Yellow-to-violet upconversion in neodymium oxide nanocrystal/titania/ormosil composite sol–gel thin films derived at low temperature

• DOI: 10.1063/1.1408262
• Publication Date: 2002-07-26T12:45:28Z
• Authors: Wenxiu Que; C. H. Kam; Y. Zhou; Y. L. Lam; Y. C. Chan
• Keywords: Photon Upconversion; Ormosil; Nanocrystalline material; Neodymium

Neodymium (III) oxide nanocrystals synthesized by the inverse microemulsion technique were dispersed in sol–gel titania/organically modified silane (ormosil) composite thin films for photonic applications. X-ray diffraction analysis and transmission electron microscopy observation show that neodymium nanoparticles have a nanocrystalline structure size of is range 5–60 nm. An intense room-temperature yellow-to-violet upconversion emission at 402 nm (4D3/2→4I13/2) was measured from film heated 100 °C upon excitation with yellow light 587 In addition to this violet emission, ultraviolet 372 blue 468 also observed. The lifetime mechanism proposed, they indicate excited-state absorption originating long-lived F3/24 excited state should be responsible upconversion.