Luminescent Hybrid Materials Research Articles

Sol–Gel Electrolytes Incorporated by Lanthanide Luminescent Materials and Their Photophysical Properties

A group of silica gel electrolytes with lanthanide luminescent hybrid materials were assembled and investigated. Photophysical studies showed that terbium and europium hybrids displayed characteristic green and red emissions within the electrolytes. The influence of different concentration of the lanthanide hybrids on the electrochemical behavior of a gelled electrolyte valve-regulated lead-acid battery were studied through cyclic voltammograms, electrochemical impedance spectroscopy, water holding experiments and mobility tests. The morphology and particle size were analyzed by scanning electron microscopy. The results proved that lanthanide (Tb3+/Eu3+) luminescent materials are effective additives which will significantly improve the electrochemical properties of lead-acid batteries.

Correlative Microscopy: Hybrid Nanoscopy of Hybrid Nanomaterials (Small 17/2017)

In article number 1603784, by Natividad Gálvez, Cristina Flors, and co-workers, the combination of complementary techniques to characterize materials at the nanoscale is explored, as a key step to the design and fabrication of new materials with improved properties and diverse functions. The combination of atomic force microscopy and super-resolution fluorescence imaging is investigated as a useful tool to characterize hybrid luminescent materials, specifically amyloid-like fibers functionalized with quantum dots.

Luminescent hybrid materials based on (8-hydroxyquinoline)-substituted metal-organic complexes and lead-borate glasses

Novel luminescent organic-inorganic hybrid materials based on 8-hydroxyquinoline metal complexes (Liq, Kq, Naq, Rbq, Mgq2, Srq2, Znq2, Scq3, Alq3, Gaq3, and Inq3) have been synthesized by a high temperature exchange reaction with 80PbF2–20B2O3 inorganic low-melting glass. The mechanical and optical properties, transmission spectra, emission an excitation photoluminescence, and luminescence kinetic of hybrid materials were studied. All hybrid materials showed a wide luminescence band in the range 400–700 nm.

Structural and spectroscopic investigation of new luminescent hybrid materials based on calix[4]arene-tetracarboxylate and Ln3+ ions (Ln = Gd, Tb or Eu)

Lanthanide-calixarene hybrid materials are of particular interest due to the combination of the interesting properties of the ligand cavity-like structure and the luminescent features of lanthanides. The aim of this study was to synthesize and investigate the photophysical properties of Eu3+, Tb3+ and Gd3+ hybrids based on calix[4]arene-tetracarboxylate. The preparation of two structurally different Tb3+ compounds (calix-TA-SC-Tb and calix-TA-Tb) was dictated by the ligand to metal molar ratio and the synthesis time. Analysis of calix-TA-SC-Tb monocrystals revealed the formation of a mononuclear complex of C2 symmetry containing Tb3+ coordinated by four calixarene ionized groups and formate anion encapsulated within the upper cavity. Syntheses of other hybrids failed in producing high-quality crystals and the structures could not be solved. The solid-state luminescent properties of hybrids were evaluated, and the structure/property relationship was investigated. Based on the emission and excitation spectra, the energy diagrams for calix-TA-Eu, calix-TA-Tb and calix-TA-Gd were proposed.

Characterization and Optical Studies of Hybrid Materials Synthesized by Covalently Linking Eu3+ Ions, Para-Aminobenzoic Acid, and Titania

Two new luminescent hybrid materials were synthesized using para-aminobenzoic acid (PABA), europium nitrate, and titania. Characterization of the synthesized hybrid materials using infrared spectroscopy and CHN elemental analysis revealed the bonding sites and compositions of the two hybrid materials. The homogenous nature of the hybrid materials was confirmed by scanning electron microscopy. The optical properties of these synthesized materials were studied using UV-visible absorption spectroscopy and photoluminescence spectroscopy. Thermogravimetric analysis revealed that the hybrid materials are thermally stable.

