Surface morphological, optical and electrical characterization of methylammonium lead bromide perovskite (CH3NH3PbBr3) thin film

Hybrid halide perovskites (CH3NH3PbX3; X=F, Cl, Br and I) have been emerging as innovative candidates in the development of optoelectronic devices. In this paper, a methylammonium lead bromide (CH3NH3PbBr3) perovskite-based heterojunction device of architecture FTO/PEDOT:PSS/CH3NH3PbBr3/PC61BM/Al has been fabricated using a low-cost spin casting method. PEDOT:PSS and PC61BM layers serve as the hole transport layer (HTL) and the electron transport layer (ETL), respectively. The photoluminescence and absorbance spectrum of perovskite have been determined with an extracted band gap using a Tauc plot. The electrical characterization of the device has been carried out using current-voltage and impedance measurements. A dark current measurement reveals low leakage current, which can be attributed to the blocking effect of the PEDOT:PSS and PC61BM layers. The photocurrent generation in the device has been explained by the energy level diagram, and the role of the ETL and HTL identified. The device exhibits the ideality factor 2.37 in the dark and 1.79 under illumination. The parameters show good correlation with the I–V results.