A novel blue-purple Ce~(3+) doped whitlockite phosphor:Synthesis,crystal structure,and photoluminescence properties

At present,the rare earth(RE) ions doped phosphors have attracted more and more attention because of their excellent properties.In this paper,a series of novel blue-purple β-Ca_3(PO_4)_2:Ce~(3+) phosphors were synthesized by a high temperature solid phase method.The X-ray diffraction(XRD),infrared spectrum,energy dispersive spectroscopy(EDS),scanning electron microscopy(SEM),X-ray photoelectron spectroscopy(XPS),photoluminescence excitation and emission spectra were used to investigate the crystal structure,composition and the luminescent properties of the resulting samples.The phosphor shows a strong absorption in the ultraviolet band.Under the excitation of 269 nm,the phosphor emits a strong purple fluorescence ranging from 360 to 520 nm.When Ce~(3+) doping content is 0.07 mol,the strongest luminescence intensity is reached,and the concentration quenching mechanism is dipole-dipole(d-d)interaction for Ce~(3+) based on Dexter theory.     

Synthesis and spectral characteristics of La2MoO6：Ln3＋ （Ln=Eu, Sm, Dy, Pr, Tb） polycrystals

The novel phosphors of La 2 MoO 6 activated with the trivalent rare earth Ln 3+ (Ln=Eu, Sm, Dy, Pr, Tb) ions were synthesized by solid state reactions at high temperature in air atmosphere, and their phase impurities and luminescent properties were studied. The photoluminescence (PL) excitation and emission spectra, and decay curves were employed to study their luminescence properties. The lifetimes of the characteristic emissions from Ln 3+ ions were in the order of millisecond except Pr 3+ ions. (LaEu 1-x ) 2 MoO 6 was a promising phosphor for practical application and the optimum concentration was x=0.075. The concentration quenching mechanism of Eu 3+ was also discussed by theoretical fitting using Burshtein model.     

Optically stimulated luminescence of Dy~(3+)-doped NaCaPO_4 glass-ceramics

Dy~(3+)-doped glass-ceramics containing NaCaPO_4 crystals were successfully fabricated by heat treatment at base glass,and the luminescence properties were investigated for potential applications in radiation measurements.The photo luminescence(PL) excitation and emission spectra exhibit transitions related to Dy~(3+) ions corresponding to the strongest excitation and emission wavelengths at 351 and 575 nm,respectively.The CW-OSL properties as a function of dopant concentration,pre-heating temperature,pre-heating time and signal fading were investigated.The most appropriate Dy~(3+)ion concentration was found to be 0.25 mol%.The TL glow curves have a broad peak feature peaking at 195±5 ℃.The fading of the OSL signal would keep stable in five days with the intensity value of about 76.11%.The samples also exhibit good signal reusability and a broad linear dose response range(0.02-1000 Gy).     

Impact of grain size,Pr~(3+) concentration and host composition on non-contact temperature sensing abilities of polyphosphate nano- and microcrystals

In this article,varied praseodymium polyphosphate hosts:M~I(Li,Na K)Pr(PO_3)_4 microcrystals and LiLa_(1-x)Pr_x(PO_3)_4(x = 0.01-1)nanocrystals were successfully synthesized by the flux method and the coprecipitation technique,respectively.The size of stoichiometric nanocrystals of LiPr(PO_3)_4 was tuned by the te mpe rature of thermal treatment in range of 35-145 nm.In order to dete rmine the most suitable material for the non-contact optical thermometric applications,the temperature sensing measurements were carried out by using luminescence intensity ratio(LIR)of emission bands corresponding to the ~3 P_1→~3H_5 and ~3P_0→~3 H_5 electronic transitions of Pr~(3+) ions into the 123-423 K temperature range.The influence of the host material composition of M~Ⅰ(Li,Na,K)Pr(PO_3)_4 microcrystals on the sensitivity of luminescent thermometers was studied.It is found that the sensitivity of lithium praseodymium polyphosphate is the highest of all micropowders under investigation.Moreover,it is found that the nanocrystals reveal much higher relative sensitivity in respect to the microcrystalline counterparts.The highest sensitivity of LIR temperature sensing is found for LiPr(PO_3)_4 nanocrystals(35 nm grain size)in the whole temperature range,reaching 0.283%/K at 164 K.The impact of the average grain size on the sensitivity of LIR based thermometers of LiPr(PO_3)_4 nanocrystals was investigated.It is found that the reduction of the grain size from 145 to 35 nm results in the enhancement of the relative sensitivity from0.156 to 0.240%/K at 223 K.Additionally it is found that the high dopant concentration possesses favorable influence on the relative sensitivity of LiLa_(1-x)Pr_x(PO_3)_4 nanocrystalline luminescent thermometers.     

