Investigation on the co‐luminescence effect of europium (III)–lanthanum(III)–dopamine–sodium dodecylbenzene sulfonate system and its application

A novel luminescence, enhancement phenomenon in the europium(III)–dopamine–sodium dodecylbenzene sulfonate system was observed when lanthanum(III) was added. Based on this, a sensitive co‐luminescence method was established for the determination of dopamine. The luminescence signal for the europium (III)–lanthanum(III)–dopamine–sodium dodecylbenzene sulfonate system was monitored at λ_ex = 300 nm, λ_em =618 nm and pH 8.3. Under optimized conditions, the enhanced luminescence signal responded linearly to the concentration of dopamine in the range 1.0 × 10^–10–5.0 × 10^–7 mol/L with a correlation coefficient of 0.9993 (n = 11). The detection limit (3σ) was 2.7 × 10^–11 mol/L and the relative standard deviation for 11 parallel measurements of 3.0 × 10^–8 mol/L dopamine was 1.9%. The presented method was successfully applied for the estimation of dopamine in samples of pharmaceutical preparations, human serum and urine. The possible luminescence enhancement mechanism of the system is discussed briefly. Copyright © 2013 John Wiley & Sons, Ltd.     

Luminescent complexes of terbium ion for molecular recognition of ibuprofen

The complexation behavior and luminescent properties of terbium (Tb³⁺) complexes containing bi‐dental ligands were studied: nitrogen – 1,10‐phenanthroline, and oxygen – trifluoroacetylacetone as well as acetylacetone ligands with ibuprofen (Ibu; a non‐steroidal anti‐inflammatory drug). Aqueous and aqueous alcohol microheterogeneous solutions were used as media. The effects of solubilization by various micellar solutions, pH and ligand type on luminescent properties of Tb³⁺ complexes were investigated. Sensitized luminescence of mixed ligand complex Tb(1,10‐phenanthroline)‐Ibu and dynamic quenching effect in complex Tb(trifluoroacetylacetone)₃‐Ibu allow Ibu determination with the limit of detection 5.3 × 10^–8 mol/L and 1.26 × 10^–6 mol/L, respectively. Copyright © 2013 John Wiley & Sons, Ltd.     

Sensitive determination of DNA based on the interaction between prulifloxacin–terbium(III) complex and DNA

A simple spectrofluorimetric method is described for the determination of DNA, based on its enhancement of the fluorescence intensity of prulifloxacin (PUFX)–Tb³⁺. The luminescence intensity of the PUFX–Tb³⁺ complex increased up to 10‐fold after adding DNA. The excitation and emission wavelengths were 345 and 545 nm, respectively. Under optimum conditions, variations in the fluorescence intensity showed a good linear relationship with the concentration of hsDNA in the range of 3.0 × 10^‐9 to 1.0 × 10^‐6 g/mL, with a correlation coefficient (R) of 0.997, and the detection limit was 2.1 × 10^‐9 g/mL. The method was successfully applied to the determination of DNA in synthetic samples, and recoveries were in the range 97.3–102.0%. The mechanism of fluorescence enhancement of the PUFX–Tb³⁺ complex by DNA is also discussed. The mechanism may involve formation of a ternary complex mainly by intercalation binding together with weak electrostatic interaction, which will increase the energy transition from ligand to Tb³⁺, increasing the rigidity of the complex, and decreasing the radiationless energy loss through O–H vibration of the H₂O molecule in the PUFX–Tb³⁺ compl+osed method is not only more robust and friendly to the environment, but also of relatively higher sensitivity. Copyright © 2013 John Wiley & Sons, Ltd.     

Intense visible multicolored luminescence from lanthanide ion‐pair codoped NaGdF4 nanocrystals

Lanthanide ion‐pair (Eu³⁺/Tb³⁺, Dy³⁺/Tb³⁺, Sm³⁺/Tb³⁺ and Eu³⁺/Dy³⁺) codoped NaGdF₄ nanocrystals using Ce³⁺ as the sensitizer were prepared via the polyol method. The nanocrystals with different codoped lanthanide ion‐pairs retain their individual optical properties and the combined spectra can be detected using single‐wavelength excitation at about 251 nm. The combined spectra intensity ratios can be adjusted through control of the doping ions molar ratios. Excited with a UV lamp at 254 nm, the as‐prepared nanocrystals in aqueous solution emit intense visible emissions of different colors. The nanocrystals were coated with SiO₂, to make them biocompatible. Copyright © 2009 John Wiley & Sons, Ltd.     

