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1.
Heliyon ; 9(8): e18731, 2023 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-37576216

RESUMO

Verticillium wilt (VW), Fusarium wilt (FW) and Root-knot nematode (RKN) are the main diseases affecting cotton production. However, many reported quantitative trait loci (QTLs) for cotton resistance have not been used for agricultural practices because of inconsistencies in the cotton genetic background. The integration of existing cotton genetic resources can facilitate the discovery of important genomic regions and candidate genes involved in disease resistance. Here, an improved and comprehensive meta-QTL analysis was conducted on 487 disease resistant QTLs from 31 studies in the last two decades. A consensus linkage map with genetic overall length of 3006.59 cM containing 8650 markers was constructed. A total of 28 Meta-QTLs (MQTLs) were discovered, among which nine MQTLs were identified as related to resistance to multiple diseases. Candidate genes were predicted based on public transcriptome data and enriched in pathways related to disease resistance. This study used a method based on the integration of Meta-QTL, known genes and transcriptomics to reveal major genomic regions and putative candidate genes for resistance to multiple diseases, providing a new basis for marker-assisted selection of high disease resistance in cotton breeding.

2.
Plant Physiol Biochem ; 201: 107853, 2023 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-37385030

RESUMO

Protein ubiquitination is essential for plant growth and responses to the environment. The SEVEN IN ABSENTIA (SINA) ubiquitin ligases have been extensively studied in plants, but information on their roles in fiber development is limited. Here, we identified GhSINA1 in Upland cotton (Gossypium hirsutum), which has a conserved RING finger domain and SINA domain. Quantitative real-time PCR (qRT-PCR) analysis showed that GhSINA1 was preferentially expressed during fiber initiation and elongation, especially during initiation in the fuzzless-lintless cotton mutant. Subcellular localization experiments indicated that GhSINA1 localized to the nucleus. In vitro ubiquitination analysis revealed that GhSINA1 has E3 ubiquitin ligase activity. Ectopic overexpression of GhSINA1 in Arabidopsis thaliana reduced the number and length of root hairs and trichomes. Yeast two-hybrid (Y2H), firefly luciferase complementation imaging (LCI), and bimolecular fluorescence complementation (BiFC) assays demonstrated that the GhSINA1 proteins could interact with each other to form homodimers and heterodimers. Overall, these results suggest that GhSINA1 may act as a negative regulator in cotton fiber development through homodimerization and heterodimerization.


Assuntos
Arabidopsis , Gossypium , Gossypium/metabolismo , Fibra de Algodão , Ubiquitina/metabolismo , Ligases/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Arabidopsis/genética , Arabidopsis/metabolismo , Regulação da Expressão Gênica de Plantas
3.
Dalton Trans ; 51(36): 13910-13918, 2022 Sep 20.
Artigo em Inglês | MEDLINE | ID: mdl-36040450

RESUMO

A high temperature solid state method was used to prepare Na3Gd(PO4)2:Eu2+,Mn2+ phosphors with good thermal stability. The phosphor shows a broadband excitation region of 250-430 nm, which can be matched with the emissions of ultraviolet (UV)/near-ultraviolet (NUV) LED chips for white light emitting diodes (w-LEDs). The energy transfer efficiency is 74.46% from the sensitizer Eu2+ ions to the activator Mn2+ ions, which enhances the intensities of the Na3Gd(PO4)2-based phosphor. In addition, by increasing the Mn2+ doping level in the phosphor, the Na3Gd(PO4)2:Eu2+,Mn2+ phosphor first shows blue light, then turns to white light, and finally emits red light under 365 nm excitation. Besides, the temperature-dependent photoluminescence measurements indicate that the prepared phosphors exhibit good thermal stability. W-LEDs fabricated by combining a 365 nm chip with the Na3Gd(PO4)2:Eu2+,Mn2+ phosphor exhibit bright white light, which has a high color rendering index (CRI) = 91.5, and a relatively low correlated color temperature (CCT) = 5198 K. Moreover, the CIE point is calculated to be at (0.3337, 0.3465), which is located in the white light region. These results indicate that the as-prepared phosphors can be considered as potential candidates for UV/NUV light-excited w-LED applications.

