Search

The Eu3+ → Eu2+ self-reduction in the air in CaBPO5 built by rigidly connected BO4 and PO4 tetrahedrons was achieved. We also demonstrate that the CaBPO5:Eu2+/Eu3+ is a promising candidate for temperature sensing with excellent performances.

Near-UV excitable near-infrared Ca2Sn2Al2O9:Cr3+,Si4+ phosphors for anti-counterfeiting and high relative sensitivity (≥1%/K) in the temperature range of 25–125 °C, especially in bio-thermometry (25–50 °C) for luminescence ratiometric thermometers.

Cr3+-doped near-infrared (NIR) afterglow phosphors have received wide recognition in the optical storage field because of the high signal-to-noise ratio and broad excitation spectra. In this article, the high-temperature TL intensity of ZnGa2O4:Cr3+ afterglow glass ceramic (ZGO:Cr3+ GC) was enhanced via partial hetero-valence substitution of Ge for Ga, demonstrating the tunability of the trapped electron levels in ZGO:Cr3+ GC. The persistent luminescence phosphor ZGO:Cr3+ GC exhibits a zero-phonon lines emission peaking at 698 nm, attributing to the 2E→4A2g transition of Cr3+ ions. Moreover, the trap levels in Zn-Ga-Ge-O:Cr3+ glass ceramic (ZGGO:Cr3+ GC) are deeper than those of the Ge-free one and the captured electrons in deeper levels cannot be released only by the ambient thermal energy, thus the optical storage capacity of ZGGO:Cr3+ GC is much larger. By means of an additional 980 nm laser photostimulation, an intense NIR emission could be obtained. In consequence, ZGGO:Cr3+ GC has a promising application prospect in optical information storage field.

CDs@NaBiF4 nanocomposites, which were obtained via a facile synthesis method, possess the intrinsic blue emission of CDs and also exhibit a new green emission from the surface state.

A new class of Ca5Ga6O14:Tb3+ mechanoluminescent phosphors with trap-independent, self-recoverable mechanoluminescence and a low mechanical stimulus threshold are reported, whose properties originate from piezoelectricity of the host with giant piezoelectric coefficients.

A novel green afterglow Na3(Y,Sc)Si3O9:Eu2+ phosphor is synthesized for optical data storage and latent fingerprint recognition.

This work highlights a novel optical thermometric phosphor SrZn0.33Nb0.67O3:Pr3+ as well as its remarkably improved temperature-sensing performance via Ga3+ doping.

A porous GaN/MoO3 heterojunction ultraviolet photodetector with visible-blind, filter-free and ultra-narrowband (FWHM

The lumen efficiency of the device is 54.27 lm W−1. The generating a triangle area was calculated as 135% of the NTSC space and 190% of the Rec. 709 space. The display with this WLED as backlight will have a wider color gamut and more vivid picture.

Potassium‐ion batteries (PIBs) are a promising candidate for next‐generation electric energy storage applications because of the abundance and low cost of potassium. However, the development of PIBs is limited by sluggish kinetics and huge volume expansion of anodes, leading to poor rate capability and cycling stability. Herein, an advanced superstructure anode, including Te-doped SnS2 nanosheets uniformly anchored on MXene surface (Te-SnS2/MXene), is rationally designed for the first time to boost K+ storage performance. Featuring with strong interface interaction and self-autoadjustable interlayer spacings, the Te-SnS2/MXene can efficiently accelerate electron/ion transfer, accommodate volume expansion, inhibit crack formation, and improve pseudocapacitive contribution during cycling. Thus, the novel Te-SnS2/MXene anode delivers a high reversible capacity (343.2 mAh g−1 after 50 cycles at 0.2 A g−1), outstanding rate capability (186.4 mAh g−1 at 20 A g−1), long cycle stability (165.8 mAh g−1 after 5000 cycles at 10 A g−1 with a low electrode swelling rate of only 15.4%), and reliable operation in flexible full battery. The present Te-SnS2/MXene becomes among the best transition metal-based anode materials for PIBs reported to date.

