Proper annealing process for a cost effective and superhydrophobic ambient-atmosphere fabricated perovskite solar cell

Abstract

The conversion efficiency of perovskite solar cells has increased rapidly in recent years, however, the balance between sustainability, efficiency and cost has become a serious challenge on the way to a competitive commercial product. Currently, ongoing research is strongly focused on how to effectively combine those issues together. In this work, the sustainability and efficiency were shown to be improved by using a simple low-cost fabrication process: with a single electron transporting layer with low-temperature heat treatment (160 °C), a single-step perovskite layer (Cs0.17FA0.83Pb(I0.83Br0.17)3) fabricated and annealed in air atmosphere, and low-cost imprinted carbon as the upper electrode. The annealing process of the active layer was studied to improve crystallinity and achieve the best grain boundary self-passivation under these conditions. Moreover, to develop sustainability, an easy-to-use superhydrophobic layer with a contact angle of ∼160o was successfully deposited using an invented method. Morphology, crystallization, and optoelectronic properties of the devices were investigated using various measurement methods. It was found that a 15-min annealing at 130 °C is required to obtain an appropriate self-induced passivation layer of PbI2 and a high-performance crystallized active layer with the lowest defect density. An optimum energy conversion efficiency of 17.34% was achieved with FF, VOC and JSC values of 76.43%, 1.04 V, and 21.67 mA cm−2, respectively. It is hoped that these results will provide new perspectives for the commercialization of perovskite solar cells.