Water‐soluble polymeric chemosensor for selective detection of Hg2+ in aqueous solution using rhodamine‐based modified poly(acrylamide–acrylic acid)

We report the fabrication of a novel easily available turn‐on fluorescent water‐soluble polymeric chemosensor for Hg²⁺ ions that was simply prepared by micellar free radical polymerization of a water‐insoluble organic rhodamine‐based Hg²⁺‐recognizing monomer (GR6GH), with hydrophilic monomers acrylamide (AM) and acrylic acid (AA). The chemical structure of the polymeric sensor was characterized by FT‐IR and ¹H NMR spectroscopy. The apparent viscosity average molecular weight M_η of poly(acrylamide–acrylic acid) [poly(AM–NaAA)] and the water‐soluble polymeric chemosensor poly(AM–NaAA–GR6GH) were 1.76 × 10⁶ and 6.84 × 10⁴ g/mol, respectively. Because of its amphiphilic property, the water‐soluble polymeric chemosensor can be used as a chemosensor in aqueous media. Upon addition of Hg²⁺ ions to an aqueous solution of poly(AM–NaAA–GR6GH), fluorescence enhancements were observed instantly. Moreover, other metal ions did not induce obvious changes to the fluorescence spectra. This approach may provide an easily measurable and inherently sensitive method for Hg²⁺ ion detection in environmental and biological applications. Copyright © 2015 John Wiley & Sons, Ltd.     

Effect of sintering temperature on the luminescence properties of Ca0.8Ba0.2TiO3:Pr3+ red‐emitting phosphor

Nanoparticles with the nominal composition Ca_0.8Ba_0.2Ti0₃:Pr³⁺ were prepared using the sol–gel process. Barium nitrate, 4‐hydrated calcium nitrate and praseodymium oxide were used as raw materials. The structural evolution and decomposition processes of the precursors were investigated by powder X‐ray diffraction, differential thermal analysis and thermogravimetric analysis. Crystalline Ca_0.8Ba_0.2Ti0₃:Pr³⁺ could be obtained at 700°C. The photoluminescence properties of the samples were investigated using excitation and emission spectra. Ca_0.8Ba_0.2Ti0₃:Pr³⁺ nanoparticles showed strong red emission, which could be assigned to the typical ¹D₂→³H₄ transition of Pr³⁺. Furthermore, the study found that sintering temperature and the introduction of Ba²⁺ influence the decay time of persistent luminescence. Copyright © 2014 John Wiley & Sons, Ltd.     

The structure and luminescence properties of Mn2+/Eu2+/Er3+‐doped MgO‐Ga2O3‐SiO2 glasses and glass‐ceramics

The MgO–Ga₂O₃–SiO₂ glasses and glass‐ceramics samples doped with Eu²⁺/Mn²⁺/Er³⁺ and heated in reductive atmosphere were prepared by the sol–gel method. The structure, morphology and the luminescence properties were studied using X‐ray diffraction, high‐resolution transmission electron microscope, fluorescence spectra, and up‐conversion emission. The luminescence characteristics of doped ions could be influenced by temperature and matrix component. The characteristic emission of Mn²⁺, Eu²⁺ and Er³⁺ were seen and the energy transfer efficiency from Eu²⁺ to Mn²⁺ was enhanced as Mn²⁺ concentration was increased. In addition, the two‐photon process was determined for the Er³⁺‐doped samples.     

Energy transfer between Ce3+ → Gd3+ or Tb3+ in KNaSO4 microphosphor

KNaSO₄ microphosphor doped with Ce,Gd and Ce,Tb and prepared by a wet chemical method was studied using X‐ray diffraction (XRD), scanning electron microscopy (SEM) and photoluminescence (PL) characterization. KNaSO₄ has a 5‐µm particle size detected by SEM. KNaSO₄:Ce³⁺,Tb³⁺ showed blue and green emission (at 494 nm, 557 nm, 590 nm) of Tb³⁺ due to ⁵D₄ → ⁷F_J (J = 4, 5, 6) transitions. KNaSO₄:Ce³⁺,Gd³⁺ showed luminescence in the ultraviolet (UV) light region at 314 nm for an excitation at 271 nm wavelength. It was observed that efficient energy transfer took place from Ce³⁺ → Gd³⁺ and Ce³⁺ → Tb³⁺ sublattices indicating that Ce³⁺ could effectively sensitize Gd³⁺ or Tb³⁺ (green emission). Ce³⁺ emission weakened and Gd³⁺ or Tb³⁺ enhanced the emission significantly in KNaSO₄. This paper discusses the development and understanding of photoluminescence and the effect of Tb³⁺ and Gd³⁺ on KNaSO₄:Ce³⁺. Copyright © 2015 John Wiley & Sons, Ltd.     

