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While numerous approaches have been devised to optimize the luminescence properties of Eu2+-activated phosphors, the quest for a simple design strategy to achieve color-tunable Eu2+ emission remains a significant challenge. Here, we present a straightforward, doping-free method to tailor the site occupation of Eu2+ and modify its luminescence properties. In the pristine sample, the NaBaB9O15 (NBB) host featuring two cation sites (Na+ and Ba2+), Eu2+ exclusively occupies the Ba2+ site, resulting in blue emission when the NBB:Eu2+ phosphor is synthesized in a H2 reducing atmosphere. When we use CO instead of a H2 reducing atmosphere, impressively, the formation energy required for heterovalent substitution of Na+ by Eu2+ is lowered, leading to the emergence of a distinct green emission band. Significantly, the resultant phosphor NBB:Eu2+@CO exhibits not only a high internal quantum yield of 85.1% and zero-thermal-quenching behavior within the temperature range of 25–200 °C but also wavelength-tunable emission. Benefitting from the multi-color luminescence of the NBB:Eu2+@CO phosphor, its optical applications will no longer be confined to general lighting but extend to anti-counterfeiting and encryption. This study provides a novel design methodology for optimizing the optical properties of Eu2+-activated phosphors. [ABSTRACT FROM AUTHOR]

Doped CaZnOS materials show great potential for mechanoluminescence (ML) applications spanning the ultraviolet-visible-near infrared (UV-vis-NIR) range. However, conflicting reports regarding the generation and reproducibility of ML hinder the understanding and practical utilization of these materials. To address this issue, a comprehensive characterization strategy combining NIR laser-assisted de-trapping, UV irradiation-induced trap-filling, in situ mechanical stimulation, and continuous ML recording is proposed. Herein, the ML behaviors of four representative doped CaZnOS materials (Mn2+, Bi3+, Er3+, and Ce3+) are investigated using this approach. The results reveal that de-trapped materials exhibit non-trap-controlled ML, wherein ML intensity gradually weakens under successive mechanical stimuli without self-recovery. In contrast, trap-filled materials demonstrate both trap-controlled ML and non-trap-controlled ML, with the former predominantly contributing to the overall ML intensity. Notably, trap-controlled ML shows only partial recovery after trap filling. The non-trap-controlled ML is attributed to plastic ML and destructive ML phenomena, while explaining trap-controlled ML through the carrier de-trapping model. These results not only clarify conflicting reports but also provide clear insights into the ML properties and mechanisms of CaZnOS-based materials, facilitating advancements in practical applications. Furthermore, the developed characterization strategy is expected to serve as a valuable reference for establishing standardized protocols to evaluate ML performance. [ABSTRACT FROM AUTHOR]

Near-infrared (NIR) phosphors with high thermal stability are significant for NIR light-emitting diodes (LEDs). For a decade, Debye temperature has been a successful indicator of structural rigidity and thermal stability for phosphors, but some exceptions exist due to its dependence on atomic mass. Inspired by the Debye temperature model that relates the elastic properties of solids, our density functional theory calculations revealed that the Vickers hardness of Cr3+-doped NIR phosphors was negatively correlated with Stokes shifts (Pearson's R = −0.81) and positively correlated with thermal stabilities (Pearson's R = 0.85) within a set of 13 distinct material types. Highlighting the predictive power of Vickers hardness, two new NIR phosphors were investigated: KMg(PO3)3:Cr3+ showed low thermal stability, correlating with its lower Vickers hardness, in contrast to the high thermal stability and correspondingly higher Vickers hardness of La2MgSnO6:Cr3+. Vickers hardness can be used to screen potential hosts for Cr3+-doped NIR phosphors with high thermal stabilities, due to the advantages of the predictable feature by density functional theory calculation and low independence on atomic mass. [ABSTRACT FROM AUTHOR]

Orange Eu2+‐doped phosphors are essential for light‐emitting diodes for cornering lights to prevent fatal road accidents at night, but such phosphors require features of high thermal, chemical stability and facile synthesis. This study reports a series of yellow‐orange‐red emitting SrAl2Si3ON6:Eu2+ oxynitride phosphors, derived from the SrAlSi4N7 nitride iso‐structure by replacing Si4+−N3− with Al3+−O2−. The introduction of a certain amount of oxygen enabled the facile synthesis under atmospheric pressure using the air‐stable raw materials SrCO3, Eu2O3, AlN and Si3N4. SrAl2Si3ON6 has a smaller band gap and lower structure rigidity than SrAlSi4N7 (5.19 eV vs 5.50 eV, Debye temperature 719 K vs 760 K), but exhibits higher thermal stability with 100 % of room temperature intensity remaining at 150 °C compared to 85 % for SrAlSi4N7. Electron paramagnetic resonance, thermoluminescence and density functional theory revealed that the oxygen vacancy electron traps compensated the thermal loss. Additionally, no decrease in emission intensity was found after either being heated at 500 °C for 2 hours or being immersed in water for 20 days, implying both of the thermal and chemical stability of SrAl2Si3ON6:Eu2+ phosphors. The strategy of oxynitride‐introduction from nitride promotes the development of low‐cost thermally and chemically stable luminescent materials. [ABSTRACT FROM AUTHOR]

