Heteroatom-Tailored Benzo[1,2,4]triazine Core: A Promising Building Block for High-Efficiency Non-Fullerene Acceptors
Zihao Deng , Yongwen Lang , Jiaquan Huang , Yunpeng Wang , Hanjian Lai , Mingpeng Li , Meihong Ou , Yuanzhu Zhang , Feng He
Chinese Journal of Chemistry ›› 2026, Vol. 44 ›› Issue (7) : 1001 -1010.
The rapid development of non-fullerene acceptors (NFAs), particularly Y6 and its derivatives, has propelled organic photovoltaics (OPVs) to power conversion efficiencies (PCEs) exceeding 20%. This achievement stems from the rational design of core structures that regulate energy levels, optical absorption, and molecular packing. However, the potential of the 1,2,4-triazine motif remains underexplored despite its unique electronic features. Here, we introduce the benzo[1,2,4]triazine (BTAZI) core as a promising building block for NFAs. Density functional theory calculations reveal that BTAZI possesses lower-lying energy levels than the benzothiadiazole (BT) unit in Y6, arising from its reduced electron density. Through heteroatom substitution (S, O, and Cl), we finely tune the σ-inductive and p-π conjugative effects, yielding three BTAZI-based acceptors: BTAZI-IC-SMe, BTAZI-IC-OMe, and BTAZI-IC-Cl. Among them, BTAZI-IC-SMe achieves an optimal balance between molecular orbital alignment and absorption profile with the donor polymer D18, affording a PCE of 18.14%, surpassing the others. This study highlights the benzo[1,2,4]triazine framework as a new core unit for efficient NFAs and offers valuable insights into the molecular design of high-performance and stable OPVs.
Organic solar cells / Quasiplanar heterojunction (Q-PHJ) / 1,2,4-Triazine / Single crystal / Energy level tuning / Meisenheimer complexes / Crystals / Crystal structure / Functionalized units
2026 SIOC, CAS, Shanghai, & WILEY-VCH GmbH
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