Lanthanide‐Containing Photoluminescent Materials: From Hybrid Hydrogel to Inorganic Nanotubes

Abstract

Functional photoluminescent materials are emerging as a fascinating subject with versatile applicability. In this work, luminescent organic-inorganic hybrid hydrogels are facilely designed through supramolecular self-assembly of sodium cholate, and lanthanide ions such as Eu(3+), Tb(3+), and Eu(3+)/Tb(3+). Fluorescence microscopy and TEM visualization demonstrates the existence of spontaneously self-assembled nanofibers and 3D networks in hybrid hydrogel. Photoluminescence enhancement of lanthanide ions is realized through coordination with cholate and co-assembly into 1D nanofibers, which can successfully shield the Eu(3+) from being quenched by water. The photoluminescence emission intensity of a hybrid hydrogel exhibits strong dependence on europium/cholate molar ratio, with maximum emission appearing at a stoichiometry of 1:3. Furthermore, the emission color of a lanthanide-cholate hydrogel can be tuned by utilizing different lanthanide ions or co-doping ions. Moreover, photoluminescent lanthanide oxysulfide inorganic nanotubes are synthesized by means of a self-templating approach based on lanthanide-cholate supramolecular hydrogels. To the best of our knowledge, this is the first time that the lanthanide oxysulfide inorganic nanotubes are prepared in solution under mild conditions.

Effects of polymers on the properties of hydrogels constructed using sodium deoxycholate and amino acid

“…Numerous studies have been performed on the effects of salts, pH, metal ions, and amino acids on the properties of NaDC hydrogels. 20,22,23 The existing results explicitly elucidate how these additives essentially affect the properties of NaDC hydrogels. Jover et al prepared NaDC hydrogels in a phosphate buffer solution (PBS) and reported that the viscoelasticity of the hydrogel from NaDC in PBS increased drastically with an increase in NaCl concentration.…”

Stimulus‐Responsive Hydrogel for Ophthalmic Drug Delivery

“…The metal coordination of fatty acids and steroids has been widely used to produce organogels during the past two decades . One successful example is the use of steroidal compounds such as a bile salt to complex with a series of metal cations in an aqueous solution to generate a supramolecular hydrogel . Inspired by an early study on metal‐bile salt supramolecular self‐assembly, we occasionally found that ophthalmic steroidal drugs (e.g., sodium phosphate dexamethasone, succinated dexamethasone) could form a supramolecular hydrogel for “self” delivery by the addition of various metal cations, such as Ca 2+ , Zn 2+ , and Mg 2+ .…”

Europium fluoride based luminescent materials: From hydrogels to porous cryogels, and crystalline NaEuF4 and EuF3 micro/nanostructures

“…Fluoride compounds with general formulae of ALnF 4 or LnF 3 (A: alkaline metal; Ln: lanthanide element) offer multiple advantages such as high transparency, large band gap, chemical stability, and low phonon energy minimizing the multiphonon relaxation and improving the luminescence efficiencies [13][14][15]. Synthesis of Eu-based fluoride compounds, such as NaEuF 4 and EuF 3 structures with different phases, shapes and sizes can be achieved by means of various synthetic approaches such as hydrothermal [11,16,17], sonochemical [18], and wet chemical routes [19,20], as well as sol-gel techniques [5,21,22]. At the same time, there have been just a few publications exploring hydrogels, aerogels or cryogels including lanthanide ions [5,21,22].…”

“…Synthesis of Eu-based fluoride compounds, such as NaEuF 4 and EuF 3 structures with different phases, shapes and sizes can be achieved by means of various synthetic approaches such as hydrothermal [11,16,17], sonochemical [18], and wet chemical routes [19,20], as well as sol-gel techniques [5,21,22]. At the same time, there have been just a few publications exploring hydrogels, aerogels or cryogels including lanthanide ions [5,21,22]. The latter are highly porous inorganic structures of extremely low density.…”