Graphene-Based Inverted Planar Perovskite Solar Cells: Advancements, Fundamental Challenges, and Prospects.

Metal halide based perovskite solar cells (PSCs) are considered among the most promising photovoltaic technologies, and already present certified efficiencies that surpass 22 %. The high performance and low fabrication cost make this technology competitive with that of state-of-the-art thin-film photovoltaics. However, PSCs present some striking disadvantages that hinder their commercialization, including short operational lifetimes, high toxicity, and hysteresis effects, which lower both the performance and long-term stability of the devices. Herein, work conducted within the last two years is summarized with regard to addressing the challenges of low-temperature-processed planar inverted PSCs composed of graphene-based materials. In addition, critical challenges and the prospects of this field are discussed and some prospects for future research directions are proposed.