In this study, HTL optimisation techniques have been used to analyse a double halide perovskite (which is lead-free) Cs2NaGaBr6 n-i-p solar cell in order to improve photovoltaic performance. A robust solar cell modeling tool called SCAPS-1D was used for all of the simulations. The suggested photovoltaic design uses a double perovskite material. With a bandgap of 1.762 eV, Cs2NaGaBr6 is a direct band gap halide double perovskite material that is extremely close to organic-inorganic perovskite material. With an improved hole transport layer (HTL) doping (1×1018 cm-3–1×1022 cm-3), the proposed solar cell had a better efficiency of 26.19%. Additionally, Jsc, Voc, FF, and PCE (η) have all been examined as photovoltaic performance parameters. In order to create effective Pb-free perovskite for solar applications, the proposed device may be used.