Tunable visible emission and persistent luminescence of BaGa₂O₄:Cu²⁺

In the field of solid-state luminescence, Cu²⁺ has long been widely acknowledged for its capacity to emit infrared light. However, the occurrence of visible emission from Cu²⁺ ions had been infrequently observed and reported. In this study, we made an intriguing discovery by examining the behavior of Cu²⁺...

Identification of rare earth elements in synthetic and natural monazite and xenotime by visible-to-shortwave infrared reflectance spectroscopy

To support the role of proximal and remote sensing in geological rare earth element (REE) resource exploration, we studied the reflectance spectroscopy of synthetic single- and mixed-REE phosphate phases. Synthesis yielded monazite for the elements La to Gd, and xenotime for Dy to Lu and Y. Visible-to-shortwave infrared (350–2500 nm)...

Evaluating the Tm2+ 4f125d1 → 4f13 and 4f13 → 4f13 Luminescence and Quenching Dynamics in Orthorhombic BaCl2

The luminescence properties of Tm2+-doped BaCl2 with an orthorhombic structure have been studied as a function of temperature and compared to other Tm2+-doped chlorides. In addition to the 2F5/2 → 2F7/2 (4f13 → 4f13) line emission, two 4f125d1 → 4f13 band emissions are observed at 20 K that can be ascribed to the spin-allowed (3H6,5d1)S=1/2 →...

Enhancing thermal degradation stability of BaSi₂O₂N₂:Eu²⁺ for white light-emitting diodes by ultra-thin Al₂O₃ layer via atomic layer deposition

The cyan-emitting BaSi₂O₂N₂:Eu²⁺ phosphor is a promising narrow-band and high-efficiency luminescent material used in wide-color-gamut white light-emitting diodes (wLEDs). However, its serious degradation under thermal attacks hinders its practical applications and needs to be improved. Herein, we...

Red-Emitting SrGa₂O₄:Cu²⁺Phosphor with Super-Long Persistent Luminescence

The red afterglow of current rare-earth-activated long persistent luminescence (LPL) phosphors is largely still less than 6 h, in contrast to the 20 or 30 h long blue- or green-emitting ones, becoming the main obstacle to realize their multiscenario applications in practice. Herein, we report a rare-earth-free red-emitting LPL phosphor SrGa...

Mechanistic insight into the improved photocatalytic degradation of dyes for an ultrathin coating of SiO₂ on TiO₂ (P25) nanoparticles

The photocatalytic mechanism of TiO₂ (P25) nanoparticles coated with SiO₂ (SiO₂:TiO₂) by atomic layer deposition was investigated. The deposition of SiO₂ on TiO₂ not only gives a photocatalytic improvement for the degradation of both Rhodamine B (3.6–fold) and Acid Blue 9 (3...

Pyrophosphate Phosphor Solid Solution with High Quantum Efficiency and Thermal Stability for Efficient LED Lighting

Phosphors with high quantum efficiency and thermal stability are greatly desired for lighting industries. Based on the design strategy of solid solution, a series of deep-blue-emitting phosphors (Sr_0.99-xBa_x)₂P₂O₇:0.02Eu²⁺ (SB_xPE x = 0–0.5) are developed. Upon...

Assessing the Role of Pt Clusters on TiO₂ (P25) on the Photocatalytic Degradation of Acid Blue 9 and Rhodamine B

The role of Pt on photocatalytic substrates such as TiO₂ (P25) for the decomposition of organic pollutants is still controversial in the scientific community. The well-observed behavior of an optimum catalytic activity as a function of the Pt loading is usually explained by the shift from charge separation to charge recombination...

Synthesis of a rationally designed multi-component photocatalyst pt:Sio₂:Tio₂ (p25) with improved activity for dye degradation by atomic layer deposition

Photocatalysts for water purification typically lack efficiency for practical applications. Here we present a multi-component (Pt:SiO₂:TiO₂ (P25)) material that was designed using knowledge of reaction mechanisms of mono-modified catalysts (SiO₂:TiO₂, and Pt:TiO₂ ) combined with the...

