Wide channel broadband CH3NH3PbI3/SnS hybrid photodetector: breaking the limit of bandgap energy operation

Abstract

Perovskite-based hybrid organic–inorganic devices have recently demonstrated high potential in optoelectronics. Yet, the preparation of perovskite-based photodetectors over a desired scale without any complex architecture is still challenging. Herein, we proposed a new CH₃NH₃PbI₃/SnS hybrid planar broadband (365 to 850 nm) photodetector, having a wide channel length of 6 mm. The growth of the device was studied by utilizing scanning electron microscopy, energy-dispersive X-ray mapping, X-ray diffraction, and optical spectroscopies. Furthermore, the efficient charge transfer from CH₃NH₃PbI₃ to SnS was confirmed by employing time-correlated single photon counting. The pure SnS device generates 0.05 μA photocurrent at 365 nm, 4 mW cm⁻², which is notably enhanced 140 times after embedding with CH₃NH₃PbI₃. Further, the hybrid device shows a significant photoresponse even below the band gaps of individual CH₃NH₃PbI₃ or SnS, which matches well with the density functional theory prediction. The observed results will create new opportunities to develop and design a low-cost, broadband, and efficient photodetector over a chosen horizontal area.