title: Silica nanoparticles for micro-particle imaging velocimetry: fluorosurfactant improves nanoparticle stability and brightness of immobilized iridium(III) complexes.
abstract: To establish highly luminescent nanoparticles for monitoring fluid flows, we examined the preparation of silica nanoparticles based on immobilization of a cyclometalated iridium(III) complex and an examination of the photophysical studies provided a good insight into the Ir(III) microenvironment in order to reveal the most suitable silica nanoparticles for micro particle imaging velocimetry (μ-PIV) studies. Iridium complexes covalently incorporated at the surface of preformed silica nanoparticles, [Ir-4]@Si500-Z, using a fluorinated polymer during their preparation, demonstrated better stability than those without the polymer, [Ir-4]@Si500, as well as an increase in steady state photoluminescence intensity (and therefore particle brightness) and lifetimes which are increased by 7-fold compared with nanoparticles with the same metal complex attached covalently throughout their core, [Ir-4]⊂Si500. Screening of the nanoparticles in fluid flows using epi-luminescence microscopy also confirm that the brightest, and therefore most suitable particles for microparticle imaging velocimetry (μ-PIV) measurements are those with the Ir(III) complex immobilized at the surface with fluorosurfactant, that is [Ir-4]@Si500-Z. μ-PIV studies demonstrate the suitability of these nanoparticles as nanotracers in microchannels.
authors.affiliation: School of Chemistry, University of Birmingham , Edgbaston, Birmingham B15 2TT, United Kingdom.
authors.forename: David J
authors.initials: DJ
authors.lastname: Lewis
authors.forename: Valentina
authors.initials: V
authors.lastname: Dore
authors.forename: Nicola J
authors.initials: NJ
authors.lastname: Rogers
authors.forename: Thomas K
authors.initials: TK
authors.lastname: Mole
authors.forename: Gerard B
authors.initials: GB
authors.lastname: Nash
authors.forename: Panagiota
authors.initials: P
authors.lastname: Angeli
authors.forename: Zoe
authors.initials: Z
authors.lastname: Pikramenou
mesh_terms: D007495:Iridium / Q000737:chemistry*; D015394:Molecular Structure; D053758:Nanoparticles / Q000737:chemistry*; D009942:Organometallic Compounds / Q000737:chemistry*; D010316:Particle Size; D055668:Photochemical Processes; D012822:Silicon Dioxide / Q000737:chemistry*; D013499:Surface Properties; D013501:Surface-Active Agents / Q000737:chemistry*
chemical_list: D009942:Organometallic Compounds; D013501:Surface-Active Agents; D007495:Iridium; D012822:Silicon Dioxide