Wenli Lv

Ultrasensitive flexible broadband photodetectors achieving pA scale dark current

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.Semiconductor physics: Energy saving flexible broadband hybrid photodetectorEnergy efficient and flexible alternative photodetector that detects both visible and invisible light comes closer to real life than ever. A group of researchers from China has developed an organic-inorganic hybrid photodetector that outperforms conventional inorganic like Si and InGaAs-based photodetectors in at least two aspects: broader detection spectral range and much lower dark current. Thanks to the structural flexibility of two hybrid photosensitive materials, methyl-ammonium lead halide and lead phthalocyanine, the team engineered the large area sub-micron thick photodetector with porous structures, which is the key to reducing the standby power consumption by more than 30 times compared to the best InGaAs and Si-based photodetectors. More importantly, the hybrid photodetector needs no additional apparatus or power to cool it for continuous operation, in contrast to the InGaAs photodetector.

Achieving Weak Light Response with Plasmonic Nanogold-Decorated Organic Phototransistors

Weak light response of organic photodetectors has fascinating potentials in fields of modern science and technology. However, their photoresponsivity is hindered by poor photocarrier excitation and transport. Decorating active-layer surface with plasmonic nanometals is considered a viable strategy to address this issue. Here, we demonstrate a plasmonic nanogold decorated organic phototransistor achieving remarkable enhancement of photoresponsivity. Meanwhile, the photoresponsive range is broadened by 4 orders of magnitude. The proposed design is substantiated by a schematic energy level model combined with theoretical simulation analysis, enabling the development of the advanced optoelectronics.