In the present study, the PL spectrum of Co 2+ doped ZnO nanopowder (shown in Fig. 5) exhibited two bands, one sharp, strong and dominated UV emission band at 386 nm and another weak suppressed band at 468 nm. The weak band at 468 nm is the characteristic feature of blue emission. The crystal quality of the synthesized nanopowde r can affect the origin and the intensity of the UV emission and hence enhancement in the UV emission is observed for the nanopowde rs with better crystal quality. Therefore betterment in the crystal quality (less structural defects and impurities, such as oxygen vacancies and Zn interstitials) leads the sharp and strong origination of UV emission in the room temperat ure PL
spectrum [22,32]. If the concentratio n of oxygen vacancie s is reduced in the synthesized products then it results in the appearance of a sharp and strong intensity NBE [33]. In present synthesized sample strong and sharp near band edge emission confirmed the good optical propertie s with less structura l defects