Tunable transparency and detectivity in ST-OPDs enabled by donor-acceptor engineering for advanced NIR imaging application

Near-infrared (NIR) semitransparent organic photodetectors (ST-OPDs) face inherent trade-off between visible transparency and NIR detectivity. This study resolves this challenge through systematic optimization of donor-acceptor material combinations and donor contents (from 50% to 5%) across nine NIR-absorbing systems. The PTB7-Th:COTIC-4F blend uniquely achieves dual optimization of average visible transmittance (AVT) more than 59% in films and shot-noise-limited specific detectivity (D*) exceeding 1012 Jones in opaque devices across all donor contents. At 40% donor content, large-area ST-OPDs (around 1 cm2) exhibit noise-corrected D* (2.96 × 1012 Jones) at 980 nm with 28% AVT, while reducing donor content to 10% enables 41% AVT while noise-corrected D* over 1011 Jones, demonstrating tunable transparency-detectivity balance. Optimized large-area ST-OPDs resolve 100 µm features under 100 µW illumination (980 nm), validated by dual-side imaging, indicating the great potential for application in scalable NIR vision systems.