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1.
Luminescence ; 39(5): e4750, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38733198

RESUMO

Ultra-high thermally stable Ca2MgWO6:xSm3+ (x = 0.5, 0.75, 1, 1.25, and 1.5 mol%) double perovskite phosphors were synthesized through solid-state reaction method. Product formation was confirmed by comparing the X-ray diffraction (XRD) patterns of the phosphors with the standard reference file. The structural, morphological, thermal, and optical properties of the prepared phosphor were examined in detail using XRD, Fourier transform infrared spectra, scanning electron microscopy, diffused reflectance spectra, thermogravimetric analysis (TGA), photoluminescence emission, and temperature-dependent PLE (TDPL). It was seen that the phosphor exhibited emission in the reddish region for the near-ultraviolet excitation with moderate Colour Rendering Index values and high colour purity. The optimized phosphor (x = 1.25 mol%) was found to possess a direct optical band gap of 3.31 eV. TGA studies showed the astonishing thermal stability of the optimized phosphor. Additionally, near-zero thermal quenching was seen in TDPL due to elevated phonon-assisted radiative transition. Furthermore, the anti-Stokes and Stokes emission peaks were found to be sensitive toward the temperature change and followed a Boltzmann-type distribution. All these marked properties will make the prepared phosphors a suitable candidate for multifield applications and a fascinating material for further development.


Assuntos
Luminescência , Substâncias Luminescentes , Samário , Temperatura , Compostos de Tungstênio , Compostos de Tungstênio/química , Substâncias Luminescentes/química , Substâncias Luminescentes/síntese química , Samário/química , Medições Luminescentes , Difração de Raios X , Compostos de Cálcio/química , Óxidos/química , Termogravimetria
2.
Luminescence ; 39(5): e4779, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38769873

RESUMO

Carbon dots have attracted widespread attention due to their excellent optical properties and so on and are therefore used in various fields such as anti-counterfeiting. There are many reports on carbon dot-based room-temperature phosphorescent materials, but there are still fewer reports on carbon dot-based room-temperature phosphorescent materials with time-dependent color-changing properties. In this work, a time-dependent color-changing carbon dot-based room-temperature phosphorescent material with the ability to change from green to blue was successfully prepared by a simple one-pot heating method using hydroxyurea as the only raw material. In this process, hydroxyurea is used as both a carbon and nitrogen source, and in the process of material formation, hydroxyurea also partially forms cyanuric acid as a matrix to make the carbon dots uniformly dispersed in it. By blending the ratio of the dual emission centers of the carbon dots themselves, the final effect of time-dependent color-changing is achieved by taking advantage of the intensity changes and color differences of each emission center. The present work provides new ideas for the preparation of time-dependent color-changing carbon dot-based room-temperature phosphorescent materials.


Assuntos
Carbono , Cor , Pontos Quânticos , Temperatura , Carbono/química , Pontos Quânticos/química , Substâncias Luminescentes/química , Substâncias Luminescentes/síntese química , Fatores de Tempo
3.
Luminescence ; 39(5): e4762, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38698695

RESUMO

Broadband near-infrared (NIR) spectroscopy has gained significant attention due to its versatile application in various fields. In the realm of NIR phosphors, Fe3+ ion is an excellent activator known for its nontoxic and harmless nature. In this study, we prepared an Fe3+-activated SrGa12O19 (SGO) NIR phosphor and analyzed its phase and luminescence properties. Upon excitation at 326 nm, the SGO:Fe3+ phosphor exhibited a broadband emission in the range 700-1000 nm, peaking at 816 nm. The optical band gap of SGO:Fe3+ was evaluated. To enhance the long-lasting phosphorescence, an oxygen vacancy-rich SGO:Fe3+ (VO-SGO:Fe3+) sample was prepared for activation. Interestingly, the increase in the oxygen-vacancy concentration indeed contributed to the activation of persistent luminescence of Fe3+ ions. The VO-SGO:Fe3+ sample has a long duration and high charge storage capacity, allowing it to perform efficiently in various applications. This work provides the foundation for further design of Cr3+-free PersL phosphors with efficient NIR PersL.


