Structural and optical properties of Co-doped ZnO nanocrystallites prepared by a one-step solution route

► Co-doped ZnO nanocrystallites were synthesized via a simple one-step solution route. ► Co2+ ions incorporated into the ZnO lattice without changing its wurtzite structure. ► Co-doping changed the energy band structure of ZnO. ► Co-doping effectively adjusted the luminescence properties of ZnO nanocrystallites.