Orange Eu2+‐doped phosphors are essential for light‐emitting diodes for cornering lights to prevent fatal road accidents at night, but such phosphors require features of high thermal, chemical stability and facile synthesis. This study reports a series of yellow‐orange‐red emitting SrAl2Si3ON6:Eu2+ oxynitride phosphors, derived from the SrAlSi4N7 nitride iso‐structure by replacing Si4+−N3− with Al3+−O2−. The introduction of a certain amount of oxygen enabled the facile synthesis under atmospheric pressure using the air‐stable raw materials SrCO3, Eu2O3, AlN and Si3N4. SrAl2Si3ON6 has a smaller band gap and lower structure rigidity than SrAlSi4N7 (5.19 eV vs 5.50 eV, Debye temperature 719 K vs 760 K), but exhibits higher thermal stability with 100 % of room temperature intensity remaining at 150 °C compared to 85 % for SrAlSi4N7. Electron paramagnetic resonance, thermoluminescence and density functional theory revealed that the oxygen vacancy electron traps compensated the thermal loss. Additionally, no decrease in emission intensity was found after either being heated at 500 °C for 2 hours or being immersed in water for 20 days, implying both of the thermal and chemical stability of SrAl2Si3ON6:Eu2+ phosphors. The strategy of oxynitride‐introduction from nitride promotes the development of low‐cost thermally and chemically stable luminescent materials. [ABSTRACT FROM AUTHOR]

To develop novel luminescent materials for optical temperature measurement, a series of Yb3+- and Er3+-doped Ca3Sc2Si3O12 (CSS) upconversion (UC) phosphors were synthesized by the sol–gel combustion method. The crystal structure, phase purity, and element distribution of the samples were characterized by powder X-ray diffraction and a transmission electron microscope (TEM). The detailed study of the photoluminescence emission spectra of the samples shows that the addition of Yb3+ can greatly enhance the emission of Er3+ by effective energy transfer. The prepared Yb3+ and Er3+ co-doped CSS phosphors exhibit green emission bands near 522 and 555 nm and red emission bands near 658 nm, which correspond to the 2H11/2→4I15/2, 4S3/2→4I15/2, and 4F9/2→4I15/2 transitions of Er3+, respectively. The temperature-dependent behavior of the CSS:0.2Yb3+,0.02Er3+ sample was carefully studied by the fluorescence intensity ratio (FIR) technique. The results indicate the excellent sensitivity of the sample, with a maximum absolute sensitivity of 0.67% K−1 at 500 K and a relative sensitivity of 1.34% K−1 at 300 K. We demonstrate here that the temperature measurement performance of FIR technology using the CSS:Yb3+,Er3+ phosphor is not inferior to that of infrared thermal imaging thermometers. Therefore, CSS:Yb3+,Er3+ phosphors have great potential applications in the field of optical thermometry. [ABSTRACT FROM AUTHOR]

Artificial light fishing technology has been used in marine fisheries for thousands of years. The light source with multi‐color adjustable output is expected to become a new generation of fish‐attracting lamps. Herein, a new method of crystal‐site engineering through reducing atmospheres is proposed for the development of Eu2+ doped single‐phase phosphor with multi‐excitation and multi‐emission properties. Following this approach, the distribution ratio of Eu2+ at Ca2+ and Sr2+ sites in CaSrSiO4 (CSO) can be modulated. Importantly, Eu2+ at both lattice sites exhibit non‐interfering optical properties, CSO:Eu2+ phosphor realizes multi‐color output from green to yellow and then to red when Eu2+ occupies the Sr2+ and Ca2+ sites in a relatively balanced ratio. Benefitting from the tunable color range covering the spectral sensitivity regions of most marine fishes, this phosphor may eventually be applied in futuristic innovative fish‐attracting lamps. [ABSTRACT FROM AUTHOR]

A Sm3+-doped YGa1.5Al1.5(BO3)4 (abbreviated as YGAB) phosphor was synthesized via a solid-state reaction with mechanical activation assistance in a high-energy density stirred bead mill. The samples were characterized by laser particle size analysis, specific surface area analysis, powder X-ray diffraction (XRD), scanning electron microscopy (SEM), differential scanning calorimetry (DSC), and fluorescence spectroscopy. In addition, the photoluminescence characteristics, luminescence decay, thermal stability, and LED application of the phosphors were also investigated. The results show that the mechanical activation of mixed raw materials before calcination can reduce the particle size and the activation energy of crystallization, resulting in the formation of the YGAB crystal phase at a lower calcination temperature. The mechanical activation in grinding can accelerate the subsequent solid-phase reaction, make Sm3+ ions more easily diffuse into the YGAB lattice, and improve the crystal structure of the synthesized phosphor, thus enhancing the optical properties of the phosphor. According to the photoluminescence emission (PL) and excitation (PLE) spectra, Sm3+ doped in the YGAB lattice can provide an efficient emission under 405 nm excitation. The optimum doping concentration of Sm3+ ions is 0.03 mol%. The optimum photoluminescence intensity, quantum yield, and fluorescence lifetime of the phosphor synthesized from mixed raw materials ground for 45 min can be obtained. The temperature-dependent PL spectra show that the emission intensity of the YGAB:0.03Sm3+ phosphor at 425 K is 84.7% of its initial intensity at room temperature. It is indicated that the YGAB:0.03Sm3+ phosphor synthesized could be used as one of the promising LED lighting materials. [ABSTRACT FROM AUTHOR]

