Synthesis of NiO and Cu-NiO nanoparticles using Syzygium samarangense fruit extract and its evolution as inorganic hole transport layer in perovskite solar cells

The current work used a bio-mediated green synthesis from the fruit extract of Syzygium samarangense to prepare nanoparticles of nickel oxide (NiO) and copper-doped NiO (Cu-NiO). X-ray diffraction (XRD), ultraviolet–visible (UV–Vis) spectroscopy, Fourier transform-infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM) with EDAX, and TEM analysis were carried out for the structural and optical characteristics of NiO and Cu-NiO nanoparticles. UV–DRS spectroscopy reveals that the NiO has high absorption peak at 311 nm and Cu-NiO has its highest peak at 325 nm. The grain size of NiO and Cu-doped NiO nanoparticles were obtained as 18.23 nm and 21.32 nm with cubic structure with agglomeration and porosity. The inferences from the optical study revealed the suitability of the material as a hole transport layer in solar cells. Graphical abstract