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ZnAl2O4 nanocrystallites doped with Cr3+ ions with mean sizes ranging from 2 to 16 nm were synthesized by the hydrothermal method. Chromium ions occupy the aluminum positions, which symmetry depends on the crystallite size. The smallest nanocrystals have a much larger unit cell than the bigger ones. The metal to ligand distance increases when the size of the nanocrystals decreases. This causes the nephelauxetic effect, which is for the first time (to our knowledge) observed as a size effect. It was also observed that ZnAl2O4:Cr3+ nanocrystals with size larger than 10 nm possesses the same spectroscopic properties as monocrystal. [ABSTRACT FROM AUTHOR]

The distinctive set containing Sm3+ ions doped LiF incorporated Alkaline borate glasses have been synthesised via the melt quenching practice. 59B 2 O 3 +20LiF+(20–X)CaCO 3 +XBaCO 3 +1Sm 2 O 3 (where X = 5, 10, 15, 20 wt%) is the composition used for the glass preparation. The effect of samarium ions concentration dependency on the absorption and emission of barium and calcium oxide has been studied through several spectroscopic studies. The current set of glasses is ionic, determined by the bonding value. The hypersensitive absorption transition is found in the visible region of the absorption spectra, and the transition from 6H 5/2 to 6P 3/2 shows the highest oscillator strength of 14.87 × 10−6. The intensity parameters are denoted by Ω λ (where λ = 2,4,6) are assessed and discussed. The results indicate that Ω 4 is higher when compared to the other two parameters. The lower Ω 2 values further ensure the ionic nature of the glass samples. Moreover, the intensity parameters are utilised to predict some radiative properties for the lasing potential evaluation, which includes cross-sections of emission (σ P E), probability of radiative transition (A), and experimental and radiative lifetime (τ exp and τ R). The decay profile was monitored for the 4G 5/2 state, and consistently non-exponential behaviour was observed in all the glasses. Through the CIE colour chromaticity analysis, the CCT (colour-correlated temperature), dominant wavelength, colour, and purity of the emitted light have been evaluated. Concerning all aspects, the glass with 20 wt% of BaCO 3 is found to be fit for photonic and optoelectronic applications. • Sm3+ ions doped LiF incorporated Alkaline borate glasses are prepared by melt quenching. • The bonding nature (Sm−O) is determined to be covalent through the analysis of nephelauxetic and bonding parameters. • The JO intensity parameters follows the trend Ω 4 >Ω 6 >Ω 2. • BLC0Ba:Sm achieve lasing action with a branching ratio of 64 %. • BLC20Ba:Sm glass exhibits the highest quantum yield of about 73 %. [ABSTRACT FROM AUTHOR]

The interaction of Praseodymium (III) with L-Aspartic Acid has been analysed theoretically through 4f-4f transition in various aquated organic solvents (DMF, ACN, Dioxane and methanol). Spectral parameters such as: Energy interaction parameters like Slater-Condon (Fk's), Lande factor (4f), Racah energy (Ek), nephelauxetic effect (ß), bonding (b1/2) and percent covalency (d), as well as intensity parameters: oscillator strength 'P' and Judd-Ofelt T (1=2,4,6) were evaluated. The degree of outer and inner sphere coordination, the level of metal 4f-4f orbital involvement in the complexation, defining the immediate coordination environment around the metal Pr(III), and the coordination number of the complex formed could be revealed through the analysis of these spectral parameters. The rate of complexation for Pr(III) with L-Aspartic acid and consequently its thermodynamic parameters have been evaluated through 4f-4f transition spectra. [ABSTRACT FROM AUTHOR]

Nd(III) complexes with GSH and Mg(II) have been studied using 4f-4f absorption spectrophotometry in different aquated organic solvents(50/50) in dioxane, methanol, acetonitrile and DMF. The mode of binding of Nd(III) with GSH and Mg(II) at pH 2, 4, 6 was also investigated. The binding behaviour of Nd(III) with GSH and Mg(II) along with the solvent and pH effect have been evaluated by using the computed energy interaction parameters like Slater-Condon (Fk, k = 2, 4, 6), Lande spin-orbit interaction (ξ4f), nephelauxetic ratio (β), bonding (b1/2) and percent covalency (δ).