The intense zero phonon line (ZPL) of the Mn4+:2E→4A2 transition can further promote the color rendering and luminous efficiency for high-quality white-emitting diodes (w-LEDs). In this article, a Mn4+-activated K3TaOF6 oxyfluoride red phosphor was synthesized via a facile two-step method. Its phase and morphology were characterized by X-ray diffraction, SEM and TEM. The as-prepared K3TaOF6:Mn4+ exhibits an intense absorption of blue light and a strong emission band peaking at 628 nm with a color purity as high as 96.4%. Attributed to the distorted octahedral coordination environment of Mn4+ ions, an intense ZPL emission was detected at 620 nm. By theoretical calculation, Mn4+ ions in the K3TaOF6 host experience a strong crystal field. In addition, the temperature-dependent PL and thermoluminescence (TL) spectra suggest that thermal ionization dominates the thermal quenching phenomenon in this phosphor.

Solid-state lithium metal batteries (LMBs) assembled with polymer electrolytes (PEs) and lithium metal anodes are promising batteries owing to their enhanced safety and ultrahigh theoretical energy densities. Nevertheless, polymer electrolytes (PEs) suffer from low ionic conductivities, low lithium-ion transference numbers (LITNs) and high flammability. To address these issues, a novel nonflammable single-ion conducting polymer electrolyte (AEP) with ultrahigh ionic conductivity, unity LITN, excellent flame retardance and high flexibility has been developed. Allylboronic acid pinacol ester (AAPE) is incorporated into the 3D cross-linking network of AEP to act as the anion acceptor that traps the anions, improving the LITN to 0.79. AEP possesses an ultrahigh ionic conductivity of 2.52 mS cm−1 at 25 °C. AEP cannot be ignited by flame. AEP can construct robust LiF-rich SEIs on lithium metal anodes and effectively suppress dendrite growth. LiFePO4 cells assembled with AEP demonstrate excellent rate capacity (specific capacity of 112.4 mA h g−1 at 5C rate) and long-term cycling stability (93.2% capacity retention after 500 cycles). This work provides a promising approach to prepare new PEs for high-safety, high-stability and high-energy LMBs.

The combination of a broadband near-infrared (NIR) phosphor and phosphor-converted light-emitting diodes (pc-LEDs) has proven to be an ideal choice for a high-efficiency NIR light source. Here, a garnet-type NIR Ca2LaHf2Al3O12:Cr3+ phosphor is obtained and its emission covered most of the NIR spectral range. Excited by 460 nm blue light, the maximum peak was located at 780 nm with a full width at half maximum (FWHM) of ∼141 nm and an internal quantum efficiency (IQE) of 33%. Moreover, the NIR spectra can be broadened by doping Yb3+ into the Ca2LaHf2Al3O12:Cr3+ garnet phosphor. A super broad FWHM of 300 nm and reduced thermal quenching were acquired, originating from the energy transfer of Cr3+→ Yb3+. The energy transfer process of Cr3+ and Yb3+ is described by means of an energy level diagram and time-resolved spectrum. Finally, a NIR pc-LED is fabricated by combining the Ca2LaHf2Al3O12:Cr3+,Yb3+ phosphor with blue chips, which has a photoelectric conversion efficiency of 10%. These results demonstrate the great potential of Ca2LaHf2Al3O12:Cr3+,Yb3+ in super broadband NIR pc-LED applications.

Toxic solvents used in the fabrication of perovskite films are a non-ignorable obstacle for the commercialization of perovskite solar cells (PSCs). CsPbBr3 based solar cells have attracted increasing attention due to their high stability in ambient air. Usually, a traditional sequential deposition route is employed to fabricate CsPbBr3 films, in which toxic DMF and methanol are separately used to dissolve PbBr2 and CsBr. In order to eliminate the solvent toxicity during the fabrication of CsPbBr3 films, we develop an anomalous sequential deposition route to prepare CsPbBr3 films. In this new route, a green solvent system composed of water with the addition of appropriate ethanol and ethylene glycol (EG) is developed to prepare the CsBr solution, and a green solvent, triethyl phosphate (TEP), is used to prepare the PbBr2 solution. Different from those obtained by the traditional sequential deposition route, CsBr films are firstly prepared from their solution, then reacted with PbBr2 through a dynamic spin-coating process, and subsequently transformed to CsPbBr3 films via annealing treatment. As a result, solar cells based on the device configuration of FTO/TiO2/CsPbBr3/carbon exhibit a power conversion efficiency of 6.86%, which is comparable to that of the PSCs prepared through the traditional sequential deposition route using toxic solvents. This work provides an environment-friendly route to prepare CsPbBr3 perovskite solar cells without efficiency loss.

