Perovskite Solar Cells are an increasing attraction in research with great strides in performance efficiencies. But their commercialization is far from fruition, due to persistent issues. Stability under prolonged exposure to external stresses is a major concern. Furthermore, the adaption of upscaling technologies in research is presently slow. This research is done on a fully scalable architecture, fabricated with technologies adaptable to mass-production. Variations in active layer (dual cation and triple cation) and Electron Transport Layer are designed into different stack combinations to discriminate the more resilient stack. Long-term stability of these stacks is tested by accelerated thermal test and light-soaking test. Light-soaking test is done from different sides and with a filter to determine the difference in behaviour of samples. From thermal testing, the dual cation perovskite was found to be more resilient. In light-soaking tests done from side of glass, all stacks failed, while the stacks illuminated from side of ETL showed a far better performance. The dual cation perovskite was again found to be more resilient. Despite the performance loss, none of the stacks demonstrated significant degradation in perovskite layer under XRD or photoluminescence. Therefore, recombination mechanisms were studied under light-intensity measurements. The presence of carrier collection problems across stacks and degradation of HTL particularly in samples of glass-side exposure are determined to be the probable cause.