ИСТИНА

Organic photovoltaics (OPVs), in particular organic solar cells (OSCs), have attracted considerable interest from the international scientific community as a promising renewable energy technology with sustainable potential [1-3]. The innovative ternary OSC concept, in which three different components are mixed to form a photoactive layer, offers opportunities to enhance the power conversion efficiency (PCE) – for example, by broadening the absorption range, improving the mixture morphology, or tuning the exciton splitting and charge extraction. Due to these possibilities, ternary systems are among the best OSCs in terms of long-term stability efficiencies, and will play a crucial role in the future of organic photovoltaics. In recent years, ternary OSCs have achieved remarkable progress with PCE exceeding 19% [4]. The integration of non-fused ring electron acceptors (NFREAs), a recently emerged class of acceptor materials, has the potential to enhance efficiency, improve stability, and reduce device cost. The design of NFREAs involves the implementation of conformational locking and steric hindrance strategies, which are employed to minimize conformational transitions of molecules and attain the desired planarity and rigidity of structures. NFREA-based OSCs have recently demonstrated PCEs exceeding 17% in binary systems, signifying promising outcomes [5]. Nonetheless, NFREAs are in the nascent stages of development and necessitate further research to address significant challenges. These challenges include the development of novel low molecular weight and polymeric NFREAs, the enhancement of stability, environmentally friendly synthesis methods and scalability, and a more profound understanding of molecular structure-properties-device performance relationships. Additionally, there are only a few works on ternary OSCs using NFREAs [6], which renders this topic highly promising and in demand. In this study, four novel NFREAs were designed and synthesized, with their chemical structures confirmed using a complex of modern techniques of analysis. The synthesized compounds demonstrated high thermal and thermo-oxidative stability, strong absorption in the red and near-infrared spectral ranges, excellent solubility in organic solvents, and a high degree of crystallinity. Furthermore, the NFREAs exhibited narrow bandgaps and well-optimized HOMO and LUMO energy levels, rendering them promising candidates for OSC applications. The photovoltaic performance of the synthesized NFREAs was evaluated in binary and ternary blends with commercially available PM6 donor and Y6 acceptor materials. Ternary OSC prototypes demonstrated that the incorporation of these NFREAs enhances photon absorption in the 620–680 nm range, resulting in more efficient charge carrier generation. Furthermore, the presence of NFREAs improves the morphology of the photoactive layer, leading to an exceptional power conversion efficiency (PCE) exceeding 18%, which is comparable to record efficiencies in the field. This study highlights the effectiveness of a multicomponent strategy in improving the performance of NFREA-based OSCs through spectral complementarity and morphology optimization, providing valuable insights for the development of next-generation non-fullerene acceptors. The work was carried out with financial support from the Ministry of Science and Higher Education of the Russian Federation (contract No. 075-15-2024-532-2 within the framework of grant No. 075-15-2024-532).