Fabrication of All-Polymer Organic Photodetectors by Optimizing Processing Conditions for Photoactive Layer

All-polymer organic photodetectors (OPDs) offer mechanical flexibility and spectral tunability; however, their performance is highly sensitive to morphology and charge transport balance in photoactive layer.In this work, we systematically investigate the effects of film thickness, postthermal annealing temperature, and donor-acceptor (D:A) ratio on the photodetection characteristics of poly [(2,6-(4,8-bis(5-(2ethylhexyl)OPDs.Thickness optimization reveals a trade-off between optical absorption and carrier transport, leading to an optimal film formation condition that minimizes dark current while maintaining sufficient photocurrent generation.Post-thermal annealing enhances molecular ordering and responsivity at moderate temperatures, whereas excessive annealing induces aggregation and performance degradation.Furthermore, D:A ratio engineering demonstrates that responsivity and detectivity are maximized under different blend compositions, reflecting the interplay between interfacial exciton dissociation and charge percolation pathways.The optimized devices exhibit enhanced specific detectivity and wide linear dynamic range at both 650 and 808 nm.This study establishes a systematic parameter optimization framework for balancing signal and noise in all-polymer OPDs and provides practical design guidelines for high-performance near-infrared photodetection.