Crystal structure, theoretical studies and luminescent properties of a new borate Na3GdB8O15 with one-dimensional broad-banded anionic framework.

Inorganic borate compounds exhibit significant diversity in their structure types, which are associated with interesting optical and magnetic properties. In our work, a new rare-earth polyborate Na3GdB8O15 was prepared with an infinite one-dimensional (1D) broad-banded framework of [B8O15]∞ running along the a-axis, in which large Gd3+ and Na+ ions reside to ensure cohesion and neutrality of the structure. The basic fundamental building block (FBB) of [B8O15]∞ is B16O32, which is composed of five BO3 and three BO4 groups and can be written as 5Δ3□: 〈2Δ□〉-〈Δ2□〉〈2Δ□〉. First principle studies reveal that Na3GdB8O15 is an indirect bandgap semiconductor and the optical absorption at 280 nm originates from the O2-→ Gd3+ transition. Solid solutions of Na3Gd1-xCexB8O15 and Na3Gd0.98-yYyCe0.02B8O15 were prepared and exhibited a bluish violet emissive luminescence by near-UV excitation due to the 5d1→ 4f1 transition of Ce3+. Substitution of Gd3+ by Y3+ enhanced the luminescence efficiency and significantly improved the thermal stability. At 423 K, the luminescence intensity of Na3Gd0.58Y0.4Ce0.02B8O15 remained 77% of that at 298 K. We hypothesize that Na3GdB8O15 is a potential inorganic luminescent host matrix.

Thermally Stable Phosphor KBa2(PO3)5:Eu2+ with Broad-Band Cyan Emission Caused by Multisite Occupancy of Eu2.

The relationship between the structure and properties is always a hot topic in the luminescent material field. In this work, a new phosphor KBa2(PO3)5:Eu2+ (KBP:Eu) was prepared by a high-temperature solid-state reaction method and characterized by X-ray diffraction, energy-dispersive X-ray spectroscopy, photoluminescence (PL), and electroluminescence studies. The polyphosphate host KBP offers three lattice environments (K1, Ba1, and Ba2) for Eu2+ ions to realize broad-band emission from 380 to 700 nm under 345 nm excitation. The distributions of Eu2+ in the three lattice sites can be proven by low-temperature PL and transient fluorescence spectroscopy. Furthermore, temperature-dependent luminescence studies for phosphor KBP:0.02Eu reveal that its luminescence intensity at 150 °C retains about 97% of the initial value at 25 °C. By composing a 365 nm UV chip and KBP:0.02Eu, CaAlSiN3:Eu2+ phosphors, a warm white-light-emitting diode (WLED) was obtained with a correlated color temperature of 5146 K and chromaticity coordinates (0.3404, 0.3384). Therefore, KBP:Eu phosphor is a potential cyan-emitting phosphor used for high-power WLEDs.

Novel tantalum phosphate Na13Sr2Ta2(PO4)9: synthesis, crystal structure, DFT calculations and Dy3+-activated fluorescence performance.

A new tantalum phosphate, tridecasodium distrontium ditantalum nonaphosphate, Na13Sr2Ta2(PO4)9, was prepared using the high-temperature flux method. The structure can be described as a three-dimensional open framework containing isolated [TaV2(PO4)9]17- units that are interlocked by Na and Sr ions. Band structure studies by the first-principles method revealed that Na13Sr2Ta2(PO4)9 is an insulator with an indirect band gap of 4.78 eV, which makes it suitable as a luminescent host matrix. A series of solid solutions, i.e. Na13Sr2-xTa2(PO4)9:xDy3+ (x = 0.01, 0.02, 0.04, 0.06, 0.08, 0.1, 0.12 and 0.14), were prepared and their photoluminescence properties studied. Under 350 nm light excitation, these emit two typical emissions of the Dy3+ ion, i.e. the 4F9/2→6H15/2 transition centred at 476 nm and the 4F9/2→6H13/2 transition centred at 570 nm.

A simple hydrazone as a multianalyte (Cu2+, Al3+, Zn2+) sensor at different pH values and the resultant Al3+ complex as a sensor for F.

A new colorimetric and fluorescence molecular chemosensor based on triazole hydrazone can be used as a multi-probe for selective detection of Al3+, Zn2+, and Cu2+ by monitoring changes in the absorption and fluorescence spectral patterns. Results show that Al3+ and Zn2+ ions can induce remarkable fluorescence enhancement at pH 6.0 and pH 10.0, respectively, while the addition of Cu2+ ions leads to a significant UV-visible absorption enhancement in the visible range at pH 6.0. In addition, the resultant Al3+ complex could act as an 'on-off' fluorescence sensor for F-. The fluorescence sensor was also used to monitor intracellular Al3+, Zn2+, and F- in Hela cells.

A high-performance nonenzymatic piezoelectric sensor based on molecularly imprinted transparent TiO2 film for detection of urea.

Transparent photocatalytic surfaces are of ever increasing importance for the enhancement of the photocatalytic efficiency. Here, the highly ordered transparent TiO2 nanotube arrays were prepared by the anodization and thermal annealing of titanium layer deposited onto the glass substrate, and a novel nonenzymatic piezoelectric sensor was developed for urea detection based on the modification of molecularly imprinted TiO2 thin film onto transparent TiO2 nanotube arrays. The performance of the fabricated sensor was evaluated and the results indicated that the sensor exhibited high sensitivity in urea detection, with a linear range from 0.04 to 120 µM and a limit of detection of 0.01 µM. Moreover, the sensor presented outstanding selectivity while used in coexisting systems containing various interferents with high concentration. The analytical application of the urea sensor confirmed the feasibility of urea detection in urine sample.

[Chromosomal localization and development of SNP markers of a serine protease gene in Farrer's scallop (Chlamys farreri)].

Disease control is a main objective in the culture of Farrer's scallop (Chalmys farreri). Many investigations have focused on the innate immune system of this species. Serine proteases amplify signals in many immune-related pathways and thus play a crucial role in innate immune system. Recently, studies on serine protease in C. farreri were mainly on sequence analysis and expression profile, but no study on gene localization was reported. In this study, a BAC clone (CFB040H03) that contains a serine protease gene of C. farreri was located on the long arms of a pair of homologous chromosomes by BAC-FISH technique. Six SNPs were found inside the serine protease gene using direct sequencing of the PCR products. The chromosomal localization of serine protease gene would provide fundamental support for further research on this gene. The SNPs obtained can be mapped to the genetic linkage map and is helpful to the construction of the integration map of C. farreri.