Lead-free perovskite Cs2NaGaBr6 n-i-p solar cell for higher power conversion efficiency to improved energy storage performance

Abstract

It is important to enhance the efficiency of perovskite solar cells (PSCs) to improve the energy storage performance within a time frame. In this study, a lead-free perovskite Cs₂NaGaBr₆ n-i-p solar cell is presented for higher PCE to improve energy storage performance. Keeping the toxicity of lead-based perovskite in mind we have made attempts to study the characteristics of n-i-p solar cells based on lead-free double halide perovskite Cs₂NaGaBr₆ novel material. In the proposed photovoltaic framework, M₂¹⁺N²⁺N³⁺X₆¹⁻ as a double perovskite material is used, where N²⁺ = Na, M₂¹⁺ = Cs, N³⁺ = Ga, and X₆¹⁻ = Br. The Cs₂NaGaBr₆ is an organic-inorganic perovskite material because of its direct band gap structure with a band gap of 1.762 eV. The solar cell proposed in the present framework has achieved a higher efficiency of 26.09% with optimized parameters specific to device design in terms of different absorber layer thicknesses (0.6–1.2 μm), and absorber layer doping concentrations (1 × 10¹⁸ cm⁻³ to 1 × 10²² cm⁻³). In the present study, improved results are obtained such as electric field, current density, energy band profile, generation and recombination factor, quantum efficiency, and generation/ recombination factor by suitably varying the absorber layer thicknesses and absorber layer doping concentrations. Additionally, many parameters related to the photovoltaic performance of solar cells such as J_sc (19.535 mA/cm²), V_oc (1.775 V), FF (91.35%), and PCE (η) (27.81%) have been evaluated in the present study. Therefore, the device, that is, solar cell based on lead-free double halide perovskite Cs₂NaGaBr₆ novel material, proposed in the present study may be used to manufacture much more efficient lead-free perovskites for photovoltaic applications and also improve the energy storage performance within a time frame.