Characteristic Emission Of Sm3 Research Articles

Self-Trapped Excitons Mediated Energy Transfer to Sm3+ in Cs2AgIn(1–x)SmxCl6:Bi Double Perovskite Nanocrystals

Lanthanide ions (Ln3+) are well-known dopants for controlling the optoelectronic properties of double perovskites (DPs). However, the excitation energy of Ln3+-doped Cs2AgInCl6 being too high (∼250–290 nm) limits its direct excitation by commercial UV light-emitting diodes (≥365 nm). To overcome this challenge, we employed Bi3+ as a sensitizer to induce the emission of Sm3+ at much lower excitation energy in Sm3+–Bi3+ codoped Cs2AgInCl6 DP nanocrystals (NCs). Spectral analysis shows that a trace amount of Bi3+ (∼1%) doping provides dual emission of self-trapped excitons (STEs) and characteristic emissions of Sm3+ assigned to 4G5/2 to 6HJ (J = 5/2, 7/2, 9/2, and 11/2) transitions with 368 nm excitation energy. Transient absorption spectroscopic results revealed the existence of nonradiative energy transfer from STE states. Subsequently, we propose a mechanism to explain the formation of energy-transfer channels from STEs to excited states of Sm3+. Our study demonstrates that Bi3+ can efficiently sensitize Sm3+ to modify the optical properties of lead-free DP NCs to expand their luminescence application.

Photoluminescence, photocatalytic and electrochemical performance of La10Si6O27:Sm3+ nanophosphor: It's applications in display, photocatalytic and electrochemical sensor

The current research work presents the preparation of Samarium (1–9 mol%) doped Lanthanum Silicate (La10Si6O27:Sm3+) nanophosphors (LNPs) by means of solution combustion synthesis utilizing Oxalidihydrazide as a fuel. The prepared LNPs were described by Powder X-ray Diffraction (PXRD) studies, Transmission Electron Microscopy (TEM), Diffuse reflectance spectroscopy (DRS), Cyclic Voltammetry (CV), Electrochemical impedance spectroscopy (EIS) and Photoluminescence (PL) studies. The normal crystallite size of oxyapatite hexagonal phase LNPs were in the range of 10–20 nm as determined by Scherrer's technique and the equivalent was confirmed by TEM. Band gap energy was found in the range of 4.8–5.1 eV utilizing DRS. PL investigations of the LNPs show all the characteristic emissions of Sm3+ cations related to transitions 4G5/2→6Hj/2 (j = 5,7,9,11) and optimal emission intensity was observed for 3 mol% addition of Sm3+ ions with orange red emission as depicted in the CIE. CV and EIS results uncover the great electrochemical properties of LNPs, which detect effectively Paracetamol and Sildenafil (Penegra) utilizing modified carbon paste electrodes. Results show that the blended LNPs can be a potential candidate for displays, catalytic and electrochemical sensor applications.

Luminescent and thermal properties of novel orange\u2013red emitting MgNb2O6:Sm3+ phosphors for displays, photo catalytic and sensor applications

Novel Sm3+ doped columbite-type orthorhombic structured MgNb2O6 (MNO) orange-red emitting phosphors were prepared by solution combustion method using ODH as a fuel. The powder phase purity, particle morphology, size, elemental composition, luminescence properties, photocatalytic behaviors and electrochemical studies of prepared samples were studied in detail. Photoluminescence emission spectra of MNO:Sm3+ nanophosphors show all the characteristic emissions of Sm3+ cations corresponds to the transitions 4G5/2 → 6Hj/2(j=5,7,9,11) when excited at 463 nm energy. Among these the strongest emission peak was at 608 nm which corresponds to 4G5/2 → 6H7/2 transition of Sm3+ cations in the host lattice. The luminescence quenching was confirmed by the dipole–dipole interaction among Sm3+ ions. As a result of J-O analysis the branching ratio (~ 58% > 50%) show that the phosphor was highly suitable for color display devices. Photocatalytic activity of MNO:Sm3+ (5 mol%) under UV light shows 99% degradation of AR-88 dye. Electrochemical Impedance Spectroscopy (EIS) confirms the reversibility of the redox reaction, which helps in sensing the presence of paracetamol and alcohol. Thus, MNO:Sm3+ phosphors have great potential applications in display, catalytic, photonic, chemical and thermal sensor applications.

Core-Shell Structured Layered Lanthanide-Organic Complexes with Stilbazolium-type Dye Encapsulation for Multifunctional Performances.