Multi-color luminescence in Eu3+/Tb3+ co-doped ZnAl amorphous materials and their annealed samples

Multi-color luminescence basing on amorphous Eu~(3+)/Tb~(3+) co-doped Zn-Al hydroxides and their annealed samples were studied in detail. Results suggest that excellent red emissions due to Eu~(3+) and green emissions attributed to Tb~(3+) appear under the excitation of favorable wavelength for all the asprepared amorphous samples. Moreover, the emission intensity depends on the Eu~(3+)/Tb~(3+) molar ratio. The samples annealed at 300, 500, and 700 ℃ still exhibit amorphous state,and multi-color luminescence kept in the samples annealed at 300 ℃, while luminescence quenched for the samples annealed at 500 and 700 ℃. However, a broad emission ranging from 450 to 650 nm occurs in some samples annealed at 900 ℃. Further, the fluorescence decay and lifetimes for the as-prepared samples and the samples annealed at 300 ℃ were investigated. It is found that all the decay curves of emissions due to Tb~(3+) and Eu~(3+) present characteristic double exponential function despite their different lifetimes.The present work may be a good example for developing new multi-color even white light emitting materials.     

Recent progress in synthesis of lanthanide-based persistent luminescence nanoparticles

Persistent luminescence nanoparticles(PLNPs) are a kind of phosphors that can remain luminescent for seconds to several days after the stoppage of excitation.Lanthanides show the special capability to largely broaden the emission range and enhance the luminescence intensity of PLNPs due to their dense energy structure and unique electronic configurations.In the past decades,various methods have been developed for the synthesis of lanthanide-based PLNPs with excellent pe rsistent luminescence pro...     

Upconversion luminescence of Gd2O3:Er3+ and Gd2O3:Er3+/silica nanophosphors fabricated by EDTA combustion method

Gd_2O_3:Er~(3+) nanophosphors were fabricated by the combustion method in presence of Na_2 ethylene diamine tetra acetic acid(EDTA-Na_2) as fuel at not high temperature(≤350℃) within a very short time of 5 min.The added concentration of Er~(3+)ions in Gd_2O_3 matrix was changed from 0.5 mol% to 5.0 mol%.The X-ray diffraction pattern of samples indicates the monoclinic structure of Gd_2O_3:Er3+.The morphology and chemical composition analysis of the Gd_2O_3:Er~(3+) samples are characterized by a field emission scanning electron microscope(FESEM) and a Fourier-transform infrared spectrometer(FTIR).The photoluminescence(PL),photo luminescence excitation(PLE) and upconversion(UC) at room temperature of the prepared materials with different concentrations of Er~(3+) were investigated.The PL of Gd_2O_3:Er~(3+)nanomaterials are shown in visible at 545,594,623,648,688 nm under excitation at 275 nm.The emission bands from transitions of Er~(3+) from ~2P_(3/2) to ~4F_(9/2) are observed,UC luminescent spectra of the Gd_2O_3:Er~(3+)/silica nanocomposites under 976 nm excitation show the bands at 548 and 670 nm.The influence of excitation power at 980 nm for transitions were measured and calculated.The results indicate that the upconversion process of Gd_2O_3:Er~(3+)/silica is two photons absorption mechanism.The low temperature dependence of UC luminescent intensities of the main bands of Gd_2O_3:Er~(3+)was investigated towards development of a nanotemperature sensor in the range of 10-300 K.     

