Flexible near-infrared polarized photodetector based on CuPc single crystal grown by microspacing in-air sublimation

Abstract

Organic semiconductor crystals with outstanding intrinsic properties, such as great charge transport properties, long exciton lifetimes and diffusion lengths, provide new opportunities for fabricating high-performance optoelectronic devices. High-performance organic photodetectors have been demonstrated in both ultraviolet (UV) and visible regions, while there are some challenges in designing and fabricating high-performance near-infrared (NIR) photodetectors with polarization response. Herein, we demonstrate a high-performance organic phototransistor based on a CuPc single crystal grown by a simple air sublimation method. The device shows an excellent broadband response covering the UV and NIR range, and the NIR responsivity can reach up to 200 A W⁻¹ at 785 nm, together with a good −3 dB bandwidth of ∼4 kHz. Intriguingly, this device exhibits excellent polarization detection performance and also achieves the special optical reversal from the visible region to the near-infrared range. Benefiting from its outstanding sensitivity and fast operation speed, we realized several high-resolution single-pixel images in the UV, visible and NIR ranges. Finally, remarkable mechanical flexibility and environmental robustness were also verified in the flexible device on a PET substrate, which retained good conductivity and stable photon detection after 1000 bending cycles even under severe bending conditions. The results suggest that the high-quality organic single crystal is a promising platform for future high-performance wearable polarized optoelectronics, and also suitable for high-speed imaging applications.