Multiply Doped Nanostructured Silicate Sol−Gel Thin Films:  Spatial Segregation of Dopants, Energy Transfer, and Distance Measurements

Minoofar, Payam; Dunn, Bruce; Zink, Jeffrey I.

doi:10.1021/ja045185e

Cited by 125 publications

(96 citation statements)

References 70 publications

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“…[124] For d-U(2000) incorporating Eu(CF 3 SO 3 ) 3 , [179] the following evidences point out that the exchange (Dexter) mechanism accounted for the energy transfer: i) the critical radius calculated according to the Förster model [179] For d-U(600) incorporating [Eu(btfa) 3 (4,4 0 -bpy) (EtOH)], the host-to-ligand and host-to-Eu 3þ energy transfer rates were quantitatively estimated using the data of Table 2, as well as the measured transitions energies, radiative lifetimes, fwhm of the hybrids emitting centers emission, singlet and triplet ligand levels and Eu 3þ intra-4f states, and the average Eu 3þ -ligands and Eu 3þ -hybrids emitting centers distances. [179] Host-to-Eu 3þ energy transfer occurs either via ligand excited states (essentially, the triplet state) or directly from the hybrid emitting centers through the dipole-dipole, dipole-2 l pole, and exchange mechanisms.…”

Section: Energy-transfer Calculationsmentioning

confidence: 99%

“…Mesostructured materials based on zeolites, [110][111][112] silicas (MCM-41, MCM-48 and SBA-15), [113][114][115][116][117][118][119][120][121][122] and functional organosilanes; [123][124][125][126][127][128] Lamellar structures of lanthanide oxide layers, equally spaced by benzoate or biphenolate molecules [129][130][131][132] and layered double hydroxides (LDHs); [133,134] Eu 3þ -doped lamellar bridged silsesquioxanes, self-templated through an hydrogen bonded array. [135,136] The design and structuring of these hierarchically-structured Ln 3þ -containing hybrids result from an extension of the method employed previously to produce highly organized lamellar monoamide [137] and diurea cross-linked alkyl/siloxanes, [138] and highlights the importance of combining sol-gel methods and self-assembly processes.…”

Section: Introductionmentioning

confidence: 99%

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Lanthanide‐Containing Light‐Emitting Organic–Inorganic Hybrids: A Bet on the Future

et al. 2009

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Interest in lanthanide-containing organic-inorganic hybrids has grown considerably during the last decade, with the concomitant fabrication of materials with tunable attributes offering modulated properties. The potential of these materials relies on exploiting the synergy between the intrinsic characteristics of sol-gel derived hosts (highly controlled purity, versatile shaping and patterning, excellent optical quality, easy control of the refractive index, photosensitivity, encapsulation of large amounts of isolated emitting centers protected by the host) and the luminescence features of trivalent lanthanide ions (high luminescence quantum yield, narrow bandwidth, long-lived emission, large Stokes shifts, ligand-dependent luminescence sensitization). Promising applications may be envisaged, such as light-emitting devices, active waveguides in the visible and near-IR spectral regions, active coatings, and bio-medical actuators and sensors, opening up exciting directions in materials science and related technologies with significant implications in the integration, miniaturization, and multifunctionalization of devices. This review provides an overview of the latest advances in Ln(3+)-containing siloxane-based hybrids, with emphasis on the different possible synthetic strategies, photoluminescence features, empirical determination.

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Section: Energy-transfer Calculationsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Lanthanide‐Containing Light‐Emitting Organic–Inorganic Hybrids: A Bet on the Future

et al. 2009

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“…[5][6][7][8] As opposed to nonporous silica nanoparticles, both the surface and the pore interior of mesostructured nanoparticles can be modified with functional groups, such that they become compatible in various solutions and are able to store different types of molecules. [9][10][11][12][13][14][15] These nanomaterials have been well demonstrated for their biocompatibility, [16,17] and in their utilization as fluorescent markers for cells, [18] gene-transfection agents, [19] and delivery vehicles for proteins and anticancer drugs. [20,21] Studies of the interaction of mesoporous silicate nanoparticles with bacteria are rare.…”

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confidence: 99%

Antimicrobial Activity of Silver Nanocrystals Encapsulated in Mesoporous Silica Nanoparticles

