Abstract
Organic-inorganic hybrid perovskites are ideal materials for photodetection owing to their high charge carrier mobility, long charge carrier diffusion length, low dark current density and sharp absorption edge. However, a relatively small band gap (1.6 eV) limits their photo-nharvesting efficiency in the near-infrared region. In the present work, we demonstrate a hybrid methylamine iodide and Pb-Sn binary perovskite as the light absorption layer in photodetectors. Experimentally, the wavelength of photo-response onset for the photodetectors can be extended to as great as 1,000 nm when the Sn content of the hybrid perovskite is increased to 30 mol%. In addition, the photodetectors exhibit a photoresponsivity of 0.39 A W-1 a specific detectivity of 7x10(12) Jones, a fast photoresponse with rise and decay time constants and an external quantum efficiency greater than 50% in the wavelength range of 350-900 nm, with a maximum value of about 80% at 550 nm.