Strategy to overcome recombination limited photocurrent generation in CsPbX 3 nanocrystal arrays

International audienceWe discuss the transport properties of CsPbBrxI3x perovskite nanocrystal arrays as a modelensemble system of caesium lead halide-based perovskite nanocrystal arrays. While this material isvery promising for the design of light emitting diodes, laser, and solar cells, very little work hasbeen devoted to the basic understanding of their (photo)conductive properties in an ensemblesystem. By combining DC and time-resolved photocurrent measurements, we demonstrate fastphotodetection with time response below 2 ns. The photocurrent generation in perovskitenanocrystal-based arrays is limited by fast bimolecular recombination of the material, which limitsthe lifetime of the photogenerated electron-hole pairs. We propose to use nanotrench electrodes asa strategy to ensure that the device size fits within the obtained diffusion length of the material inorder to boost the transport efficiency and thus observe an enhancement of the photoresponse by afactor of 1000