Ultrasensitive flexible broadband photodetectors achieving pA scale dark current

Abstract

Organolead halide perovskite is a newly emerging low-cost, solution-processable material with a broadband absorption from the ultraviolet (UV) to visible (Vis) region, which has attracted a great deal of interest in high-performance optoelectronic devices. However, some practicable applications need a cover of UV–Vis–NIR region for photoelectric conversion, a task that remains a significant challenge for further extending the absorption toward the near-infrared radiation (NIR) region. Here, to the best of our knowledge, we prove for the first time an ultrasensitive flexible broadband photodetector based on porous organolead perovskite-phthalocyanine heterostructure, which combines the synergetic properties of high UV–Vis absorbance of perovskite with enhanced NIR absorption for triclinic lead phthalocyanine. The photosensitivity of the as-prepared devices reaches up to 104 at a low intensity of 10 mW cm−2, which is among the largest values reported for broadband photodetectors. Significantly, performed at room temperature, the device achieves a pA scale dark current along with an ultrafast response speed of less than 0.6 ms for as-adopted full spectra. Our results provide an easy and promising route to develop low-cost, flexible and highly sensitive UV–Vis–NIR photodetectors.