Host-guest encapsulation of functional organic dye into a porous metal-organic framework can give rise to the development of new functional materials. In this work, by intercalating the stilbazolium-type dye (DEAST)I (4'-diethylamino-N-methyl stilbazolium) into four lanthanide layered metal-organic complexes (Ln-LMOCs), i. e. {[Ln(BTB)(H2 O)2 ]⋅3(DMF)⋅2(H2 O)}n (Ln=La (1), Nd (2), Sm (3), Er (4)), four responsive (DEAST)I@Ln-LMOC composites have been prepared, serving as multifunctional performance platform. The core-shell structures of (DEAST)I@Ln-LMOC composites have been fully characterized by IR, UV/Vis, PXRD, SEM, TEM, TGA and ESR. Significantly, after intercalation of dyes, the (DEAST)I@Ln-LMOC composites exhibit enhanced luminescent sensing properties in detecting Fe3+ with much higher water stabilities. The luminescent sensing behavior stems from the fluorescence resonance energy transfer (FRET) from the π-electron-rich BTB ligands to the Fe3+ , and their higher water stabilities are induced by electrostatic interactions and lower porosity. Specially, the characteristic emissions of Sm3+ will not be affected after the encapsulation guest dyes, which provide a theoretical guide for the modulation of luminescence devices. Finally, better ion conductivities and diminished photocurrents can be achieved after the embedding of the functional organic dye. In all, the formation of (DEAST)I@Ln-LMOC composites with core-shell structures can be utilized as a multifunctional platform with good stability.

Ba2ZnWO6:Sm3+ as promising orange-red emitting phosphors: Photoluminescence properties and energy transfer process

Novel orange-red emitting phosphors, Ba2Zn1-xWO6:xSm3+ (x = 0.03, 0.04, 0.05, 0.06 and 0.07) (BZW:Sm3+), were prepared using a high-temperature solid-state reaction method. Their crystal structure and photoluminescence properties were characterized and the mechanism of energy transfers between Ba2ZnWO6 and Sm3+ elucidated in detail. It was found that the phosphors had a cubic structure with space group Fm3¯m. They can be excited by near-ultraviolet light, and the characteristic emissions of Sm3+ ions are observed at 564 nm, 598 nm and 645 nm, corresponding to 4G5/2 → 6H5/2, 4G5/2 → 6H7/2 and 4G5/2 → 6H9/2 transitions, respectively. The 4G5/2 → 6H9/2 transitions shows the greatest intensity, which indicates that Sm3+ ions occupy the noncentrosymmetric sites. The optimal doping concentration of Sm3+ ions in Ba2ZnWO6 is about 5 mol% and the phenomenon of concentration quenching occurs when the content of Sm3+ ions exceeds 5 mol%. All results show that the Ba2ZnWO6:Sm3+ phosphor holds great promise for use in high-quality white light-emitting diodes.

Photoluminescence, cathodoluminescence and thermal stability of Sm3+ -activated Sr3 La(VO4 )3 red-emitting phosphors.

A series of Sm3+ -activated Sr3 La(VO4 )3 phosphors were synthesized by a facile sol-gel method. X-ray diffraction patterns and photoluminescence (PL)/cathodoluminescence (CL) spectra as well as PL decay curves were employed to characterize the obtained samples. Upon 402 nm light excitation, the characteristic emissions of Sm3+ ions corresponding to 4 G5/2 →6 HJ transitions were observed in all the as-prepared products. The PL emission intensity was increased with increase in Sm3+ ion concentration, while concentration quenching occurred when the doping concentration was over 4 mol%. The non-radiative energy transfer mechanism for concentration quenching of Sm3+ ions was dominated by dipole-dipole interaction and the critical distance was around 21.59 Å. Furthermore, temperature-dependent PL emission spectra revealed that the obtained phosphors possessed good thermal stability with an activation energy of 0.19 eV. In addition, the CL spectra of the samples were almost the same as the PL spectra, and the CL emission intensity showed a tendency to increase with increase in accelerating voltage and filament current. These results suggest that the Sm3+ -activated Sr3 La(VO4 )3 phosphors with good color coordinates, high color purity and superior thermal stability may be a potential candidate for applications in white light-emitting diodes and field-emission displays as red-emitting phosphors.

Synthesis and photoluminescence properties of red, green and blue emitting LaYO3:M (M = Eu3+, Tb3+, Sm3+,Bi3+, Pb2+) phosphors

Red, green and blue light emitting Eu3+, Sm3+, Tb3+, Bi3+ and Pb2+ ions doped LaYO3 phosphors were synthesized by co-precipitation method and their photoluminescence (PL) properties were studied. The Eu3+-doped LaYO3 compound exhibited characteristic emissions of Eu3+. The intensity of PL emission peak found to be more at 614nm than 595nm. LaYO3:Sm3+ phosphor showed PL emission at 570nm, 608nm and 660nm which is characteristic emission of Sm3+. Tb3+ doped LaYO3 compound show intense emission at 545nm which again characteristic emission of Tb3+ in LaYO3 host. Eu3+, Tb3+ and Sm3+ doped LaYO3 phosphors displayed charge transfer band in UV region which is responsible for intense emission in red, orange and green region. Transition metal ions such as Pb2+ and Bi3+ doped LaYO3 phosphor exhibited PL emission in blue region. Prepared phosphors are useful to be used in display devices and related applications.

