POS5-1182
Efficient Dark Current Suppression in Organic Photodiodes via Solid Additive-Assisted Morphology Control
When and Where
Nov 30, -0001
00:00 - 00:00
Presenter(s)
ChangWoo Yu (Kongju National University)
Co-Author(s)
Abstract
Organic photodiodes (OPDs) have attracted significant attention as next-generation optical and image sensor devices due to their excellent mechanical flexibility and tunable absorption across a wide spectral range. However, during the formation of the active-layer thin film, solvent evaporation induces molecular disorder and macroscopic phase separation, which generates a high density of structural trap states. These defect states facilitate leakage charge transport under reverse bias, resulting in elevated dark current and severely degrading the signal-to-noise ratio (SNR) and specific detectivity of the device. To overcome these limitations, we introduced solid additives into the active layer to precisely control the nanoscale morphology and effectively suppress dark current. Analysis verified that the solid additive precisely regulated the molecular aggregation and crystallization behaviors, preventing excessive aggregation between donor and acceptor molecules, while promoting ordered π–π stacking orientation of polymer chains. This induced the formation of an ideal bi-continuous nanofibrillar phase-separated network for charge transport. Such structural optimization significantly reduced the trap density within the thin film, thereby blocking the trap-limited dark current mechanism under reverse bias. As a result, leakage current pathways were eliminated, leading to markedly improved noise characteristics in the dark state. Simultaneously, the nanofibrillar morphology enhanced photocharge extraction, yielding synergistic improvements in fill factor (FF) and photoresponse efficiency. This study clearly demonstrates that solid-additive-assisted microstructural control of thin films provides a practical and essential methodology for realizing high-performance, low-noise organic photodetectors suitable for commercialization.