Assuntos
Luminescência , Substâncias Luminescentes , Oxigênio , Oxigênio/química , Substâncias Luminescentes/química , Estrôncio/química , Medições Luminescentes , Compostos Férricos/química , Gálio/química , Ferro/química , Espectroscopia de Luz Próxima ao Infravermelho
4.
J Am Chem Soc ; 146(19): 13406-13416, 2024 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-38698549

RESUMO

Bioluminescent indicators are power tools for studying dynamic biological processes. In this study, we present the generation of novel bioluminescent indicators by modifying the luciferin molecule with an analyte-binding moiety. Specifically, we have successfully developed the first bioluminescent indicator for potassium ions (K+), which are critical electrolytes in biological systems. Our approach involved the design and synthesis of a K+-binding luciferin named potassiorin. Additionally, we engineered a luciferase enzyme called BRIPO (bioluminescent red indicator for potassium) to work synergistically with potassiorin, resulting in optimized K+-dependent bioluminescence responses. Through extensive validation in cell lines, primary neurons, and live mice, we demonstrated the efficacy of this new tool for detecting K+. Our research demonstrates an innovative concept of incorporating sensory moieties into luciferins to modulate luciferase activity. This approach has great potential for developing a wide range of bioluminescent indicators, advancing bioluminescence imaging (BLI), and enabling the study of various analytes in biological systems.


Assuntos
Luciferases , Medições Luminescentes , Potássio , Potássio/metabolismo , Potássio/química , Animais , Medições Luminescentes/métodos , Camundongos , Luciferases/química , Luciferases/metabolismo , Humanos , Engenharia de Proteínas , Substâncias Luminescentes/química , Luciferina de Vaga-Lumes/química , Luciferina de Vaga-Lumes/metabolismo
5.
Biosens Bioelectron ; 256: 116236, 2024 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-38608494

RESUMO

Au nano-clusters (Au NCs) were promising electrochemiluminescence (ECL) nano-materials. However, the small size of Au NCs presented a challenge in terms of their immobilization during the construction of an ECL biosensing platform. This limitation significantly hindered the wider application of Au NCs in the ECL field. In this work, we successfully used the reducibility of Ti3C2 to fabricate in situ a self-enhanced nano-probe Ti3C2-TiO2-Au NCs. The strategy of in situ generation not only improved the immobilization of Au NCs on the probe but also eliminated the requirement of adding reducing agents during preparation. In addition, in situ generated TiO2 could serve as a co-reaction accelerator, shortening the electron transfer distance between S2O82- and Au NCs, thereby improving the utilization of intermediates and enhancing the ECL response of Au NCs. The constructed ECL sensing platform could achieve sensitive detection of polynucleotide kinase (PNK). At the same time, the 5'-end phosphate group of DNA phosphorylation could chelate with a large amount of Ti on the surface of Ti3C2, thereby achieving the goal of specific detection of PNK. The sensor based on self-enhanced ECL probes had a broad dynamic range spanning for PNK detection from 10.0 to 1.0 × 107 µU mL-1, with a limit of detection of 1.6 µU mL-1. Moreover, the ECL sensor showed satisfactory detection performance in HeLa cell lysate and serum. This study not only provided insights for addressing the issue of ECL luminescence efficiency in Au NCs but also presented novel concepts for ECL self-enhancement strategies.


Assuntos
Técnicas Biossensoriais , Ouro , Limite de Detecção , Medições Luminescentes , Polinucleotídeo 5'-Hidroxiquinase , Titânio , Titânio/química , Técnicas Biossensoriais/métodos , Humanos , Medições Luminescentes/métodos , Ouro/química , Polinucleotídeo 5'-Hidroxiquinase/análise , Técnicas Eletroquímicas/métodos , Nanopartículas Metálicas/química , Substâncias Luminescentes/química
6.
Luminescence ; 39(5): e4751, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38666358

