.27% and a high fill factor (FF) of 75.94%. Systematic studies of the mixed halogenation analogues in devices reveal that the higher FF is consistent with the longer carrier lifetime, faster charge extraction, weaker bimolecular recombination, and is associated with the favorable BTR‐Cl:BTP‐FC1‐FC1 domain size and molecular packing, all of which are derived from the different halogen atoms. The results demonstrate that selecting suitable halogen atoms is vital in achieving high‐performance organic solar cells.

Machine Learning Study on the Virtual Screening of Donor–Acceptor Pairs for Organic Solar Cells

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Organoboron-embedded functional materials: recent developments in photovoltaic and luminescence properties

“…1 (d), the HOMO energy levels of the building blocks PPAB, BODIPY, BNBP and BF 2 bdks are calculated to be À3.60, À5.87, À5.56 and À7. 22, respectively. The LUMO energy levels are calculated to be À1.63, À3.28, À2.51 and À2.07 eV, respectively.…”

DPP-bridged narrow band gap oligomer-like donor materials: significant effect of molecular structure regulation on photovoltaic performance

“…Organic solar cells (OSCs) have emerged as highly promising candidates for converting solar energy into electricity owing to their distinctive advantages, including lightweight design, mechanical flexibility, diverse material options, and simplified device technology. 1 The efficient OSC employs a blend of donor (D) and acceptor (A) materials in the photoactive layer of bulk heterojunction (BHJ) devices, facilitating effective exciton dissociation and charge transfer. 1 d The donor material absorbs photons, generates excitons, and diffuses to the D–A interface, subsequently dissociating into carriers (electrons and holes) driven by the built-in electric field, which subsequently migrate to the electrode, resulting in the generation of photocurrent.…”