Aggregation-Controlled Vacuum-Deposited Non-Fullerene Acceptors for High-Performance Organic Photodetectors

Solution-processed organic photodetectors (OPDs) have been widely investigated for low-cost and large-area optoelectronic applications. However, their practical use is still limited by insufficient scalability and reproducibility. Vacuum-deposited OPDs offer an attractive alternative due to their precise thickness control, high film uniformity, and compatibility with established OLED manufacturing processes. Nevertheless, most vacuum-deposited OPDs still rely on fullerene-based acceptors, which suffer from limited absorption tunability, high material cost, and insufficient thermal robustness, thereby restricting further material diversification and performance improvement. Herein, we report a series of vacuum-depositable donor–acceptor non-fullerene acceptors (NFAs) designed by systematically modulating acceptor electronegativity. These structural modifications cause only minor changes in frontier energy levels but strongly alter intermolecular interactions and aggregation behavior in thermally evaporated films. Notably, increased acceptor electronegativity induced pronounced J-aggregation, which extends intermolecular electronic coupling, improves molecular ordering, and reduces energetic disorder. This J-aggregate-driven ordering effectively reduced trap-state formation, thereby suppressing trap-assisted recombination, noise current, and the voltage dependency of dark current under reverse bias. As a result, the NFA-based OPDs exhibited markedly improved responsivity, specific detectivity, bias-stable dark-current characteristics, and thermal stability compared with conventional C60-based devices. The optimized device outperformed the fullerene reference, demonstrating that J-aggregation control is an effective strategy for enhancing vacuum-deposited OPD performance. Furthermore, the optimized vacuum-deposited NIR-OPD was seamlessly integrated with a CMOS platform, enabling high-performance NIR imaging. These findings establish aggregation-oriented molecular design as a viable route to replacing fullerene acceptors and expanding the material platform of high-performance vacuum-deposited OPDs.