RESUMO

This study describes the luminous properties of Pb5(PO4)3Br doped with RE3+ (RE = Dy3+, Eu3+ and Tb3+) synthesised using the solid-state method. The synthesised phosphor was characterised using Fourier-transform infrared, X-ray diffraction, scanning electron microscopy and photoluminescence measurements. Dy3+-doped Pb5(PO4)3Br phosphor exhibited blue and yellow emissions at 480 and 573 nm, respectively, on excitation at 388 nm. Eu3+-doped Pb5(PO4)3Br phosphor exhibited orange and red emissions at 591 and 614 nm, respectively, on excitation at λex = 396 nm. Pb5(PO4)3Br:Tb3+ phosphor exhibited the strongest green emission at 547 nm on excitation at λex = 380 nm. Additionally, the effect of the concentration of rare-earth ions on the emission intensity of Pb5(PO4)3Br:RE3+ (RE3+ = Dy3+, Eu3+ and Tb3+) phosphors was investigated.


Assuntos
Európio , Luminescência , Substâncias Luminescentes , Európio/química , Substâncias Luminescentes/química , Substâncias Luminescentes/síntese química , Térbio/química , Fosfatos/química , Medições Luminescentes , Difração de Raios X , Chumbo/química
7.
Inorg Chem ; 63(18): 8320-8328, 2024 May 06.
Artigo em Inglês | MEDLINE | ID: mdl-38660721

RESUMO

Histidine plays an essential role in most biological systems. Changes in the homeostasis of histidine and histidine-rich proteins are connected to several diseases. Herein, we report a water-soluble Cu(II) coordination polymer, labeled CuCP, for the fluorimetric detection of histidine and histidine-rich proteins and peptides. Single-crystal structure determination of CuCP revealed a two-dimensional wavy network structure in which a carboxylate group connects the individual Cu(II) dimer unit in a syn-anti conformation. The weakly luminescent and water-soluble CuCP shows turn-on blue emission in the presence of histidine and histidine-rich peptides and proteins. The polymer can also stain histidine-rich proteins via gel electrophoresis. The limits of quantifications for histidine, glycine-histidine, serine-histidine, human serum albumin (HSA), bovine serum albumin, pepsin, trypsin, and lysozyme were found to be 300, 160, 600, 300, 600, 800, 120, and 290 nM, respectively. Utilizing the fluorescence turn-on property of CuCP, we measured HSA quantitatively in the urine samples. We also validated the present urinary HSA measurement assay with existing analytical techniques. Job's plot, 1H NMR, high-resolution mass spectrometry (HRMS), electron paramagnetic resonance (EPR), fluorescence, and UV-vis studies confirmed the ligand displacement from CuCP in the presence of histidine.


Assuntos
Cobre , Histidina , Peptídeos , Proteínas , Água , Cobre/química , Cobre/análise , Histidina/química , Histidina/análise , Histidina/urina , Humanos , Água/química , Peptídeos/química , Proteínas/química , Proteínas/análise , Complexos de Coordenação/química , Complexos de Coordenação/síntese química , Solubilidade , Polímeros/química , Bovinos , Corantes Fluorescentes/química , Corantes Fluorescentes/síntese química , Substâncias Luminescentes/química , Substâncias Luminescentes/síntese química , Animais
8.
Talanta ; 274: 126000, 2024 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-38608630

RESUMO

Luminescent ß-diketonate-europium(III) complexes have been found a wide range of applications in time-gated luminescence (TGL) bioassays, but their poor water solubility is a main problem that limits their effective uses. In this work we propose a simple and general strategy to enhance the water solubility of luminescent ß-diketonate-europium(III) complexes that permits facile synthesis and purification. By introducing the fluorinated carboxylic acid group into the structures of ß-diketone ligands, two highly water-soluble and luminescent Eu3+ complexes, PBBHD-Eu3+ and CPBBHD-Eu3+, were designed and synthesized. An excellent solubility exceeding 20 mg/mL for PBBHD-Eu3+ was found in a pure aqueous buffer, while it also displayed strong and long-lived luminescence (quantum yield φ = 26%, lifetime τ = 0.49 ms). After the carboxyl groups of PBBHD-Eu3+ were activated, the PBBHD-Eu3+-labeled streptavidin-bovine serum albumin (SA-BSA) conjugate was prepared, and successfully used for the immunoassay of human α-fetoprotein (AFP) and the imaging of an environmental pathogen Giardia lamblia under TGL mode, which demonstrated the practicability of PBBHD-Eu3+ for highly sensitive TGL bioassays. The carboxyl groups of PBBHD can also be easily derivatized with other reactive chemical groups, which enables PBBHD-Eu3+ to meet diverse requirements of biolabeling technique, to provide new opportunities for developing functional europium(III) complex biolabels serving for TGL bioassays.


