Recent startling interest for lanthanide luminescence is stimulated by the continuously expanding need for luminescent materials meeting the stringent requirements of telecommunication, lighting, electroluminescent devices, (bio-)analytical sensors and bio-imaging set-ups. This critical review describes the latest developments in (i) the sensitization of near-infrared luminescence, (ii) “soft” luminescent materials (liquid crystals, ionic liquids, ionogels), (iii) electroluminescent materials for organic light emitting diodes, with emphasis on white light generation, and (iv) applications in luminescent bio-sensing and bio-imaging based on time-resolved detection and multiphoton excitation (500 references).

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Lanthanide luminescence for functional materials and bio-sciences

Control of spontaneously emitted light lies at the heart of quantum optics. It is essential for diverse applications ranging from miniature lasers and light-emitting diodes, to single-photon sources for quantum information, and to solar energy harvesting. To explore such new quantum optics applications, a suitably tailored dielectric environment is required in which the vacuum fluctuations that control spontaneous emission can be manipulated. Photonic crystals provide such an environment: they strongly modify the vacuum fluctuations, causing the decay of emitted light to be accelerated or slowed down, to reveal unusual statistics, or to be completely inhibited in the ideal case of a photonic bandgap. Here we study spontaneous emission from semiconductor quantum dots embedded in inverse opal photonic crystals. We show that the spectral distribution and time-dependent decay of light emitted from excitons confined in the quantum dots are controlled by the host photonic crystal. Modified emission is observed over large frequency bandwidths of 10%, orders of magnitude larger than reported for resonant optical microcavities. Both inhibited and enhanced decay rates are observed depending on the optical emission frequency, and they are controlled by the crystals’ lattice parameter. Our experimental results provide a basis for all-solid-state dynamic control
of optical quantum systems.

Controlling the dynamics of spontaneous emission from quantum dots by photonic crystals

A review of some properties of chalcogenide glasses and the current status of their applications is given. Techniques to characterize the linear and non-linear properties of these glasses are introduced and used to measure the optical constants of chalcogenide glasses in the form of bulk, thin film and fiber. Different techniques for the fabrication of gratings and waveguides in these glasses are described. Achievable efficiencies of gratings, as well as propagation losses of fabricated waveguides, are presented. The possibilities of fabricating active devices, such as fiber amplifiers and lasers, are presented. Finally, a novel application of chalcogenide glasses, namely all-optical switching for the fabrication of efficient femtosecond switches, is introduced.

Optical properties and applications of chalcogenide glasses: a review

The chemistry of post transition metals is dominated by the group oxidation state N and a lower N-2 oxidation state, which is associated with occupation of a metal s2 lone pair, as found in compounds of Tl(I), Pb(II) and Bi(III). The preference of these cations for non-centrosymmetric coordination environments has previously been rationalised in terms of direct hybridisation of metal s and p valence orbitals, thus lowering the internal electronic energy of the N-2 ion. This explanation in terms of an on-site second-order Jahn–Teller effect remains the contemporary textbook explanation. In this tutorial review, we review recent progress in this area, based on quantum chemical calculations and X-ray spectroscopic measurements. This recent work has led to a revised model, which highlights the important role of covalent interaction with oxygen in mediating lone pair formation for metal oxides. The role of the anion p atomic orbital in chemical bonding is key to explaining why chalcogenides display a weaker preference for structural distortions in comparison to oxides and halides. The underlying chemical interactions are responsible for the unique physicochemical properties of oxides containing lone pairs and, in particular, to their application as photocatalysts (BiVO4), ferroelectrics (PbTiO3), multi-ferroics (BiFeO3) and p-type semiconductors (SnO). The exploration of lone pair systems remains a viable a venue for the design of functional multi-component oxide compounds.

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Stereochemistry of post-transition metal oxides: revision of the classical lone pair model.

Advances in solid state white lighting technologies witness the explosive development of phosphor materials (down-conversion luminescent materials). A large amount of evidence has demonstrated the revolutionary role of the emerging nitride phosphors in producing superior white light-emitting diodes for lighting and display applications. The structural and compositional versatility together with the unique local coordination environments enable nitride materials to have compelling luminescent properties such as abundant emission colors, controllable photoluminescence spectra, high conversion efficiency, and small thermal quenching/degradation. Here, we summarize the state-of-art progress on this novel family of luminescent materials and discuss the topics of materials discovery, crystal chemistry, structure-related luminescence, temperature-dependent luminescence, and spectral tailoring. We also overview different types of nitride phosphors and their applications in solid state lighting, including general ...