4.
ACS Omega ; 7(19): 16837-16846, 2022 May 17.
Artigo em Inglês | MEDLINE | ID: mdl-35601342

RESUMO

Fe3O4 is a promising alternative for next-generation lithium-ion batteries (LIBs). However, its poor cycle stability due to the large volume effect during cycling and poor conductivity hinders its application. Herein, we have successfully designed and prepared a carbon-coated ternary transition-metal-oxide composite (noted as (FeCoNi)3O4@C), which is derived from FeCoNi-MOF-74 (denoted as FeCoNi-211-24). (FeCoNi)3O4@C perfectly inherited the long spindle-shaped precursor structure, and (FeCoNi)3O4 particles grew in situ on the precursor surface. The ordered particles and the carbon-coated structure inhibited the agglomeration of particles, improving the material's cycle stability and conductivity. Therefore, the electrode exhibited excellent electrochemical performance. Specifically, (FeCoNi)3O4@C-700 presented excellent initial discharge capacity (763.1 mAh g-1 at 0.2 A g-1), high initial coulombic efficiency (73.8%), excellent rate capability, and cycle stability (634.6 mAh g-1 at 0.5 A g-1 after 505 cycles). This study provides a novel idea for developing anode materials for LIBs.

5.
Inorg Chem ; 61(7): 3263-3273, 2022 Feb 21.
Artigo em Inglês | MEDLINE | ID: mdl-35133813

RESUMO

The modifications of local structure in solid solution are a crucial step to regulate the photoluminescence properties of rare-earth ion-based phosphors. However, the structural diversity of host matrices and the uncertain occupation of activators make it challenging to obtain phosphors with both high stability and tailored emission. Herein, We synthesized a series of ß-Ca3(PO4)2-type Ca8ZnGa(1-x)Lax(PO4)7:Eu2+ solid solution phosphors by design. By modifying the Ga/La ratio, controllable regulation of the emission spectrum and thermal stability of the phosphors can be achieved at the same time. The introduction of La3+ can regulate the crystal field splitting strength of the Eu2+ activators, causing redshifts in the emission spectrum while increasing Ga3+ content will lead to enhanced energy transfer between the oxygen vacancy and Eu2+, as well as improved thermal stability. Through local structure modification, the spectrum and thermal stability of phosphors can be facilely tuned. The results indicate that this series of phosphors have versatile potentials in various applications.

6.
Molecules ; 26(11)2021 May 28.
Artigo em Inglês | MEDLINE | ID: mdl-34071526

RESUMO

Developing a porous separation membrane that can efficiently separate oil-water emulsions still represents a challenge. In this study, nanofiber membranes with polydopamine clusters polymerized and embedded on the surface were successfully constructed using a solution blow-spinning process. The hierarchical surface structure enhanced the selective wettability, superhydrophilicity in air (≈0°), and underwater oleophobicity (≈160.2°) of the membrane. This membrane can effectively separate oil-water emulsions, achieving an excellent permeation flux (1552 Lm-2 h-1) and high separation efficiency (~99.86%) while operating only under the force of gravity. When the external driving pressure was increased to 20 kPa, the separation efficiency hardly changed (99.81%). However, the permeation flux significantly increased to 5894 Lm-2 h-1. These results show that the as-prepared polydopamine nanocluster-embedded nanofiber membrane has an excellent potential for oily wastewater treatment applications.

7.
Plant Divers ; 42(3): 189-197, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32695952

RESUMO

Gene flow patterns and the genetic structure of domesticated crops like cotton are not well understood. Furthermore, marker-assisted breeding of cotton has lagged far behind that of other major crops because the loci associated with cotton traits such as fiber yield and quality have scarcely been identified. In this study, we used 19 microsatellites to first determine the population genetic structure and patterns of gene flow of superior germplasm resources in upland cotton. We then used association analysis to identify which markers were associated with 15 agronomic traits (including ten yield and five fiber quality traits). The results showed that the upland cotton accessions have low levels of genetic diversity (polymorphism information content = 0.427), although extensive gene flow occurred among different ecological and geographic regions. Bayesian clustering analysis indicated that the cotton resources used in this study did not belong to obvious geographic populations, which may be the consequence of a single source of domestication followed by frequent genetic introgression mediated by human transference. A total of 82 maker-trait associations were examined in association analysis and the related ratios for phenotypic variations ranged from 3.04% to 47.14%. Interestingly, nine SSR markers were detected in more than one environmental condition. In addition, 14 SSR markers were co-associated with two or more different traits. It was noteworthy that NAU4860 and NAU5077 markers detected at least in two environments were simultaneously associated with three fiber quality traits (uniformity index, specific breaking strength and micronaire value). In conclusion, these findings provide new insights into the population structure and genetic exchange pattern of cultivated cotton accessions. The quantitative trait loci of domesticated cotton identified will also be very useful for improvement of yield and fiber quality of cotton in molecular breeding programs.