Synthesis and luminescence properties of blue‐emitting phosphor Ca12Al14O32F2:Eu2+ for white light‐emitting diode

A blue‐emitting phosphor Ca₁₂Al₁₄O₃₂F₂:Eu²⁺ was synthesized using a high‐temperature solid‐state reaction under a reductive atmosphere. The X‐ray diffraction measurements indicate that a pure phase Ca₁₂Al₁₄O₃₂F₂:Eu²⁺ can be obtained for low doping concentration of Eu²⁺. The phosphor has a strong absorption in the range 270–420 nm with a maximum at ~340 nm and blue emission in the range 400–500 nm with chromatic coordination of (0.152, 0.045). The optimal doping concentration is ~0.24. In addition, the luminescence properties of the as‐synthesized phosphor were evaluated by comparison with those of Ca₁₂Al₁₄O₃₂Cl₂:Eu²⁺ and the commercially available phosphor BaMgAl₁₀O₁₇:Eu²⁺. The emission intensity of Ca₁₂Al₁₄O₃₂F₂:Eu²⁺ was ~72% that of BaMgAl₁₀O₁₇:Eu²⁺ under excitation at λ = 375 nm. The results indicate that Ca₁₂Al₁₄O₃₂F₂:Eu²⁺ has potential application as a near‐UV‐convertible blue phosphor for white light‐emitting diodes.     

Magnesium methoxide‐induced chemiluminescent decomposition of bicyclic dioxetanes bearing a 2′‐alkoxy‐2‐hydroxy‐1,1′‐binaphthyl‐7‐yl moiety

Bicyclic dioxetanes 2a–c bearing a 2′‐alkoxy‐2‐hydroxy‐1,1′‐binaphthyl‐7‐yl moiety were effectively synthesized and their base‐induced chemiluminescent decomposition was investigated by the use of alkaline metal (Na⁺ and K⁺) or Mg²⁺ alkoxide in MeOH. When 2a–c were treated with tetrabutylammonium fluoride (TBAF) in dimethyl sulfoxide (DMSO) as a reference system, they showed chemiluminescence as a flash of orange light (maximum wavelength λ_max^CL = 573–577 nm) with efficiency Φ^CL = 6–8 × 10^–2. On the other hand, for an alkaline metal (Na⁺ or K⁺) alkoxide/MeOH system, 2a–c decomposed slowly to emit a glow of chemiluminescence, the spectra of which were shifted slightly toward red from the TBAF/DMSO system, and Φ^CL (= 1.4–2.3 × 10^–3) was considerably decreased. In addition, Mg(OMe)₂ was found to play a characteristic role as a base for the chemiluminescent decomposition of 2a–c through coordination to the intermediary oxidoaryl‐substituted dioxetanes 13. Thus, Mg²⁺ increased Φ^CL to more than twice those with Na⁺ or K⁺, while it shifted λ_max^CL considerably toward blue (λ_max^CL = 550–566 nm). Copyright © 2012 John Wiley & Sons, Ltd.     

Thermoluminescence and photoluminescence studies on γ‐ray‐irradiated Ce3+,Tb3+‐doped potassium chloride single crystals

Single crystals of KCl doped with Ce³⁺,Tb³⁺ were grown using the Bridgeman–Stockbarger technique. Thermoluminescence (TL), optical absorption, photoluminescence (PL), photo‐stimulated luminescence (PSL), and thermal‐stimulated luminescence (TSL) properties were studied after γ‐ray irradiation at room temperature. The glow curve of the γ‐ray‐irradiated crystal exhibits three peaks at 420, 470 and 525 K. F‐Light bleaching (560 nm) leads to a drastic change in the TL glow curve. The optical absorption measurements indicate that F‐ and V‐centres are formed in the crystal during γ‐ray irradiation. It was attempted to incorporate a broad band of cerium activator into the narrow band of terbium in the KCl host without a reduction in the emission intensity. Cerium co‐doped KCl:Tb crystals showed broad band emission due to the d–f transition of cerium and a reduction in the intensity of the emission peak due to ⁵D₃–⁷F_j (j = 3, 4) transition of terbium, when excited at 330 nm. These results support that energy transfer occurs from cerium to terbium in the KCl host. Co‐doping Ce³⁺ ions greatly intensified the excitation peak at 339 nm for the emission at 400 nm of Tb³⁺. The emission due to Tb³⁺ ions was confirmed by PSL and TSL spectra. Copyright © 2015 John Wiley & Sons, Ltd.     