Hybrid luminescent materials of graphene oxide and rare-earth complexes with stronger luminescence intensity and better thermal stability

It is a huge challenge to synthesize high luminescent performance of graphene oxide-rare earth hybrid materials, due to the strong quenching effect of graphene oxide. Herein we reveal a novel graphene oxide/rare-earth complexes hybrid materials that the Eu3+-2-thenoyltrifluoroacetone (TTA)-pyromellitic acids (PMA) were deposited on the surface of graphene oxide sheets (GOSs) via noncovalent approach between GOSs and PMA. This materials exhibit stronger luminescence intensity, longer decay lifetime and better thermal stability than pure Eu3+ complexes. It is confirmed by Fourier transform infrared spectroscopy, scanning electron microscopy, X-ray diffraction and luminescent data. Moreover, we observed PMA plays a significant role in improving the luminescence intensity and prolonging the decay lifetime of hybrid materials.

Highly luminescent hybrid materials based on smectites with polyethylene glycol modified with rhodamine fluorophore

Highly luminescent anisotropic materials are promising for light harvesting systems, sensors, solid lasers and optical devices. To achieve this, polyethylene glycol (PEG) was derivatized with a reactive rhodamine B (RhB) fluorophore to produce a luminescent, water-soluble and positively-charged polymer (RhPEG) that can be intercalated between layers of smectites. An optimal degree of polymer derivatization was applied to avoid fluorescence quenching. The optical properties of RhPEG were similar to those of the RhB precursor. Colloids were prepared using RhPEG and the montmorillonite Kunipia (Mt) and the synthetic saponite Sumecton (Sap), with polymer/smectite mass ratios of 0.05–0.25, and were cast into thin solid films by a vacuum filtration deposition technique. The luminescent hybrid films exhibited a similar structure to those obtained by the intercalation of non-modified PEG. Optical properties depended considerably on the smectite type. The hybrid films made of Sap, the smectite with low charge density, negligibly induced the molecular aggregation of RhPEG and had high fluorescence quantum yields, similar to dilute solutions of RhB or RhPEG. On the other hand, the results of spectroscopic methods indicated molecular aggregation of RhPEG when intercalated between Mt layers leading to considerable fluorescence quenching, making this material unsuitable for the fabrication of photoactive optical films.

Europium (III) Organic Complexes in Porous Boron Nitride Microfibers: Efficient Hybrid Luminescent Material.

We report the design and synthesis of a novel kind of organic-inorganic hybrid material via the incorporation of europium (III) β-diketonate complexes (Eu(TTA)3, TTA = 2-thenoyltrifluoroacetone) into one-dimensional (1D) porous boron nitride (BN) microfibers. The developed Eu(TTA)3@BN hybrid composites with typical 1D fibrous morphology exhibit bright visible red-light emission on UV illumination. The confinement of Eu(TTA)3 within pores of BN microfibers not only decreases the aggregation-caused quenching in solid Eu(TTA)3, but also improves their thermal stabilities. Moreover, The strong interactions between Eu(TTA)3 and porous BN matrix result in an interesting energy transfer process from BN host to TTA ligand and TTA ligand to Eu3+ ions, leading to the remarkable increase of red emission. The synthetic approach should be a very promising strategy which can be easily expanded to other hybrid luminescent materials based on porous BN.

AIEgens-Functionalized Inorganic-Organic Hybrid Materials: Fabrications and Applications.

Inorganic materials functionalized with organic fluorescent molecules combine advantages of them both, showing potential applications in biomedicine, chemosensors, light-emitting, and so on. However, when more traditional organic dyes are doped into the inorganic materials, the emission of resulting hybrid materials may be quenched, which is not conducive to the efficiency and sensitivity of detection. In contrast to the aggregation-caused quenching (ACQ) system, the aggregation-induced emission luminogens (AIEgens) with high solid quantum efficiency, offer new potential for developing highly efficient inorganic-organic hybrid luminescent materials. So far, many AIEgens have been incorporated into inorganic materials through either physical doping caused by aggregation induced emission (AIE) or chemical bonding (e.g., covalent bonding, ionic bonding, and coordination bonding) caused by bonding induced emission (BIE) strategy. The hybrid materials exhibit excellent photoactive properties due to the intramolecular motion of AIEgens is restricted by inorganic matrix. Recent advances in the fabrication of AIEgens-functionalized inorganic-organic hybrid materials and their applications in biomedicine, chemical sensing, and solid-state light emitting are presented.

