Low-pressure assisted solution synthesis of CH₃NH₃PbI_3-xCl_x perovskite solar cells

During the preparation of perovskite film, the common one-step method always generates an island-like structure. Large exposed areas lead to direct contact between positive and negative electrodes. Thus, the photoelectric performance is seriously deteriorated. Here, a low-pressure assisted method was introduced to fabricate dense halide perovskite films. The crystalline quality of the films was investigated by X-ray diffraction (XRD) spectroscopy. The film morphology and the device structure were characterized by atomic force microscope (AFM) and field emission scanning electron microscopy (FESEM). The effects of film quality on charge transport were discussed. After low-pressure treatment, the open-circuit voltage (V_oc), short-circuit photocurrent (J_sc), fill factor (FF) and power conversion efficiency (PCE) for the device were improved to 0.755 V, 20.045 mA cm⁻², 0.52% and 7.9%, respectively. The optimized and centrally distributed performance parameters illustrate that the low-pressure assisted method can be used to improve the quality and uniformity of perovskite films.