Crystal Growth and Photoluminescence Properties of Sm<SUP>3+</SUP> Doped CeO<SUB>2</SUB> Nanophosphors by Solvothermal Method

The phosphor of CeO2 activated with the trivalent rare-earth Sm3+ ions were synthesized by using a solvothermal method. The CeO2:Sm3+ powders were finally obtained through calcination process sintered in the air at 800-1200 degrees C. The synthesized phosphors were characterized systematically by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), photoluminescence (PL) and photoluminescence excitation spectra (PLE). The XRD and FE-SEM results reveal that the phosphor exhibit agglomerated spherical shape and with the increase of sintering temperature peaks become sharper and narrower and the crystal sizes also increase, respectively. The room temperature photoluminescence spectra of Sm3+ doped CeO2 powders were recorded on a PTI (Photon Technology International) flurimeter using a Xe-arc lamp with a power of 60 W. The emitted radiation was dominated by the orange light with the characteristic emission of Sm3+ from the transitions of 4G5/2 --> 6H5/2,7/2. The sharp emission properties show that the CeO2 has the potential to serve as a host material for rare-earth doped laser crystal and phosphor material.

Luminescence Properties of Electron Trapping Material CaB<sub>4</sub>O<sub>7</sub>:Sm<sup>3+</sup>

A novel electron trapping material of CaB4O7:Sm3+ was synthesized by high temperature solid-state reaction, and its characterization and luminescent properties were investigated at room temperature. The results indicate that ultraviolet light can be used as exciting source to store energy. After exposed under ultraviolet, the sample was stimulated by 980nm laser. As a result, an obvious luminescence at 556, 596 and 643 nm were detected. The photo-stimulated emission spectrum was three bands peaking at 562, 599 and 646 nm that are the characteristic emission of Sm3+ ions due to the f→f transitions 4G5/2→6HJ (J = 5/2, 7/2, 9/2), respectively. The TL glow curve contains two overlapping glow peaks at around 541 and 598 K.was synthesized by high temperature solid-state reaction, and its characterization and luminescent properties were investigated at room temperature. The results indicate that ultraviolet light can be used as exciting source to store energy. After exposed under ultraviolet, the sample was stimulated by 980nm laser. As a result, an obvious luminescence at 556, 596 and 643 nm were detected. The photo-stimulated emission spectrum was three bands peaking at 562, 599 and 646 nm that are the characteristic emission of Sm3+ ions due to the f→f transitions 4G5/2→6HJ (J = 5/2, 7/2, 9/2), respectively. The TL glow curve contains two overlapping glow peaks at around 541 and 598 K.

Fluorescence enhancement in Sm3+/TiO2 nanocrystallites doped PVP matrix

The hybrid matrix containing TiO2 nanocrystals and Sm3+ ions prepared by the non hydrolytic sol–gel method, displays the characteristic emission of Sm3+ ions at the excitation energy corresponding to the energy gap of the TiO2 nanocrystals. On the other hand, emission of Sm3+ was too weak to be observed for the sample containing Sm3+ ions alone. The structural and optical analyses of the samples were carried out using X-ray diffraction technique, transmission electron microscopy, Raman spectroscopy and emission spectroscopy. The TEM image of the sample shows that the TiO2 nanocrystals are well dispersed in the PVP matrix and the XRD confirms the anatase phase of the TiO2 nanocrystals. The enhancement of the Sm3+ emission is attributed to the energy transfer from the TiO2 nanocrystals to Sm3+ ions.

PREPARATION AND FLUORESCENCE PROPERTIES OF SAMARIUM COMPLEXES CONTAINING POLYARYLETHERKETONES BEARING PENDANT CARBOXYL GROUPS

The carboxyl-containing polyaryletherketones (PEK-1,PEK-2 and PEK-3) with excellent thermal properties and good film-formations prepared in our group were used as macromolecular ligands. Using 1,10-phenanthroline (Phen) as co-ligand and samarium ( Sm3 + ) as the central ion,a series of novel samarium coordination polymers (PEK-Sm3 + -Phen) were prepared. The FTIR and UV-Vis absorption spectra suggested that both the oxygen atoms of carboxyl groups of PEK and the nitrogen atoms of Phen were coordinated with Sm3 + ions. The XRD curves indicated Sm3 + ions could distribute homogeneously within the polymer matrix due to the formation of coordination bonds between Sm3 + and the carboxyl groups of PEK. The fluorescence spectra showed that all the coordination polymers obtained could exhibit the intense characteristic emission of Sm3 + ions under UV excitation. Moreover,their emission intensities were much higher than that of the corresponding small molecular complex ( Sm3 + -Phen) due to the introduction of PEK with the rigid polymer chain,which could result in the stable coordination structure and the low coordination symmetry around Sm3 + ion in the PEK-Sm3 + -Phen system. In addition,among the three coordination polymers obtained,PEK-1-Sm3 + -Phen showed the highest fluorescence intensity. The emission intensity of PEK-1-Sm3 + -Phen could reach a maximum value at the Sm3 + content of 15. 73 wt%.