Playing with nanosegregation in discotic crown ethers: from molecular design to OFETs, nanofibers and luminescent materials

ABSTRACTDiscotic liquid crystals are promising materials for electronic device applications. Combining extended π-systems with crown ethers may further open access to functional supramolecular hybrid materials. In the present publication, we briefly summarise recent literature developments and focus in a second part on our work in the field of discotic crown ethers. The crown ether derivatives are conveniently accessible by convergent syntheses which allow a high degree of variation with respect to side chains, mesogenic unit, size and symmetry of the crown core, metal complexation and counterion. This set of compounds provides a basis for systematic structure–property relationship investigations. Numerous experimental studies identified factors being crucial for mesophase stabilisation and geometry and furthermore led to novel room-temperature crown ether mesogens. The latter were obtained by congestion of the mesogenic units and even introduction of peripheral δ-methyl branched side chains. The formation of molybdenum clustomesogens and their application as luminescent hybrid materials is also described.

Photofunctional hybrid based lanthanide functionalized metal-organic frameworks by ion exchange and coordination modification for luminescent sensing

In this paper, bio-MOF-1 (Zn8(ad)4(BPDC)6O·2Me2NH2, ad=adeninate, BPDC=biphenyldicarboxylate) is modified to afford series of luminescent lanthanide hybrid material systems through both ion exchange of Ln3+ (Ln=Eu, Sm, Nd and Yb), and coordination modification of HBN (6-hydroxybenz[de]anthracen-7-one) ligand. The resulted hybrids formulated as HBN-Ln-bio-MOF-1 show the characteristic luminescence to Ln3+ in both visible (for Eu3+, Sm3+) and near infra-red region (for Nd3+ and Yb3+), respectively. Furthermore, HBN-Eu-bio-MOF-1 is selected for sensing metal ions and small molecules. Interestingly, it shows highly sensitive sensing for both Fe3+ and Fe2+ ions, and especially for Fe3+, which can be expected to have potential application for recognizing iron ion species. Besides, it also shows the sensitive sensing for acetone molecules. The results are benefit for the further application of functionalized bio-MOFs in practical fields.

Synthesis of graphene oxide/rare-earth complex hybrid luminescent materials via π-π stacking and their pH-dependent luminescence

2-Thenoyltrifluoroacetone (Tta) and 1,10-Phenanthroline hydrate (Phen) were used as ligands for Eu3+ ions to prepare graphene oxide (GO)/rare-earth (RE) complex hybrid luminescent materials by a new method. The as-prepared products are characterized via fluorescence microscopy, transmission electron microscopy, Fourier-transform infrared spectroscopy, UV–Vis absorption spectroscopy, X-ray diffraction, fluorescence spectroscopy, and thermogravimetric analysis. The hybrid materials exhibit good solubility, long luminescent lifetime, high fluorescence quantum yield, good thermal and photo stability. Moreover, their fluorescence properties in sodium acetate/acetic acid buffer solution over the pH range from 3.6 to 5.4 are also studied. These properties of hybrid materials provide an important basis for their application in medicine, as potential biological markers, and as drug delivery vehicles.

Zirconia-based luminescent organic-inorganic hybrid materials with ternary europium (III) complexes bonded

In this work, a novel red-emitting organic-inorganic hybrid material with europium (III) lanthanide β-diketonate complexes linked to a zirconia was reported, which was realized by adduct formation with zirconia-tethered terpyridine moieties. Luminescence enhancement of the hybrid material has been observed compared with pure Eu(tta)3·2H2O. Transparent and strongly luminescent thin films based on PMMA were also prepared at room temperature, which are highly luminescent under UV-light irradiation and possess a promising prospect in the area of optics.

