title: Iron oxide-induced thermal effects on solid-state upconversion emissions in NaYF4:Yb,Er nanocrystals.
abstract: Multifunctional materials exhibiting photon upconversion show promising applications for biological imaging and sensing. In this study, we examine the solid-state upconversion emission of NaYF4:Yb,Er nanoparticles in the presence of iron oxide nanoparticles. Fe3O4 nanoparticles (6 nm) were mixed with NaYF4:Yb,Er nanoparticles (either 10 or 50 nm) in varying proportions by drying chloroform solutions of nanoparticles onto glass slides. Upconversion spectra were acquired, and a laser power-dependent emission was observed and correlated with the iron oxide content in the mixture. Changes in the lattice temperature of the upconverting particles were monitored by careful observation of the relative intensities of the (2)H11/2 and (4)S3/2 →( 4)I15/2 transitions. The emission characteristics observed are consistent with an iron oxide-induced thermal effect that is dependent on both the laser power and the proportion of iron oxide. The results highlight that the thermal effects of mixed nanoparticle systems should be considered in the design of luminescent upconverting hybrid materials.
authors.affiliation: School of Chemistry and Biochemistry, The University of Western Australia, 35 Stirling Highway, Crawley 6009, Australia.
authors.forename: Michael
authors.initials: M
authors.lastname: Challenor
authors.forename: Peijun
authors.initials: P
authors.lastname: Gong
authors.forename: Dirk
authors.initials: D
authors.lastname: Lorenser
authors.forename: Melinda
authors.initials: M
authors.lastname: Fitzgerald
authors.forename: Sarah
authors.initials: S
authors.lastname: Dunlop
authors.forename: David D
authors.initials: DD
authors.lastname: Sampson
authors.forename: K Swaminathan
authors.initials: KS
authors.lastname: Iyer
mesh_terms: D005290:Ferric Compounds / Q000737:chemistry*; D005459:Fluorides / Q000737:chemistry*; D049408:Luminescent Agents / Q000737:chemistry; D053758:Nanoparticles / Q000737:chemistry*; D017785:Photons; D015019:Yttrium / Q000737:chemistry*
chemical_list: D005290:Ferric Compounds; D049408:Luminescent Agents; C525362:sodium yttriumtetrafluoride; C000499:ferric oxide; D015019:Yttrium; D005459:Fluorides