Sol‐gel synthesis and luminescent properties of red‐emitting Y(P,V)O4:Eu3+ phosphors

Eu³⁺‐activated Y(P,V)O₄ phosphors were prepared by the EDTA sol‐gel method, and the corresponding morphologies and luminescent properties were investigated. The sample particles were relatively spheroid with size of 2–3 µm and had a smooth surface. The excitation spectra for Y(P,V)O₄:Eu³⁺ consisted of three strong excitation bands in the 200–350 nm range, which were attributed to a Eu³⁺‐ O^2? charge‐transfer band and ¹A₁?¹ T₁/¹ T₂ transitions in VO₄^3?. The as‐synthesized phosphors exhibited a highly efficient red luminescence at 613 nm due to the Eu^{3+ 5}D₀?⁷ F₂ electric dipole transition. With the increase in the V⁵⁺/P⁵⁺ ratio, the luminescence intensity of the red phosphor under UV excitation was greatly improved due to enhanced VO₄^3? → Eu³⁺ energy transfer. Copyright © 2015 John Wiley & Sons, Ltd.     

Sol–gel preparation and luminescent properties of red‐emitting phosphor Sr‐Ba‐Mo‐W‐O‐(Eu3+,Sm3+)

Two series of red‐emitting phosphors Sr‐Ba‐Mo‐W‐O:Eu,Sm and Sr‐Ba‐Mo‐W‐O:Eu have been synthesized by a sol–gel method. The effects of the chemical composition, concentrations of Sm³⁺ and Eu³⁺, the Sr²⁺/Ba²⁺ ratio, and the W⁶⁺/Mo⁶⁺ ratio on the luminescent properties were investigated. The as‐prepared phosphors were characterized by X‐ray diffraction and Raman spectra. Results showed that single phases of the two series were prepared. The compositions of Sr_0.6Ba_0.13Mo_0.8 W_0.2O₄:Eu_0.10Sm_0.08 and Sr_0.75Ba_0.1Mo_0.8 W_0.2O₄:Eu_0.10 had the strongest luminescent intensity. The excitation spectra of Sm³⁺, Eu³⁺ co‐doped phosphors were broader and the strongest peak moved to 404 nm when compared with that of Eu³⁺ single‐doped phosphors. The luminescent intensity of the Sr_0.6Ba_0.13Mo_0.8 W_0.2O₄:Eu_0.10Sm_0.08 at 618 nm were 2.8 times greater than that of Sr_0.75Ba_0.1Mo_0.8 W_0.2O₄:Eu_0.10. The luminescent intensity of Sr_0.6Ba_0.13Mo_0.8 W_0.2O₄:Eu_0.10Sm_0.08 and Sr_0.75Ba_0.1Mo_0.8 W_0.2O₄:Eu_0.10 at 150 °C decreased to 56.8% and 50.3% of the initial value at room temperature, respectively. Copyright © 2015 John Wiley & Sons, Ltd.     

Luminescent properties of single‐phase Ba2‐x‐1.5y‐1.5zP2O7:xEu2+,yCe3+, zTb3+ phosphors for white light‐emitting diode

A series of Ba₂P₂O₇:xEu²⁺,yCe³⁺,zTb³⁺ phosphors was synthesized via a co‐precipitation method, then their crystal structure, quantum efficiency and luminescent properties were analyzed by XRD and FL, respectively. The results showed that these phosphors not only presented the excitation characteristics of Ba₂P₂O₇:xEu²⁺,zTb³⁺, but also exhibited that of the Ba₂P₂O₇:yCe³⁺,zTb³⁺ phosphor. Meanwhile, the tri‐doped phosphor showed a stronger absorption around 320 nm in contrast with the Eu²⁺/Ce³⁺:Tb³⁺ co‐doped phosphor. Not only can energy transfer from Ce³⁺→Eu²⁺ be observed; the energy transfer mechanism from Eu²⁺ to Tb³⁺ is discussed in the tri‐doped system. Ce³⁺ affects the luminescence properties of Ba₂P₂O₇:xEu²⁺,yCe³⁺,zTb³⁺ phosphors just as the sensitizer whereas Eu²⁺ is considered both as the sensitizer and the activator. The chromaticity coordinates of tri‐doped phosphors excited at 320 nm stayed steadily in the bluish‐white light region,and the emitted color and color temperature (CCT) of these phosphors could be tuned by adjusting the relative contents of Eu²⁺, Ce³⁺ and Tb³⁺. Hence, the single phase Ba₂P₂O₇:xEu²⁺,yCe³⁺,zTb³⁺ phosphors may be considered as potential candidates for white light‐emitting diodes.     

