Influence of ultrasonication times on the tunable colour emission of ZnO nanophosphors for lighting applications

This paper reports on the sonochemical synthesis of zinc oxide (ZnO) nanophosphors (NPr) at different ultrasonication times (5 min, 30 min, 1 h, 5 h, 10 h and 15 h) for near white light emission applications. X-ray photoelectron spectroscopy indicated that the O1s peak consists of two components. These were O1 (ZnO) and O2 (deficient oxygen; OH groups) centred at 529.7 ± 0.3 eV and 531.1 ± 0.3 eV, respectively. All samples showed UV and defect level emission (DLE). The DLE enhancement was due to the increase in oxygen related defects such as oxygen vacancies/interstitials. Due to the combination of near UV and DLE near white light emission in ZnO NPr was obtained. The emission could be tuned with different ultrasonic times. It was found that the ultrasonication time influenced the growth mechanism and luminescence properties of the ZnO NPr.