Fullerene-based electrode interlayers for bandgap tunable organometal perovskite metal–semiconductor–metal photodetectors

Perovskite photoconductor-type photodetector with metal-semiconductor-metal (MSM) structure is a basic device for photodetection applications. However, the role of electrode interlayer in MSM-type perovskite devices is less investigated compared to that of the pin diode structure. Here, a systematic investigation on the influence of phenyl-C-61-butyric acid methyl ester (PCBM) and indene-C-60 bisadduct (ICBA) interfacial layers for MSM perovskite photodetectors is reported. It is found that the fullerene-based interlayer significantly enhances the photocurrent of the MSM photodetectors. On one hand, the PCBM interlayer is more suitable for CH3NH3PbI3 photodetector, with the responsivity two times higher than that of the device with ICBA interlayer. The ICBA layer, on the other hand, becomes more effective when the band gap of perovskite is enlarged with bromine composition, denoted as CH3NH3Pb(I1-xBrx)(3) (0 <= x <= 1). It is further found that the specific detectivity of photodetectors with ICBA interlayer becomes even higher than those with PCBM when the bromine compositional percentage reaches 0.6 (x > 0.6).