Double-side operable perovskite photodetector using Cu/Cu₂O as a hole transport layer

In this study, a perovskite is integrated with an ultra-thin Cu/Cu₂O (CCO) composite film, a transparent material with high mobility, to achieve a double-side and low-voltage operable photodetector. Compared to photodetectors that utilize metal electrode with perovskite, the use of CCO significantly enhances the photocurrent (from nA up to mA). It acts as a large-scale hole transport layer. The photodetector exhibits high responsivities of 6.79 AW^-1 [illuminated via the fluorine-doped tin oxide (FTO) side] and 10.23 AW^-1 (illuminated via CCO side). The detectivities obtained at both illuminated sides are as high as over 10¹¹ Jones. Additionally, the Cu/Cu₂O-covered perovskite effectively prevents the reaction of perovskite in the interface. This work reveals that the perovskite/CCO heterojunction photodetector can be considered a promising candidate for applications in bifacial-illuminated and flexible/wearable optoelectronic technologies.