Non-contact temperature sensors have important application prospects in the optoelectronic field, and their highly sensitive response to wide-range temperature changes is an important development direction. Herein, we propose an Eu2+-activated Sr3−xLa1+xP3−xSixO12 phosphor which shows an outstanding ratiometric temperature sensing performance over a super broad temperature range from 303 to 533 K (a relative sensitivity Sr of ≥1% K−1 and a repeatability capability of over 99%). The structural and luminescence investigations reveal an uncommon phenomenon, i.e. Eu2+ ions were located at a single crystallographic site but produced two emission bands due to the disordering of O1 and O2. As confirmed by the theoretical Debye temperature, the rigid and soft local structures of O1 and O2 coordinated to Eu2+ lead to the thermally stable purple and thermally sensitive yellow emission bands, respectively. Our findings offer useful inspiration for investigating high-performance luminescent thermometers and understanding the structure–property relationships in materials science.

CsPbBr3 films have attractive applications in resistive switching memory, light-emitting diodes, photodetectors, and especially in perovskite solar cells (PSCs) because of their high stability and ease of fabrication under open air conditions. However, toxic solvents are usually employed to prepare CsPbBr3 films in these devices and pose potential threats to the health of manufacturers and the environment. Here, we develop a novel approach to achieve environment-friendly production of high quality CsPbBr3 films using water-soluble precursors of Pb(NO3)2 and CsBr in combination with phenethylammonium bromide (PEABr). In this approach, only green solvents of water and 2-propanol (IPA) are used to prepare CsPbBr3 films. After integrating into a solar cell with a typical configuration of FTO/TiO2/CsPbBr3/carbon, the best solar cell exhibits a power conversion efficiency (PCE) of 6.25% and has excellent stability in open air. This work not only provides a new approach to prepare high quality CsPbBr3 films, but also addresses the solvent toxicity during the fabrication of CsPbBr3 films, which makes it have extensive applications toward environment-friendly production of various CsPbBr3-based optoelectronic devices.

Mn4+-activated oxide-fluoride phosphors are attractive for application in a wide range of solid-state lighting devices because of their distinct red emission at about 630 nm and the abundant storage of Mn ions. However, the zero-phonon line (ZPL) of Mn4+ ions is too weak to be detected in most host materials due to the magnetic dipole nature. In this article, we introduce a co-precipitation method for synthesizing a Mn4+-doped oxyfluoride perovskite KNaMoO2F4 phosphor containing [MoO2F4]2− building units. The electron paramagnetic resonance (EPR) spectra are consistent with the presence of a MnF62− species at g = 1.991. The KNaMoO2F4:0.01Mn4+ phosphor exhibits strong absorption under blue light and an internal quantum yield (IQE) of 65.8%. Attributed to the distorted octahedral environment of the Mn4+ ions, visible ZPL emission was detected at 625 nm. Based on theoretical calculations, the Mn4+ ions in the KNaMoO2F4 host exist in a strong crystal field with a high Dq/B value of ∼3.86. A series of photoluminescence-dependent low-temperature spectra indicates that the Mn4+ emissive state experiences weak electron–phonon interactions upon calculating the Huang–Rhys factor. Benefiting from the ZPL, a warm white-light-emitting diode is achieved using YAG:Ce3+ and KNaMoO2F4:Mn4+ as color converters, in which the color rendering index was Ra = 83.5 and CCT = 4490 K.

