In this work, the enhanced photovoltaic performance of lead-free double halide perovskite Cs2naGaBr6 n-i-p solar cell has been analyzed by ETL optimization techniques. All the simulations have been performed using a powerful solar cell simulation tool SCAPS-1D. A double perovskite material M21+N2+N3+X61− is used in the proposed photovoltaic architecture, where M21+=Cs,N2+=Na,N3+=Ga , and X61−=Br . Cs2naGaBr6 is a direct band gap halide double perovskite material having a bandgap of 1.762 eV which is very similar to organic-inorganic perovskite material. The proposed solar cell achieved higher efficiency of 25.86% with optimized doping concentration (1×1018cm−3−1×1022cm−3) of the electron transport layer (ETL). The improved results are obtained in terms of energy band profile, electric field, current density, and quantum efficiency. Moreover, the photovoltaic performance parameters have also been evaluated as Jsc, V oc , FF, and PCE (η) . Thus, the proposed device may use to develop efficient Pb-free perovskite for photovoltaic applications.