Abstract

• In recent years, lead halide perovskite solar cell efficiency has tremendously reached up to 22.7% due to excellent optoelectronics properties with various fabrication methods. However, stability in ambient air for perovskite solar cells is a lack of effective solution to the problem until now. On the other hand, fabrication processes in a glovebox are strictly limited for large scale production due to high operational costs. Hence, perovskite films are fabricated by two-step deposition method in ambient air relative humidity (RH) of 45 ± 5% to acquire high quality films and good crystallization. For the first step, 1 M of lead iodide/N, N-dimethylformamide (PbI2/DMF) solution is deposited on the glass substrate. In a second step, separated amount of 10 to 25 mg of methylammonium iodide (MAI) in 1 ml of isopropanol (IPA) solution is deposited on the PbI2 film. To optimize the highpurity phase, 1% of N, N-dimethylformamide (DMF) is added to MAI/IPA solution. Meanwhile, residual PbI2 peaks transform in the final perovskite films indicate that DMF additive increases the full reaction state of perovskite film. Furthermore, three different annealing times (10, 15 and 30 min) are investigated at 110 ℃ in air. The highest purity phase achieved for 25 mg/ml (MAI/IPA) increases crystalline size up to 51.8 nm from 35.2 nm (10 mg/ml) analyzed by X-ray diffraction (XRD) and ultraviolet−visible (UV−vis) spectrum exhibits higher absorbance intensity in the longer wavelength as well. Thus, solvent additive method facilitates mass production fabricated in an ambient environment due to increase crystalline growth of perovskite films.