Boosting the Performance of Organic Photodetectors with a Solution‐Processed Integration Circuit toward Ubiquitous Health Monitoring

Abstract Organic photodetectors, as an emerging wearable photoplethysmographic (PPG) technology, offer exciting opportunities for next‐generation photonic healthcare electronics. However, the mutual restraints among photoresponse, structure complexity, and fabrication cost have intrinsically limited the development of organic photodetectors for ubiquitous health monitoring in daily activities. Here, an effective route to dramatically boost the performance of organic photodetectors with a solution‐processed integration circuit for health monitoring application is reported. Through creating an ideal metal–semiconductor junction interface that minimizes the trap states within the device, solution‐printed organic field‐effect transistors (OFETs) are achieved with an ultrahigh signal amplification efficiency of 37.1 S A⁻¹, approaching the theoretical thermionic limit. Consequently, monolithic integration of the OFET with an organic photoconductor enables the remarkable amplification of photoresponse signal‐to‐noise ratio by more than four orders of magnitude from 5.5 to 4.6 × 10⁵, which is able to meet the demand for accurately extracting physiological information from the PPG waveforms. This work offers an effective and versatile approach to greatly enhance the photodetector performance, promising to revolutionize health monitoring technologies.