Au nanoparticles (NPs) attached to various TiO2 supports are widely studied as plasmonic catalysts for driving chemical reactions under visible light irradiation. However, plasmonic catalysis still suffers from unsatisfactory efficiencies due to limited light-harvesting abilities. Here we reported a new tactic to enhance the light-harvesting ability of plasmonic Au NPs by utilizing a light reflection-promoted model – a vertically <001> oriented anatase mesocrystal (meso-TiO2) rooted on Ti foil as the support, and thus achieving efficient photocatalytic sulfur-containing volatile organic compound elimination and hydrogen evolution from water. Experimental evidence and theoretical simulations confirm that the Au NPs in this architecture more effectively harvest visible light because of the simultaneous absorption of both the incident and the back-reflected photons from the meso-TiO2/Ti foil surface, where Ti foil serves as the reflective substrate. The enhanced light absorption of Au NPs in this light reflection-promoted model excited strong localized surface plasmon resonance to yield more reactive species that drive the redox reactions. This research could inspire a new paradigm to improve the photocatalytic performance of plasmonic metals by utilizing the light reflection model. [ABSTRACT FROM AUTHOR]

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)O6 : Cr3+ phosphors with a pyroxene‐type structure under blue light excitation. The CaScAlSiO6 : Cr3+ end member of Ca(Sc,Mg)(Al,Si)O6 : Cr3+ phosphor led to broadband emission at a full‐width half maximum of 215 nm, whereas the CaMgSi2O6 : Cr3+ end member exhibited high thermal stability at 150 °C, with an intensity of 88.4 % of that at room temperature. The structural analysis and density functional theory calculations revealed the absence of soft conformations and local space confinement contributed to the high structural rigidity and weakened the thermal quenching effect. [ABSTRACT FROM AUTHOR]

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)O6 : Cr3+ phosphors with a pyroxene‐type structure under blue light excitation. The CaScAlSiO6 : Cr3+ end member of Ca(Sc,Mg)(Al,Si)O6 : Cr3+ phosphor led to broadband emission at a full‐width half maximum of 215 nm, whereas the CaMgSi2O6 : Cr3+ end member exhibited high thermal stability at 150 °C, with an intensity of 88.4 % of that at room temperature. The structural analysis and density functional theory calculations revealed the absence of soft conformations and local space confinement contributed to the high structural rigidity and weakened the thermal quenching effect. [ABSTRACT FROM AUTHOR]

The two-spotted spider mite, Tetranychus urticae, is an important pest of horticultural crops worldwide and has developed resistance against multiple kinds of pesticides. To date, information on the resistance to pesticides is inadequate for T. urticae populations in Hainan, south China. In the current study, we determined the resistance to seven pesticides in five field populations of T. urticae that were collected on cucurbit crops in Hainan in 2021. The results showed that T. urticae populations developed high to extremely high resistance to abamectin and bifenthrin and medium to high resistance to pyridaben, profenofos, and cyflumetofen. However, four of the five populations were either susceptible to or had only low resistance to bifenazate and B-azolemiteacrylic. We also determined the frequencies of mutations previously associated with T. urticae resistance to abamectin, pyrethroids, organophosphates, bifenazate, or pyridaben; mutation frequencies as high as 100% were detected for some of the mutations in some of the populations. The results should facilitate the development of rational strategies for the chemical control of T. urticae populations in Hainan, China. [ABSTRACT FROM AUTHOR]

Red-light-emitting materials, as pivotal components of warm white light-emitting diodes (WLEDs), have drawn increasing public focus. Among these, Mn4+-doped red light-emitting fluorides have drawn considerable attention when combined with an InGaN chip; however, they suffer from poor water stability under humid conditions. In this work, a novel fluoride red phosphor, Cs30(Nb2O2F9)9(OH)3·H2O:xMn4+ (CNOFM), with good water resistance was synthesized for the first time using a facile co-precipitation method at ambient temperature. Experiments were implemented for the precise analysis of its crystal structure, optical properties, micro-morphology, thermal behavior, and waterproof properties. 6.66% Mn4+-doped CNOFM maintained a stable crystal structure and possessed strong PL intensity located at 633 nm with high color purity of 96%. CNOFM showed better thermal and waterproof stability compared with the commercial K2SiF6:Mn4+ red phosphor. Without any surface modifications, the PL intensity remained at about 83% of the initial value after immersion in water for 60 min, and the mechanism was investigated. Finally, a warm WLED with a CRI of 92.3 and CCT of 3271 K was fabricated using the CNOFM red phosphor. [ABSTRACT FROM AUTHOR]

We report an organic solvent–assisted (OSA) co-precipitation strategy for the production of Mn4+-activated K2TiF6 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. The photoluminescence (PL) properties of K2TiF6:Mn powders strongly depend on the size and thickness of the particles. The addition of n-butanol during the synthesis increases the emission intensity of K2TiF6:Mn by 208%. The PL quantum efficiency of phosphors prepared using the n-butanol-assisted strategy is much higher (98.2%) than that of conventionally prepared phosphors (89.9%). Our findings demonstrate a way to prepare the K2TiF6:Mn phosphor with targeted morphology and very high quantum efficiency and also provide the route for the optimization of all Mn4+-activated fluoride phosphors used in white light-emitting diodes. [ABSTRACT FROM AUTHOR]