Down-Conversion Nitride Materials for Solid State Lighting: Recent Advances and Perspectives.

We report on the elastic properties of xMnO-Al2O3-(6-x)SiO2 manganese aluminosilicate glasses, in which pronounced exchange coupling and antiferromagnetic interaction occurs among the paramagnetic Mn2+ ions. X-ray absorption reveals a Mn-O bond length of ∼2.1 Å, and a distance of ∼3 Å between Mn2+ ions in sixfold coordination, further corroborated by electron paramagnetic resonance and dynamic photoluminescence spectroscopy. This indicates the presence of edge-sharing MnO6 units, in resemblance to edge-sharing MnO8 in the crystalline Spessartine garnet Mn3Al2[SiO4]3. We argue that these cluster species have a profound effect on material stiffness: the compact structure of manganese aluminosilicate glasses enables a Young's modulus in the 100 GPa range and a Poisson's ratio of about 0.3. This exceeds the compositional trend with cation field strength observed for other aluminosilicate glasses. 

Cation speciation, compactness and structure‐property correlations in manganese aluminosilicate glasses

The present invention relates to a method for synthesizing chalcogel, which is an adsorbent for radioactive materials and, more particularly, to a method for synthesizing chalcogel, comprising the steps of: (a) dissolving a nickel compound is a solvent to create a nickel-based (Ni base) solution, dissolving a cobalt compound in a solvent to create a cobalt-based (Co base) solution, and dissolving a molybdenum compound in a solvent to create a molybdenum-based (Mo base) solution; (b) mixing the nickel-based (Ni base) solution, the cobalt-based (Co base) solution, and the molybdenum-based (Mo base) solution; (c) gelling the mixed solution produced in step (b); and (d) subjecting the solvent of the mixed solution gelled in step (c) into solvent replacement with deionized water.

A synthesis method of chalcogel sorbent using freeze-drying method

The present disclosure relates to a borate glass wasteform to immobilize radioactive rare earth waste generated in a pyrogenic process and a manufacturing method thereof. The borate glass wasteform includes: a glass medium containing boron oxide (B_2O_3), calcium oxide (CaO), and aluminum oxide (Al_2O_3); and a radioactive rare earth waste. It is possible to maintain a process temperature.

Borate glass wasteform to immobilize rare-earth oxides from pyro-processing and manufacturing method thereof

Silicate glasses with different Nd₂O₃ concentrations were prepared through conventional melt-quenching methods while PbS quantum dots (QDs) were precipitated through heat treatment. The peak wavelengths of absorption and the photoluminescence of PbS QDs shifted to the short-wavelength side as the concentration of Nd₂O₃ increased. The electron energy loss spectroscopy (EELS) indicated that Nd 3+ ions were preferentially distributed inside the PbS QDs instead of the glass matrix. In addition, there was no significant change in the lifetimes of the Nd 3+ :⁴F 3/2 fluorescence between the as-prepared glass (607 μs) and the heattreated glass(576 μs). Nd 3+ ions were surrounded by oxygen instead of sulfur and the Nd-O clusters probably acted as nucleating centers for the formation of PbS QDs inside the glasses.

Optical Properties of PbS Quantum Dots (QDs) Precipitated in Nd 3+ -Containing Glasses

The present invention relates to an IGZO thin film for an organic solar cell and a manufacturing method thereof. Disclosed are the IGZO thin film which is formed by adding a rare-earth element to the base composition of IGZO including In, Ga, Zn, and O and the manufacturing method thereof which includes the steps of: manufacturing IGZO solutions by mixing the rare-earth element with the base material of the IGZO thin film; coating a glass substrate with the IGZO solutions; and performing the ultraviolet curing or the thermal treatment of the dried glass substrate after drying the coated glass substrate.

Jong Heo

Papers

Cation speciation, compactness and structure‐property correlations in manganese aluminosilicate glasses

A synthesis method of chalcogel sorbent using freeze-drying method

Borate glass wasteform to immobilize rare-earth oxides from pyro-processing and manufacturing method thereof

Optical Properties of PbS Quantum Dots (QDs) Precipitated in Nd 3+ -Containing Glasses

Igzo thin film for organic solar cell and method for manufacturing the same