Device Structures of Perovskite Solar Cells: A Critical Review

In recent years, perovskite solar cells (PSCs) have been in huge demand because of their ease of production, low cost, flexibility, long diffusion length, lightweight, and higher performance than their counterparts. The PSCs have demonstrated remarkable progress with power conversion efficiency (PCE) up to 25.7% using FAPbI(3) as an active layer component. However, lower PCE and device stability restrict PSCs' commercial viability. Further, the photocurrents in PSCs are close to the maximum Shockley-Queisser (SQ) limit. The focus now is on enhancing the open-circuit voltage and fill factor through modifying charge-selective contacts, the morphology of perovskite material, and interface modification. The large grain size, uniformity, and coverage area distinguish the crucial factors affecting the PCE of PSCs. Long-term device stability and degradation mechanisms have also shown significant dependence on the device structure. Therefore, the tailoring of the device structure continues to play a crucial role in the device's performance and stability. In this review, the illustration of the structural development of perovskite solar cells, including advanced interfacial layers and their associated parameters, is discussed in detail. In addition, the challenges that hinder the PSCs' performance are also discussed.