Structural heterogeneity: We have first performed structural analysis of as-synthesized doped-PNCs to trace the origin of their enhanced optical properties and improved ambient stability. Full-Survey and High-resolution XPS spectra of doped PNCs for Pb 4f yield two distinct gaussianshaped peaks due to spin-orbit coupling of 4f-orbital, as shown in Figure . The Pb 4f peaks in XPS spectrum of Ni:Co:PNC and Co:PNC appears at 142.7 eV (4f5/2) and 137.8 eV (4f7/2), nearly at same position of the undoped-CsPbBr3. The Pb 4f peaks of Ni:PNC are shifted to higher binding energy, that is, at 143.4 eV (4f5/2) and 138.6 eV (4f7/2). The spin-obit splitting of Pb(II) for both remains same, 4.9 eV. XPS peak positions of core-level spectra are vastly affected by chemical environment (surrounding electron-cloud) of that element. It therefore suggests that Ni(II) greatly impacts chemical environment around Pb(II) in nanocrystal. The Ni-doping might enhance the chemical bonding of Pb with neighboring bromide ion causing peak in higher-binding energy. ). Cs-atom in Ni:Co:PNC systematically shifts towards the surface of the orthorhombic structure which forms an irregular hexagon (Figure ). However, the Cs ions get displaced in one direction for Ni:PNC, therefore, does not construct such systematic dodecahedron structure (Figure ). Eventually, the one-directional movement of Cs-atom in Ni:PNC suggests the possibility of spatial inversion symmetry breakings. We have imaged the doped perovskite nanocrystals-Ni:PNC and Ni:Co:PNC by using transmission electron microscopy (TEM) to further support such changes in crystal structure. The augmented photoluminescence properties of doped-PNCs may be accounted for by invoking either Spin-Orbit Coupling (quantum hoping) or structural (facet) engineering. We have found that Ni:PNC and Ni:Co:PNC are relatively more stable than Co:PNC (Figure ). The stability of Ni:PNC is in agreement with reported results. Crystal stiffening caused by smaller ionic radii of Ni(II) ion has been attributed to the improved stability of Ni:PNC as well. The average photoluminescence lifetimes, avg of Ni:PNC, Ni:Co:PNC in toluene are 4.68 ns, 5.47 ns respectively, whereas that of Co:PNC is relatively low, 2.57 ns (Table , Figure & S10). It can be mentioned that toluene acts as a photoluminescent quencher for doped-PNC. Hence, this photophysical study serves as a reference point for energy transfer studies in toluene medium.