High‐Detectivity All‐Polymer Photodiode Empowers Smart Vitality Surveillance and Computational Imaging Rivaling Silicon Diodes

Abstract Near‐infrared (NIR) organic photodetectors (OPDs), particularly all‐polymer‐based ones, hold substantial commercial promise in the healthcare and imaging sectors. However, the process of optimizing their active layer composition to achieve highly competitive figures of merit lacks a clear direction and methodology. In this work, celebrity polymer acceptor PY‐IT into a more NIR absorbing host system PBDB‐T:PZF‐V, to significantly enhance the photodetection competence, is introduced. The refined all‐polymer ternary broadband photodetector demonstrates superior performance metrics, including experimentally measured noise current as low as 6 fA Hz^−1/2, specific detectivity reaching 8 × 10¹² Jones, linear dynamic range (LDR) of 145 dB, and swift response speed surpassing 200 kHz, striking a fair balance between sensitivity and response speed. Comprehensive morphological and photophysical characterizations elucidate the mechanisms behind the observed performance enhancements in this study, which include reduced trap density, enhanced charge transport, diminished charge recombination, and balanced electron/hole mobilities. Moreover, the practical deployment potential of the proof‐of‐concept device in self‐powered mode is demonstrated through their application in a machine learning‐based cuffless blood pressure (BP) estimation system and in high‐resolution computational imaging across complex environments, where they are found to quantitatively rival commercial silicon diodes.