Interfacial engineering with reduced graphene oxide for high-performance perovskite solar cells

High-performance perovskite solar cells (PSCs) have exhibited limited long-term stability, mainly driven by layer-to-layer ion diffusion in the perovskite/hole-transport layer (HTL) interface, resulting in a decrease in the HTL and component loss in the perovskite. Graphene derivatives are commonly used in PSC thanks to their high electrical conductivity and charge mobility. By using numerical simulations, reduced graphene oxide (rGO) is introduced at the formamidinium lead triiodide (FAPbI 3 ) perovskite/HTL heterojunction to introduce interfacial engineering, allowing for improvement of the charge dynamics. The modeled rGO-based PSC devices exhibit suppressed interfacial charge accumulation and improved energy band alignment, significantly enhancing charge recombination resistance. The optimization findings demonstrate that the best-performing PSC is attained with a perovskite layer thickness of 0.8[Formula: see text] [Formula: see text]m, a trap-state density of 10[Formula: see text] [Formula: see text]cm[Formula: see text], and an effective density of states of 10[Formula: see text] [Formula: see text]cm[Formula: see text]. As a result, the simulated FTO/SnO 2 /FAPbI 3 /rGO/Spiro-OMeTAD/Au structure incorporating the rGO interlayer achieves a theoretical efficiency of 28.56% (a 5.65% improvement relative to the unmodified devices) with an open-circuit voltage ([Formula: see text]) of 1.273[Formula: see text]V, a short-circuit current ([Formula: see text]) of 26.495[Formula: see text]mA[Formula: see text]cm[Formula: see text], and a fill factor (FF) of 85.624%. More importantly, the simulated rGO-based PSCs exhibit tolerance to elevated trap states, parasitic resistance variations, and thermal stress. The optimized rGO-based devices maintained 82% of their original PCE after simulating at 460[Formula: see text]K. The findings of this study originate from SCAPS-1D simulation, providing a guideline for experimental realization of graphene-engineered PSCs.