Solution-processed visible-blind UV-A photodetectors based on CH3NH3PbCl3 perovskite thin films

Abstract

In this contribution, methylammonium lead trichloride (CH₃NH₃PbCl₃) perovskite thin films were fabricated via a two-step spin coating and solvent-vapor-assisted thermal annealing method at low temperature. The films exhibited a cubic crystalline structure and pinhole-free morphologies. The possible charge traps were investigated via the analysis of photoluminescence (PL) spectra of perovskite films prepared with different lead chloride (PbCl₂) precursor concentrations while maintaining the same concentration of methylammonium chloride (CH₃NH₃Cl). Prototypical ultraviolet (UV) photodetectors with the structure of ITO/CH₃NH₃PbCl₃/poly(triaryl amine) (PTAA)/Al were fabricated and showed a low dark current density of 1.60 × 10⁻⁵ mA cm⁻² under a reverse bias of −1 V, a strong photoresponse in the 300–400 nm region, and a high UV-visible rejection ratio of up to 500 under a bias of 0 or −0.5 V. All the results demonstrated that low-temperature solution-processed CH₃NH₃PbCl₃ perovskite thin films offer great potential for making flexible, lightweight visible-blind UV-A photodetectors.