Size-Selective ZnO Nanocrystals as Spectral Energy Converters for Use in Advanced Display Devices

In this paper, we report the synthesis of size-selective zinc oxide (ZnO) nanocrystals by three different techniques namely, auto-combustion, co-precipitation and atomizer and their effective energy conversion from harmful ultra-violet (UV, 365 nm) to visible green light. All the three methods are facile and convenient for the controlled synthesis of ZnO nanocrystals with an average crystallite size ranging 12-35 nm. The structural characterization using XRD revealed that the phase of ZnO nanocrystals was wurtzite. The morphology of the ZnO nanocrystals in all the three cases was found to be spherical and uniform as determined by High Resolution Transmission Electron Microscope. The novelty of the current work is to synthesize highly luminescent ultra-small ZnO nanocrystals without any dopant and their possible use as efficient spectral converters in displays. This result is further supported by steady-state photoluminescence spectra recorded under UV (365 nm) radiation as excitation. The presence of quantum confinement effect and increased surface to volume ratio perfectly established that ZnO nanocrystals synthesized by various routes have significant impact in the fields of optoelectronics, biomedical fields and advanced active display devices.