Hole transport layers (HTLs) are one of the most significant elements influencing the performance of perovskite solar cells (PSCs). PEDOT:PSS (= Poly (3,4-ethylenedioxythiophene):poly(styrenesulfonate)) is regarded to be the most conducting polymer to use as an organic HTL for the inverted structure of PSCs. Due to the highly acidic behavior, PEDOT:PSS-based PSCs have shown limited stability. Additionally, the valence band mismatch of the PEDOT:PSS layer with the adjacent perovskite layer often results in low open-circuit voltage (V_OC) of the overall PSC. To address these issues, we have incorporated a thin layer of ethylenediamine functionalized graphene (EDA-FG) between the indium tin oxide (ITO) anode and the PEDOT:PSS layer yielding a bilayer HTL. The new bilayer successfully matches the energy valence band at the HTLs/perovskite layer interface. The photoluminescence (PL) confirms that the deposited EDA-FG/PEDOT:PSS quenched the perovskite layer more than PEDOT:PSS. Based on the enhanced electrical and optical properties, a champion PCE of 17.66% was obtained for the respective PSCs. Additionally, the PSCs showed stable photovoltaic behavior up to 500 h.