Assuntos
Európio , Solubilidade , Água , Európio/química , Água/química , Humanos , Medições Luminescentes/métodos , Soroalbumina Bovina/química , Complexos de Coordenação/química , Complexos de Coordenação/síntese química , Giardia lamblia/efeitos dos fármacos , Luminescência , Animais , Bioensaio/métodos , Substâncias Luminescentes/química , Substâncias Luminescentes/síntese química , Estreptavidina/química , Fatores de Tempo , Bovinos , Cetoácidos/química
9.
Anal Chem ; 96(18): 6978-6985, 2024 May 07.
Artigo em Inglês | MEDLINE | ID: mdl-38652863

RESUMO

Drug-induced liver injury (DILI) is a common liver disease with a high rate of morbidity, and its pathogenesis is closely associated with the overproduction of highly reactive hypochlorite (ClO-) in the liver. However, bioluminescence imaging of endogenous hypochlorite in nontransgenic natural mice remains challenging. Herein, to address this issue, we report a strategy for imaging ClO- in living cells and DILI mice by harnessing a bioluminescent probe formylhydrazine luciferin (ClO-Luc) combined with firefly luciferase (fLuc) mRNA-loaded lipid nanoparticles (LNPs). LNPs could efficiently deliver fLuc mRNA into living cells and in vivo, expressing abundant luciferase in the cytoplasm in situ. In the presence of ClO-, probe ClO-Luc locked by formylhydrazine could release cage-free d-luciferin through oxidation and follow-up hydrolysis reactions, further allowing for bioluminescence imaging. Moreover, based on the luciferase-luciferin system, it was able to sensitively and selectively detect ClO- in vitro with a limit of detection of 0.59 µM and successfully monitor the endogenous hypochlorite generation in the DILI mouse model for the first time. We postulate that this work provides a new method to elucidate the roles of ClO- in related diseases via bioluminescence imaging.


Assuntos
Doença Hepática Induzida por Substâncias e Drogas , Ácido Hipocloroso , Lipossomos , Luciferases de Vaga-Lume , Medições Luminescentes , Nanopartículas , RNA Mensageiro , Animais , Ácido Hipocloroso/metabolismo , Camundongos , Nanopartículas/química , Luciferases de Vaga-Lume/genética , Luciferases de Vaga-Lume/metabolismo , Doença Hepática Induzida por Substâncias e Drogas/metabolismo , Doença Hepática Induzida por Substâncias e Drogas/diagnóstico por imagem , RNA Mensageiro/metabolismo , RNA Mensageiro/genética , Substâncias Luminescentes/química , Humanos , Lipídeos/química , Imagem Óptica
10.
Angew Chem Int Ed Engl ; 63(21): e202319780, 2024 May 21.
Artigo em Inglês | MEDLINE | ID: mdl-38523406

