Over the last decade, perovskite solar cells have shown tremendous development for a large variety of applications i.e. flexible or tandem solar cells, in which perovskites showed to be a material with superior optoelectronic properties. However, their device stability has lagged behind the progress in power conversion efficiency. The possible strategies to address the poor lifetime and stability problems are to develop novel stable perovskite materials and encapsulate them with high-barrier performance materials. This research used both approaches to improve the overall device stability. We investigated the degradation of quadruple cation lead bromide thin films (fabricated under ambient conditions) and exposed these perovskite thin films to humidity, illumination, and elevated temperatures. For encapsulation poly(methyl methacrylate) (PMMA), silicon elastomer, novel superhydrophobic SiO2 nanoparticles, and their combination were utilized. Ultimately the development of the quadruple-cation bromide perovskite solar cells coupled with the superhydrophobic encapsulation method led to notable device stability. We demonstrated that under continuous illumination, elevated temperature (85 °C) and ambient humidity (average 60 %), 70 % of the initial efficiency could be obtained after 100 hours. Therefore, in this study by optimizing the perovskite solar cells first we could fabricate high-performance cells in ambient conditions, and by utilizing novel superhydrophobic SiO2 we could receive more than 100 hours of stability under harsh environmental conditions that pave the way for commercialization of perovskite solar cells.