Phytate modifies the hole transport layer and assists in blade coating to prepare efficient perovskite solar cells

The blade coating method is considered a promising large-scale manufacturing technology for its economy and applicability to the large-scale roll-to-roll process. However, the performance of devices currently produced by doctor blade coating remains lagging behind that of spin-on devices for their low film quality and inadequate coverage. In this study, an inter-layer of physic acid sodium (PAS) was introduced between the NiOx hole transporting layer (HTL) and the perovskite absorption layer to enhance the film quality and coverage. By regulating the flow and the drying process of the one-step perovskite solution in dimethyl sulfoxide (DMSO) and gamma-butyrolactone (GBL) solvent, a complete high-quality perovskite film was formed, and the domain size considerably increased from about 50 mu m to 100-200 mu m. According to the lower VB value of - 5.3 eV achieved by the PAS modified NiOx film, the device with PAS inter-layer could more effectively fit energy level and extract holes. Moreover, PAS also promoted a better contact between NiOx layer and the perovskite layer; thus, the filling factor (FF) was up-regulated from 52.96% to 60.82% by enhancing the interfacial properties. Lastly, the power conversion efficiency (PCE) of the perovskite solar cell device fabricated by doctor blade coating in the atmospheric environment was up-regulated from 10.07% to 13.19% (aperture, 1 cm(2)). The finding of this study can guide the preparation of perovskite films by doctor blade coating.