Tailoring Multidimensional Traps for Rewritable Multilevel Optical Data Storage.

In the current "big data" era, the state-of-the-art optical data storage (ODS) has become a front-runner in the competing data storage technologies. As one of the most promising methods for breaking the physical limitation suffered by traditional ones, the advance of optically stimulated luminescence (OSL) based optical storage technique is now still limited by the simultaneous single-level write-in and readout in a same spot. In this work, to bridge the data-capacity gap, we report for the first time a novel and promising nonphysical multidimensional OSL-based ODS flexible medium for erasable multilevel optical data recording and reading. We tailor multidimensional traps with discrete, narrowly distributed energy levels through (multi-)codoping of selective trivalent rare-earth ions into Eu2+-activated barium orthosilicate (Ba2SiO4). Upon UV/blue light illumination, information can be sequentially recorded in different traps assisted by thermal cleaning with an increase of storage capacity by orders of magnitude, which is addressable individually in the whole domain or bit-by-bit mode without the crosstalk by designed thermal/optical stimuli. Remarkably, good data retention and robust fatigue resistance have been achieved in recycle data recording. Insight is forged from charge carrier dynamics and interactions with traps for a universal method of data storage, and proof-of-concept applications are also demonstrated, thereby providing the way to not only rewritable multilevel ODS but also high-security encryption/decryption.

Li5 Zn8 Ga5 Ge9 O36 : Cr3+ , Ti4+ : A Long Persistent Phosphor Excited in a Wide Spectral Region from UV to Red Light for Reproducible Imaging through Biological Tissue.

Near-infrared (NIR) long-persistent phosphors (LPPs) have emerged as a potential solution for bio-imaging applications over the past few years. However, there are enormous challenges regarding their in situ application based on their dependence on short-wavelength excitation. In this paper, we report a multi-spectral excited NIR LPP, Li5 Zn8 Ga5 Ge9 O36 : 1.5 % Cr3+ , 0.5 % Ti4+ , which overcomes the limitations of functional processes in biological tissues and other complex systems. This LPP exhibits a high luminescent intensity and a long emission duration in the NIR region (700-800 nm). The applicability of this phosphor to tissue imaging is demonstrated experimentally. Its persistent luminescence (PersL) can easily penetrate approximately 2 mm of pork flesh. More importantly, this phosphor can be re-charged in situ using a red LED or laser diode array to provide renewed NIR PersL for biological tissues, which is beneficial for long-term biological tissue imaging applications with high signal-to-noise ratios. Systematic investigations of the nature of energy traps and PersL mechanisms are also reported in this paper.

Crystal field modulation-control, bandgap engineering and shallow/deep traps tailoring-guided design of a color-tunable long-persistent phosphor (Ca, Sr)Ga4O7:Mn2+,Bi3+ .

In this paper, a new color tunable long persistent phosphor (Ca, Sr)Ga4O7:Mn2+,Bi3+ has been successfully synthesized via a high-temperature solid-state reaction. Crystal field modulation and band gap engineering controlled by Sr2+ substitution for Ca2+ realizes the color tunable Mn2+ emission from 580 to 556 nm. Guided by the tailoring of traps distribution, the long persistence luminescence (LPL) performance of CaGa4O7:Mn2+ is greatly enhanced to 33 times higher brightness and much longer persistent time through Bi3+ co-doping. Furthermore, aided by the Rietveld refinement method, steady/transient-state fluorescence and thermoluminescence (TL) techniques with the combination of DFT calculations, the crystal structure evolution, electronic structure, trap distribution tailoring, self reduction of Mn4+, and the related color tunable Mn2+ photoluminescence/enhanced LPL properties are systematically characterized. Finally, a schematic diagram is proposed for a detailed illustration of the photoluminescence and LPL mechanisms.

Correction: Luminescence properties of the pink emitting persistent phosphor Pr3+-doped La3GaGe5O16.

[This corrects the article DOI: 10.1039/C5RA05116A.].

[Luminescence investigation of Na(z)Ca(1-x-2y-z)Bi(y)MoO4 : Eu(x+y)3+, red phosphors].

A series of red phosphors with the composition Na(z)Ca(1-x-2y-z), Bi(y) MoO4 : Eu(x+y)3+ (y, z = 0, x = 0.24, 0.26, 0.30, 0.34, 0.38; x = 0.30, y = 0.01, 0.02, 0.03, 0.03, 0.05, 0.06, 0.07; x = 0.30, y = 0.04, z = 0.38) were prepared via traditional solid-state method. The crystal structures of the obtained phosphors were identified by X-ray powder diffraction (XRD) method. The photoluminescence properties of the samples were characterized by fluorescence spectrophotometer. The results indicated that the concentration of Eu3+ single doped Ca(1-x) MoO4 : Eu3+ with the maximum luminescence intensity was found to be 0.30 (namely, Ca0.70 MoO4 : Eu(0.30)3+); the photoluminescence properties with different ratio of Bi3+/Eu3+ codoped Ca0.70-2y Bi(y) MoO4 : Eu(0.30+y)3+, were also investigated, and the results showed that the charge band (CTB) reached the maximum value when the y value was equal to 0.03; for the characteristic excitation peaks of Eu3+, however, the intensity of the excitation spectral line locating at 393 nm was stronger than that at 464 nm when y < 0.03, while the intensity at 464 nm was greater than that at 393 nm when y > or = 0.03; the intensity of excitation peaks locating at 393 and 464 nm respectively both reached the maximum intensity when the y value was 0.04. The relative intensity of the excitation and emission of the above phosphor was enhanced greatly when Na2CO3 acting as charge compensation was added. The above results showed that the relative intensity between 393 and 464 nm could be changed by adjusting the ratio of Bi3+ /Eu3+ codoping concentrations.

Clinical applications of 18F-fluorodeoxyglucose positron emission tomography/computed tomography in carcinoma of unknown primary.

BACKGROUND: Carcinoma of unknown primary (CUP) encompasses a heterogeneous group of tumors with varying clinical features. The management of patients of CUP remains a clinical challenge. The purpose of this study was to evaluate the clinical applications of integrated (18)F-fluorodeoxyglucose positron emission tomography/computed tomography (FDG PET/CT) information in patients with CUP, including detecting the occult primary tumor and effecting on disease therapy. METHODS: One hundred and forty-nine patients with histologically-proven metastases of CUP were included. For all patients, the conventional diagnostic work-up was unsuccessful in localizing the primary site. Whole-body PET/CT images were obtained approximately 60 minutes after intravenous injection of 350 - 425 MBq of (18)F-FDG. RESULTS: In 24.8% of patients, FDG PET/CT detected primary tumors that were not apparent after conventional workup. In this group of patients, the overall sensitivity, specificity, and accuracy rates of FDG PET/CT in detecting unknown primary tumors were 86.0%, 87.7%, and 87.2%, respectively. FDG PET/CT imaging also led to the detection of previously unrecognized metastases in 29.5% of patients. Forty-seven (31.5%, 47 of 149) patients underwent a change in therapeutic management. CONCLUSIONS: FDG PET/CT is a valuable tool in patients with CUP, because it assisted in detecting unknown primary tumors and previously unrecognized distant metastases, and optimized the management of these patients.