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

Abstract

ABSTRACT 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 10 12 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.