On the relations between the bandgap, structure and composition of the M–Si–N (M = alkali, alkaline earth or rare-earth metal) nitridosilicates

Relations between the bandgap and structural properties and composition of the M–Si–N nitridosilicates (M = alkali, alkaline earth or rare earth metal) have been obtained, using experimental data collected from literature; and qualitative models are presented to explain the observed trends. Compounds with a higher degree of condensation, i.e. a...

Transition of Emission Colours as a Consequence of Heat-Treatment of Carbon Coated Ce3+-Doped YAG Phosphors

To modify the luminescence properties of Ce³⁺-doped Y₃Al₅O₁₂ (YAG) phosphors, they have been coated with a carbon layer by chemical vapor deposition and subsequently heat-treated at high temperature under N₂ atmosphere. Luminescence of the carbon coated YAG:Ce³⁺ phosphors has...

Thermal quenching of Eu2+ emission in Ca- and Sr-Ga2S4 in relation with VRBE schemes

Structural and optical properties of MGa2S4 (M = Mg, Zn, Ca, Sr, Ba) compounds have been compared, and the vacuum referred binding energy (VRBE) schemes were constructed for the lanthanide ions in the iso-structural compounds CaGa2S4 and SrGa2S4 employing literature data. The VRBE of an electron in the 5d excited state of Eu2+ was found at 0.75...

Intriguing luminescence properties of (Ba, Sr)₃Si₆O₉N₄: Eu²⁺ phosphors via modifying synthesis method and cation substitution

Synthesizing pure phase Ba₃Si₆O₉N₄ by the conventional solid-state reaction method is challenging because of easily formed secondary phase Ba₃Si₆O₁₂N₂ showing similar crystal structure. In this work, an alternative low temperature synthesis method is...

Enhanced Optical Performance of BaMgAl₁₀O₁₇: Eu²⁺ Phosphor by a Novel Method of Carbon Coating

Many strategies have been adopted to improve thermal degradation of phosphors. Because of the stability and high transmittance of graphene, here we report a novel method of carbon coating on BaMgAl₁₀O₁₇:Eu²⁺ (BAM) phosphor particles through chemical vapor deposition. The chemical composition, microstructure,...

Performance improvement by alumina coatings on Y₃Al₅O₁₂: Ce³⁺ phosphor powder deposited using atomic layer deposition in a fluidized bed reactor

To improve the thermal stability, Al₂O₃ has been successfully coated on a Y₃Al₅O₁₂:Ce³⁺ (YAG:Ce) phosphor powder host by using the Atomic Layer Deposition (ALD) approach in a fluidized bed reactor. Transmission Electron Microscopy (TEM) and Energy Dispersive X-ray spectroscopy ...

Tunable Luminescence of CeAl11O18 Based Phosphors by Replacement of (AlO)+ by (SiN)+ and Co-Doping with Eu

A series of Si-N or Eu-Li doped CeAl11O18 and CeAl12O18N phosphors are prepared by solid–state reaction. Their structure and luminescence are researched carefully. Si-N doping with the concentration less than 8% can be successfully dissolved into CeAl11O18 crystal lattice and doesn't change the matrix structure, only resulting in crystal lattice...

Efficiency enhancement calculations of state-of-the-art solar cells by luminescent layers with spectral shifting, quantum cutting, and quantum tripling function

Solar cells of which the efficiency is not limited by the Shockley-Queisser limit can be obtained by integrating a luminescent spectral conversion layer into the cell structure. We have calculated the maximum efficiency of state-of-the-art c-Si, pc-Si, a-Si, CdTe, GaAs, CIS, CIGS, CGS, GaSb, and Ge solar cells with and without an integrated...

Photoluminescence Properties of Red-Emitting Mn2+-Activated CaAlSiN3 Phosphor for White-LEDs

Mn2+-doped CaAlSiN3 phosphors have been prepared by a solid-state reaction method at high temperature and the solubility of Mn2+ in the host lattice as well as their photoluminescence properties were investigated. In CaAlSiN3, not only Ca2+ sites, but also Al3+ sites can be substituted by Mn2+ ions. CaAlSiN3 : Mn2+ absorbs blue light in the...