Origin of the red emission in zinc oxide nanophosphors

•UV and orange-red light emitting ZnO nano-phosphors were synthesised.•Zinc nitrate and zinc acetate were used as precursors and urea as a fuel.•O1s XPS peaks consist of three components: O1 (ZnO), O2 (deficient oxygen; OH groups) and O3 (adsorbed species).•A broad orange-red defect emission from the ZnO prepared with the nitrate precursor.•A sharp UV band, due to the possible passivation of defects, from ZnO prepared with the acetate precursor.

UV and orange-red light emitting zinc oxide nano-phosphors (ZnO NPr) were synthesised by a combustion method using zinc nitrate and zinc acetate as precursors and urea as a fuel. Hexagonal wurtzite structures of ZnO were synthesised. X-ray photoelectron spectroscopy (XPS) indicated that the O1s peak consist of three components: O1 (ZnO), O2 (deficient oxygen; OH groups) and O3 (adsorbed species) centred at 530.3, 531.2 and 532.6 eV, respectively. A broad orange-red emission from 500 to 850 nm was obtained from the ZnO NPr prepared with the nitrate precursor which may be attributed to different kinds of defects, and a sharp UV band, due to the possible passivation of defects, at 392 nm from ZnO NPr prepared with acetate precursor.