Luminescent properties of Ce~(3+)/Tb~(3+) co-doped glass ceramics containing YPO_4 nanocrystals for W-LEDs

Ce~(3+)/Tb~(3+) co-doped transparent glass ceramics containing YPO_4 nanocrystals were prepared using high temperature melting method,and their structural and luminous properties were investigated.XRD analysis and TEM images confirmed the existence of YPO_4 nanocrystals in glass ceramics.The transmission spectra proved that the glass ceramics specimens still maintained a high transparency.Then the excitation and emission spectra of the Ce~(3+) and Tb~(3+) single-doped and co-doped glass and glass ceramics were discussed,which proved that the glass ceramics had better luminescent properties.Under the near ultraviolet(331 nm)excitation,the broadband emission located at 385 nm was observed which was ascribed to 5d→~2F_(5/2) and ~2F_(7/2) transition of Ce~(3+) ions.Several characteristic sharp peaks centered at 489,543,578 and 620 nm originated from the ~5D_4 to ~7F_J(J=6,5,4,3)of Tb~(3+) ions.The decay time of Tb~(3+) ions at 543 nm and the relevant energy levels of Ce~(3+) ions and Tb~(3+) ions illustrated the transfer process from Ce~(3+) ions to Tb~(3+) ions.The best CIE chromaticity coordinate of the glass ceramics specimen was calculated as(x=0.3201,y=0.3749),which was close to the NTSC standard values for white(x=0.333,y=0.333).All the results suggested that the YPO~4-based Ce~(3+)/Tb~(3+) co-doped glass ceramics could act as potential luminescent materials for white light-emitting diodes.     

Influence of reaction parameters on the luminescence properties of monodisperse NaGd(1−x−y)(WO4)2:xEu3+,yTb3+ phosphor by molten salt synthesis

Eu~(3+) activated and Eu~(3+), Tb~(3+) co-activated monodisperse sodium double tungstates NaGd(WO4)2 phosphors were prepared by molten salt method at 750 ℃ for 10 h using NaCl as a flux. The crystal structure and morphology of the as-synthesized phosphors were measured by XRD and SEM, respectively. The photoluminescence properties were characterized by PL spectra, decay lifetime and CIE. The presence of NaCl plays an important role in the morphology and luminescence properties. In this work,NaCl and one of the raw material Na_2 CO_3 in a certain proportion will form a low eutectic salt to decrease the reaction temperature and benefit the formation of monodisperse NaGd(WO_4)_2 crystals. The color of Eu~(3+) and Tb~(3+) co-doped NaGd(WO_4)_2 phosphors can be tuned from creamy white to orange, red and green by adjusting the doping concentration of rare earth ions, since the emission contain the broad blue-green emission origin from NaGd(WO_4)_2 host and characteristic red and green emission origin from Eu~(3+) and Tb~(3+) ions. The electroluminescent spectra and CIE measurement shows that the LED device with NaGd_((1-x))(WO_4)_2:xEu~(3+)(x = 0.24) phosphor can be excited by 365 nm and 380 nm LED chip, and their CIE coordinate is(x = 0.45, y = 0.45) and(x = 0.36, y = 0.37), Ra is 80.3 and 86.3, T_c is 3196 and4556 K, respectively. As a single-component phosphor, NaGd(WO_4)_2:Eu~(3+),Tb~(3+) have potential application in UV-pumped WLEDs.     

Luminescence properties of Eu~(3+) doped YBO_3 for temperature sensing

YBO_3:2 at.% Eu~(3+) was prepared by the solid state reaction and its temperature dependent luminescence was investigated for possible applications in temperature sensing. Phase composition of this material was confirmed by X-ray powder diffraction analysis and excitation and emission spectra were also provided. Under excitation of 355 nm, the fluorescence originating from ~5D_0 and ~5D_1 states varied as the temperature rose in a region from 333 to 773 K. The fluorescence intensity ratio(FIR) of ~5D_0 and ~5D_1 was investigated which increased significantly with the rise of temperature. The maximal relative sensitivity in the whole temperature range was 1.8% K~(–1)(at 333 K). The results recommended YBO_3:Eu~(3+) as a new material of the FIR method for non-contact optical thermometry.     

