Synergistic effects of hole blocking and Förster resonance energy transfer process in high-performance photomultiplication organic photodetectors

Organic photodetectors (OPDs) are a potential next-generation photodetection technology because they are lightweight, flexible, and have customizable spectral responses. However, high dark currents with low detectability remain major challenges, limiting the widespread application of photomultiplication OPDs (PM-OPDs). This work describes a straightforward interface modification strategy based on the PBDB-T:N2200 bulk heterojunction (BHJ) structure to improve the PM-OPD performance. Introducing a thin rubrene layer achieves the synergistic effects of hole blocking and the Förster resonance energy transfer (FRET) process, resulting in a two-order-of-magnitude reduction in dark current density and an increased responsivity of 19.77 A W−1 at 660 nm. Moreover, the external quantum efficiency improves significantly through FRET, and a specific detectivity of 4.39 × 1013 Jones is demonstrated at 660 nm, which is the highest value among existing PM-OPDs, using BHJ structures. An impressive increase in the linear dynamic range from 91 to 144 dB was obtained due to the improved photocurrent density and balanced charge transport. The broad applicability of the strategy was verified through a PM6:Y6-based OPD system. Our approach offers more general application prospects by improving the detection capability of photodetectors for low-light environments.