Minimizing Thermally Activated Carrier Generation for Ultra-Low Dark Current Density and Enhanced Thermal Stability in Air-Stable All-Polymer Photodetectors

We introduce a ternary blend strategy that effectively mitigates dark current density (Jd) in organic photodetectors (OPDs). By incorporating PTQ10 into the PM6:PY-IT system, we significantly reduce non-radiative recombination and trap density. The addition of PTQ10 to the PM6:PY-IT blend film not only suppresses unfavorable molecular packing but also modifies energy level alignment within the ternary system, thereby suppressing leakage current generation. This leads to improved device performance without compromising responsivity. The addition of PTQ10 to PM6:PY-IT blend films not only suppresses unfavorable molecular packing but also optimizes energy level alignment in the ternary system, thereby suppressing thermally activated carrier generation. This results in a remarkably low Jd of less than 10–9 A cm–2 under a −2 V bias, outperforming control binary OPDs and setting a new benchmark for OPD performance in the literature. Additionally, the optimized ternary OPD exhibits an impressive detectivity (Dsh) of 5.00 × 1013 Jones at −2 V (measured at 830 nm). These devices also demonstrate a high cut-off frequency, good linear dynamic range, and ultrafast response time, making them highly suitable for market development. The ternary OPD demonstrated exceptional environmental and thermal robustness, retaining over 89% of its initial Rλmax after prolonged exposure to 120 °C thermal stress and 98% under air conditions (25 °C, 40% relative humidity). This approach underscores the potential of cost-effective OPD technology with superior performance metrics.