Purpose: The aim of this study was to investigate differentially expressed proteins (DEPs) and their functions in the uteruses of primary dysmenorrhea (PD) rats using label-free quantitative proteomics analysis. Methods: The PD rat model was induced by injecting both estradiol benzoate and oxytocin. Twenty rats were equally divided into two groups: a control group (normal rats), a PD model group (PD rats). Writhing scores and serum levels of Prostaglandin E2 (PGE2) and Prostaglandin F2α (PGF2α) were used to evaluate the success of the rat PD model. The DEPs were identified and analyzed by label-free quantitative proteomics and bioinformatics analyses. Results: A total of 276 DEPs were identified, including 119 up-regulated DEPs and 157 down-regulated DEPs. Bioinformatics revealed that the DEPs were mainly associated with 'protein binding', 'metabolism', 'signal conduction' and 'focal adhesion'. The proteomic findings were verified by western blot analysis, which confirmed that myosin light-chain kinase (MLCK), heat shock protein 90 AB1 (HSP90AB1), apolipoprotein A1 (Apoa1), p38 MAP kinase, c-Jun N-terminal kinase (JNK), and extracellular signal-related kinase 1/2 (ERK1/2) were significantly differentially expressed in the control and PD samples. Conclusions: These results provide a deeper understanding of the molecular pathogenesis of PD. The DEPs found in the present study may provide new ideas for further study of the mechanism of PD and aid the search for biomarkers for early diagnosis and treatment. [ABSTRACT FROM AUTHOR]

A high color rendering index white light emitting diode (WLED) is generally produced by combining yellow and red mixed phosphors on a blue chip. Herein we report a single component phosphor based on CaY2Al4SiO12 (CYAS) to achieve warm white light emission with a high color rendering index (Ra), which can be up to 90.5. Ce3+, Mn2+ singly doped and co-doped CYAS phosphors have been synthesized by solid state reactions, respectively, for comparative investigations. The Rietveld X-ray diffraction (XRD) refinements show that the CYAS host crystallizes in a cubic structure with the Ia3¯d space group. The valence states of Ce and Mn inside the CYAS host have been confirmed by XPS and EPR. Ce3+ occupies the Ca2+/Y3+ site and generates a yellow emission band around 543 nm from its characteristic 5d–4f transition. Mn2+ occupies both the dodecahedron Ca2+/Y3+ and octahedral Al3+ sites, emitting red and deep red lights at 616 nm and 750 nm, respectively. These two emission bands are attributed to the 4T1(4G)–6A1(6S) transitions of Mn2+. Upon 460 nm light excitation, both the Ce3+ and Mn2+ characteristic emissions can be obtained, in which the emissions of Mn2+ result from the occurrence of energy transfer from Ce3+ in CYAS. All the results indicate that the prepared CYAS:Ce3+,Mn2+ could be a promising single component phosphor for blue chip WLEDs. [ABSTRACT FROM AUTHOR]

Improving the high‐rate performance of spinel lithium titanate (Li4Ti5O12, LTO) is one of the critical requirements to promote its practical application in Li‐ion batteries (LIBs). Herein, the possible Li+ ion diffusion routes in LTO are theoretically analyzed and compared by computational investigation. The calculations show that the most feasible diffusion path for Li+ ions is along the [110] direction indicated by the lowest energy barrier. Inspired by this prediction, ultrathin [110]‐confined LTO nanoflakes are rationally prepared through a function‐led targeted synthesis. The [110] orientation of the material sufficiently provides preferable transport channels which can promote the anisotropic diffusion of lithium ions within LTO nanoflakes. Furthermore, the ultrathin 2D nanostructure effectively shortens the diffusion length along the [110] direction, facilitating ion transport across the nanoflakes and thus improving the diffusion kinetics. Owing to these unique features, the LIB composed of optimized [110]‐confined LTO exhibits remarkable high rate capability and long‐term cycling stability, with a capacity of 146 mAh g‐1 at an ultrahigh rate of 100 C and a capacity retention of 88% even after 1500 cycles at 50 C. The as‐prepared [110]‐confined LTO nanoflakes have promising applications and show commercial viability for high‐power facilities. [ABSTRACT FROM AUTHOR]

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. Cs2TiF6:Mn4+ (CTFM) single crystal provides enhancement of quantum efficiency, moisture resistance, and thermal stability compared to polycrystalline powders. The internal quantum efficiency can reach as high as 98.7 %. To further improve waterproof stability, the Cs2TiF6 (CTF) shell with tunable thickness has been epitaxially grown on the CTFM single crystal surface and a unique three‐step photoluminescence intensity evolution mechanism has been proposed. By combining as‐prepared CTFM@CTF core–shell structured single crystal, YAG:Ce single crystal and blue‐chip, warm WLEDs with excellent color rendition (Ra=90, R9=94), low correlated color temperature (CCT=3155 K), and high luminous efficacy were fabricated without any organic resins. [ABSTRACT FROM AUTHOR]

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. Cs2TiF6:Mn4+ (CTFM) single crystal provides enhancement of quantum efficiency, moisture resistance, and thermal stability compared to polycrystalline powders. The internal quantum efficiency can reach as high as 98.7 %. To further improve waterproof stability, the Cs2TiF6 (CTF) shell with tunable thickness has been epitaxially grown on the CTFM single crystal surface and a unique three‐step photoluminescence intensity evolution mechanism has been proposed. By combining as‐prepared CTFM@CTF core–shell structured single crystal, YAG:Ce single crystal and blue‐chip, warm WLEDs with excellent color rendition (Ra=90, R9=94), low correlated color temperature (CCT=3155 K), and high luminous efficacy were fabricated without any organic resins. [ABSTRACT FROM AUTHOR]

