Sunlight-Activated Orange Persistent Luminescence from Bi-Doped SrBaZn2Ga2O7 for Warm-Color Optical Applications.

A warm persistent luminescence (PersL) material SrBaZn2Ga2O7:Bi3+ was prepared using the conventional high-temperature solid-phase reaction method. We first investigated the PersL properties of SrBaZn2Ga2O7:Bi3+ in detail via PersL spectra, PersL excitation spectrum, PersL decay curves, and thermoluminescence (TL) spectra. The highlight of this study is that in addition to the 254 nm light source, the low-energy light source of 365 nm and sunlight can effectively excite electrons and charge traps, resulting in preferable orange PersL performance. The PersL decay time of the representative sample can last for 960 s after excitation by a 365 nm light source and 900 s after excitation by simulated sunlight. Meanwhile, the PersL color can be regulated by changing the excitation wavelength. In order to explain the infrequent PersL phenomena after different light source excitations, we recorded a series of TL spectra as a function of different light sources, different charging times, and different decay times to reveal the distribution of traps in the material and the influence of trap distribution on trapping and detrapping processes. This novel sunlight-activated orange PersL material is expected to promote the development of sunlight-activated PersL materials and expand potential applications in solar energy utilization and anticounterfeit marking.

Research Advances on Human-Eye-Sensitive Long Persistent Luminescence Materials.

Based on the actual application requirements of multicolor long persistent luminescence (LPL) materials, we highlight the recent developments in the last decade on human-eye-sensitive LPL materials and try to make a full list of known LPL compounds possessing wavelengths of 400-600 nm and a duration time longer than 10 h (>0.32 mcd/m2); these are more sensitive to the human eye's night vision and can be used throughout the night. We further emphasize our group research of novel LPL materials and the regulation of LPL color to enable a full palette. In the end, we try to summarize the challenges and perspectives of LPL materials for potential research directions based on our limited understandings. This review could offer new enlightenment for further exploration of new LPL materials in the visible light range and related applications.

New phenomena of photo-luminescence and persistent luminescence of a Eu2+,Tb3+ codoped Ca6BaP4O17 phosphor under high hydrostatic pressure.

In this study, we present a photo-luminescence (PL) and persistent luminescence (PersL) investigation of Ca6BaP4O17:Eu2+,Tb3+ (CBPO:Eu,Tb) at high hydrostatic pressure in the range of 0-11.04 GPa. More importantly, there is a significant increase of PL intensity and extension of PersL duration time at a pressure point of ∼0.15 GPa.

Designing a novel red to near-infrared persistent phosphor CaMgGe2O6:Mn2+,Sm3+ based on a vacuum referred binding energy diagram.

In this work, we designed and successfully synthesized a novel germanate-based persistent luminescence (PersL) phosphor host, CaMgGe2O6, via a solid-state reaction. We constructed an empirical energy level scheme of the CaMgGe2O6:Ln2+/Ln3+ phosphors according to the Dorenbos model. Then, we successfully theoretically predicted the choice of the optimal codopant of CaMgGe2O6:Mn2+ phosphors using this empirical energy level scheme. As a result, after co-doping with Sm3+, the PersL intensity is increased 16 times and the time duration is effectively improved 52 times due to the high concentration of new traps. CaMgGe2O6:Mn2+,Sm3+ shows red to near-infrared long persistent emission located at 675 nm, which can be sustained for about 60 minutes above the recognizable intensity level (≥0.32 mcd m-2), and the persistence duration of samples was three times that of the red commercial phosphor Y2O2S:Eu3+. The experimental results coincide well with the theoretical predictions. These results demonstrate that the strategy concepts of this work are feasible for the design of persistent luminescence materials. Moreover, a possible afterglow mechanism is studied and discussed with the assistance of thermoluminescence (TL) curves.

Design, synthesis and characterization of a novel bluish-green long-lasting phosphorescence phosphor BaLu2Si3O10:Eu2+, Nd3.