In this study, the energy parameters such as Slater–Condon (FK) factor, Lande spin-orbit coupling constant (), nephelauxetic ratio (β), bonding parameter (b1/2), and percent covalency (δ), have been evaluated involving the interaction between Nd(III) and Pr(III) with DL-serine by using their absorption spectra as a probe. The effect of Zn(II) was also investigated on their interaction in different solvents namely DMF, dioxane, methanol and acetonitrile. The variation in the values of these parameters were observed which revealed the formation of a bond between Nd(III) and DL-serine and also between Pr(III) and DL-serine. Further, oscillatory strength and Judd–Ofelt parameters were also calculated for every concern transitions. In both the interactions, it has been found that the solvent DMF promoted 4f–4f electric dipole intensity most out of the four different solvents. [ABSTRACT FROM AUTHOR]

• Optical basicity is a non-invasive metric for glass and molten salt Lewis basicity. • An oxide or halide system is doped with metal ions to observe orbital expansion. • Electronegativity and glass composition can be used as basicity predictors. • Discussion of obstacles to measuring optical basicity. • Discussion of tools to measure optical basicity. Over several decades, extensive research has been devoted to developing the optical basicity concept to quantify Lewis basicity of oxidic media. Spectroscopy (ultraviolet (UV), infrared (IR), and fluorescence) was originally used to experimentally determine optical basicity, but linear refractive index and x-ray photoelectron spectroscopy (XPS) have been more recent techniques for determining basicity of glasses. While glasses have been one media of study, slags, oxyanion melts, and molten halide salts are also of interest. The concept has been only briefly explored in molten salts, but optical basicity could be a valuable tool for assessing its corrosivity. This review summarizes different techniques used to determine optical basicity, their pitfalls, and the preliminary work outlined for molten salts. [ABSTRACT FROM AUTHOR]

8-Hydroxyquinolate complexes of lanthanide have a variety of applications in electroluminescent devices due to their unique luminescence properties. But, the simple 8HQ ligand has a tendency to form polynuclear complexes. However, linking several 8HQ units to a single moiety facilitates the formation of mononuclear complexes due to flexibility, preorganization, π-stacking and entropy effect. Mononuclear complexes of europium and terbium ions with a new chelator, [1,4,7-tris-{(5-methylene-8-hydroxyquinoline)-1,4,7-triazacyclononane}], embedded with these prerequisites are synthesized and characterized. Each Ln(III) is nine-coordinate and bonded to three sets of O,N-donors of 8HQ units and three water resulting in a pseudo-C3 symmetric tricapped trigonal prismatic geometry. In silico studies suggest that the metal ion can easily be encapsulated in the central cavity of the ligand without changing its basic structure. Interesting, diverse behavior was observed for photoluminescence spectral studies in solid and solution state. At room temperature, an antenna effect was observed for the complexes only in the powder form. The experimental photoluminescence studies have been explained with the help of TDDFT. The nature of bonding between the lanthanide and the ligand, interpreted by NBO and ETS-NOCV, suggest that the Ln-L bonds are ∼25% covalent. The Slater Condon parameters, spin-orbital coupling constants, and the nephelauxetic parameters were calculated from LF-DFT. [ABSTRACT FROM AUTHOR]

Abstract The luminescence properties of Ce3+-doped Gd x Y 3- x Al 5- y Si y O 12- y N y (x = 0, 1 and 2; y = 0.25) oxynitride garnet phosphors were investigated and compared with corresponding oxide garnet phosphors (y = 0). The measured photoluminescence spectra exhibit redshift of the emission peak wavelength by the partial nitridation of oxide garnet phosphors because of the strong crystal field splitting and the nephelauxetic effect. Temperature dependence studies of the photoluminescence intensity revealed that the quenching temperature decreased by partial nitridation and Gd substitution. The thermal activation energy, estimated from temperature dependence of the fluorescent lifetime, was found to decrease from 0.85 eV (x = 0, y = 0) to 0.27 eV (x = 2, y = 0.25). Highlights • Ce3+-doped Gd x Y 3- x Al 5- y Si y O 12- y N y (x = 0, 1 and 2; y = 0 and 0.25) oxynitride garnet phosphors were investigated. • Gd substitution and nitridation led to redshifts of the Ce3+ emission. • Crystal field splitting and the nephelauxetic effect caused the redshift. • The quenching temperature decreased by partial nitridation and Gd substitution. • Thermal activation energies of the oxynitride garnet phosphors decreased. [ABSTRACT FROM AUTHOR]