It is known that the use of magnesium doped zinc oxide (ZnMgO) nanoparticles results in a serious exciton quenching and unbalanced charge carriers inside the quantum dot light-emitting diodes (QLEDs), leading to an inferior device performance (particularly in blue QLEDs). Herein, we use water as a passivation agent to fix the interface between QDs and ZnMgO. On the one hand, the oxygen atoms in water could contact with metal atoms through an electrostatic interaction to fill the oxygen vacancies on the surface of ZnMgO and remove the surface defects so that the excitons formed inside QDs are less quenched. On the other hand, it slightly decreases the electron transport from ZnMgO to QDs, resulting in much more balanced holes and electrons inside the QD emissive layers. Therefore, the blue QLEDs made by the water-passivated ZnMgO exihibit an improved external quantum efficiency (EQE) of 11.0% and luminance of over 20 000 cd m−2 at 6 V, which is significantly higher than those of blue QLEDs made by pristine ZnMgO. To further understand the improved performance among the blue QLEDs, photoluminescence (PL) spectroscopy, transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS) were used to characterize these water-passivated ZnMgO nanoparticles.

A series of Gd2−xMoO6:xEu3+ (x = 0.18–0.38) nanophosphors were synthesized by the solvothermal method. The properties of these nanophosphors were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), fluorescence spectroscopy and diffuse reflectance spectroscopy. Gd2−xMoO6:xEu3+ nanophosphors have a strong excitation band in the NUV region and emit red light with high color purity by efficient energy transfer from the MoO66− group to Eu3+ ions. Red LEDs and WLEDs were fabricated using a 370 nm chip and Gd2−xMoO6:0.26Eu3+ nanophosphors, which showed good electroluminescence performance. At a driving current of 20 mA, WLEDs displayed CIE coordinates of (0.3297, 0.3869), a correlated color temperature (CCT) of 5604 K and a high color rendering index (Ra) of 91.6. This work demonstrates that Gd2−xMoO6:xEu3+ phosphors are promising red phosphors excited by a NUV chip for WLEDs.

Over the last two decades, suitable compositions have been investigated to make new phosphors because they are key materials for use in solid-state lighting and security applications. Aliovalent cations have different radii, electronegativity and valence states, and can thus be used to remarkably modify crystal structures. Here, we report a new Sr33Lu6(PO4)28 phase produced from Sr3(PO4)2via the method of aliovalent cation substitution. Density functional theory calculations were used to predict the possibility of the formation of a new phase when substituting three Sr2+ for two Lu3+ ions in the material. The new phase, Sr33Lu6(PO4)28, was confirmed by X-ray diffraction, electron diffraction and photoluminescence spectroscopy. Different from the purple phosphor Sr3(PO4)2:Eu2+, Sr33Lu6(PO4)28:Eu2+ exhibits broad green emission under near-UV excitation due to the multi-site occupancy of Eu2+. Combining near-UV chip, blue, red and Sr33Lu6(PO4)28:Eu2+ green phosphors, a white light-emitting diode with a high colour rendering index (∼92) was made, with potential lighting applications. Additionally, a transparent security ink fabricated using the Sr33Lu6(PO4)28:Eu2+ phosphor shows high concealment and recognition. This work is not confined to the report of a new Sr33Lu6(PO4)28:Eu2+ phosphor and its corresponding applications; it is expected that aliovalent cation substitution will be useful as a general method for the discovery of new materials.

The minimization of thermal quenching, which leads to luminescence loss at high temperatures, is one of the most important issues for near-infrared phosphors. In the present work, we investigated the properties of near-infrared Ca(Sc,Mg)(Al, Si)O

Lithium-ion batteries (LIBs) have been widely applied in electronic devices and electric vehicles. Nevertheless, safety of LIBs still remains a challenge. Conventional LIBs consist of highly flammable liquid electrolytes (LEs). LEs can be ignited under abuse conditions, leading to thermal runaways, fires and explosions of LIBs. It is essential to develop electrolytes with good flame retardance. Incorporating appropriate flame-retardant additives or nonflammable solvents into LEs and gel polymer electrolytes (GPEs) can reduce their flammability, achieving nonflammable LEs and nonflammable GPEs. Nonflammable LEs and nonflammable GPEs can reduce the fire risk of LIBs, significantly enhancing the safety of LIBs. LIBs assembled with optimal nonflammable LEs and nonflammable GPEs even showed better performances than the LIBs assembled with conventional LEs. In this paper, we review nonflammable LEs and nonflammable GPEs for LIBs in terms of flame retardant mechanism, characterization methods of flammability limits, flame-retardant additives, nonflammable solvents, preparation methods, flame retardant properties and electrochemical performances. The challenges and future perspectives of nonflammable LEs and nonflammable GPEs are presented.