8.
Molecules ; 25(3)2020 Jan 27.
Artigo em Inglês | MEDLINE | ID: mdl-32012682

RESUMO

The fabrication and luminescent performance of novel phosphors Na2YMg2V3O12:Dy3+ were investigated by a conventional solid-state reaction method. Under near-UV light, the Na2YMg2V3O12 host self-activated and released a broad emission band (400-700 nm, with a peak at 524 nm) ascribable to charge transfer in the (VO4)3- groups. Meanwhile, the Na2YMg2V3O12:Dy3+ phosphors emitted bright yellow light within both the broad emission band of the (VO4)3- groups and the sharp peaks of the Dy3+ ions at 490, 582, and 663 nm at a quenching concentration of 0.03 mol. The emission of the as-prepared Na2YMg2V3O12:Dy3+ phosphors remained stable at high temperatures. The obtained phosphors, commercial Y2O3:Eu3+ red phosphors, and BaMgAl10O17:Eu2+ blue phosphors were packed into a white light-emitting diode (WLED) device with a near-UV chip. The designed WLED emitted bright white light with good chromaticity coordinates (0.331, 0.361), satisfactory color rendering index (80.2), and proper correlation to a color temperature (7364 K). These results indicate the potential utility of Na2YMg2V3O12:Dy3+ phosphor as a yellow-emitting phosphor in solid-state illumination.


Assuntos
Disprósio/química , Luminescência , Substâncias Luminescentes/química , Magnésio/química , Óxidos/química , Sódio/química , Vanádio/química
9.
Adv Sci (Weinh) ; 7(3): 1902051, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-32042559

RESUMO

Metal-based nanocatalysts supported on carbon have significant prospect for industry. However, a straightforward method for efficient and stable nanocatalysts still remains extremely challenging. Inspired by the structure and comptosition of cell walls and membranes, an ion chemical bond anchoring, an in situ carbonization coreduction process, is designed to obtain composite catalysts on N-doped 2D carbon (C-N) loaded with various noble and non-noble metals (for example, Pt, Ru, Rh, Pd, Ag, Ir, Au, Co, and Ni) nanocatalysts. These 2 nm particles uniformly and stably bond with the C-N support since the agglomeration and growth are suppressed by anchoring the metal ions on the cell wall and membrane during the carbonization and reduction reactions. The Pt@C-N exhibits excellent catalytic activity and long-term stability for the hydrogen evolution reaction, and the relative overpotential at 100 mA cm-2 is only 77 mV, which is much lower than that of commercial Pt/C and Pt single-atom catalysts reported recently.

10.
Sci Rep ; 9(1): 16321, 2019 Nov 08.
Artigo em Inglês | MEDLINE | ID: mdl-31705034

RESUMO

To improve the catalyst properties of TiO2 under visible light irradiation, chitin-modified TiO2 was synthesized via a hydrothermal method on the surface of carbon fibers. The microstructure and interface properties of the so-prepared photocatalyst were investigated via X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy, and UV-visible diffuse reflectance spectroscopy. Our results indicated that the synergetic effect of the crystal phase of TiO2, carbon fiber, and chitin is the main reason leading to the improvement of the photocatalytic activity of the composite catalyst. The modified TiO2 sample with chitin content of 0.6 wt% exhibited the highest photocatalytic activity under visible light irradiation when RhB was chosen as the target degradation product. Compared to the pure TiO2/carbon fiber, the sample of TiO2/carbon fiber with 0.6 wt% of chitin exhibits enhanced visible light activity with an apparent rate of degradation about 2.25 times. The enhancement of the photocatalytic performance of the sample with chitin can be attributed to the relatively high adsorption capacity of the particular network structure and photosensitivity of chitin, which can effectively separate the photoelectron-hole pair recombination. Furthermore, the new composite photocatalyst shows excellent catalytic stability after multiple degradation cycles, indicating that it is a promising photocatalytic material for degrading organic pollutants in wastewater.

