Enhanced Exciton Delocalization in Organic Near-Infrared Photodetectors via Solid Additive-Mediated J-Aggregation

Near-infrared organic photodetectors (NIR-OPDs) have emerged as increasingly significant in optoelectronics, offering unparalleled advantages for applications in health monitoring and night vision. The development of self-powered devices with low dark currents and enhanced NIR sensitivity involves complex engineering that requires careful material selection, defect state density control, and environmental consideration. In this study, an innovative approach is introduced that utilizes solid additive (DIB) to induce improvements in the J-aggregation morphology and exciton delocalization in acceptor molecules. The goal is to broaden the response spectrum of the device and augment its detection capabilities. The key findings revealed that solid additive exhibit an electrostatic affinity for acceptors, which facilitates their orderly face-to-face stacking and controls the π-π stacking distance. These enhanced intermolecular interactions lead to the delocalization of electron-hole pairs, reduced exciton recombination, and increased charge separation efficiency. Consequently, the modified devices exhibited exceptional specific detectivity, exceeding 10¹⁴ Jones across the wavelength range of 695-860 nm, thereby establishing a new standard for NIR response in organic photodetection. Overall, this study successfully addressed the compatibility challenges associated with self-powered NIR-OPDs, thereby expanding their potential applications in various settings.