This PhD project investigates two independent strategies for suppressing dark current in organic photodetectors, aiming to enhance their overall detectivity.

From a material design perspective, bulky polymer donors with sterically hindered side chains were synthesized to introduce efficient hole-trapping effects, resulting in a significant reduction in dark current.

From a device architecture standpoint, a gradient bulk heterojunction (BHJ) structure was developed, enabling further suppression of leakage current compared to conventional BHJ devices.

Based on these approaches, high-performance organic photodetectors were successfully fabricated, including short-wave infrared (SWIR) devices with spectral response beyond 1200 nm and semitransparent photomultiplication-type photodetectors.

These results demonstrate effective pathways for advancing low-noise, flexible optoelectronic devices for future imaging and sensing applications.