Synthesis, Structural, Morphological, and Optical Properties of Promising Lead-Free Double Perovskite Na2CuBiBr6: A Sustainable Material for Photovoltaic Applications

•Synthesis of Na2CuBiBr6 nanocrystals by antisolvent recrystallization approach.•XRD pattern confirms the creation of cubic Na2CuBiBr6.•TEM analysis verifies the creation of Na2CuBiBr6 double perovskite and polycrystalline nature.•UV–vis spectroscopy reveals a band gap of 1.37 eV.•Lower reflectivity within the visible spectrum makes Na2CuBiBr6 appropriate for photovoltaics. This work primarily focuses on synthesizing and evaluating the structure, morphology, and optical features of double perovskite Na2CuBiBr6 forphotovoltaic devices. In the present investigation, Na2CuBiBr6 is created by a solution-based antisolvent recrystallization approach. A comprehensive experimental investigation is conducted on the Na2CuBiBr6 double perovskite, encompassing its structural configuration, morphology, and optical features. X-ray diffraction analysis verifies the creation of Na2CuBiBr6 double perovskite and showcases its exceptional phasestability in the cubic phase. Scanning electron microscopy reveals the presence of multidirectional crystals ofNa2CuBiBr6crystals. The presence of polycrystalline cubic Na2CuBiBr6 is confirmed using transmission electron microscopy and electron diffraction investigation. In addition, energy-dispersive X-ray spectroscopy demonstrates the consistent distribution of elements within Na2CuBiBr6. UV–vis spectroscopy reveals a band gap of 1.37 eV. The optical characteristics demonstrate that Na2CuBiBr6 exhibits a greater absorbance level and a lower reflectivity level within the visible spectrum. The results of this study suggest that the Na2CuBiBr6 double perovskite, which is both lead-free and environmentally benign, has significant potential for applications in photovoltaic and thermoelectric devices.