Through drawing upon a solid-state reaction, a newly proposed long-lasting phosphor BaLu2Si3O10:Eu2+, Nd3+ is presented and prepared in this work. The thermoluminescence properties of the phosphor are substantially extended, and the long-lasting phosphorescence behavior is markedly intensified by virtue of the consolidation of Nd3+ ions which serve as trap centers. In line with density functional theory calculations, the conduction band is mostly composed of Lu 5d states while the Ba 5d states only have a tiny contribution. We analyzed the relationship between the phosphor's electronic structure and its optical properties. The photoluminescence emission spectrum shows a blue emitting band with a wide asymmetric property and an extremum of 426 nm, arising from the 5d-4f transitions of the Eu2+ ions which occupy the Ba and Lu sites. It is asserted that the long-lasting phosphorescence of the Eu2+ ions which take up both Ba and Lu sites stems from the special form of conduction band and the occupying environment of the emission center. Yet, they have different contributions and induce an interesting phenomenon in which the blue emitting phosphor shows a bluish-green phosphorescence. The long-lasting phosphorescence can last in excess of 6 h at the recognized intensity level (0.32 mcd m-2) after excitation for 10 min. This work provides a new way of thinking for the development of multicolored LLP materials. This work analyzes and sheds light on the specific courses and provides a likely mechanism for the process.

Establishment and characterization of a cell line from the Chinese soft-shelled turtle Pelodiscus sinensis.

The establishment and partial characterization of Pelodiscus sinensis continuous cell line is described here. A novel P. sinensis fibroblast cell line, designated PSF, was established from heart tissue by the semi-digestion explant culture technique. Since its initiation in July 2013, the cell line has been subcultured at 30°C in minimal essential medium (MEM) containing 15% (v/v) fetal bovine serum for more than 50 passages. The growth curve of the cell line revealed the population doubling time was 51.1 h. Karyotyping analysis indicated the modal chromosome number was 66, and no microbial contamination was detected. The PSF cell line produced significant fluorescent signals after transfection with plasmid pEGFP-C3. Analysis of mitochondrial cytochrome D-loop sequences revealed 96% identity among other Chinese turtle subspecies. Several cell line characterizations included morphological analysis and immunocytochemistry, which revealed the origin of the PSF cell line was fibroblast-like cells. Measurement of the isoenzymes lactic dehydrogenase and malic dehydrogenase showed no cross-contamination of this cell line with other species. This newly established cell line will be a valuable tool for transgenic and genetic manipulation studies and will act as an efficient instrument for studies of the viral diseases of the soft-shelled turtle.

Size-Selective Cu Nanocrystals Growth on Single and 2-3 Layers Graphene Films.

Cu nanoparticles decorated CVD growth single layer and 2-3 layers graphene films have been synthesized by sputtering deposition and annealing process. The wrinkles were observed on single layer graphene due to high annealing temperature (700 degrees C) and rapid cooling process, which were proved by HRSEM and Raman spectra. Smaller mean diameter and narrower size distribution of Cu nanoparticles were observed on 2-3 layers graphene film than that on single layer graphene. The large particles grow at the expense of small particles, and the particle growth was governed by the Ostwald ripening process.

Luminescence properties of a new green afterglow phosphor NaBaScSi2O7:Eu(2+).

A novel green afterglow phosphor NaBaScSi2O7:Eu(2+) was prepared by a solid state reaction under a reductive atmosphere. The NaBaScSi2O7:Eu(2+) phosphor shows two emission bands centered at about 424 (weak) and 502 nm (strong) due to the substitution of Eu(2+) in both Ba(+) and Na(2+) sites, and energy transfer from EuBa (424 nm) to EuNa (502 nm) was found. Both EuBa and EuNa contribute to the afterglow process while EuNa dominates. Na0.99BaScSi2O7:0.01Eu(2+) exhibits green long lasting phosphorescence, whose duration is more than 1 h. The thermoluminescence properties of NaBaScSi2O7:Eu(2+) and the relationship between thermoluminescence and thermal quenching properties were discussed in detail. This work provides a new and efficient candidate for long lasting phosphorescence materials.