Highly selective fluorescent sensing for fluoride based on a covalently bonded europium mesoporous hybrid material

A novel silylated ligand (L–Si) derived from a derivative of phenanthroline (2-(2-hydroxyphenyl)-imidazo[4,5-f]-1,10-phenanthroline, denoted as L) was designed, and it played key roles in the assembly of new organic-inorganic mesoporous hybrid functional material. Firstly, the two N atoms of pyridine rings can coordinate to europium ions and sensitize its luminescence. Secondly, the NH of imidzole ring could form hydrogen bonds with fluoride anions. Thirdly, the silylated group can covalently bonded to the frame of SBA-15 mesoporous silica via in-situ synthesis approach. In addition, 2-thenoyltrifluoroacetonate (TTA) was selected as the second ligand for the purpose of better luminescence. Finally, the europium luminescent mesoporous hybrid material Eu(L–S15)2TTA was obtained through the coordination reaction between europium ion and L–S15 as well as the second ligand TTA. Eu(L–S15)2TTA not only exhibits excellent luminescent properties and high thermal stability, but also retains the ordered mesoporous structures. More importantly, it displays a high-sensitivity sensing function with respect to fluoride ion. The limit of detection for the fluoride ion is as low as 1.6×10−9M for the fluoride ion.

Synthesis and luminescence of octacarboxy cubic polyhedral oligosilsesquioxanes coordinated with terbium

Through the combination of polyhedral oligosilsesquioxane (POSS) and a lanthanide complex, a hybrid material with enhanced luminescent properties was achieved. FTIR, XRD, SEM, and photoluminescence spectroscopy were employed to characterize the obtained material. Improved photo- and thermal-stability were observed in the hybrid material when compared to the mono-modified POSS derivative and individual lanthanide complex. Modification at each silicon vertex of the POSS core effectively increased the lanthanide concentration that was doped in the hybrid material and the 3D divergent configuration of octa-benzoic acid functionalized POSS (OBAPOSS) ensured the uniform distribution of lanthanide in the hybrid material to prevent aggregation of the lanthanide complex at a high concentration. The combination of POSS with lanthanide used in this study for designing and preparing luminescent hybrid materials is simple and applicable, and has provided new facilities for the design of optical devices and the substitution of pure lanthanide complexes in crystal engineering. The unique luminescence properties of the hybrid material, together with its good stability and processability, make it an ideal candidate for a wide range of applications such as materials for flat-panel displays, luminescent probes in bioassays, UV sensors and as laser materials and optoelectronic devices.

ChemInform Abstract: Sol‐Gel Organic‐Inorganic Hybrid Materials Containing Lanthanide Complexes with Polydentate Acyclic and Cyclic Ligands: Synthesis and Spectral‐Luminescent Properties

AbstractReview: 54 refs.

Luminescent hybrid materials based on an europium organic complex and borate glasses

Hybrid materials (HM) were synthesized by high temperature reactions of inorganic glass matrices with an organometallic phosphor; B2O3 and 80PbF2–20B2O3 were used as glassy matrices. The organometallic complex was tris(4,4,4-trifluoro-1-(2-naphthyl) butane-1,3-dionato-(1,10-phenanthroline) europium (III), (Eu(NTA)3(Phen)). The fabricated HMs were shaped as thin glassy plates. The PL spectra of HMs based on fused B2O3 contained only the bands corresponding to Eu3+ ion transitions and were similar to the spectra of the Eu(NTA)3(Phen) powder. For the HM made from an unfused B2O3, we observed the 503nm PL band attributed to the ligand, but the Eu3+ lines were more intense. The 80PbF2–20B2O3-based HM had a broad PL band (480nm), which was more intense than the narrow Eu3+ lines. To explain the obtained results, an exchange reaction that was accompanied by partial decomposition of the organic complex in the glass matrix was proposed. The Eu3+ displacement in an oxide–fluoride environment led to a decreased PL intensity to values that have typically been attributed to Eu3+ doped inorganic glasses. Simultaneously, the ligands formed complexes with Pb, which resulted in an increased PL intensity.

