Di Wu

All Publications

• Strain-induced modification of optical selection rules in lanthanide-based upconverting nanoparticles Nano Letters Wisser, M., Chea, M., Lin, Y., Wu, D., Mao, W. L., Salleo, A., Dionne, J. 2015: 1891–97

  Abstract

  NaYF4:Yb(3+),Er(3+) nanoparticle upconverters are hindered by low quantum efficiencies arising in large part from the parity-forbidden nature of their optical transitions and the nonoptimal spatial separations between lanthanide ions. Here, we use pressure-induced lattice distortion to systematically modify both parameters. Although hexagonal-phase nanoparticles exhibit a monotonic decrease in upconversion emission, cubic-phase particles experience a nearly 2-fold increase in efficiency. In-situ X-ray diffraction indicates that these emission changes require only a 1% reduction in lattice constant. Our work highlights the intricate relationship between upconversion efficiency and lattice geometry and provides a promising approach to modifying the quantum efficiency of any lanthanide upconverter.

  View details for DOI 10.1021/nl504738k