Hydrothermal synthesis of blue-emitting YPO4：Yb3＋ nanophosphor

The blue-emitting YPO4 phosphors doped with Yb3＋ were prepared by a simple hydrothermal method. All the products were characterized by XRD and TEM, which revealed that they were zircon structure with leaf-like morphology. According to the analysis of photoluminescence spectra, upon ultraviolet （275 nm） excitation, the Yb3＋ doped YPO4 phosphor showed an intense blue emission composed of two main bands at 420 and 620 nm assigned to charge transfer state （CTS） → 2Fs/2 and CTS →ZF7/2, respectively. Moreover, the optimum doping concentration of Yb3＋ in YPO4 phosphor was 1%, which exhibited the maximum emission intensity. The possible physical mechanism of concentration quenching was discussed, and the critical transfer distance determined to be 23.889 A. In particular, the color purity of the as-synthesized Yb3＋ doped YPO4 phosphor was as high as 83%, which made it an excellent candidate for blue-emitting materials.

Synthesis,optical properties and self-organization of blue-emitting butterfly-shaped dithienobenzosiloles

Ten novel butterfly-shaped dithienobenzosilole-based luminogens,which are peripherally installed with a variety of substituents including hydrogen,phenyl and substituted phenyl groups,have been readily prepared via an iodine-induced intramolecular electrophilic double-cyclisation reaction and subsequent deiodination or coupling reactions.The optical and electrochemical properties of these compounds were systematically investigated to clarify the relationships between their structures and properties,supported by theoretical calculations.These compounds exhibit deep-blue to sky-blue emissions and high photoluminescence quantum yields up to 0.84 in solution and solid states which are regulated by the functional blades and their steric hindrance on theα–andβ–positions of thiophene rings.Their high thermal-and photo-stabilities have been revealed and mainly attributed to the dithienobenzosilole core.

Anthracene-based Derivatives： Synthesis, Photophysical Properties and Electrochemical Properties

A series of anthracene-based derivatives, namely, 9-（4-phenyl）anthracene（1）, 9-（4-phenylethynyl）- anthracene（2） and 9, 10-bis（phenylethynyl）anthracene（3）, was synthesized by the Suzuki/Sonogashira cross-coupling reactions in good yields. These compounds were fully characterized by X-ray crystallography, thermogravimetric analysis（TGA）, differential scanning calorimetry（DSC）, UV-Vis absorption and fiuorescence（FL） spectroscopy, as well as density functional theory（DFT） calculations. Single-crystal X-ray analysis revealed that the packing structures were influenced by the terminal substitutions. All the compounds exhibited high thermal stability（Td=221---484 ~C） and blue emission with a high quantum yield（~bf =0.20--0.75）. As the number of substituents increased, the decomposition temperatures（Td） of these compounds increased in the following order： 1〈2〈3. Experiments on the photophysical properties revealed that different substituents strongly affected the optical properties. In particular, compound lb with the electron-withdrawing group（--CHO） exhibited a larger Stokes shift（113 nm） than the other compounds. Investigation of the electrochemical properties of these compounds showed that the HOMO-LUMO energy gaps（Egap） decreased obviously as the degree of conjugation increased.

Seeking new,ultra-narrow-band blue emitting phosphors with high color purity for wide color gamut displays

Ultra-narrow-band phosphors have gained widespread applications in lighting and displays to enhance brightness and improve color saturation.Typical phosphor designs employ UCr_(4)C_(4)-type compounds and designing new narrow-band phosphors with high color purity is a major challenge.Here,we explored a Eu^(2+)-doped Ba_(5)GeO_(4)Br_(6)phosphor,showing a narrow-band blue emission(λ_(em)=436 nm) excitation at the near-ultraviolet light with a full width at half maximum of 30.7 nm and high color purity of 96.6%.In addition,attractive cathodoluminescence characteristics were systematically analyzed by varying filament current(30-70 mA) and accelerating voltage(3-7 eV).Robust anti-degradation behavior and color point stability under continuous electron beam bombardment were confirmed.Given its excellent performance in photoluminescence and cathodoluminescence,application in wide color gamut displays appears promising.Using commercial phosphors β-SiAlON:Eu^(2+)and K_(2)SiF6:Mn^(4+)as green and red light co nverte rs respectively,and the title phosphor as the blue light converters,the fabricated w-LED exhibits a wide color gamut of 82% NTSC.

Synthesis of Aqueous CdTe Nanocrystals with High Efficient Blue-Green Emission of Exciton

As one of the most popular nanocrystals （NCs）, aqueous CdTe NCs have very weak green emission under con- ventional synthesis conditions. In this work, we report the first example of blue-emitting CdTe NCs directly synthe- sized in aqueous solution by slowing down the growth rate after nucleation. The key for the synthesis is the optimi- zation of NC growth conditions, namely pH range of 7.5 to 8.5, TGA/Cd ratio of 3.6, Cd/Te ratio of 10, and Te concentration of 2 × 10-5 mol/L, to get a slow growth rate after nucleation. The as-prepared blue-emitting CdTe NCs have small size （as small as 1.9 nm） and bright emission [with 4% photoluminescence quantum yield （PL QY） at 486 nm and 17% PLQY at 500 nm]. Transmission electron microscopy （TEM） images of the as-prepared CdTe show monodispersed NCs which exhibit cubic zinc blend structure. Moreover, time-resolved PL decay and X-ray photoelectron spectroscopy （XPS） results show the as-prepared NCs have better surface modification by ligand, which makes these luminescent small CdTe NCs have higher photoluminescence quantum yield, compared with NCs synthesized under conventional conditions.