Selective doping of Ni2+ in octahedral sites provided by nanocrystals embedded in glass-ceramics (GCs) is crucial to the enhancement of broadband near-infrared (NIR) emission. In this work, a NIR emission with a full-width-at-half-maximum (FWHM) of 288 nm is first reported from ZnGa2O4: Ni2+ nano-spinels embedded GCs with excellent transparency. A comparison is made of the NIR luminescence properties of Ni2+ doped GCs containing ZnGa2O4, germanium-substituted ZnGa2O4 nano-spinels (Zn1+xGa2−2xGexO4), and Zn2GeO4/Li2Ge4O9 composite nanocrystals that are free of Ga3+. The results show that ZnGa2O4: Ni2+ GCs exhibit a significantly enhanced NIR emission. The incorporation of the nucleating agent TiO2 is favored in terms of the increased luminescence intensity and prolonged lifetime. The possible causes for the enhancement effect are identified from the crystal structure/defects viewpoint. The newly developed GCs incorporate good reproducibility to allow for a tolerance of thermal treatment temperature and hence hold great potential of fiberization via the recently proposed “melt-in-tube” method. They can be considered as promising candidates for broadband fiber amplifiers.

Selective doping of optically active ions into the nanocrystalline phase(s) of glass ceramics is of interest for photoluminescence (PL) applications to control the energy transfer (ET) processes between dopants on the nanometer length scale. Here, the focus is on explaining the essential knowledge of the distribution of two groups of active ions: transition metal (Ni2+ and Cr3+) and rare earth (Yb3+ and Er3+) ions, which are doped into i) single‐phase Ga2O3 and ii) dual‐phase Ga2O3 and YF3 nanocrystals (NCs). These NCs are obtained by thermally crystallizing ternary silicate‐ and quinary fluorosilicate‐based glasses, respectively. It is found that the two types of active ions can successfully be doped into Ga2O3 NCs, resulting in enhanced ET between the dopants because of the small separation distance of, e.g., <10 Å, whereas ET is significantly suppressed when Ga2O3 and YF3 NCs are coprecipitated. In this case, the studied rare earth ions have a high propensity for being selectively doped in YF3 NCs. The studied transition‐metal ions can always be found in Ga2O3 NCs irrespective of the presence of the fluoride phase. The selective doping and the ET between the two types of active ions can be controlled simultaneously on annealing. This may allow for the achievement of diverse PL properties, such as ultrabroadband near‐infrared and upconversion‐mediated Stokes emissions.

The partitioning of rare earth ions (REs: Yb3+, Er3+, Eu3+ and Nd3+) in γ-Ga2O3 nanocrystals (NCs) precipitated in a nanostructured silicate glass ceramic is revealed, and the enrichment of REs in the NCs (bulk doping) rather than on the interfaces between the NCs and the surrounding glassy phase (surface doping) is differentiated.

Defects present ubiquitously in glasses exert a strong influence on the optical qualities and performances of glass, a phenomenon that has not been well studied to date.

Ni2+/Yb3+/Er3+/Tm3+ codoped transparent glass‐ceramics (GCs) containing both hexagonal β‐YF3 and spinel‐like γ‐Ga2O3 dual‐phase nanoparticles (NCs) are synthesized by melt‐quenching and subsequent heating procedures. Two techniques of transmission electron microscopy (TEM) nanoanalytics and optical spectroscopy are conjugated to understand the distribution of the rare‐earth ions (REs) and transition metals (TMs) in the nanostructured GCs. It is found that the REs are located predominantly in β‐YF3, whereas the TMs in γ‐Ga2O3 NCs. As a result, energy transfer (ET) between the REs and TMs is considerably suppressed due to the large spatial separation (> 3 nm), but it is enhanced between the REs partitioned in the β‐YF3 NCs. This has important implications for intended and demanding photoluminescence functions. For example, an ultrabroadband near‐infrared (NIR) emission in the wavelength region of 1000‐2000 nm covering the entire telecommunications window is observed for the first time. Meanwhile, intense upconversion (UC) emissions covering the 3 primary colors and locating in the first biological window can be also recorded under excitation by a single pump source at 980 nm.

