MAPbI Photodetectors with 4.7 MHz Bandwidth and Their Application in Organic Optocouplers.

The photodetector based on methylammonium lead iodide (MAPbI) is a promising device for wide wavelength range (380-780 nm) sensitivity. However, its industrial application is limited by the relatively low response speed to the light signal, which has received little attention. Only a few reports show low-bandwidth characteristics (less than 1 MHz at 0.1 cm). Here, when a cosolvent strategy to manipulate the thickness and the crystallinity of the MAPbI film is adopted, photodetectors with a -3 dB bandwidth of 4.7 MHz are achieved (at 0.16 cm photo detecting area). The performance is significantly better than most of the organic and hybrid photodetectors reported so far. Based on this photodetector and an organic light-emitting diode (OLED), an organic optocoupler system with 1 MHz response frequency is successfully set up. Our results suggest that thickness-manipulated cosolvent strategy is a promising method in high-speed MAPbI-based photodetectors.