Enhancing Specific\nDetectivity and Device Stability\nin Vacuum-Deposited Organic Photodetectors Utilizing Nonfullerene\nAcceptors

Organic photodetector (OPD) studies have undergone a\nrevolutionary\ntransformation by introducing nonfullerene acceptors (NFAs), which\nprovide substantial benefits such as tunable band gaps and enhanced\nabsorption in the visible spectrum. Vacuum-processed small-molecule-based\nOPD devices are presented in this study by utilizing a blend of boron\nsubphthalocyanine (SubPc) and chlorinated subphthalocyanine (Cl<sub>6</sub>SubPc) as the active layer. Four different active layer thicknesses\nare further investigated to understand the intrinsic phenomena, unveiling\nthe suppression of dark current density while maintaining photoexcitation\nand charge separation efficiency. Experimental results reveal that,\nat an applied bias of −3 V, the 50-nm-thick active layer achieves\na remarkably low dark current density of 1.002 nA cm<sup>–2</sup> alongside a high external quantum efficiency (EQE) of 52.932% and\na responsivity of 0.226 A W<sup>–1</sup>. These impressive\nperformance metrics lead to a specific detectivity of 1.263 ×\n10<sup>13</sup> Jones. Furthermore, the findings offer new insights\ninto intrinsic phenomena within the bulk heterojunction (BHJ), such\nas thermally generated current and exciton quenching. This integration\nis potentially well-heeled to revolutionize display technology by\ncombining high-sensitivity photodetection, offering new possibilities\nfor novel display panels with sensing applications.