High-sensitivity deep shortwave infrared organic photodetectors enabled by selenium-integrated quinoidal molecular semiconductor

Developing organic photodetectors (OPDs) that can detect in deep shortwave infrared (deep-SWIR) region (1.2–1.6 μm) is technologically important. Yet, the performance of the state-of-the-art deep-SWIR OPDs remains substantially limited. Herein, we report a selenium-integrated quinoidal small molecular acceptor, SeBz-4Cl, enabling highly sensitive deep-SWIR photodetection. Selenium incorporation enhances quinoidal character along the conjugated backbone of the molecules, thus expanding absorption approaching 1.5 μm. Moreover, SeBz-4Cl with strengthened intermolecular interactions led to an ideal film morphology, which reduced Urbach energy and favored charge dynamics. Under −1 V voltage bias, the SeBz-4Cl-based OPD achieved a low dark current density of 2.97 × 10−7 A cm−2 and an external quantum efficiency (EQE) of 7.8% at 1310 nm, together with a high specific detectivity (D*) exceeding 1011 Jones across 500–1400 nm, representing advanced deep-SWIR OPD performance. Furthermore, an optical communication system and a flexible imager under 1.2 μm illumination were demonstrated, highlighting potential of these deep-SWIR OPDs for information electronics and next generation optoelectronic applications in future. Organic photodetectors for deep shortwave infrared light remain limited in sensitivity and spectral reach. Wei et al. developed a selenium-integrated molecule with a high specific detectivity exceeding 1011 Jones across 500–1400 nm, which enables flexible imaging and optical communication.