RESUMO

Tumor-associated macrophages (TAMs) play a role in both pro- and anti-tumor functions; and the targeted polarization from M2 to M1 TAMs has become an effective therapy option. Although detection of M1 TAMs is imperative to assess cancer immunotherapeutic efficacy, existing optical probes suffer from shallow tissue penetration depth and poor specificity toward M1 TAMs. Herein, we report a tandem-locked NIR chemiluminescent (CL) probe for specific detection of M1 TAMs. Through a combined molecular engineering approach via both atomic alternation and introduction of electron-withdrawing groups, near-infrared (NIR) chemiluminophores are screened out to possess record-long emission (over 800 nm), record-high CL quantum yield (2.7 % einstein/mol), and prolonged half-life (7.7 h). Based on an ideal chemiluminophore, the tandem-locked probe (DPDGN) is developed to only activate CL signal in the presence of both tumour (γ-glutamyl transpeptidase) and M1 macrophage biomarkers (nitric oxide). Such a tandem-lock design ensures its high specificity towards M1 macrophages in the tumor microenvironment over those in normal tissues or peripheral blood. Thus, DPDGN permits noninvasive imaging and tracking of M1 TAM in the tumor of living mice during R837 treatment, showing a good correlation with ex vivo methods. This study not only reports a new molecular approach towards highly efficient chemiluminophores but also reveals the first tandem-locked CL probes for enhanced imaging specificity.


Assuntos
Macrófagos Associados a Tumor , Animais , Camundongos , Imagem Óptica , Humanos , Substâncias Luminescentes/química , Medições Luminescentes
11.
Chembiochem ; 25(9): e202400094, 2024 May 02.
Artigo em Inglês | MEDLINE | ID: mdl-38488304

RESUMO

Phosphorescent iridium(III) complexes are widely recognized for their unique properties in the excited triplet state, making them crucial for various applications including biological sensing and imaging. Most of these complexes display single phosphorescence emission from the lowest-lying triplet state after undergoing highly efficient intersystem crossing (ISC) and ultrafast internal conversion (IC) processes. However, in cases where these excited-state processes are restricted, the less common phenomenon of dual emission has been observed. This dual emission phenomenon presents an opportunity for developing biological probes and imaging agents with multiple emission bands of different wavelengths. Compared to intensity-based biosensing, where the existence and concentration of an analyte are indicated by the brightness of the probe, the emission profile response involves modifications in emission color. This enables quantification by utilizing the intensity ratio of different wavelengths, which is self-calibrating and unaffected by the probe concentration and excitation laser power. Moreover, dual-emissive probes have the potential to demonstrate distinct responses to multiple analytes at separate wavelengths, providing orthogonal detection capabilities. In this concept, we focus on iridium(III) complexes displaying fluorescence-phosphorescence or phosphorescence-phosphorescence dual emission, along with their applications as biological probes for sensing and imaging.


Assuntos
Complexos de Coordenação , Irídio , Irídio/química , Complexos de Coordenação/química , Complexos de Coordenação/síntese química , Humanos , Técnicas Biossensoriais/métodos , Imagem Óptica , Substâncias Luminescentes/química , Substâncias Luminescentes/síntese química , Animais , Medições Luminescentes , Corantes Fluorescentes/química , Corantes Fluorescentes/síntese química
12.
Luminescence ; 39(1): e4591, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-37675627

RESUMO

Cerium has been widely used as a dopant in luminescent materials due to its unique electronic configurations. It is generally anticipated that the luminescence properties of rare-earth-doped materials are closely related to the local environment of activators, especially for Ce3+ . In addition, it is convenient to modulate its emission wavelength by adjusting the composition and structure. In this study, we systematically analyzed the microstructure of the Ce-doped CaYAlO4 system at atomic resolution. The quantitive results indicated that the structure distortion greatly influenced the valence state of the Ce dopant, which is critical to its luminescence efficiency. In addition, valence variations also exist from surface to inner structure due to the big distortion area around the surface. Our results unravel the interplay of local structure and valence transitions in Ce-doped aluminate phosphors, which has the potential to be applied in other luminescent materials.


