Progress in Near-Infrared Organic Photodetector Research

Release time：

2025-11-21

Flexible sensors demonstrate promising applications across diverse fields including wearable electronics, embodied intelligence, and biomedical imaging.Organic photodetectors (OPDs) based on conjugated polymer photosensitive materials have gained significant attention due to their intrinsic flexibility, low cost, and low power consumption.Current flexible OPDs still face challenges such as relatively low detection performance and inadequate mechanical stability, limiting their practical applications.

Researchers from the Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, have developed a novel polymer donor material (PBPyT) and systematically investigated its molecular structure-packing morphology relationship, thereby significantly enhancing the detection performance and mechanical stability of flexible near-infrared OPDs.

The research team proposed a molecular design strategy based on localized molecular packing modulation. By incorporating the strong electron-withdrawing thiadiazolopyridine (PyT) unit, they enhanced intermolecular interactions between polymer chains, optimized crystalline domains, and achieved rapid charge transport in the photoactive layer.Concurrently, the steric hindrance effects from alkylthiophene bridges induced molecular chain distortion, leading to localized disordered packing that creates stress dissipation sites.The study systematically revealed the key modulation mechanism governing the "molecular structure–packing morphology–device performance" relationship.Flexible OPDs based on the novel polymer donor PBFPyT minimize performance degradation during fabrication and operation while exhibiting significantly enhanced mechanical stability.

Furthermore, by leveraging alkyl side chains to modulate intermolecular interactions and molecular packing, the team developed the PBPyT-EH donor with exceptional performance and versatility. This donor exhibits significantly enhanced intermolecular interactions, inducing highly ordered π-π stacking in the photoactive layer, which promotes charge transport while effectively suppressing defect state density.The PBPyT-EH-based near-infrared OPDs achieved a dark current density (Jd) of 1.88 nA/cm², responsivity (R) of 0.542 A/W, and specific detectivity (D*) of 2.2×10¹³ Jones.

These research results have been published in Advanced Functional Materials and Chemical Engineering Journal.This research was supported by the Shandong Provincial Natural Science Foundation, among other projects.