By hetero-valence substituting Ba2+-Si4+ for Lu3+-Al3+ pair in Lu3Al5O12: Ce3+, a new green phosphor Ba1.5Lu1.5Al3.5Si1.5O12: Ce3+ (BLAS: Ce3+) has been obtained. It crystallizes in garnet structure with space group Ia-3d (230). In the structure, Ba2+ ions are incorporated into both dodecahedral Lu3+ and octahedral Al3+ sites while Si4+ ions only occupy tetrahedral Al3+ sites. Under the blue light irradiation of 450 nm, an intense green light peaking at 520 nm was observed and the PL spectrum can be fitted in two Gaussian components, due to the crystal field splitting of Ce3+ 5d states under D2 symmetry constrains. The optical doping concentration of BLAS: Ce3+ is 6% mol, of which the IQE and EQE are 89.1% and 51.8%, respectively. Furthermore, this sample exhibits an extremely good thermal stability, i.e. the integrated emission intensity is still more than 90% of the initial intensity at 480 K. Then, a w-LED device was fabricated from this new green phosphor BLAS: Ce3+ and commercial red phosphor (Ca,Sr)AlSiN3: Eu2+, which shows a quite high color rendering (Ra = 88.2) and a relatively low color temperature 4772 K. Besides, the phosphor exhibits a stable chromaticity under different acceleration voltages. The phosphor may be promising material for the development of solid-state lighting and display systems.

In this work, we reported the effects of annealing temperature on the morphologies and electrical and optical properties of sputtered ZnO thin films grown on Si(100) and Si(111) substrates. Annealing at 600 °C leads to smooth and porous ZnO thin films (internal holes) with root mean square (RMS) surface roughness values of 0.56 and 0.81 nm on Si(100) and Si(111) substrates, respectively. In contrast, 900 °C annealing results in slightly rough, porous ZnO thin films with exposed holes and RMS surface roughness values of 6.1 and 6.5 nm for Si(100) and Si(111) substrates, respectively. XPS and photoluminescence spectra show that a high annealing temperature reduces the number of oxygen vacancies/defects and Zn defects and slightly decreases the binding energy for the Zn 2p3/2 peak. Meanwhile, metallic Zn was present in porous ZnO thin films grown on Si(111) substrates annealed at 600 °C but disappeared as the annealing temperature increased to 900 °C. In addition, the porous ZnO thin film grown on Si(111) substrate annealed at 900 °C exhibited the best optical properties and had only a few interstitial oxygen defects.

It is necessary to develop novel high-efficiency red or far-red-emitting LEDs in order to facilitate the phosphor-converted light-emitting diodes (pc-LEDs) for plant growth. This work reports a series of novel far-red emitting (Ba,Sr)LaZnTaO6:xMn4+ phosphors with double perovskite structure synthesized by the traditional high-temperature solid-state reaction (SSR). The crystal structure and morphology of (Ba,Sr)LaZnTaO6 were investigated by high-resolution TEM, SEM, and XRD Rietveld refinement. The photoluminescence properties were systematically explored and analyzed by diffuse reflectance (DR) spectra, photoluminescence emission (PL) and excitation (PLE) spectra, decay curves, and temperature-dependent spectra. Mn4+ ions occupy Ta5+ sites located at the [TaO6] octahedral emitting red light with the peak at 698 nm in BaLaZnTaO6:Mn4+ and 695 nm in SrLaZnTaO6:Mn4+ under n-UV and blue light excitation. The critical quenching concentration of Mn4+ was determined to be 0.008. The concentration quenching mechanism could be a dipole–dipole interaction between the Mn4+ ions. In addition, the PL intensity of (Ba,Sr)LaZnTaO6:xMn4+ phosphors decreases with increasing temperature. The SrLaZnTaO6:xMn4+ sample has better thermal stability than BaLaZnTaO6:xMn4+. Interestingly, (Ba,Sr)LaZnTaO6:0.008Mn4+ exhibits outstanding internal quantum efficiency (IQE ≥ 80%). Finally, the fabricated LEDs were combined with SrLaZnTaO6:0.008Mn4+ phosphors combined with 460 nm InGaN chips, which emit blue and red light. Based on the above properties, the rare-earth-free (Ba,Sr)LaZnTaO6:xMn4+ phosphors have great potential in being applied as far-red emitting phosphors in high-power plant growth LEDS.