Assuntos
Cério , Substâncias Luminescentes , Metais Terras Raras , Luminescência , Substâncias Luminescentes/química , Metais Terras Raras/química , Cério/química
13.
Luminescence ; 39(1): e4555, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-37461122

RESUMO

A green phosphor Sr2 ZnGe2 O7 :Mn2+ with a melilite structure was prepared using a high-temperature solid-state reaction. When the 535 nm emission was monitored, the excitation spectrum of the Sr2 ZnGe2 O7 :Mn2+ was found to contain two excitation bands in the ultraviolet (UV) region. When excited by UV light, the sample shows bright green emission at 535 nm, which corresponds to the distinctive transition of Mn2+ (4 T1 →6 A1 ). Moreover, the quantum efficiency of Sr2 ZnGe2 O7 :Mn2+ could reach 67.6%. Finally, a high-performance white-light-emitting diode (WLED) with a low correlated colour temperature of 4632 K and a high colour rendering index (CRI) of 92.3 were packaged by coating commercial blue and red phosphors with an optimized Sr2 ZnGe2 O7 :Mn2+ sample on a 310 nm UV chip. This indicated that Sr2 ZnGe2 O7 :Mn2+ has the potential application as a green component in the WLED lighting field.


Assuntos
Substâncias Luminescentes , Substâncias Luminescentes/química , Luz Verde , Luminescência , Raios Ultravioleta
14.
Luminescence ; 39(1): e4612, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-37927204

RESUMO

Red and green rare-earth ion (RE3+ ) (RE = Eu, Tb):MgLa2 V2 O9 micro-powder phosphors were produced utilizing a standard solid-state chemical process. The X-ray diffraction examination performed on the phosphors showed that they were crystalline and had a monoclinic structure. The particles grouped together, as shown in the scanning electron microscopy (SEM) images. Powder phosphors were examined using a variety of spectroscopic techniques, including photoluminescence (PL), Fourier-transform infrared, and energy dispersive X-ray spectroscopy. Brilliant red emission at 615 nm (5 D0  â†’ 7 F2 ) having an excitation wavelength (λexci ) of 396 nm (7 F0  â†’ 5 L6 ) and green emission at 545 nm (5 D4  â†’ 7 F5 ) having an λexci  = 316 nm (5 D4  â†’ 7 F2 ) have both been seen in the emission spectra of Tb3+ :MgLa2 V2 O9 nano-phosphors. The emission mechanism that is raised in Eu3+ :MgLa2 V2 O9 and Tb3+ :MgLa2 V2 O9 powder phosphors has been explained in an energy level diagram.


Assuntos
Substâncias Luminescentes , Metais Terras Raras , Substâncias Luminescentes/química , Pós , Metais Terras Raras/química , Microscopia Eletrônica de Varredura , Espectrometria por Raios X
15.
Chem Commun (Camb) ; 59(68): 10188-10204, 2023 Aug 22.
Artigo em Inglês | MEDLINE | ID: mdl-37551645

RESUMO

In the last few years, tin(IV) complexes have emerged as very attractive candidates in the field of molecular imaging due to their unique photophysical properties. Despite the few reviews published to date covering the chemistry of organotin and tin complexes and their cytotoxic potential, there are no reviews devoted to their live cell imaging properties. Therefore, this feature article summarizes the discussion of the fundamental photophysical properties of fluorescent tin metal complexes focusing on their recent advances in "biomedical molecular imaging". A debate on the design of tin complexes as cellular imaging agents relating to their chemical, electronic and photophysical properties is enclosed. This paper also discusses the imaging applications of tin complexes in cells, tissues, and organisms via confocal and multiphoton imaging for sensing mechanisms in cellular media, bioimaging, and therapeutic labeling. In addition, it explores and explains the current challenges and prospects associated with these tin complexes as emerging luminescent cellular agents for potential clinical use.


Assuntos
Complexos de Coordenação , Substâncias Luminescentes , Compostos Orgânicos de Estanho , Estanho , Complexos de Coordenação/toxicidade , Complexos de Coordenação/química , Substâncias Luminescentes/química , Compostos Orgânicos de Estanho/farmacologia , Compostos Orgânicos de Estanho/química , Corantes , Imagem Molecular
16.
Luminescence ; 38(10): 1814-1824, 2023 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-37522552