11.
ACS Omega ; 4(20): 18627-18636, 2019 Nov 12.
Artigo em Inglês | MEDLINE | ID: mdl-31737822

RESUMO

Ferrihydrite/manganese dioxide composites (FH-M) were synthesized from ferrihydrite (FH) and manganese compounds by ex situ synthesis and characterized using X-ray diffraction, scanning electron microscopy, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy in the present work. The influences of experimental parameters such as the solution pH value and initial concentration of adsorbate on the adsorption uptake of Cd(II)/As(V) was systematically investigated. The adsorption kinetics was analyzed by fitting quasi-first-order and quasi-second-order kinetic equations. The results showed that with increase in the pH value, the adsorption rate of Cd(II) is increased, while that of As(V) is increased first and then decreased. For the kinetic adsorption process, the adsorption performance of FH-M to As(V) was better than that to Cd(II). The quasi-second-order kinetic equation and Freundlich equation were more suitable to describe the adsorption of Cd(II)/As(V). The ligand exchange of Cd(II)/As(V) with the -OH in the composites was confirmed by analyzing the characterization results of X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy. The high adsorption ability of the FH-M makes it a potentially attractive adsorbent for the removal to Cd(II) and As(V) with a good application prospect.

12.
Molecules ; 24(7)2019 Apr 03.
Artigo em Inglês | MEDLINE | ID: mdl-30987075

RESUMO

The development of white-light-emitting diodes (w-LEDs) makes it meaningful to develop novel high-performance phosphors excited by blue light. Herein, BiOCl:Pr3+ green-yellow phosphors were prepared via a high-temperature solid-state reaction method. The crystal structure, luminescent properties, lifetime, thermal quenching behavior, and quantum yield were studied in detail. The BiOCl:Pr3+ phosphors presented several emission peaks located in green and red regions, under excitation at 453 nm. The CIE coordinates could be tuned along with the changed doping concentration with fair luminescence efficiency. The results also indicated that the optimized doping concentration of Pr3+ ions was at x = 0.0075 because of the concentration quenching behavior resulting from an intense exchange effect. When the temperature reached 150 °C, the intensity of the emission peak at 495 nm could remain at 78% of that at room temperature. The activation energy of 0.20 eV also confirmed that the BiOCl:Pr3+ phosphor exhibited good thermal stability. All these results indicate that the prepared products have potential to be used as a high-performance green-yellow-light-emitting phosphor for blue-light-based w-LEDs.


Assuntos
Luminescência , Substâncias Luminescentes/química , Substâncias Luminescentes/síntese química , Modelos Moleculares , Termodinâmica , Difração de Raios X
13.
J Phys Condens Matter ; 31(1): 015801, 2019 Jan 09.
Artigo em Inglês | MEDLINE | ID: mdl-30499453

RESUMO

Ba2FeMoO6 has been reported to exhibit a ferromagnetic to a paramagnetic transition with a Curie temperature above room temperature, and thus it is a potential material for spintronics. These exciting properties are related, at least in part, to combined structural and magnetic instabilities. A conventional analysis of lattice parameter data from the present study and literature in terms of spontaneous strain shows that the magnetic ordering is accompanied by a significant volume strain, which implies a strong coupling behavior of magneto-elastic properties in Ba2FeMoO6. In addition, to address the correlation between anti-site defects (ASD) and magnetic properties, we have carried out a comparative study of six cubic Ba2FeMoO6 polycrystals with different degrees of ASD. The correlations among the Curie temperature, low-temperature saturation magnetism, and ASD are discussed in detail using a combination of diffraction and magnetic measurements. This systematic study, especially the strain analysis, of Ba2FeMoO6 will facilitate its potential applications in the field of spin electronics and thin film engineering.