Transition metal chalcogenides have been known as cost-effective and energy-efficient electrocatalysts for the oxygen reduction reaction (ORR). Crystal phase control is vital for tailoring their ORR performances. Herein, hexagonal (h-FeSe) and tetragonal FeSe (t-FeSe) ultrafine nanocrystals are jointly encapsulated in a N-doped carbon matrix without agglomeration. Their phase evolution at different pyrolysis temperatures is explicitly elucidated. The resultant material that contains the highest amount of h-FeSe nanocrystals exhibits remarkable performances with a positive onset potential of 0.97 V, large limiting current density of 5.4 mA cm−2 and low H2O2 yield of 6.6%. The material also delivers outstanding catalytic stability and methanol crossover tolerance. Theoretical studies confirm that h-FeSe outperforms t-FeSe in O2 adsorption and O–O bond dissociation of *OOH intermediates on active Fe-sites. Thus, h-FeSe is more efficient than t-FeSe towards alkaline ORR. We believe it will provide great inspiration for designing other ORR-efficient transition metal-based electrocatalysts by controlling crystal phases. [ABSTRACT FROM AUTHOR]

The practical applications of non‐aqueous lithium‐oxygen batteries are impeded by large overpotentials and unsatisfactory cycling durability. Reported here is that commonly encountered fatal problems can be efficiently solved by using a carbon‐ and binder‐free electrode of titanium coated with TiO2 nanotube arrays (TNAs) and gold nanoparticles (AuNPs). Ultraviolet irradiation of the TNAs generates positively charged holes, which efficiently decompose Li2O2 and Li2CO3 during recharging, thereby reducing the overpotential to one that is near the equilibrium potential for Li2O2 formation. The AuNPs promote Li2O2 formation, resulting in a large discharge capacity. The electrode exhibits excellent stability with about 100 % coulombic efficiency during continuous cycling of up to 200 cycles, which is due to the carbon‐ and binder‐free composition. This work reveals a new strategy towards the development of highly efficient oxygen electrode materials for lithium‐oxygen batteries. [ABSTRACT FROM AUTHOR]

The practical applications of non‐aqueous lithium‐oxygen batteries are impeded by large overpotentials and unsatisfactory cycling durability. Reported here is that commonly encountered fatal problems can be efficiently solved by using a carbon‐ and binder‐free electrode of titanium coated with TiO2 nanotube arrays (TNAs) and gold nanoparticles (AuNPs). Ultraviolet irradiation of the TNAs generates positively charged holes, which efficiently decompose Li2O2 and Li2CO3 during recharging, thereby reducing the overpotential to one that is near the equilibrium potential for Li2O2 formation. The AuNPs promote Li2O2 formation, resulting in a large discharge capacity. The electrode exhibits excellent stability with about 100 % coulombic efficiency during continuous cycling of up to 200 cycles, which is due to the carbon‐ and binder‐free composition. This work reveals a new strategy towards the development of highly efficient oxygen electrode materials for lithium‐oxygen batteries. [ABSTRACT FROM AUTHOR]

The environmentally friendly and low‐priced CaYAlO4:Tb3+ nanophosphors are combined with good optically transparent materials for the application in 3D printing. For ultraviolet (UV) light‐emitting diode excitation, CaYAlO4:Tb0.07Cey and CaYAlO4:Ce0.05Tbx nanophosphors are prepared by a sol–gel route and systematically studied for optimal excitation at 380 nm to give strong green emission to which human and aquatic animals eyes are generally sensitive. This is benefited from the dipole and spin allowed transition of Ce3+ and the 92.5% efficient energy transfer from Ce3+ to Tb3+ in this host. Polydimethylsiloxane, with 92% transmittance in the visible spectral region, is a valid choice to make the shaped artwork by a templating method, combined with the nanoparticles to give a uniform distribution, as determined by X‐ray microcomputed tomography. Polylactic acid is also employed to create a frog artwork by the fused deposition modeling method. The final 3D‐printed colorful artwork is displayed herein together with that produced by the templating method under different light source excitation to suggest a novel expression of aesthetic concepts and a potential application in the future marine environment such as a lamp to attract aquatic animals or a buoy to guide ships. [ABSTRACT FROM AUTHOR]

The rational design of electrode structure with catalysts adequately utilized is of vital importance for future fuel cells. Herein, a novel 3D oriented wholly integrated electrode comprising core–shell Fe3O4@N‐doped‐C (Fe3O4@NC) nanoparticles embedded into N‐doped ordered interconnected hierarchical porous carbon (denoted as Fe3O4@NC/NHPC) is developed for the oxygen reduction reaction (ORR). The as‐prepared catalyst possesses novel structure and efficient active sites. In rotating disk electrode measurements, the Fe3O4@NC/NHPC exhibits almost identical ORR electrocatalytic activity, superior durability, and much better methanol tolerance compared with the commercial Pt/C in acidic media. To the authors' knowledge, this is among the best non‐precious‐metal ORR catalysts reported so far. Importantly, the Fe3O4@NC/NHPC is successfully in situ assembled onto carbon paper by the electrophoresis method to obtain a well‐designed 3D‐ordered electrode. With improved mass transfer and maximized active sites for ORR, the 3D‐oriented wholly integrated electrode shows superior performance to the one fabricated by the traditional method. [ABSTRACT FROM AUTHOR]

