Dilution Effect for High-Performance Multiple-Component Near-Infrared Organic Photodetectors

Despite the demonstrated efficacy of multiple-component (MC) blends in enhancing the performance of near-infrared organic photodetector (NIR-OPD), elucidating the fundamental working mechanism and material design criteria is still crucial for further optimizing MC NIR-OPDs. Here we elucidate a dilution effect as mechanism in MC-OPDs featuring two highly miscible constituents. Compared with the binary NIR-OPD, the MC device with dilution effect enables higher luminescence quantum efficiencies for suppressing non-radiative decay, significant reduction in dark current density (J_d) to 1.52 × 10^-10 A cm^-2 at -0.2 V, and leading to a high detectivity (D^*) of 6.98 × 10¹³ Jones at 840 nm. Additionally, we revealed that electrons can transfer between different acceptors, governed by their energy level offset, which contributes to the largely unperturbed charge transport and faster response time of 0.63/3.59 µs. Moreover, we successfully validate the efficacy of dilution effect in high-fidelity pulse signal detection and low-light NIR imaging, demonstrating great promise for next-generation wearable health/imaging-monitoring technologies.