RESUMO

The CaAlBO4 :RE (RE = Dy3+ , Eu3+ , Sm3+ ) phosphor were prepared via combustion synthesis and studied by X-ray diffraction (XRD), Fourier-transform infrared (FTIR) analysis, scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), photoluminescence (PL) spectra and CIE coordinates. The phase formation of the obtained phosphor was analyzed by XRD and the result was confirmed by standard PDF Card No. 1539083. XRD data successfully indicated pure phase of CaAlBO4 phosphor. The crystal structure of CaAlBO4 phosphor is orthorhombic with space group Ccc2 (37). The SEM image of CaAlBO4 phosphor reveals an agglomerated morphology and non-uniform particle size. The EDS image provides evidence of the elements present and the chemical makeup of the materials. Under the 350 nm excitation, the emission spectrum of Dy3+ activated CaAlBO4 phosphor consists of two main groups of characteristic peaks located at 484 and 577 nm which are ascribed to 4 F9/2 → 6 H15/2 and 4 F9/2 → 6 H13/2 transition of Dy3+ respectively. The PL emission spectra of CaAlBO4 :Eu3+ phosphor shows characteristics bands observed around 591 and 613 nm, which corresponds to 5 D0 → 7 F1 and 5 D0 → 7 F2 transition of Eu3+ respectively, upon 395 nm excitation wavelength. The emission spectra of Sm3+ activated CaAlBO4 phosphor shows three characteristic bands observed at 565, 601 and 648 nm which emits yellow, orange and red color. The prominent emission peak at the wavelength 601 nm, which is attributed to 4 G5/2 → 6 H7/2 transition, displays an orange emission. The CIE color coordinates of CaAlBO4 :RE (RE = Dy3+ , Eu3+ , Sm3+ ) phosphor are calculated to be (0.631, 0.368), (0.674, 0.325) and (0.073, 0.185). As per the obtained results, CaAlBO4 :RE (RE = Dy3+ , Eu3+ , Sm3+ ) phosphor may be applicable in eco-friendly lightning technology.


Assuntos
Európio , Substâncias Luminescentes , Európio/química , Substâncias Luminescentes/química , Disprósio/química , Microscopia Eletrônica de Varredura , Difração de Raios X , Luminescência
17.
Luminescence ; 38(9): 1607-1617, 2023 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-37350180

RESUMO

A dysprosium (Dy3+ )-activated potassium calcium silicate (K4 CaSi3 O9 ) phosphor was prepared using a solid-state synthesis route. The phosphor had a cubic structure with the space group Pa 3 ¯ as confirmed using X-ray diffraction (XRD) measurements. Details of surface morphology and elemental composition of the as-synthesized undoped KCS phosphor was obtained using scanning electron microscopy (SEM) and energy-dispersive X-ray (EDX) spectroscopy. The chemical structure as well as the vibrational modes present in the as-prepared KCS phosphor was analyzed using Fourier transform infrared (FT-IR) spectroscopy. Diffuse reflectance spectra (DRS) were used to determine the optical bandgap of the phosphors and were found to be in the optical range 3.52-3.71 eV. Photoluminescence (PL) spectra showed intense yellow emission corresponding to the 4 F9/2 →6 H13/2 transition under 350 nm excitation. Commission International de l'Eclairage colour chromaticity coordinates were evaluated using the PL spectral data lie within the white region. Dexter theory and the Inokuti-Hirayama (I-H) model were applied to study the nature of the energy transfer mechanism in the as-prepared phosphors. The relatively high activation energy of the phosphors was evaluated using temperature-dependent PL (TDPL) data and confirmed the high thermal stability of the titled phosphor. The abovementioned results indicated that the as-prepared KCS:Dy3+ phosphor was a promising candidate for n-UV-based white light-emitting diodes.