Effect of Li+ ion concentration on upconversion emission and temperature sensing behavior of La2O3:Er3+ phosphors

The effects of Li~+ co-doping concentration on the structure, upconversion luminescence and temperature sensing behavior of Er~(3+):La_2O_3 phosphors were investigated. X-ray diffraction and scanning electron microscopy observations reveal that Li~+ ion co-doping can change the lattice parameter of La_2O_3 host and increase the particle size of the samples. The optical investigation shows that co-doping of Li~+ ions can enhance the upconversion emission of Er~(3+) ions in La_2O_3 matrix effectively. Most importantly, the temperature sensing sensitivity of the samples is found to be dependent on Li~+ co-doping concentration,when the emission intensity ratio of the(~2H_(11/2)→~4 I_(15/2)) and(~4 S_(3/2)→~4 I_(15/2)) transitions of Er~(3+) is chosen as the thermometric index. Both of the optimum upconversion luminescence and temperature sensing sensitivity are obtained for 7 mol% Li~+ co-doped sample. When the Li~+ concentration is beyond 7 mol%,both the quenching in upconversion intensity and the degradation of temperature sensitivity are observed, which may be due to the serious distortion in local crystal field around Er~(3+) ions caused by the excess Li~+ ions.     

Luminescence of Eu~(2+) and Eu~(2+)-Mn~(2+) in sodium scandium diphosphate NaScP_2O_7 crystal

In this work, the photoluminescence(PL) of NaScP_2O_7:Eu~(2+) and NaScP_2O_7:Eu~(2+),Mn~(2+) was investigated. Phase purity was checked using X-ray powder diffractometry(XRD). PL excitation and emission spectra were recorded to elucidate the PL properties of NaScP_2O_7:Eu~(2+) and NaScP_2O_7:Eu~(2+),Mn~(2+). Furthermore, fluorescence lifetime measurements were performed. PL and lifetime measurements were carried out from 10 to 525 K. Moreover, the Eu~(2+) site occupation was discussed. It turned out that the incorporated Eu~(2+) ions substituted for Na+ site and occupied two different sites. Temperature dependent PL measurements indicated the emission intensity decreased with increasing temperature due to temperature quenching in NaScP_2O_7:Eu~(2+). Fluorescence lifetimes of Eu~(2+) in NaScP_2O_7:Eu~(2+) almost did not change with a decay constant τ=~0.53 μs in the temperature range of 10–280 K, and then shortened due to temperature quenching. The luminescent lifetime reached ~0.05 μs at T=525 K. Finally, it was found that energy transfer occurred from Eu~(2+) to Mn~(2+) in co-doped NaScP_2O_7:Eu~(2+),Mn~(2+).     

High thermal stability and blue-violet emitting phosphor CaYA1O_4:Ti~(4+)with enhanced emission by Ca~(2+)vacancies

Blue-violet light can not only enhance the total content of biomass and glucoside but also enrich the taste of the fruit.Thus,it is meaningful to study the blue-violet luminescent materials for plant cultivation.In this study,titanium(IV)-activated CaYAlO_4(CYAO) phosphors were synthesized by conventional hightemperature solid-state reaction.X-ray powder diffraction was employed to analyze the crystalstructure of CYAO.It is found that the doped Ti~(4+) ions do not change obviously the crystal structure of phosphors.Upon 246 nm excitation,CaYAl_(1-x)O_4:xTi~(4+)phosphors exhibit broad blue-violet emission band peaking at 395 nm,which can be attributed to the charge transfer of Ti~(4+)-O~(2-).Moreover,this phosphor exhibits strong thermal stability.The luminescence emission intensity at 150℃maintained about 91 mol% of its initial value at room temperature.Additionally,the electron transition process and concentration quenching mechanism of CaYAl_(1-x)O_4:xTi~(4+)are discussed in detail.The excellent luminescent properties indicate that CaYAl_(1-x)O_4:xTi~(4+)phosphor may have promising application in indoor plant cultivation.     

Effect of BaF2 addition on luminescence properties of Er3+/Yb3+ co-doped phosphate glasses

Er~(3+)/Yb~(3+) co-doped phosphate glasses(P_2O_5-Al_2O_3-BaO-BaF_2-K_2O-Er_2O_3-Yb_2O_3) with varying BaF_2 content,were prepared by a conventional melt quenching technique and their spectroscopic properties were examined through the Raman, absorption, emission and decay measurements. Raman spectra(350-1400 cm~(-1)) of the Er~(3+)/Yb~(3+) co-doped phosphate glasses with varying BaF_2 content, were recorded upon laser excitation at 785 nm. Near infrared luminescence spectra were measured in the1400-1600 nm region under 970 nm diode laser excitation and characteristic band was observed at1533 nm corresponding to ~4Ⅰ_(13/2)→~4Ⅰ_(15/2) transition of Er~(3+) ion. The decay curves for the ~4Ⅰ_(13/2) level of Er~(3+)ion, were measured and the lifetime is found to decrease from 7.94 to 7.70 ms when BaF_2 content increases from 0 to 8 mol% and then increases up to 7.83 ms with further increase in BaF_2 content(12 mol%). The emission cross-section.lifetime and figure of merit for the ~4Ⅰ_(13/2)→~4Ⅰ_(15/2) transition of Er~(3+) ion were evaluated and compared to the other host matrices. The upconversion luminescence was measured and intense red emission was observed for all the studied samples.     