Water has been labeled as a devil in fabrication and stability of perovskite solar cells. The inherent cognition impels researchers to prepare perovskite films in water-controlled conditions. Herein, water is used as a green solvent to prepare CsPbBr3 films through a two-step spin-coating method. Due to the high solubility of CsBr but low solubility of PbBr2 in water, it provides a possibility to deposit CsBr onto PbBr2 from water solution without destroying the film. Here, high-quality CsPbBr3 films are fabricated by spin-coating concentrated CsBr/H2O solution onto the PbBr2 film followed by annealing. As a result, the solar cells basing on a configuration of FTO/TiO2/CsPbBr3/Carbon exhibit a power conversion efficiency of 6.12%. This work provides a simple and easy way to prepare high-quality CsPbBr3 films for efficient solar cells. It makes a solid step toward reducing the solvent toxicity in the fabrication process of perovskite solar cells. It also breaks the forbidden zone for fabricating perovskite films from water and updates the inherent understanding of water in the research study of perovskite solar cells.

Mn

The intense zero phonon line (ZPL) of the Mn

While the external quantum efficiency (EQE) of iridium(iii) (Ir(iii)) phosphor based near-infrared organic light-emitting diodes (NIR OLEDs) has been limited to 5.7% to date, there is no significant EQE improvement for these types of OLEDs due to the lack of efficient Ir(iii) emitters. Here, a convenient approach within three synthetic steps is developed to afford two novel and efficient deep-red to near-infrared (DR-NIR) emitting phosphors (CNIr and TCNIr), in which a cyano group is added into a commercial red emitter named Ir(piq)2(acac) to significantly stabilize the lowest unoccupied molecular orbitals of the newly designed Ir(iii) complexes. They emit strong DR-NIR phosphorescence emissions at a wavelength of around 700 nm, with relatively high absolute quantum efficiencies of around 45% for their doped films. DR-NIR OLEDs made using CNIr and TCNIr exhibit high-efficiencies, affording peak EQEs of 10.62% and 9.59% with emission peak wavelengths of 690 and 706 nm, respectively. All these devices represent the most efficient Ir(iii)-based DR-NIR OLEDs with a similar color gamut. The simplified synthesis procedure of the DR-NIR-emitting phosphors in conjunction with their excellent performance in OLEDs confirms our efficient strategy to achieve the DR-NIR-emitting Ir(iii) phosphors., The simplest and the most efficient deep-red to near-infrared-emitting emitters afford a new record external quantum efficiency for iridium(iii) complex based deep-red to near-infrared organic light-emitting diodes.

Currently, the study of Mn4+-doped oxide red phosphor is a hot research topic to solve the lack of red component in phosphor-converted white-light-emitting diodes (pc-WLEDs). In this Article, we designed Gd3+/Nb5+ cation substitution by Bi3+/Mn4+ in Ba2GdNbO6 with double-perovskite structure based on the radius and coordination of the cations through high-temperature solid-state reaction. The phase purity and microstructure of double-perovskite Ba2GdNbO6:Bi3+,Mn4+ phosphors were characterized by X-ray diffraction and scanning electron microscopy examination. The crystal structures were also determined by the Rietveld refinement, and the photoluminescence (PL) properties were systematically studied. Bi3+ and Mn4+ ions can be effectively doped in the Ba2GdNbO6 matrix with an optical band gap of 3.94 eV. Upon 315 nm UV excitation, the Ba2GdNbO6:Bi3+,Mn4+ phosphor shows two emission bands at 464 nm from Bi3+ and 689 nm from Mn4+, respectively. By the design of Bi3+ → Mn4+ energy transfer, systematic luminescence tuning from blue to red could be achieved because of spectral overlap between the emission spectrum of Bi3+ and the excitation spectrum of Mn4+. The corresponding mechanism of the Bi3+ → Mn4+ energy-transfer process was investigated in detail by the fluorescence decays and PL spectra. The red emission intensity of Mn4+ has been greatly improved by Bi3+ → Mn4+ energy transfer. Moreover, the phonon vibration and zero phonon line of Mn4+ were studied through temperature-dependent PL. Finally, a WLED was fabricated using a 460 nm blue chip with a yellow YAG:Ce3+ phosphor and a red Ba2GdNbO6:0.01Bi3+,0.01Mn4+ phosphor, which has a low correlated color temperature (3550 K) and a high color rendering index (89.6). The above results imply that the improved red emission phosphors have a potential application in warm pc-WLED lighting.

