Solution-Processable Pyrite FeS2 Nanocrystals for the Fabrication of Heterojunction Photodiodes with Visible to NIR Photodetection



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A heterojunction photodiode with NIR photoresponse using solution processable pyrite FeS2 nanocrystal ink is demonstrated which has the advantages of earth-abundance and non-toxicity. The device consists of a FeS2 nanocrystal (NC) thin film sandwiched with semiconducting metal oxides with a structure of ITO/ZnO/FeS2 NC/MoO3/Au, which exhibits an excellent photoresponse with a spectral response extended to NIR wavelengths of up to 1150 nm and a high photocurrent/dark current ratio of up to 8000 at -1 V under AM1.5 illumination (100 mW cm−2).