Enhancing Photodetectivity of Si/Perovskite Heterojunction-Based Broad Spectral Photodiodes by Introducing C60 Hole Blocking Layer

The applications of broad spectral photodetectors in the fields of biological imaging and environmental remote sensing have received considerable attention in the past decades. However, the specific photodetectivity representing the lowest optical signal that can be detected by a photodetector remains unsatisfactory. Here. we reported the unprecedent enhancement of specific photodetectivity of broad spectral photodiodes based on the heterojunction of p-Si/polyvinyl pyrrolidone (PVP)-modified perovskite by introducing fullerene (C60) as the hole blocking layer (HBL). The results showed that, by inserting a C60 HBL between the PVP-perovskite and the top electrode, the dark current is significantly reduced and strongly dependent on C60 thickness. The dark current reaches a minimum at C60 thickness of 10 nm, which is only roughly one-thirtieth of that without the C60 layer. At the optimized C60 thickness, the specific photodetectivity is enhanced about an order of magnitude due to significantly reduced dark current, while the photoresponsivity (
${R}$
) only slightly reduced.