A quantitative study of the crystal field, nephelauxetic, and Stokes shift effects on the 5d → 4 f levels of Eu ^2+ ions incorporated in ZnS films is presented. The magnitude of the crystal effect was calculated using the simplest point charge model to express the crystal field splitting of Eu ^2+ 5 d orbitals surrounded by four S ^2− ligands in tetrahedral coordination symmetry. The shift of the centroid of the 5 d levels by nephelauxetic effect was analyzed using a model that involves the polarizability of the anion ligands, similar to that used to investigate this effect for Ce ^3+ in many inorganic compounds. The Stokes shift was evaluated according to the Frank-Condon principle, under the idealized situation where the Stokes shift and the emission bandwidth can be expressed in terms of the Huang-Rhys parameter. We found that the redshift $\left({{\epsilon }}_{cfs}=0.32\,{\rm{eV}}\right)\,$ of the 5d → 4 f transition for the free Eu ^2+ ion, due to crystal field splitting was half of the redshift due to the nephelauxetic effect. This result is consistent with the large size, large polarizability, and low electronegativity of the sulfide ions. We also found a relatively large Stokes shift which can be attributed to the autoionization of the 5d electrons to the conduction band levels. The total redshift of the 5 d and 4 f energy levels with respect to the 5 d and 4 f energy gap for a free Eu ^2+ in vacuum fits quite well with the blue luminescence peaked at 2.73 eV for Eu ^2+ ions incorporated in the ZnS films. Based on the experimental results and the calculations for the crystal field splitting, nephelauxetic, and Stokes shift effects, we also propose a simplified energy band and levels diagram which helps to explain the excitation-emission mechanisms of the blue luminescence of the Eu ^2+ ions incorporated in the ZnS films.

A diverse array/unique set of Dysprosium (Dy3+) activated alkali boro-tellurite glasses were synthesized for the current study using the conventional approach of glass fabrication, and its potential for photonic applications were explored utilizing optical absorption, emission, and decay measurement methods. In the interest of assessing the Rare Earth (RE) ions bonding behavior with the neighboring metal ligand site, and to establish the glasses ionic/covalence nature, bonding parameters (δ) and Nephelauxetic ratios were computed from the absorption band locations. For the as-prepared samples, the Judd-Ofelt parameters and oscillator strengths were determined in order to scrutinize the uniformity of the ligands surrounding Dy3+ ions. The calculated JO values consistently pursue Ω 2 > Ω 4 > Ω 6 pattern for all samples, indicating their asymptotic character. When excited at 387 nm, the emission spectra demonstrate three intense transitions; 4F 9/2 →6H 15/2 , 4F 9/2 →6H 13/2 and 4F 9/2 →6H 11/2. Among them, strong yellow emission was observed owing to the increased transfer of electrons to 6H 13/2 level. Besides, using JO parameters, radiative parameters were determined which was followed by lifetime studies to actualize the novel applications. The photoluminescence spectra were employed to estimate the CIE coordinates (x, y) and Yellow/Blue ratio, furthermore the (x, y) values were used to calculate the colour purity followed by colour correlated temperature (CCT). This demonstrates that the prepared samples have the ability to emit neutral white light. [ABSTRACT FROM AUTHOR]

It is of great significance to explore changing behavior and adjustment method of the refractive index. Expression of the refractive index, which was derived from the electron-cloud conductor model, contains the equivalent volume V of the electron clouds and the molecular density ρ. The expression shows that the refractive index increases with V and ρ. Based on this expression, main factors influencing the refractive index of solid medium are analyzed and summarized: the Nephelauxetic Effect, number of bonding electrons in the molecule, chemical bond property, number of nonbonding electrons in outermost layer of the molecule, and molecular density of the medium (electromagnetic wave factor is not considered). The relationship between the refractive index and the Nephelauxetic Effect is established. The calculations show that the Nephelauxetic Effect helps to increase the refractive index. Some viewpoints related to the Nephelauxetic Effect are supplemented. Characteristics of the solid medium that has a high refractive index are proposed: (1) Covalent bond component is high, and number of covalent bonds in one molecule is large. (2) Periodic number is as large as possible without increasing the ionic bond component. (3) Molecular density is high. According to these characteristics, method of adjusting the refractive index is discussed, and the results are consistent with the real situations. [ABSTRACT FROM AUTHOR]

