Highly Sensitive All‐Polymer Short‐Wavelength Infrared Photodetectors for Complementary Metal Oxide Semiconductor Integrated Imaging Enabled by Dual‐Acceptor n‐Type Polymers

Short-wavelength infrared (SWIR) organic photodetectors (OPDs), particularly all-polymer ones, hold substantial commercial promise in vital monitoring and imaging. However, the development of all-polymer SWIR OPDs has been limited by the lack of high-performance n-type ultralow-bandgap polymer semiconductors. Herein, we report two dual-acceptor polymers (ThDPP-CNBTz and ThDPP-CNBSz), with dicyano-benzothiadiazole/benzoselenidazole as strong acceptor units, diketopyrrolopyrrole as a sub-strong acceptor unit, and thiophene as a donor moiety. Both polymers possess ultralow optical bandgaps and deep HOMO/LUMO, making them ideal acceptor materials for all-polymer SWIR OPDs. Owing to more efficient charge generation and transport, ThDPP-CNBTz-based all-polymer OPDs show superior responsivity ≥0.150 A W^-1 from 780 to 1060 nm. The ThDPP-CNBSz-based OPDs show lower noise currents, attributed to the larger thermal activation energy of dark current and lower trap density. As a result, ThDPP-CNBTz- and ThDPP-CNBSz-based OPDs deliver similar specific detectivity, exceeding 10¹² Jones in the spectral range of 780-1140 nm and 350-1240 nm, respectively. Furthermore, ThDPP-CNBTz-based stretchable OPDs show a small performance attenuation after 1000 cycles of stretching at 20% strain, heralding potential application in wearable vital monitoring. By monolithically integrating PDPP-3T:ThDPP-CNBTz-based OPDs with silicon-based readout integrated circuits, high-resolution imaging has also been demonstrated for infrared penetration and material discrimination.