2009

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MCM-41 type mesoporous silicate particles have attracted a significant amount of research interest due to the ordered porous structure of the materials, their facile synthetic methods, and their broad range of applications. [1][2][3][4] Further developments in the synthesis and modification of nanosized mesoporous silica materials have created new possibilities for biomedical applications. [5][6][7][8] As opposed to nonporous silica nanoparticles, both the surface and the pore interior of mesostructured nanoparticles can be modified with functional groups, such that they become compatible in various solutions and are able to store different types of molecules. [9][10][11][12][13][14][15] These nanomaterials have been well demonstrated for their biocompatibility, [16,17] and in their utilization as fluorescent markers for cells, [18] gene-transfection agents, [19] and delivery vehicles for proteins and anticancer drugs. [20,21] Studies of the interaction of mesoporous silicate nanoparticles with bacteria are rare. The nanoparticles were modified with dye molecules to enable studies of possible interaction using fluorescence microscopy. Rhodamine B isothiocyanate (RITC) was reacted with aminopropyltriethoxysilane and mixed with the silica precursor tetraethylorthosilicate (TEOS) to functionalize the interior pores and surface of the particles with the dye molecules without disrupting the mesostructure. [6,21,22] For our previous studies, two types of bacteria were used: Bacillus anthracis BH450 (B. anthracis), as the Gram-positive model, and Escherichia coli BL21 DE3 (E. coli), as the Gram-negative model. Upon mixing the nanoparticles with bacteria, red fluorescence of the nanoparticles was found to overlap with B. anthracis, but not with E. coli, suggesting that the particle adherence to the bacteria may depend on the bacterial strain and surface characteristic of the nanoparticles (Fig. S1, Supporting Information). Encouraged by these initial results and the report on use of nitric oxidereleasing silica nanoparticles as bactericidal agents, [23] we continued the studies in order to develop mesostructured silica nanocomposites that can store large amounts of antimicrobial materials and slowly release the bactericidal agents over an extended time period.The ability to encapsulate inorganic materials by growing mesostructured silica around them introduces additional functionality to the nanoparticles. Gold, semiconductor, and iron oxide nanocrystals can be incorporated within mesoporous silica nanoparticles to create a yolk/shell architecture without collapsing the mesostructure. [24][25][26][27] In comparison to the traditional coating of inorganic nanocrystals with nonporous silica or polymer, [28][29][30][31][32] the mesoporous silica shell offers the advantage of being able to store molecules or to slowly release the encapsulated inorganic materials. [33,34] Based on the works by Trewyn et al. in synthesizing mesoporous nanoparticles that release bactericidal cationic surfactants, [35] and Jiang et al. in prepar...

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“…24 Spread-coating has also been employed in the fabrication of thin films of mesoporous silica and ferritin films for application in photo-responsive materials, membrane base separation, catalysis, electrochemical biosensors, electronics, and optics. 24,26,28 Extending this technique towards the fabrication of micron scale or sub-micron thin organic polymer films presents a new challenge. For this application it is critical to establish parameters, under which the self-assembly of hydrophilic and hydrophobic domains of such polymers occurs at the time-scale of the coating deposition.…”

Section: Thin Film Formationmentioning

confidence: 99%

Controlled Deposition of Structured Polymer Films: Chemical and Rheological Factors in Chitosan Film Formation

et al. 2012

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The technique of spread-coating was utilized to create thin films of chitosan polymer. The effect of deposition rate on film thickness was characterized for solutions of deacetylated and butyl-modified chitosan. For the range of deposition rates analyzed, the relationship between film thickness and increasing deposition rate fell into three distinct regions: an initial inverse relationship, a second linearly increasing relationship, and a final region wherein the film thickness remained constant. Results suggest that film thickness was both controllable and reproducible and that hydrophobic modification of the polymer extends the range over which a linear relationship between film thickness and deposition rate is achieved.Viscometry and fluorescence spectroscopy were employed to characterize the micellar characteristics of solutions of both deacetylated and butyl-modified chitosan.Deacetylated chitosan solutions possessed more interconnected hydrophobic domains that had more intermolecular micellar characteristics, while butyl-modified chitosan solutions had more intramolecular micellar characteristics and less interconnected hydrophobic domains.

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Multiply Doped Nanostructured Silicate Sol−Gel Thin Films: Spatial Segregation of Dopants, Energy Transfer, and Distance Measurements

Cited by 125 publications

References 70 publications

Lanthanide‐Containing Light‐Emitting Organic–Inorganic Hybrids: A Bet on the Future

Lanthanide‐Containing Light‐Emitting Organic–Inorganic Hybrids: A Bet on the Future

Antimicrobial Activity of Silver Nanocrystals Encapsulated in Mesoporous Silica Nanoparticles

Controlled Deposition of Structured Polymer Films: Chemical and Rheological Factors in Chitosan Film Formation

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