Abstract Y 2.85 Al 5-y Si y O 12-(3x-y)/2 N x : Ce3+ 0.15 phosphors were prepared using aluminum nitride (AlN) and silica (SiO 2) as the sources of N and Si by the high temperature solid state reaction method. XRD patterns of the phosphors present a pure phase but have a slight translation compared to the standard card of Y 3 Al 5 O 12 (YAG). The Al3+-N3- bonds and Y3+-N3- bonds were detected by the analysis of X-ray photoelectron spectroscopy (XPS). The tendency to bond with N3− ions for the cations changes from Y3+>Ce3+ to Ce3+>Y3+ for the samples introduced SiO 2. Photoluminescence spectra (PL & PLE) show that the crystal field splitting (CFS) and the nephelauxetic effect (NE) play a conflicting role in spectral shifting. When x = y, NE plays a major role and the emission red shift reaches the maximum. The thermoluminescence tests (TL) confirm that temperature quenching of the phosphors is caused by the thermally-activated crossover process. Graphical abstract Image 1 Highlights • The Y 2.85 Al 5 O 11.55 N 0.3 : Ce3+ 0.15 phosphors are prepared using AlN and SiO 2 as the sources of N3− and Si4+. • The CFS and NE play a conflicting role in spectral tuning in the resultant phosphors. • The tendency to bond with N3− for the cations changes from Y3+>Ce3+ to Ce3+>Y3+ when Si4+ were introduced. • Both red-shift and FWHM of emission spectra reach the maximum when N3− and Si4+ have the same amount. [ABSTRACT FROM AUTHOR]

Abstract CaSn(OH) 6 , CaSnO 3 and CaSnF 6 compounds were elaborated from a “one-batch” synthesis route: the coprecipitation of the pure double hydroxide leads to pure double oxide or fluoride after annealing treatments under air or HF as anhydrous gas, respectively. Structural and morphological features of the three matrices were carefully investigated by X Ray Diffraction analysis and Scanning Electron Microscopy, respectively. In addition, the luminescent properties of the Pr-doped compounds were performed and compared. The nanometric size of the double hydroxide inhibits the luminescence. The interpretation of the emission spectra obtained for Pr-doped CaSnO 3 and CaSnF 6 compounds is based on the covalence/ionic balance of the M–O or M–F bonds. Graphical abstract fx1 Highlights • Structural filiation of stannates compounds. • 119Sn Mossbauer analysis of Sn-X chemical bonding (X = OH, O, F). • Nephelauxetic effect observed in the luminescence of Pr3+ doped stannate compounds. [ABSTRACT FROM AUTHOR]

A new series of Dy 3+ -doped sodium lead alumino borosilicate glasses are prepared by the melt quenching technique with the chemical composition 20Na 2 O- 10PbO-(5-x)Al 2 O 3 -40B 2 O 3 –25SiO 2 -xDy2O3 (where x = 0, 0.5, 1.0 and 1.5 mol%) and are characterized by various spectroscopic techniques such as XRD, FT-IR, Optical absorption spectra, Fluorescence spectra and Decay measurements. Optical and Luminescence spectra of all the glasses are recorded at room temperature. From the optical absorption spectra, optical band gap and Urbach energies of Dy 3+ -doped titled glasses have been evaluated. The oscillator strengths and the intensity parameters, Ω λ (λ = 2, 4 and 6) are calculated using Judd-Ofelt analysis. The various lasing parameters like transition probability (A T ), branching ratio (β R ), stimulated emission cross-section (σ e ) and the radiative lifetime (τ rad ) for different emission levels of Dy 3+ ions have been evaluated. Fluorescence spectra show sharp emission peaks are observed at 482 nm (blue), 575 nm (yellow) and 665 (red) under 385 nm excitation, which are attributed to 4 F 9/2 → 6 H 15/2 , 6 H 13/2 and 6 H 11/2 transitions respectively. The yellow-to-blue intensity ratio (Y/B) increase up to 1.0 mol% Dy 3+ ion content and beyond it decreases because of concentration quenching which occurs due to the energy transfer between Dy 3+ and Dy 3+ ions. The x, y coordinates of the prepared glasses pass through the white light region in the CIE 1931 chromaticity diagram. The results reveal that these glasses emit quality white light which is suitable for the development of W-LEDs. The color purity and the correlated color temperature (CCT) are also calculated for the present work. Various physical parameters such as density, refractive index, and ion concentration etc., are calculated. Among the prepared glasses, NPABSDy10 glass exhibits higher σ e , β R , σ e xτ R , and σ e xΔλ eff values corresponding to the 4 F 9/2 → 6 H 13/2 emission band and these are in turn specifies its suitability for W-LEDs and visible laser applications. [ABSTRACT FROM AUTHOR]