Efficient near-infrared (NIR) luminescent PMMA-supported hybrid materials doped with tris-β-diketonate Ln3+ complex (Ln = Nd or Yb)

Abstract Based on the self-assembly of a trifluorinated and acylpyrazole-modified β-diketonate ligand HL ((Z)-3-methyl-1-phenyl-4-(2,2,2-trifluoro-1-hydroxyethylidene)-1 H -pyrazol-5(4H)-one), LnCl3·6H2O (Ln = La, Nd, Yb, Er, Gd, Eu or Tb) and 2,2′-bpy (2,2′-bipyridine), seven tris-β-diketonate complexes [Ln(L)3(2,2′-bpy)] (Ln = La, 1; Ln = Nd, 2; Ln = Yb, 3; Ln = Er, 4; Ln = Gd, 5; Ln = Eu, 6 or Ln = Tb, 7) were obtained, respectively, where the relatively lower ligands-based 3ππ* energy level results in the good NIR luminescent properties (ФLLn = (0.068–1.12% and ηsens = 54-83%) for complexes 2 and 3. Especially for their series of PMMA-supported hybrid materials [Ln(L)3(2,2′-bpy)]@PMMA, the doping not only causes the improved thermal stability and film-forming property, but also endows more efficient NIR luminescent property even at a doping concentration up to 1:200.

Luminescent hybrid materials functionalized with lanthanide ethylenodiaminotetraacetate complexes containing β-diketonate as antenna ligands

Three organic–inorganic hybrid materials based on silica gel functionalized with (3-aminopropyl)trimethoxysilane (APTS), [3-(2-aminoetilamino)-propil]-trimetoxissilano (DAPTS) and 3-[2-(2-aminoetilamino)etilamino] propiltrimetoxysilane (TAPTS) and subsequently modified with EDTA derivative were prepared by nonhomogeneous route and were then characterized. The resulting materials named SilXN-EDTA (X=1 for APTS, 2 for DAPTS and 3 for TAPTS) were used to obtain new lanthanide Ln3+-β-diketonate (Ln3+=Eu3+, Gd3+ and Tb3+) complexes covalently linked to the functionalized silica gel surfaces (named SilXN-EDTALn-dik, dik=tta, dbm, bzac and acac). The photophysical properties of the new luminescent materials were investigated and compared with those with similar system presenting water molecules coordinated to the lanthanide ions, SilXN-EDTALn-H2O. The SilXN-EDTAEu-dik and SilXN-EDTATb-dik systems displayed characteristic red and green luminescence when excited by UV radiation. Furthermore, the quantitative results showed that the emission quantum efficiency (η), experimental intensity parameters Ω2 and Ω4, and Einstein's emission coefficient (A0J) of the SilXN-EDTAEu-dik materials were largely dependent on the ligands. Based on the luminescence data, the most efficient intramolecular energy transfer processes were found to the SilXN-EDTAEu-dik (dik: tta and dbm) and SilXN-EDTATb-acac materials, which exhibited more pure emission colors. These materials are promising red and green phosphors, respectively.

Highly stable and luminescent layered hybrid materials for sensitive detection of TNT explosives.

Self-assembly is an effective way to fabricate optical molecular materials. However, this strategy usually changes the nanoenvironment surrounding fluorescence molecules, yielding low luminescence efficiency. Herein, we report the intercalation of a ruthenium polypyridine (Ru) complex into the interlayer galleries of layered double hydroxides (LDHs), forming a Ru/LDH hybrid. The Ru complex exists as an ordered monolayer state, and the hybrid exhibits high thermal and photo stability. Its luminescence efficiency and lifetime are increased by ∼1.7 and ∼1 times, respectively, compared to those of free molecules. We constructed a Ru/LDH sensing platform based on a fluorescence quenching effect for highly sensitive detection of TNT with a detection limit of 4.4 μM.