Probing the optical properties and luminescence mechanism of a UV‐emitting SrBPO5:Ce3+ phosphor

Ce‐doped (1 × 10^?5 to 3.0 mol%) SrBPO₅ phosphors were synthesized using a conventional solid‐state reaction route at 1273 K in an air atmosphere. Phase and morphology of the samples were studied from powder X‐ray diffraction (XRD) patterns and scanning electron microscope (SEM) micrographs, respectively. The band gap energies of the pure and Ce‐doped SrBPO₅ phosphors were calculated from the recorded diffuse reflectance spectra. Photoluminescence (PL) and Ce³⁺ lifetime were recorded at 300 and 77 K. Photoluminescence lifetime measurements revealed two‐lifetime values for Ce³⁺ at both 300 K (17 and 36 nsec) and 77 K (12 and 30 nsec), suggesting the presence of two different environments around Ce³⁺. Time‐resolved emission spectroscopy (TRES) studies confirmed the presence of Ce³⁺ in two different environments. In addition, SrBPO₅:Ce exhibited intense UV emission, signifying its possible use as an efficient sensitizer for solid‐state lighting applications. The effect of γ‐irradiation on PL was also determined. Thermally stimulated luminescence (TSL) glow curves of the γ‐irradiated phosphor, along with trap parameters, dose–response, and the possible TSL mechanism were also investigated. Positron annihilation lifetime spectroscopy was carried out to probe defects present in undoped and Ce‐doped SrBPO₅.     

Design,synthesis and luminescence properties of Ba2YB2O6Cl‐ and Ba2YB2O6F‐based phosphors

Using a high‐temperature solid‐state reaction, the chlorine in Ba₂YB₂O₆Cl is gradually replaced by F, and a new compound with the nominal chemical formula Ba₂YB₂O₆F and two phosphors doped with Ce³⁺ and Eu³⁺, respectively, are obtained. X‐Ray diffraction and photoluminescence spectroscopy are used to characterize the as‐synthesized samples. The as‐synthesized Ba₂YB₂O₆Cl exhibits bright blue emission in the spectral range ~ 330–410 nm with a maximum around 363 nm under X‐ray or UV excitation. Ba₂YB₂O₆F:0.01Ce³⁺ exhibits blue emission in the range ~ 340–570 nm with a maximum around 383 nm. Ba₂YB₂O₆F:0.01Eu³⁺ exhibits a predominantly ⁵D₀–⁷ F₂ emission (~610 nm) and the relative intensities of the ⁵D₀–⁷ F_0,1,2 emissions are tunable under different wavelength UV excitation. The luminescence behaviors of the two phosphors are explained simply in terms of the host composition and site occupancy probability of Ce³⁺ and Eu³⁺, respectively. The results indicate that these phosphors have potential application as a blue phosphor or as a red phosphor. Copyright © 2014 John Wiley & Sons, Ltd.     

Luminescence investigation of novel MgPbAl10O17:Tb3+ green‐emitting phosphor for solid‐state lighting

In this work, we studied the luminescence properties of Tb³⁺‐doped MgPbAl₁₀O₁₇ green phosphor. To understand the excitation mechanism and corresponding emission of the prepared phosphor, its structural, morphological and photoluminescence properties were investigated. In general, for green emission, Tb³ is used as an activator and the obtained excitation and emission spectra indicated that this phosphor can be effectively excited by a wavelength of 380 nm, and exhibits bright green emission centered at 545 nm corresponding to the f → f transition of trivalent terbium ions. The chromaticity coordinates were (C_x = 0.263, C_y = 0.723). The impact of Tb³⁺ concentration on the relative emission intensity was investigated, and the best doping concentration was found to be 2 mol%. This study suggests that Tb³⁺‐doped MgPbAl₁₀O₁₇ phosphor is a strong candidate for a green component in phosphor‐converted white light‐emitting diodes. Copyright © 2015 John Wiley & Sons, Ltd.     

