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

Abstract

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.

Progress on lanthanide-based organic–inorganic hybrid phosphors

“…The significant number of published examples that can be found were extensively reviewed elsewhere. [2][3][4] Here we will emphasise some illustrative examples in which the hybrid host belongs to one of the following classes: amineand amide-functionalized matrices; 5,6 organosilicas; 7,8 mesostructured materials; 9,10 ionogels; 11,12 and liganddecorated nanoparticles (NPs). [13][14][15] Besides the intra-4f lines, the emission spectra of Ln 3+ -based amine-and amide-functionalized organic-inorganic hybrids display a broad emission in the blue-green spectral region (380-550 nm) ascribed to the hybrid host.…”

“…This large broad band, already observed in the nondoped matrices, results from a convolution of the emission originated in the cross-linkages between the organic and inorganic counter parts with electron-hole recombinations occurring in the siloxane nanoclusters. [4][5][6] The relative intensity between the hybrid host broad band and the intra-4f lines strongly depends on the activation/deactivation of the host-to-Ln 3+ energy-transfer processes, 4 allowing, therefore, the fine-tuning of the hybrids emission chromaticity across the Commission Internationale d'Eclairage (CIE) diagram. This emission-colour fine tuning along the CIE chromaticity diagram can be also modulated by chemical factors (Ln 3+ concentration, polymer chain length, nature of the cross-linkage and anion type) and physical parameters (excitation wavelength and temperature), Fig.…”

“…12 Embedding Ln 3+ ions in hybrid NPs, rather than incorporating Ln 3+ organic complexes into organicinorganic hybrid hosts, as in the above examples, makes an attractive alternative for developing pure colour (e.g. YVO 4 : Eu, LaPO 4 : Ce and LaPO 4 : Ce,Tb, 15 Fig . 5) and white light efficient phosphors, namely for biomedical applications.…”

“…1 The tailoring of these hybrid structures (and hence of their corresponding properties) passes for the capability of exploiting the synergy between the intrinsic characteristics of sol-gel derived organic-inorganic hybrid hosts-such as highly controlled purity, versatile shaping and patterning, easy control of the refractive index, photosensitivity, encapsulation of large amounts of isolated emitting centres, mechanical, optical and/or electronic properties, thermal and chemical stability, biocompatibility, hydrophobic-hydrophilic balance-and the luminescence features of Ln 3+ ions-such as high luminescence quantum yield, narrow bandwidth, long-lived emission, large Stokes shifts, and ligand-dependent luminescence sensitization. [2][3][4] All of these features offer excellent prospects for designing new luminescent materials with enhanced desired characteristics and high added value for specific targeted applications, thus opening exciting new directions in materials science and related technologies, with noteworthy results in the ecofriendly integration, miniaturization and multifunctionalization of devices.…”

Ionic liquid as plasticizer for europium(iii)-doped luminescent poly(methyl methacrylate) films

“…[1][2][3][4][5][6][7] Processable lanthanide-based luminescent molecular materials can be obtained by doping the lanthanide(III) complex in a polymer matrix. 8,9 Typical applications of such polymer films are in organic light emitting diodes (OLEDs) [10][11][12][13][14] or in active optical polymer fibers for data transmission.…”