High-nickel layered transition-metal oxides with large reversible capacity typically suffer from crystal instability and fast capacity decay during cycling. Herein, we report a co-substitution strategy using traditional solid state sintering technology to incorporate zirconium (Zr) and fluorine (F) into LiNi0.8Co0.15Al0.05O2 cathode materials. The effects of the substitution on the crystal structure, morphology and electrochemical performance of LiNi0.8Co0.15Al0.05O2 were investigated by the combinations of XRD, SEM, EDS, XPS, CV, galvanostatic charge-discharge tests and EIS. The results show that F substitution stabilizes the crystal structure. However, it increases the degree of the cation mixing and degrades the reversible capacity. Zr substitution effectively stabilizes the crystal structure and reduces the cation mixing due to the strong bond dissociation energy of Zr–O. Our study suggests that the Zr and F co-substitution facilitates the transport of lithium ions, mitigates the electrochemical polarization and significantly enhances the structural stability. The Zr and F co-doped sample shows capacity retention of 90.5% after 200 cycles at 1 C, while that of bare sample remained only 75.8%. This work sheds lights on understanding the effects of multi-ion substitution on improving electrochemical performance of high-nickel layered cathodes.

Shangchuan Island lies in the southern part of the Guangdong Province in China. Historically it is considered as an important berthing wharf of the South China Sea for the Maritime Silk Roads, witnessing the early Sino-Portuguese trades. Related research on the cultural relics in the region has attracted significant attention from archaeologists. In this study, blue-and-white porcelains excavated from Shangchuan Island were analyzed by multi-micro analytical techniques. In-glaze decoration and under-glaze decoration processes were suggested for the glaze painting process, as revealed by digital microscopy. Silica-aluminum system with flux agents of calcium, potassium and sodium, as well as the main elements of blue pigment with iron, manganese, cobalt and nickel, were found by analysis of micro X-ray fluorescence spectrometry. By calculating the discriminate functions (F) for the chemical compositions of porcelains body, as well as the Si value for porcelain glaze, the origin of these blue-and-white porcelains were identified with the origin of the Jingdezhen kiln in the Ming dynasty. Anorthite (CaAl2Si2O8) crystals were observed in glaze layer of porcelain by micro-Raman spectroscopy, as well as α-quartz (SiO2) and calcite. These archeological evidences not only helped to understand the history of the early Sino-Portuguese relations, but also proved the important historical status of Shangchuan Island and contributed to the study of the history of Chinese ancient Maritime Ceramic Road.

A Phosphor NaBaPO4:Eu2+, Mn2+ with good thermal stability has been synthesized by high temperature solid state reaction. The phase and surface morphology were measured by XRD and SEM. Luminescence properties were characterized by photoluminescence excitation and emission spectra from 77 K to 480 K. In addition, we have studied energy transfer mechanism by Fluorescence spectrum and Raman spectra. The results shows that Eu2+ has strong excitation band in UV–Vis range and emit blue light, and also can transfer energy to Mn2+, which exhibits an intense yellow-green emission. The emitting light of Eu2+, Mn2+ co-doped NaBaPO4 could be tunable from blue to cool whit by changing the,molar ratio of Eu2+and Mn2+.