Application of Two-dimensional Materials in Perovskite Solar Cells; Recent Progress, Challenges and Prospective Solutions

Perovskite solar cells (per-SCs) with high performance and cost-effective solution processing have been the center of interest for researchers in the past decade. Power conversion efficiencies (PCEs) have been gradually improved up to 25.2% with relatively improved stability, which is an unparalleled progress in all generations of solar cell (SC) technology. However, there are still some prevailing challenges regarding stability and upscaling of these promising devices. Recently, 2D layered materials (LMs) have been extensively explored to overcome the prevailing challenges of poor stability (under moisture, light soaking and high temperature), halide segregation, hysteresis, involvement of toxic materials (i.e. lead) and upscaling of devices. A critical review addressing the recent developments in the use of 2D materials, especially transition metal dichalcogenides (TMDCs) is hence necessary. Although, several reviews are available on use of 2D materials in photovoltaic (PV) technology, no comprehensive review papers have yet been reported on use of these 2D-LMs in per-SCs, to the best of our knowledge. This review summarizes the recent progress and challenges in application of 2D materials in per-SCs and outlines the future pathways to further extend the PCE beyond 25 %. This review particularly focuses on 2D materials (such as carbon and transition metal dichalcogenides (TMDs), etc.) as electrode materials and additives, the underlying charge (electron-hole) transport phenomenon in the layered materials and their chemical and structural stability etc.