MAPbI 3 Photodetectors with 4.7 MHz Bandwidth and Their Application in Organic Optocouplers.

The photodetector based on methylammonium lead iodide (MAPbI 3 ) 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 2 ). Here, when a cosolvent strategy to manipulate the thickness and the crystallinity of the MAPbI 3 film is adopted, photodetectors with a -3 dB bandwidth of 4.7 MHz are achieved (at 0.16 cm 2 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 3 -based photodetectors.