research to applied industrial and social applications including but certainly not limited to window glasses, windscreens, kitchen cooktops, microscope and telescope lens, and optics, and so on, owing to such unmatched and outstanding properties as ease of large-scale and complex shape production as well as chemical and mechanical durability. [1] However, glasses, usually made by the traditional melt-quenching method viz., cooling a viscous liquid fast enough to avoid crystallization (known as supercooling), [2] are seriously constrained to those that entail an acceptable degree of glass-forming ability unless otherwise being made under extremely harsh conditions (e.g., superfast cooling or high-energy irradiation, etc.) that are not readily available to ordinary glass-making labs and factories. [3] This leads to a significantly limited range of available constituents and functions of the obtained glasses. For example, spectroscopic features of active dopants (e.g., rare-earth (REs) ions, transition, and main group metals) are closely associated with their chemical states and the surrounding chemical environments provided by the glass host; hence, it is possible to induce new photoluminescence (PL) functions such as ultrabroadband and enhanced up-/down-conversion emissions via proper doping, post thermal, and magnetic treatments or A new method is reported to achieve the manufacture of glass of arbitrary ratio of SiO 2 /P 2 O 5 which cannot be made by conventional melt-quenching method. The new method is termed "melt-in-melt" which encapsulates the key step in the glass manufacturing process, i.e. one molten glass is poured into another molten glass with a stirring at high temperatures. Because of near unlimited possibilities in designing new glass compositions, there is a correspondingly great degree of freedom in the topological engineering of the glass structure, which in turn strongly influences the photoluminescence (PL) properties of active dopants. As a proof concept, bismuth and erbium are selected as the indicator dopants for emphasizing the real advantages of the new method as an effective means to tailoring the PL properties of the doped glasses. The micro structure and element distribution within the fabricated glasses are comprehensively characterized by high-resolution scanning electron microscopy, micro-Raman and high-performance X-ray fluorescence spectroscopy. Phase separation occurring at both nano-and meso-scale is observed. Apart from the developed glasses being themselves promising broadband emission phosphors, the new glass-making method may extend the possible applications of glass for important photonic applications (e.g. optical sensing, lighting, display, optical amplification and lasing etc.).

Emissions due to inter‐configurational 4f15d1‐4f2 electronic transitions of Pr3+ ions are scarcely observed in phosphate glasses. In this work, the intense UV emissions (at 311 and 327 nm) owing to the inter‐configurational f‐d transitions of Pr3+ have been reported in Pr3+‐doped strontium phosphate glasses. Characteristic blue (481, 488 nm), green (522 nm), orange (597, 610 nm), and red (638 nm) emissions are also observed due to the intra‐configurational f‐f transitions. Possible mechanisms controlling the intra‐ and inter‐configurational transitions of Pr3+ ions are discussed.

The photoluminescence properties of dopants are strongly correlated with their distributions in host phosphors, the knowledge of which, however, is not well established yet. In this paper, the distribution of the active dopants, for example, trivalent ytterbium (Yb3+) and bivalent nickel (Ni2+) in a highly transparent germanate glass‐ceramic containing thermally grown Zn1+xGa2−2xGexO4 (0 ≤ x ≤ 1) nanospinels, is revealed by an analytical transmission electron microscope. The elemental mapping and linescan analysis confirm that both Yb3+ and Ni2+ accumulate preferentially in the germanium‐substituted ZnGa2O4 nanospinels embedded in the glass. The influence of glass crystallization on the electric transition properties of Yb3+ is presented. An enhanced ultrabroadband near infrared emission of Ni2+ is observed as a result of efficient energy transfer from Yb3+ to Ni2+ accumulated in the nanocrystals. Discussions are given to account for the detailed mechanisms of the efficient energy transfer occurring between the dopants.