14.
Front Plant Sci ; 9: 376, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29619041

RESUMO

Cotton is one of the most economically important fiber crop plants worldwide. The genus Gossypium contains a single allotetraploid group (AD) and eight diploid genome groups (A-G and K). However, the evolution of repeat sequences in the chloroplast genomes and the phylogenetic relationships of Gossypium species are unclear. Thus, we determined the variations in the repeat sequences and the evolutionary relationships of 40 cotton chloroplast genomes, which represented the most diverse in the genus, including five newly sequenced diploid species, i.e., G. nandewarense (C1-n), G. armourianum (D2-1), G. lobatum (D7), G. trilobum (D8), and G. schwendimanii (D11), and an important semi-wild race of upland cotton, G. hirsutum race latifolium (AD1). The genome structure, gene order, and GC content of cotton species were similar to those of other higher plant plastid genomes. In total, 2860 long sequence repeats (>10 bp in length) were identified, where the F-genome species had the largest number of repeats (G. longicalyx F1: 108) and E-genome species had the lowest (G. stocksii E1: 53). Large-scale repeat sequences possibly enrich the genetic information and maintain genome stability in cotton species. We also identified 10 divergence hotspot regions, i.e., rpl33-rps18, psbZ-trnG (GCC), rps4-trnT (UGU), trnL (UAG)-rpl32, trnE (UUC)-trnT (GGU), atpE, ndhI, rps2, ycf1, and ndhF, which could be useful molecular genetic markers for future population genetics and phylogenetic studies. Site-specific selection analysis showed that some of the coding sites of 10 chloroplast genes (atpB, atpE, rps2, rps3, petB, petD, ccsA, cemA, ycf1, and rbcL) were under protein sequence evolution. Phylogenetic analysis based on the whole plastomes suggested that the Gossypium species grouped into six previously identified genetic clades. Interestingly, all 13 D-genome species clustered into a strong monophyletic clade. Unexpectedly, the cotton species with C, G, and K-genomes were admixed and nested in a large clade, which could have been due to their recent radiation, incomplete lineage sorting, and introgression hybridization among different cotton lineages. In conclusion, the results of this study provide new insights into the evolution of repeat sequences in chloroplast genomes and interspecific relationships in the genus Gossypium.

15.
Sci Rep ; 7(1): 18103, 2017 12 22.
Artigo em Inglês | MEDLINE | ID: mdl-29273765

RESUMO

Discovery of novel phosphors is one of the main issues for improving the color rendering index (CRI) and correlated color temperature (CCT) of white light-emitting diodes (w-LEDs). This study mainly presents a systematic research on the synthesis, crystal structure variation and photoluminescence tuning of novel (oxy)nitride solid solution Ca3Si3-x O3+x N4-2x : Eu2+ phosphors. XRD refinements show that lattice distortion occurs when x value diverges the optimum one (x = 1). The lattice distortion causes a widening of emission spectrum and an increase of Stokes shift (ΔSS), which leads to a bigger thermal quenching. With decrease of x value, the emission spectrum shows an obvious red-shift from 505.2 to 540.8 nm, which is attributed to the crystal field splitting. The enhanced crystal field splitting also broadens the excitation spectrum, making it possible to serve as the phosphor for near ultraviolet (n-UV) LEDs. A 3-phosphor-conversion w-LED lamp was fabricated with the as-prepared phosphor, which exhibits high CRI (Ra = 85.29) and suitable CCT (4903.35 K). All these results indicate that the Ca3Si3-x O3+x N4-2x : Eu2+ phosphor can serve as the green phosphor for n-UV w-LEDs, with a tunable spectrum by controlling the crystal structure and morphology.

16.
Sci Rep ; 7(1): 10482, 2017 09 05.
Artigo em Inglês | MEDLINE | ID: mdl-28874878

RESUMO

Novel silica nanowires and interconnected nanorings were firstly synthesized on a graphite paper by typical thermal catalytic chemical vapor deposition method, using silicon and carbon black powders as raw materials. The field emission scanning electron microscopy, energy dispersive x-ray spectroscopy, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and transmission electron microscopy were used to investigate the composition and structure characterization, which indicates that the silica nanowires and interconnected nanorings were amorphous. The growth of the as-prepared silica nanowires and interconnected nanorings was related to the vapor-liquid-solid mechanism, but the nanowire-ring structure may be due to the polycentric nucleation and periodic stable growth with gradual direction changes. The room temperature photoluminescence emission spectrum showed that the silica nanostructures emitted strong blue light at 460 nm, resulting from the combination of neutral oxygen vacancy (≡Si-Si≡) and selftrapped excitons. The as-synthesized novel silica nanowires and interconnected nanorings could be a potential candidate for applications in future light-emitting diodes and optoelectronic nanodevices.