Assuntos
Luminescência , Substâncias Luminescentes , Substâncias Luminescentes/química , Espectroscopia de Infravermelho com Transformada de Fourier , Compostos de Cálcio
18.
Luminescence ; 38(4): 462-468, 2023 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-36828789

RESUMO

In this study, SrGe4 O9 :Mn4+ red phosphors for plant illumination were prepared using a high-temperature solid-phase method. The samples were characterized and analyzed by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), fluorescence spectroscopy, and other techniques. The phase structure, apparent morphology, and luminescence properties of the SrGe4 O9 :Mn4+ red phosphors were investigated. The results indicated that the dopant Mn4+ was incorporated into the matrix structure by substituting some Ge4+ ions without any changes in the crystal structure of the SrGe4 O9 matrix. The samples comprised micron-scale particles and exhibited high purity and uniform distribution of elements. The SrGe4 O9 :Mn4+ phosphors exhibited relatively strong red light emission at 660 nm under the excitation of a 430-nm blue light, and the luminescence intensity was the highest when the Mn4+ doping amount was 1%. Proper doping of Ti4+ or Sn4+ could effectively improve the luminescence intensity of the SrGe4 O9 :Mn4+ phosphors. The light-emitting diode (LED) device packaging showed that the SrGe4 O9 :Mn4+ red phosphors could be used for plant growth illumination.


Assuntos
Luminescência , Substâncias Luminescentes , Substâncias Luminescentes/química , Iluminação , Fósforo , Luz
19.
Molecules ; 28(1)2023 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-36615547

RESUMO

In this study, a new series of phosphors, Ca9−xZnxGd0.9(PO4)7:0.1Eu3+ (x = 0.00−1.00, step dx 0.05), was synthesized, consisting of centro- and non-centrosymmetric phases with ß-Ca3(PO4)2-type structure. Crystal structures with space groups R3c (0.00 ≤ x < 0.35) and R3¯c (x > 0.8) were determined using X-ray powder diffraction and the method of optical second harmonic generation. In the region 0.35 ≤ x ≤ 0.75, phases R3c and R3¯c were present simultaneously. Refinement of the Ca8ZnGd(PO4)7 crystal structure with the Rietveld method showed that 71% of Gd3+ ions are in M3 sites and 29% are in M1 sites. A luminescent spectroscopy study of Ca9−xZnxGd0.9(PO4)7:0.1Eu3+ indicated the energy transfer from the crystalline host to the Gd3+ and Eu3+ luminescent centers. The maximum Eu3+ luminescence intensity corresponds to the composition with x = 1.


Assuntos
Substâncias Luminescentes , Substâncias Luminescentes/química , Európio/química , Luminescência , Íons , Zinco
20.
Luminescence ; 38(2): 176-187, 2023 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-36610019

RESUMO

A luminescent double perovskite phosphor Sr2 YNbO6 doped with Eu3+ crystallized to the monoclinic phase and was synthesized successfully via a conventional high-temperature combustion method. The formation of the crystal structure, phase purity, and surface morphology were studied using X-ray diffraction patterns and scanning electron microscopy. The characteristic vibrations between the atoms of the functional groups present in phosphor were studied using Fourier transform infrared spectra analysis. The luminescence properties of the prepared phosphors were investigated in terms of photoluminescence (PL) and thermoluminescence (TL). PL excitation spectra exhibited charge transfer bands and the characteristic 4f6 transitions of Eu3+ . A prominent PL emission was obtained for the phosphor doped with 4 mol% Eu3+ under the 396 nm excitation wavelength. PL emission quenching was observed for the higher doping concentrations due to a multipole-multipole interaction. A highly intense PL emission arose due to the hypersensitive 5 D0 -7 F2 electric dipole transition of Eu3+ that dominated the emission spectra. The thermal stability of the phosphor was examined through temperature-dependent PL. The TL properties of the Sr2 YNbO6 double perovskites irradiated with a 90 Sr beta source at different doses were measured. The double perovskite phosphors under study showed a linear dose-response with increasing beta dose, ranging from 1 Gy to 10 Gy. Trapping parameters of the TL glow curves were determined using Chen's peak shape method and computerized glow curve deconvolution (CGCD). CGCD fitting of the TL glow curves revealed that it was consisted of three major peaks and followed second-order kinetics. The estimated activation energies were determined using different methods and were comparable and significant.


Assuntos
Európio , Substâncias Luminescentes , Európio/química , Substâncias Luminescentes/química , Compostos de Cálcio , Óxidos , Difração de Raios X , Luminescência
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