Synthesis of rare-earth doped ZnO nanorods and their defect–dopant correlated enhanced visible-orange luminescence
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© The Royal Society of Chemistry 2016. We report the synthesis of size controlled ZnO and rare-earth doped ZnO nanorods in the sub-10 nm diameter regime. The preferential anisotropic growth of the nanostructures along the polar c-axis leads to the formation of wurtzite phase ZnO nanorods. Photoluminescence measurements reveal enhancement of visible luminescence intensity with increasing RE 3+ concentrations upon excitation of host ZnO into the band gap. The broad visible luminescence originates from multiple intrinsic or extrinsic defects. The luminescence from RE 3+ is enabled by energy transfer from defect centers of the host nanocrystal lattice to dopant sites. Host-guest energy transfer facilitates efficient intra-4f orbital transitions ( 5 D 4 → 7 F j for Tb 3+ and 5 D 0 → 7 F j for Eu 3+ ) related characteristic green or red emission. Interestingly, different decay rates of host defects and RE 3+ emission transition also allow temporal control to achieve either pure green or red color. This study suggests that manipulation of defects through bottom-up techniques is a viable method to modulate the energy transfer dynamics, which may help enable the future applications of ZnO-based phosphor materials in optoelectronic and multicolor emission displays.
author list (cited authors)
Layek, A., Banerjee, S., Manna, B., & Chowdhury, A.