The valencies of the lanthanides vary more than was once thought. In addition to valencies associated with a half-full shell, there are valencies associated with a quarter- and three-quarter-full shell. This can be explained on the basis of Slater’s theory of many-electron atoms. The same theory explains the variation in complexing constants in the trivalent state (the “tetrad effect”). Valency in metallic and organometallic compounds is also discussed. [ABSTRACT FROM AUTHOR]

A narrow-band K 2 LiGaF 6 :Mn 4+ red phosphor with octahedra and self-assembled microspheres morphologies was prepared through the two-step co-precipitation and hydrothermal methods, respectively. The forming mechanism of the regular octahedral crystals and self-assembled microspheres have been explored by SEM and HRTEM. The Mn 4+ doping concentration and reaction time were optimized for improving its optical properties. The emission intensity of K 2 LiGaF 6 :Mn 4+ can still keep 87% when it worked at 150 °C, indicating its excellent thermal stability. Moreover, the as-prepared K 2 LiGaF 6 :Mn 4+ have better photoluminescence intensity and thermal stability than the previously reported K 2 LiAlF 6 :Mn 4+ , which should be attributed the optimization of morphology and structure. Especially, the slight shift of peak position of K 2 LiGaF 6 :Mn 4+ than K 2 LiAlF 6 :Mn 4+ was also analyzed in detail. Finally, the as-prepared K 2 LiGaF 6 :Mn 4+ phosphor was packaged on WLED through combining the YAG:Ce phosphor. Excellent warm white light with the CCT = 4296 K, R a = 91, and luminous efficiency = 137.56 lm·W −1 was obtained, making it becoming the promising red phosphor candidates for white light-emitting diodes. [ABSTRACT FROM AUTHOR]

Eu 3+ /Nd 3+ -codoped Ba 2 LaF 7 transparent bulk glass ceramics were successfully fabricated by glass self-crystallization. The structure and morphology of the sample were investigated by X-ray diffraction, transmission electron microscopy (TEM), high-resolution TEM, and selected area electron diffraction. The fluorescence intensity ratios of Nd 3+ emission at 800 nm to the Eu 3+ emission at 699 nm ( 5 D 0 → 7 F 4 ) were measured under 578.3 nm laser excitation in a wide temperature range from 290 to 740 K. A relatively good temperature sensing performance was obtained with a maximum relative sensitivity of 1.02% K −1 at 420 K. Both the emission peaks for temperature sensing were located in the optical window of biological tissue, which is favorable for biomedical applications. The results indicate that Ba 2 LaF 7 :Nd 3+ /Eu 3+ glass ceramics have a potential application as temperature probes. [ABSTRACT FROM AUTHOR]

The improvement of temperature sensing performance for optical thermometers based on thermally coupled energy levels of a certain rare earth ion is constrained by the intrinsic operating principle. Here, a novel strategy has been presented for further improving the sensitivity by employing the cooperation of Eu 3+ and Nd 3+ in Y 2 O 3 nanoparticles. Drastic temperature dependence of the fluorescence intensity ratio between Eu 3+ and Nd 3+ is achieved in the range from 300 to 510 K. It is demonstrated that such dependence is attributed to the nephelauxetic effect of Eu 3+ and each thermally coupled property of Eu 3+ and Nd 3+ as well as the energy transfer process from Eu 3+ to Nd 3+ . We conclude that such strategy and the investigated nanoparticles have great potential for optical thermometry with high sensing performance. [ABSTRACT FROM AUTHOR]

Effect on structural and spectroscopic behaviour caused by the replacement of lead cations with the aluminium cations in the Eu 3+ doped heavy metal oxide borophosphate glasses have been studied with the chemical composition (55B 2 O 3 +19.5TeO 2 +10K 2 O+(15−x)PbO+xAl 2 O 3 +0.5Eu 2 O 3 (where x=0, 2.5, 5, 7.5, 10, 12.5 and 15 in wt%) prepared by melt quenching technique. The FTIR and Raman spectral studies reveal the presence of various fundamental vibrational units and are used to identify the phonon energy of the title glasses. The positive values of bonding parameter (δ) indicate the formation of covalent bonds between the dopant (Eu 3+ ) and the anions (O 2− ). Luminescence spectra of all the titled glasses exhibit five emission bands due to the electronic transitions of the trivalent europium ions. The radiative properties such as transition probability (A), stimulated emission cross-section ( σ p E ) and branching ratio (β R ) of the various emission transitions of the Eu 3+ ions have been estimated using Judd-Ofelt (JO) theory. The characteristic emission was identified through CIE 1931 color chromaticity diagram and McCamy's formula have been used to estimate the correlated color temperature (CCT) using (x,y) chromaticity coordinates. The luminescence decay profile pertaining to the 5 D 0 metastable state of the Eu 3+ ions exhibits single exponential behaviour uniformly for all the titled glasses and the experimental lifetime values were obtained following the curve fitting method. [ABSTRACT FROM AUTHOR]

