KLiScF:Cr/Mn fluoride phosphor with enhanced broadband emission for NIR pc-LEDs.

Trivalent chromium ion-activated broadband near-infrared (NIR) luminescence materials have shown great application prospects as next-generation NIR light sources, but improvement of the luminescence efficiency remains a challenge. Herein, novel KLiScF:Cr and KLiScF:Cr/Mn broadband fluoride NIR phosphors are designed and prepared by a combination of hydrothermal and cation exchange methods for the first time. The crystal structure and photoluminescence (PL) properties of KLiScF:Cr are studied in detail, which shows strong absorption in the blue light region ( = 432 nm) and broadband NIR emission ( = 770 nm) with a PL quantum efficiency of 77.

Boosting Red Luminescence of Mn in Tantalum Heptafluoride Based on an Ab Initio-Facilitated Sensitizer and Hydrophobic Surface Modification.

A narrow-band red-light component is critical to establish high color rendition and a wide color gamut of phosphor-converted white-light-emitting diodes (pc-WLEDs). In this sense, Mn-doped KSiF fluoride is the most successful material that has been commercialized. As with KSiF:Mn phosphors, Mn-doped tantalum heptafluoride (KTaF:Mn) fulfills a similar luminescence behavior and has been brought in a promising narrow-band red phosphor.

Temperature sensing of SrYGeO:Bi,Sm garnet phosphors with tunable sensitivity.

In this study, a novel temperature-sensitive material, SrYGeO:Bi,Sm phosphor, was successfully synthesized by a solid-state reaction method. Under 376 nm light excitation, the as-prepared phosphor presents both blue emissions of Bi and orange red emissions of Sm due to energy transfer from Bi to Sm. Owing to the significant difference in thermal quenching properties and the distinguishable emission between Bi and Sm ions, the temperature sensing performance of the prepared phosphor was evaluated by measuring the fluorescence intensity ratio (FIR) of Sm Bi.

Preliminary Analysis of Volume-Based Resting-State Functional MRI Characteristics of Successful Aging in China.

Background: Resting-state function MRI (rs-fMRI) research on successful aging can provide insight into the mechanism of aging with a different perspective from aging-related disease.

Objective: rs-fMRI research was used to analyze the brain function characteristics of successful aging.

Methods: A total of 47 usual aging individuals and 26 successful aging (SA) individuals underwent rs-fMRI scans and neuropsychological tests.

A Study of Dementia Prediction Models Based on Machine Learning with Survey Data of Community-Dwelling Elderly People in China.

Background: For community-dwelling elderly individuals without enough clinical data, it is important to develop a method to predict their dementia risk and identify risk factors for the formulation of reasonable public health policies to prevent dementia.

Objective: A community elderly survey data was used to establish machine learning prediction models for dementia and analyze the risk factors.

Methods: In a cluster-sample community survey of 9,387 elderly people in 5 subdistricts of Wuxi City, data on sociodemographics and neuropsychological self-rating scales for depression, anxiety, and cognition evaluation were collected.

Crystal-field induced tuning of luminescence properties of NaGaAlF:Cr phosphors with good thermal stability for NIR LEDs.

Cr-Activated broadband near-infrared (NIR) luminescence materials are attracting much attention as next-generation smart NIR light sources that are widely used in night vision, bioimaging, medical treatment, and many other fields. Herein, a series of NaGaAlF:Cr NIR phosphors with broadband emission and tunable luminescence properties were designed and prepared. The luminescence intensity, peak position and full width at half maximum (FWHM) of the materials can be controlled by adjusting the crystal field strength.

Organic solvent-assisted co-precipitation synthesis of red-emitting KTiF:Mn phosphors with improved quantum efficiency and optimized morphology.

We report an organic solvent-assisted (OSA) co-precipitation strategy for the production of Mn-activated KTiF phosphor. The phosphor particle size was controlled through the selection of organic solvents with an alcohol functional group and different carbon chain lengths used in the synthesis. The synergistic effect of the organic solvent and hydrofluoric acid results in large smoothed hexagonal-shaped crystal sheets of particles that become larger as the carbon chain length of the organic solvent increases.

Color tunable CaZnM(PO) (M = Lu/Tb, Lu/Eu, Tb/Eu) phosphors: luminescence, energy transfer and thermal stability studies for n-UV white LEDs.

A series of Tb- and Eu-doped CaZnLu(PO) (CZLP:Tb and CZLP:Eu) as well as CaZnTb(PO):Eu (CZTP:Eu) phosphors have been prepared via the traditional high-temperature solid-state reaction. X-ray powder diffraction (XRD) patterns of the as-prepared phosphors indicate that the introduction of Tb or Eu affects neither the phase impurity nor the crystal structure of the CZLP host lattice. The concentration dependent photoluminescence (PL) spectra reveal that even if Lu was fully substituted by the dopants, Tb or Eu, the phenomenon of concentration quenching would not occur.

Single-Crystal Red Phosphors and Their Core-Shell Structure for Improved Water-Resistance for Laser Diodes Applications.

A solvent-vapor transport route produces centimeter-sized single-crystal red phosphors. The epitaxial growth route to yield its core-shell structure at ambient temperature was adopted. These red phosphors could be applied in all-inorganic WLED devices.

Layered Structure Produced Nonconcentration Quenching in a Novel Eu-Doped Phosphor.

Energy migration (energy transfer among identical luminescence centers) is always thought to be related to the concentration quenching in luminescence materials. However, the novel Eu-doped BaGdTiO phosphor seems to be an exception. In the series of BaGdTiO: xEu ( x = 0.

Thermally Stable White Emitting Eu Complex@Nanozeolite@Luminescent Glass Composite with High CRI for Organic-Resin-Free Warm White LEDs.

Nowadays, it is still a great challenge for lanthanide complexes to be applied in solid state lighting, especially for high-power LEDs because they will suffer severe thermal-induced luminescence quenching and transmittance loss when LEDs are operated at high current. In this paper, we have not only obtained high efficient and thermally chemical stable red emitting hybrid material by introducing europium complex into nanozeolite (NZ) functionalized with the imidazolium-based stopper but also abated its thermal-induced transmittance loss and luminescence quenching behavior via coating it onto a heat-resistant luminescent glass (LG) with high thermal conductivity (1.07 W/mK).