Energy Transfer Studies in Tb3+-Yb3+ Co-Doped Phosphate Glasses

Detailed optical properties of Tb3+-Yb3+ co-doped phosphate glasses were performed based on their emission spectra and decay measurements. Under blue excitation of Tb3+ at 488 nm, the intensity of Yb3+ emissions gradually enhanced upon increasing the Yb3+ content until 1 mol% indicated an energy transfer from Tb3+ to Yb3+. Otherwise, under near infrared excitation of Yb3+ at 980 nm, these glasses exhibit intense green luminescence, which led to cooperative sensitization of the 5D4 level of Tb3+ ions. A cooperative energy transfer mechanism was proposed on the basis of the study on the influence of Yb3+ concentration on up-conversion emission intensity, as well as the dependence of this up-conversion intensity on near infrared excitation power. Moreover, the temporal evolution of the up-conversion emissions have been studied, which was in positive agreement with a theoretical model of cooperative up-conversion luminescence that showed a temporal emission curve with rise and decay times of the involved levels.

Effect of Samarium Oxide on Structural and Optical Properties of Zinc Silicate Glass Ceramics from Waste Material

This work indicates the synthesis of samarium doped zinc silicate (willemite) glass ceramics with different weight concentrations. Solid-state reaction technique was used to make up the samples, with waste rice husks as silicate source. The measurement of X-ray diffraction revealed sharp and broad diffraction peaks. Besides, the Field emission scanning electron microscope exhibited the poly grains morphology of the crystalline samples. Consequently, samarium strips were growing in size as the weight percent of dopant was increased. While Fourier transforms infrared spectra, showed slight variation peaks with diverse dopant concentrations. Then the energy band gaps of samarium doped willemite glass ceramics were reduced with the increment of samarium dopant concentrations. The photoluminescence measurement exhibited the red emission which agreed to the 4G5/2 → 6H11/6 (646.71 nm) under the blue excitation.

Laser-free super-resolution microscopy

We report that single-molecule superresolution microscopy can be achieved with a conventional epifluorescence microscope setup and a Mercury arc lamp. The configuration termed as laser-free super-resolution microscopy (LFSM), is an extension of single molecule localisation microscopy (SMLM) techniques and allows single molecules to be switched on and off (a phenomenon termed as “blinking”), detected and localised. The use of a short burst of deep blue excitation (350-380 nm) can be further used to reactivate the blinking, once the blinking process has slowed or stopped. A resolution of 90 nm is achieved on test specimens (mouse and amphibian meiotic chromosomes). Finally, we demonstrate that STED and LFSM can be performed on the same biological sample using a simple imaging medium. It is hoped that this type of correlative imaging will provide a basis for a further enhanced resolution.

Broad near-ultraviolet and blue excitation band induced dazzling red emissions in Eu3+-activated Gd2MoO6 phosphors for white light-emitting diodes

A series of Eu3+-activated Gd2MoO6 phosphors were synthesized via a citric acid-assisted sol–gel route.

Broad red-emission of Sr3Y2Ge3O12:Eu2+ garnet phosphors under blue excitation for warm WLED applications

By blending a novel Sr3Y2Ge3O12:Eu2+ red phosphor with a commercial Y3Al5O12:Ce3+ phosphor, a warm WLED was fabricated with a CRI value of 85.81.

Two blue-light excitable yellow-emitting LMOF phosphors constructed by triangular tri(4-pyridylphenyl)amine

Two luminescent metal–organic-frameworks (LMOFs) constructed by a molecular chromophore [tri(4-pyridylphenyl)amine] (tppa) emit intense yellow color under blue excitation.