The complexation between methyl acetoacetate and certain lanthanides was studied in the mixed ethanol–water solvent (90% ethanol) using electronic absorption spectroscopy. The formation of the cationic 1:2 type complexes was shown at alkalescent medium. Based on the energy of the f–f transitions, the interelectronic repulsion parameters (Slater integrals) were determined by a least-square fit using effective Hamiltonian comprised of electrostatic and spin–orbit components and the nephelauxetic ratio was calculated as a ratio of the second-order Slater integrals. The nephelauxetic ratio was found to be proportional to the relative shortening of the lanthanide–oxygen bond length when the geometry of the complexes was optimized by semiempirical Sparkle/Parametric Method 7. [ABSTRACT FROM PUBLISHER]

Co-doping of Eu 3+ ions in Dy 3+ single doped glasses improves white light emission. This manuscript reports correlation between the structural rearrangement and its effect on the optical properties of the title glasses. The nephelauxetic effect on absorption transitions have been used to elucidate the bonding nature of the RE 3+ ions with their surrounding ligands. It reveals the predominant ionic nature of the dysprosium bonds while that of Eu ions exhibit covalent nature. Effect of Eu 3+ ions on the symmetry of the ligand field around the Dy 3+ ions have been predicted using JO theory and asymmetric (Y/B) intensity ratio. It is found that asymmetry around Dy 3+ ions increases with Eu 3+ ions concentration. Tuneable nature of the white light emission from the Eu 3+ /Dy 3+ co-doped aluminofluoro-borophosphate glasses was confirmed through the CIE 1931 chromaticity coordinates for glasses containing different concentrations of europium. The energy transfer process takes place between Dy 3+ and Eu 3+ ions has also been confirmed through lifetime measurements. Fitting the decay curves using IH model thus reveal the dipole–dipole nature of interaction. [ABSTRACT FROM AUTHOR]

A new series of Sm 3+ /Tb 3 co-doped leadfluoro-borophosphate glasses with the composition 50B 2 O 3 + (19.5 − x)P 2 O 5 + 10Li 2 O + 10ZnF 2 + 10PbO + 0.5Sm 2 O 3 + xTb 2 O 3 (where x = 0, 0.05, 0.1, 0.25, 0.5, 1 and 2 in wt%) have been prepared following the melt quenching technique. The presence of fundamental vibrational groups such as BO 3 , BO 4 and PO 4 were explored through the FTIR and Raman spectral measurements. The nephelauxetic effect on the absorption transitions have been used to elucidate the bonding nature of the Sm 3+ ions with the surrounding ligands thus reveal the predominant ionic nature. Effect of Tb 3+ ions on the symmetry of the ligand field around the Sm 3+ ions have been predicted using asymmetric intensity ratio values. It is observed that asymmetry around the Sm 3+ ion increases with Tb 3+ ion concentration upto 1 wt% due to the chaos of both the rare earth ions and after that Tb 3+ ion concentration dominates thus in-turn creates lower asymmetrical environment. Luminescence quenching effect due to the presence of RE 3+ ions concentration has never seen upto almost 2.5 wt% (for both RE ions) hence the present host possess the capability to incorporate more number of RE ions. The decay profile of the Tb 3+ ion ( 5 D 4 ) is found tobe single exponential and Sm 3+ ion ( 4 G 5/2 ) is found to be non-exponential nature. The decreasing trend in the experimental lifetime value of the Tb 3+ ions confirms the energy transfer process takes place from Tb 3+ ions to Sm 3+ ions and the interaction takes place between Tb 3+ and Sm 3+ ions is of dipole-dipole nature and the same is analyzed using IH model. The energy transfer efficiency is found to increase from 47% to 54% with Tb 3+ ion concentration. The CIE color chromaticity coordinates have been calculated to identify the characteristic emission of the prepared glasses and the correlated color temperature, color purity were also determined. All these results suggest that, BPLS0.5T glass is a potential candidate for warm white light applications with minimal blue hazards. [ABSTRACT FROM AUTHOR]