Modulation of structural order–disorder transition and structural oxygen defects can provide fundamental insights in the optimization of luminescence performances of phosphors. In this study, the luminescence of Ba3ZnTa2O9 (BZT) was systematically elucidated, including the emission arising from the charge transfer (Nb5+/Ta5+ → O2−) and anti-site oxygen defect emission due to the B-site disordering (defect type: [2ZnNb3− + 3Vo2+]), as corroborated by the electronic structural calculations and detailed experiments. We present a two-step design for the optimization of luminescence properties of Ba3ZnTa2O9 phosphor. In the first step, the B-site equivalent doping (Ta5+ substituted by Nb5+) was used to modulate the B-site atomic arrangement, which induced the formation of the cubic phase with B-site full disordering. In the second step, the A-site nonequivalent doping (Ba2+ substituted by Eu3+) was used to decrease the oxygen defect concentration. After the two-step optimization, the photoluminescence excitation spectrum of Ba3−yEuyZnNb2O9 (y = 0.1) shows a broad band excitation (300–400 nm), which is a good match with the near-UV LED chip emission. Even more importantly, the emission spectrum covers the entire visible spectral region and exhibits a remarkably enhanced emission intensity (a 40 times enhancement when compared to that of the intrinsic BZT). The fabricated LED device comprising an n-UV chip (λ = 370 nm) and a single-component Ba3−yEuyZnNb2O9 (y = 0.1) phosphor coating emits a warm white light with a low correlated color temperature (CCT = 4813 K) and a good color rendering index (Ra = 82.36). [ABSTRACT FROM AUTHOR]

Crystal phosphors have many unique advantages compared with powdery ones. Herein, room‐temperature‐grown millimeter‐sized single‐crystal phosphors of Cs2XF6:Mn4+ (X = Ge, Si, and Ti) with remarkably higher external quantum efficiency than the corresponding powdery samples are reported. In addition, as compared with the powdery ones, the crystal samples exhibit much better stability toward water under different pH conditions. The red light‐emitting diodes (LEDs) based on Cs2XF6:Mn4+ crystals show significantly improved luminous efficiency than those based on their corresponding powders. An assembled white LED device composed of the two layers of phosphors, i.e., the crystal (such as Cs2GeF6:Mn4+) and commercial Y3Al5O12:Ce3+, on a blue chip exhibits intense warm white light with high luminous efficiency (up to 193 lm W−1), high color rendering indexes (88), and low correlated color temperatures (3107 K). Hence, these crystals with greatly improved efficiency and stability can be potentially applied in high‐quality LED backlighting display and white LED lighting, especially inside the micro‐LED devices. [ABSTRACT FROM AUTHOR]

A binder-free electrode consisting of Pd clusters and vanadium oxide (VO) has been prepared via gas-phase-cluster beam deposition on carbon cloth. The Pd clusters largely improve the stability of the VO-Pd-based electrode, which can be reversibly and continuously cycled for more than 120 cycles in a Li–O2 based battery. [ABSTRACT FROM AUTHOR]

In this work, a novel fluoroaluminate red phosphor of Cs2NaAl3F12:Mn4+ with excellent color purity was fabricated via the introduction of Mn4+ in the octahedral center. The crystal and electronic structures, luminescence properties and optical performances were characterized and investigated in detail. The evidences showed that Cs2NaAl3F12:Mn4+ well-crystallized into a single phase with particulate morphology, and the non-equivalent occupation in Cs2NaAl3F12 resulted in sharp red emissions with improved color purity upon blue light illumination. For solid-state lighting, the optical parameters consisted of the "blue-yellow-red" contributions significantly improved to a high color-rendering index of 88.7 and a low color temperature of 3856 K, indicating the potential use of Cs2NaAl3F12:Mn4+ for warm white light-emitting diode applications. [ABSTRACT FROM AUTHOR]

Transition metal phosphides, especially copper phosphide nanocrystals, afford promising anode material candidates for sodium ion batteries. However, despite their high specific capacity, their performance is generally thwarted by rapid capacity fading due to limited cycling stability. To address this issue, we report a three-dimensional nanoarchitecture comprising a heterostructured assembly of Cu3P@C nanosheets synthesized via a simple combined epitaxial phosphidation growth/carbon deposition process. In each individual nanosheet, the thin carbon shell serves as an electron conductor and accommodates volume change of the Cu3P single-crystalline nanosheet. On a macroscopic level, the assembled 3D nanoarchitecture offers fast ion transfer pathways and prevents aggregation of the nanosheets. As a result, the 3D Cu3P@C nanoarchitecture delivers an exceptionally high capacity retention of 286 mA h g−1 after 300 cycles at 0.1 A g−1 and 156 mA h g−1 after 1000 cycles at 1 A g−1. This work, therefore, shows that achieving a synergistic multidimensional structure is possible via a simple one-pot method, and opens avenues to explore other metal phosphides in the same heterostructured format. [ABSTRACT FROM AUTHOR]

The discovery of novel single-phase and emission-tunable phosphors based on the strategy of Eu2+–Mn2+ energy transfer (ET) is a topic of ongoing interest due to the potential applications of near-ultraviolet (n-UV) converted white light-emitting diodes (WLEDs). Herein, we developed a brand-new Eu2+/Mn2+-codoped Ca8ZnLu(PO4)7 (CZLP) phosphor and investigated its structural and luminescence properties in more detail for the purpose of verifying its single-phase and emission-tunability character. The crystal structure of CZLP and the preferential site occupations of the Eu2+ and Mn2+ dopants were identified and confirmed in the framework of the β-Ca3(PO4)2-type structure by combined simultaneous application of the Rietveld refinement and first-principles calculations. Moreover, the CZLP:Eu2+,Mn2+ phosphors under an excitation of 360 nm exhibited color tuning from cyan (0.186, 0.292) to white (0.302, 0.273) with variation in the concentration ratio of Eu2+ to Mn2+. This tuning strategy to generate white light emission can be realized in our samples because of the Eu2+–Mn2+ ET process via predominant dipole–quadrupole interactions with a maximum ET efficiency of 65.55%. To finally evaluate the application potential of the as-synthesized phosphors, a WLED package was fabricated using a 360 nm n-UV chip and the optimal phosphor CZLP:0.03Eu2+,0.20Mn2+. The test results indicate that the obtained white-light device had a much better color rendering index (CRI ∼ 88.6) and correlated color temperature (CCT ∼ 4842 K) in comparison with the traditional combination of a blue light-emitting InGaN chip and Y3Al5O12:Ce3+ phosphor. [ABSTRACT FROM AUTHOR]