Synthesis,crystal structure and fluorescence properties of terbium complexes with phenoxyacetic acid and 2,4,6‐tris‐(2‐pyridyl)‐s–triazine

Two complexes of Tb³⁺, Gd³⁺/Tb³⁺ and one heteronuclear crystal Gd³⁺/Tb³⁺ with phenoxyacetic acid (HPOA) and 2,4,6‐tris‐(2‐pyridyl)‐s–triazine (TPTZ) have been synthesized. Elemental analysis, rare earth coordination titration, inductively coupled plasma atomic emission spectrometry (ICP‐AES) and thermogravimetric analysis‐differential scanning calorimetry (TG‐DSC) analysis show that the two complexes are Tb₂(POA)₆(TPTZ)₂·6H₂O and TbGd(POA)₆(TPTZ)₂·6H₂O, respectively. The crystal structure of TbGd(POA)₆(TPTZ)₂·2CH₃OH was determined using single‐crystal X‐ray diffraction. The monocrystal belongs to the triclinic system with the P‐1 space group. In particular, each metal ion is coordinately bonded to three nitrogen atoms of one TPTZ and seven oxygen atoms of three phenoxyacetic ions. Furthermore, there exist two coordinate forms between C₆H₅OCH₂COO^– and the metal ions in the crystal. One is a chelating bidentate, the other is chelating and bridge coordinating. Fluorescence determination shows that the two complexes possess strong fluorescence emissions. Furthermore, the fluorescence intensity of the Gd³⁺/Tb³⁺ complex is much stronger than that of the undoped complex, which may result from a decrease in the concentration quench of Tb³⁺ ions, and intramolecular energy transfer from the ligands coordinated with Gd³⁺ ions to Tb³⁺ ions. Copyright © 2015 John Wiley & Sons, Ltd.     

A terbium‐sensitized spectrofluorimetric method for determination of catecholamines in a serum sample with micelle medium

A terbium‐sensitized spectrofluorimetric method has been developed for determination of catecholamines such as norepinephrine (NE), epinephrine (EP) and dopamine (DA), using sodium dodecyl benzene sulphonate (SDBS). Fluorescence sensitization of terbium ions (Tb³⁺) by complexation with catecholamines in the presence of SDBS was observed. The fluorescence intensities of the Tb³⁺–catecholamine complexes were highly enhanced by introducing SDBS with an emission maximum at 545 nm after excitation at 290 nm. The conditions for the complex formation of Tb³⁺–catecholamine were investigated systematically and optimized to determine catecholamines in a serum sample. Under the optimum conditions, the fluorescence intensities of the Tb³⁺–catecholamine complexes were increased linearly with the concentration of NE, EP and DA over the ranges 2.5 × 10^–10–1.0 × 10^–8, 2.5 × 10^–10–1.0 × 10^–8 and 2.5 × 10^–9–1.0 × 10^–7 g/mL with correlation coefficients of 0.999, 0.999 and 0.9996, respectively. The limits of detection (3δ) of NE, EP and DA were found to be 4.6 × 10^–11, 7.8 × 10^–11 and 8.38 × 10^–10 g/mL, respectively. Precision of the method was tested at the concentration level of 1.2 × 10^?7 g/mL for five replicate measurements of NE, EP and DA, giving relative standard deviations (RSDs) of 1.41%, 1.23% and 1.89%, respectively. The interaction mechanism of the Tb³⁺–catecholamine complexes system was investigated and presented with ultraviolet absorption spectra. The proposed method has been applied for the quantitative determination of NE, EP and DA in a spiked serum sample and a pharmaceutical preparation sample. Copyright © 2011 John Wiley & Sons, Ltd.     

Green‐light emission through energy transfer from Ce3+ to Tb3+ ions in the Li2SO4–Al2(SO4)3 system

An energy transfer process from Ce³⁺ to Tb³⁺ ions was successfully achieved in a Li₂SO₄–Al₂(SO₄)₃ mixed‐sulphate system. A wet‐chemical synthesis was employed to prepare the Li₂SO₄–Al₂(SO₄)₃ system by doping Ce³⁺ and Tb³⁺ ions individually as well as collectively. The phases were identified using X‐ray diffraction studies. The as‐prepared samples were characterized by FT‐IR and photoluminescence measurements. Green‐light emission was exhibited by Ce³⁺, Tb³⁺ co‐doped Li₂SO₄–Al₂(SO₄)₃ system, thus, indicating its potential as a material for display devices or in the lamp industry.