Significantly enhanced UV luminescence by plasmonic metal on ZnO nanorods patterned by screen-printing

A smart synthetic method is conceived to construct large batches of ZnO nanostructures to meet market demand for light-emitting diodes. Utilizing the localized surface plasmon resonance of metal nanoparticles (NPs) facilitates the recombination of electron-hole pairs and the release of photons. Compared to raw ZnO nanorods (NRs), ZnO NRs@HfO2@Al NPs show a ∼120× enhancement in ultraviolet (UV) photoluminescence (PL), while ZnO NRs@HfO2@Ag NPs show a six-fold enhancement. Because the surface plasmon energy of Al is nearer the ZnO band gap, the PL enhancement of ZnO NRs covered with Al is stronger than that of those covered with Ag. Based on this analysis, three-dimensional graphical ZnO NR arrays were manufactured by screen-printing, a mass production technique. After covering the arrays with layers of HfO2 and Al NPs, the UV PL intensities of the corresponding substrates were increased by approximately 16×. This indicates the potential to mass-produce highly efficient optoelectronic devices.