Luminescence of monoclinic lithium metatitanate (Li2TiO3) powders activated with different quantities of Mn4+ is studied in detail. Its strong deep‐red emission arising from the Mn4+ 2Eg → 4A2g spin forbidden transition is centered at around 688 nm and is suitable for luminescence thermometry. Structural and electron paramagnetic resonance analyses show that Mn4+ ions are equally distributed in two almost identical Ti4+ sites in which they are octahedrally coordinated by six oxygen ions. Calculations based on the exchange charge model of the crystal field provided values of Racah parameters (B=760 cm−1, C= 2993 cm−1), crystal‐field splitting Dq= 2043 cm−1, and the nephelauxetic parameter β1=0.9775. The maximal quantum efficiency of 24.1% at room temperature is found for 0.126% Mn4+ concentration. Temperature quenching of emission occurs by a cross‐over via 4T2 excited state of the Mn4+ ions with T1/2=262 K and is quite favorable for the application in the lifetime‐based luminescence thermometry since relative changes in emission decay values are exceptionally‐large (around 3.21% at room temperature). We derived theoretical expressions for the temperature dependence of the absolute and relative sensitivities and discuss the influence of host material properties on lifetime sensitivities. [ABSTRACT FROM AUTHOR]

Metal halide perovskite solar cells (PSCs) have been studied over the past few years and high power conversion efficiency (PCE) has been achieved. However, the adverse instability remains a key factor restricting wider application of PSCs. Herein, we report, for the first time, a viable strategy to incorporate a down conversion nanophosphor Sr2CeO4:Eu3+ (SCOE) into PSCs, and more importantly SCOE enables the PSCs with improvement in photovoltaic performance and UV-light stability. The SCOE-coated PSCs achieve a high current density of 23.70 mA cm−2 and a high PCE of 18.95%, which are increased by 9% and 14.15%, respectively, when compared to those of control devices (without an SCOE layer). Moreover, the SCOE-based PSCs retain 80% of their initial PCE value after 70 hours under UV-light irradiation and retain 78% of their initial PCE value after 75 days under ambient environment with 20–25% relative humidity. These results suggest that the incorporated SCOE down conversion material is a functional component of PSCs which broadens the solar spectral response, improving photovoltaic performance, and reduces UV-light-induced photodegradation by converting UV light to visible light, prolonging the device stability. [ABSTRACT FROM AUTHOR]

(Ca1−x−yMgxSryCl2/SiO2):Eu2+ phosphors with intense violet-blue emission were synthesized through a high temperature solid-state reaction method. The colour of the emission is tunable from violet-blue to blue as well as to the violet spectral region by adjusting the concentration of Mg2+ or Sr2+, respectively. An abnormal shift in emission wavelength with the ratio of alkaline earth metal ions was observed and explained by combining electronegativity with the crystal field splitting equation. The UV light content in the emission spectra of (Ca0.8Mg0.2Cl2/SiO2):0.003Eu2+ was successfully reduced below 0.1%, thus providing a safer violet-blue light source for phototherapy. Moreover, the measurement results showed an emission band peaked at 440 nm with a full-width at half maximum of 40 nm under 343 nm excitation, which matches with the most effective range for the treatment of hyperbilirubinemia. CIE chromaticity coordinates of (0.156, 0.044) and an internal quantum efficiency of 41.7% were obtained. The temperature-dependent photoluminescence spectra of (Ca0.8Mg0.2Cl2/SiO2):0.003Eu2+ were also presented. These excellent properties reveal that the violet-blue emitting phosphor could be a potential candidate in converting near-UV radiation to violet-blue emission for phototherapy when combined with UV LED chips. [ABSTRACT FROM AUTHOR]

Single-component white light phosphors with a broad and full color spectrum are urgently required to overcome residual problems with commercial phosphors. In this paper, we describe how Eu3+, as the dopant of Sr3ZnTa2O9 (SZT), plays an important role in structural modulation (including structural order–disorder and intrinsic oxygen defects), as demonstrated by electronic structural calculations and systematic experiments. Furthermore, 5D0→7F2 emission of Eu3+ provides the red component of the emission spectrum and increases the color rendering index of SZT:Eu3+ phosphors. Consequently, the resulting phosphor SZT:10%Eu3+ shows significantly enhanced emission intensity, and its broadband emission covers the entire visible region from 400 nm to 720 nm. A fabricated LED device using a near-ultraviolet 370 nm chip coated with a single-component, the SZT:10%Eu3+ phosphor, shows warm white emission with a high color rendering index (Ra = 82). [ABSTRACT FROM AUTHOR]

A series of red-emitting phosphors composed of Li2ZrF6:Mn4+ (LZF:Mn) have been synthesized via an ionic-exchange reaction route at room temperature. The microstructure and optical characterizations have been investigated according to the detailed experiments. The morphology of the phosphor LZF:Mn changes with the concentration of HF, the reaction time and temperature. The uniform crystals of LZF:Mn with regular hexagonal tablets have been obtained in 30–40 wt% HF solutions by conducting the reaction at room temperature for about 8 h. The influences of reaction parameters on the morphology and photoluminescence properties of LZF:Mn have been systematically investigated. The luminescence intensity of LZF:Mn has been optimized by controlling the synthesis procedure and parameters. The white light-emitting diode (WLED) fabricated with LZF:Mn and Y3Al5O12:Ce3+ (YAG:Ce) on InGaN LED chip displays a warm white light with correlated color temperature (CCT) at 3789.4 K and color rendering index (CRI) of 91. [ABSTRACT FROM AUTHOR]

