For the synthesis of Cesium-Oleate precursor, first, cesium carbonate (1.31 g), oleic acid (4 mL), and octadecene (16 mL) are mixed in a 100 mL three-neck round-bottom flask and then kept in a vacuum oven for 15 min (120 o C, -700 mmHg). The solution mixture is heated to 120 °C under vigorous stirring for 60 min while purging with N2 gas to remove the moisture. Afterward, the mixture is heated to 150 °C until the solution became transparent brown colour indicating formation of Cesium Oleate. In a typical synthesis of metal doped-CsPbBr3 nanocrystal, oleic acid (6 mL), oleylamine (6 mL), and octadecene (9 mL) are taken in a 100 mL three-neck round-bottom flask and dried under vacuum for 30 min at 120 °C to remove the moisture content from the above chemicals. For synthesis of pristine PNC-1.0 g of PbBr2 while for Ni:PNC -1.0 g of PbBr2 ( Reitveld Refinement Process: Rietveld refinement entails adjusting various parameters describing the diffraction pattern to align with observed data by fitting a calculated X-ray or neutron diffraction pattern. Initially, a theoretical diffraction pattern is computed using the initial structural model. To assess the fit quality between calculated and experimental patterns, statistical measures such as Rietveld refinement factors are employed, offering insights into the adequacy of the refined structural model. In a typical Rietveld refinement, individual scale factors pertaining to phase concentration, as well as profile, background, and lattice parameters, are variably adjusted. The refinement process is iterative, with parameters readjusted until convergence between calculated and experimental patterns occurs, stabilizing refinement parameters. Upon achieving a satisfactory fit, the refined structural model furnishes precise information regarding the material's crystal structure, encompassing atomic positions, unit cell dimensions, bond lengths, bond angles, and other structural parameters. In Rietveld refinement, the χ² statistic is a measure of the goodness of fit between the observed diffraction data and the calculated diffraction pattern.