Abstract
We developed organic photodetectors with high photocurrent gain by enhancing the electron tunneling from the electrode owing to the effect of interface charge trapping. Furthermore, we utilized a down-conversion material to enhance the photoresponse in the deep-ultraviolet (UV) range. As a result, the photodetectors achieved an external quantum efficiency (EQE) of as high as 4000% while the photoresponsivity remained at 9 A W-1 at the UV wavelength of 250 nm. Finally, a high-performance organic photodetector with broad-photoresponse covering the spectral range from deep-UV (200 nm) to near-infrared (1000 nm) was successfully realized. The maximum EQE exceeds 10000% at a wavelength of 780 nm, and the photoresponsivity and specific detectivity are up to 70 A W-1 and 4 x 10(12) Jones, respectively.