Broad emission with a full and continuous color spectrum realized by crystal engineering is extensively desired to simulate natural sunlight and improve the white color quality. Herein, new insight into the modulation of B site order–disorder and intrinsic oxygen defects for complex perovskite (A3B′B2′′O9) Sr3−xScxZnNb2O9 (0 ≤x≤ 0.1) phosphors is demonstrated for broad-band emission via crystal engineering. We elucidate that the spectrum of Sr3ZnNb2O9 synthesized at an optimal temperature exhibits two emission bands under near-ultraviolet excitation (λex = 374 nm) which is readily available from near ultraviolet chips. The two broad emission bands can be ascribed to charge transfer from the empty 4d (t2g)-orbitals of Nb5+ ions to the filled 2p-orbitals of O2− ions and the intrinsic oxygen defects. Further, as a proposed strategy to optimize the luminescence property of Sr3ZnNb2O9 (SZN), we realized A-site nonequivalent doping to induce B-site disordering and cancel the luminescence quenching which results from B site ordering. The A-site nonequivalent doping efficiently offsets intrinsic oxygen defects, as validated by systematic analyses of experiments and DFT calculations. Consequently, the novel phosphor Sr3−xScxZnNb2O9 (x = 0.1) shows a high color rendering index (Ra = 82.2) and negligible color shift. In addition, its emission intensity is enhanced by ∼70 times as compared to the pristine Sr3ZnNb2O9. [ABSTRACT FROM AUTHOR]

Red phosphors composed of Mn4+-activated complex fluorides have attracted considerable attention for applications in warm white light-emitting diodes (WLEDs). In the present study, we report a facile strategy to synthesize a novel red phosphor LiSrGaF6:Mn4+ (LSGF:Mn) at room temperature, and we also discuss its formation mechanism. Mn4+ ions occupy Ga3+ sites located at the centers of distorted [GaF6]3− octahedrons and emit intense red luminescence when excited by UV or blue light. The effects of synthesis conditions such as the type of strontium salts, the concentrations of K2MnF6 and NH3·H2O, and the reaction temperature have been investigated. The luminescence intensity of the phosphor LSGF:Mn has been improved by optimizing the synthetic parameters. The as-prepared phosphor LSGF:Mn exhibits broad and intense absorption in the blue region and bright luminescence in the red region, which indicate that it is promising for applications in warm WLEDs. [ABSTRACT FROM AUTHOR]

Abstract: Sn‐based materials can be potentially used as anode in lithium‐ion batteries (LIBs), though challenges still exist. Herein, SnO2/C composites with ultrafine SnO2 nanocrystals uniformly anchored to the carbon matrix are simply synthesized via a one‐pot solvothermal method. In this structure, the nano‐sized SnO2 can offer abundant electroactive sites and effectively shorten the lithium‐ion diffusion length. The interfacial structure between SnO2 and the carbon matrix restricts the particle within a specific space, allowing elastic buffering and alleviating the agglomeration and pulverization. Therefore, the capacity decay due to volume variation upon cycling can be refrained remarkably. Moreover, the unique interfaces facilitate electron transfer, as well as additional lithium storage (i. e., pseudocapacitance). Benefiting from these unique architectural merits, our optimized SnO2/C composite exhibits high specific capacity (600 mAh g−1 at 0.2 A g−1) and superior rate capability (185 mAh g−1 at 11.7 A g−1) when applied to LIBs anodes. Even without an additional conductive agent, the electrode can maintain its extremely stable performance. The strategy proposed here proves the feasibility to enhance electrochemical properties, utilizing the synergetic effect between SnO2 nanocrystals and the carbon base. Thus, the optimized SnO2/C is a promising candidate for applications as anode material in LIBs. [ABSTRACT FROM AUTHOR]

Orthosilicate phosphors with desirable properties are used as commercial materials in the fields of lighting and display. Herein, a series of Ce3+ and Sm3+ singly- or doubly-doped CaSrSiO4 phosphors with charge compensations by co-doping of Na+ ions were successfully prepared using a conventional solid-state method and their crystal structures were determined from XRD profiles and refinement with the Rietveld method. Emphatically, Ce3+ or Sm3+ singly-doped CaSrSiO4 phosphors exhibited good photoluminescence properties. In doubly-doped phosphors, the red emission of Sm3+ was enhanced by energy transfer (ET) from Ce3+ to Sm3+ ions. The mechanism of ET was deduced to be dipole–dipole interaction using the Inokuti–Hirayama (I–H) model. The red emission intensity of Ca0.97Sr0.97Ce0.01Sm0.02Na0.03SiO4 at 425 K was 85.21% of that at 300 K, indicating satisfactory thermal stability of fluorescence. The obtained white LED device fabricated with Ca0.97Sr0.97Ce0.01Sm0.02Na0.03SiO4 phosphor, Sr2SiO4:Eu2+ and an ultraviolet (UV) chip displayed a bright white light with CIE chromaticity coordinates (0.32, 0.38), correlated colour temperature (CCT) of 6056 K and colour rendering index (Ra) of 73.5. [ABSTRACT FROM AUTHOR]