Broadband, sensitive and spectrally distinctive SnS nanosheet/PbS colloidal quantum dot hybrid photodetector.

Photodetectors convert photons into current or voltage outputs and are thus widely used for spectroscopy, imaging and sensing. Traditional photodetectors generally show a consistent-polarity response to incident photons within their broadband responsive spectrum. Here we introduced a new type of photodetector employing SnS nanosheets sensitized with PbS colloidal quantum dots (CQDs) that are not only sensitive (~10 A W) and broadband (300-1000 nm) but also spectrally distinctive, that is, show distinctive (positive or negative) photoresponse toward incident photons of different wavelengths. A careful mechanism study revealed illumination-modulated Schottky contacts between SnS nanosheets and Au electrodes, altering the photoresponse polarity toward incident photons of different wavelengths. Finally, we applied our SnS nanosheet/PbS CQDs hybrid photodetector to differentiate the color temperature of emission from a series of white light-emitting diodes (LEDs), showcasing the unique application of our novel photodetectors.