PbS quantum dots-induced trap-assisted charge injection in perovskite photodetectors

In this study, we report solution-processed photodetectors fabricated by methylammonium triiodide perovskite (CH3NH3PbI3) incorporated with PbS quantum dots (QDs) through the trap-assisted charge-injection effect. In order to increase the photo-responsivity by eliminating the charge injection barrier from the cathode electrode, PbS QDs, which possesses large amount of trap states, are introduced into the CH3NH3PbI3 thin film for establishing ohmic contact at the CH3NH3PbI3/aluminum (Al) interface. As a result, an external quantum efficiency of similar to 4500%, a photoresponsivity of similar to 15,000 mA/W and a detectivity of over 6x10(13) Jones (1 Jones=1 cmHz(1/2) W-1) at a small bias of 2 V, and a photoresponse time of 11.5 mu s are observed from the solution-processed photodetectors fabricated by the CH3NH3PbI3:PbS QDs nanocomposites thin film.