2D Ruddlesden-Popper perovskite interface engineering for efficient perovskite solar cells with exceptional stability

This paper presents an appropriate method of fabricating stable and efficient 3D (top)/2D (bottom) perovskite solar cells (PSCs). The method involves three-step spin-coating deposition, where 3D triple-cation perovskites are used as a light-absorbing material and phenyl trimethylammonium iodide (PTAI) serves to form a 2D Ruddlesden-Popper perovskite. Moisture penetration into the pores of porous structures is a significant degradation factor for perovskite porous solar cells. On the other hand, the high quality of the underlayer can play a crucial role in improving perovskite formation. In this study, different PTAI deposition processes were investigated for their effects on perovskite formation, surface morphology, optical properties, and device stability. As the results showed, a step-by-step post-annealing process after deposition was optimal for forming 2D perovskites, enhancing the device stability and efficiency. The efficiency of the optimized PSCs was improved for 24%, compared to the reference PSCs. Furthermore, this solar cell maintained 92% of its efficiency for a year.