17.
Angew Chem Int Ed Engl ; 56(14): 3886-3891, 2017 03 27.
Artigo em Inglês | MEDLINE | ID: mdl-28244628

RESUMO

Aluminum-nitrogen six-fold octahedral coordination, [AlN6 ], is unusual and has only been seen in the high-pressure rocksalt-type aluminum nitride or some complex compounds. Herein we report novel nitrides LnAl(Si4-x Alx )N7 Oδ (Ln=La, Sm), the first inorganic compounds with [AlN6 ] coordination prepared via non-high-pressure synthesis. Structure refinements of neutron powder diffraction and single-crystal X-ray diffraction data show that these compounds crystallize in the hexagonal Swedenborgite structure type with P63 mc symmetry where Ln and Al atoms locate in anticuboctahedral and octahedral interstitials, respectively, between the triangular and Kagomé layers of [SiN4 ] tetrahedra. Solid-state NMR data of high-purity La-114 powders confirm the unusual [AlN6 ] coordination. These compounds are the first examples of the "33-114" sub-type in the "114" family. The additional site for over-stoichiometric oxygen in the structure of 114-type compounds was also identified.

18.
J Nanosci Nanotechnol ; 16(4): 3684-9, 2016 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-27451689

RESUMO

In this paper, M3(VO4)2 (M = Mg, Ca, Sr, and Ba) self-activated phosphors were prepared by a solid-state reaction method at 1,000 °C for 5 h. The phase formation and micrographs were analyzed by X-ray diffraction and scanning electron microscopy. The Ca3(VO4)2 phosphor does not show any emission peaks under excitation with ultraviolet (UV) light. However, the M3(VO4)2 (M = Mg, Sr, and Ba) samples are effectively excited by UV light chips ranging from 200 nm to 400 nm and exhibit broad emission bands due to the charge transfer from the oxygen 2p orbital to the vacant 3d orbital of the vanadium in the VO4. The color of these phosphors changes from yellow to light blue via blue-green with increasing ionic radius from Mg to Sr to Ba. The luminescence lifetimes and quantum yield decrease with the increasing unit cell volume and V-V distance, in the order of Mg3(VO4)2 to Sr3(VO4)2 to Ba3(VO4)2. The emission intensity decreases with the increase of temperatures, but presents no color shift. This confirms that these self-activated M3(VO4)2 phosphors can be suggested as candidates of the single-phase phosphors for light using UV light emitting diodes (LEDs).

19.
Sci Rep ; 6: 22459, 2016 Mar 04.
Artigo em Inglês | MEDLINE | ID: mdl-26940294

RESUMO

Uniform silica nanoparticles and jellyfish-like nanowires were synthesized by a chemical vapour deposition method on Si substrates treated without and with Ni(NO3)2, using silicon powder as the source material. Composition and structural characterization using field emission scanning electron microscopy, transmission electron microscopy, energy dispersive X-ray spectroscopy and fourier-transform infrared spectroscopy showed that the as-prepared products were silica nanoparticles and nanowires which have amorphous structures. The form of nanoparticles should be related to gas-phase nucleation procedure. The growth of the nanowires was in accordance with vapour-liquid-solid mechanism, followed by Ostwald ripening to form the jellyfish-like morphology. Photoluminescence and cathodoluminescence measurements showed that the silica products excited by different light sources show different luminescence properties. The emission spectra of both silica nanoparticles and nanowires are due to the neutral oxygen vacancies (≡Si-Si≡). The as-synthesized silica with controlled morphology can find potential applications in future nanodevices with tailorable photoelectric properties.

20.
Dalton Trans ; 45(3): 1007-15, 2016 Jan 21.
Artigo em Inglês | MEDLINE | ID: mdl-26648132

RESUMO

A series of apatite solid solution phosphors Ca(2+x)La(8-x)(SiO4)(6-x)(PO4)xO2:Eu(2+) (x = 0,2,4,6) were synthesized by a conventional high-temperature solid-state reaction. The phase purity was examined using XRD, XPS and XRF. The crystal structure information, such as the concentration, cell parameters and occupation rate, was analyzed using a Rietveld refinement, demonstrating that the Eu(2+) activated the Ca2La8(SiO4)6O2 and Ca8La2(PO4)6O2 to form continuous solid solution phosphors. Different behaviors of luminescence evolution in response to structural variation were verified among the series of phosphors. Two kinds of Eu(2+) ion sites were proved using low temperature PL spectra (8k) and room temperature decay curves. The substitution of large La(3+) ions by small Ca(2+) ions induced a decreased crystal field splitting of the Eu(2+) ions, which caused an increase in emission energy from the 5d excited state to the 4f ground state and a resultant blue-shift from 508 nm to 460 nm. Therefore, with the crystal structure evolution, the emitted color of the series of phosphors could be tuned from green to blue by adjusting the ratio of Ca/La.

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