Synthesis and luminescent properties of BaGd2O4:Eu3+ phosphors with highly efficient red-emitting

The BaGd_(2-2 x)Eu_(2 x)O_4(BG, x = 0.01-0.09) phosphors were successfully synthesized via the sol-gel method,and BaY_(2-2 y)Eu_(2 y)O_4(BY, y = 0.005-0.07) phosphors were included for comparison. The pure phase BG phosphors with the ordered CaFe_2 O_4-type structure are obtained by annealing at 1300℃ for5 h. The phosphors with uniform particle size of 120 nm and good dispersion display typical Eu~(3+)emission with the strongest peak at 613 nm(~5 D_0→~7 F_2 transition of Eu3+) under optimal excitation band at 262 nm(CTB band). The presence of Gd~(3+) excitation bands on the PLE spectra monitoring the Eu3+emission directly proves an evidence of Gd~(3+)-Eu~(3+) energy transfer. Owing to the concentration quenching, the optimum content of Eu3+ addition is 5 at%(x = 0.05), and the quenching mechanism is determined to be the exchange reaction between Eu3+. All the BG samples have similar color coordinates and temperature of(0.64 ± 0.02, 0.36 ± 0.01) and 2000 ± 100 K,respectively. The lifetime value of BaGd_(1.9)Eu_(0.1)O_4 for 613 nm is fitted to be 2.19 ± 0.01 ms, and the Eu~(3+) concentration does not change the lifetime significantly. Owing to the Gd~(3+)-Eu~(3+) energy transfer, the luminescent intensity of the BaGd_(1.9)Eu_(0.1)O_4 phosphor is better than BY system. The BG system served as a new type of phosphor is expected to be widely used in lighting and display areas.     

Synthesis and thermometric properties of Yb~(3+)-Er~(3+) co-doped K_2GdF_5 up-conversion phosphors

Yb~(3+)-Er~(3+) co-doped K_2GdF_5 up-conversion phosphor was successfully synthesized by a solid-state reaction method. The phase purity and structure of the sample were characterized by powder X-ray diffraction. The sample emitted orange light at room temperature and its up-conversion spectra at different temperatures were recorded under the excitation of a 980 nm diode laser. The energy transfer from Yb~(3+) to Er~(3+) notably enhanced the up-conversion luminescence intensity. The possible up-conversion mechanisms and processes were proposed based on the power dependence of the luminescence intensities. The temperature-dependent up-conversion luminescence and temperature sensing performances of the sample were discussed according to the fluorescence intensity ratio of green emissions originating from ~2H_(11/2)/~4S_(3/2)→~4I_(15/2) transitions of Er~(3+) in the range from 307 K to 570 K under the excitation of 980 nm laser with power of 260 mW. The dependence of the fluorescence intensity ratio on temperature was fitted with an exponential function and the effective energy difference obtained was 690 cm~(–1), which further gave a relative temperature sensitivity of 1.1%/K at 307 K. The results suggested that the Yb~(3+)-Er~(3+) co-doped K_2GdF_5 sample is a promising candidate for optical temperature sensor.     

Synthesis and luminescence properties of Tb3+/Eu3+ co-doped GdAlO3 phosphors with enhanced red emission

The(Gd_(0.97-x)Eu_xTb_(0.03))AIO_3(x= 0.005-0.07) phosphors were synthesized by the co-precipitation method,using ammonium bicarbonate as a precipitant.The combined technologies of FT-IR,XRD,FESEM,PLE/PL and photo luminescence decay analysis were used to study the phase evolution,morphologies and luminescent properties.The phosphors with good dispersion exhibit strong vivid red emission located at 617 nm(~5 D_0-~7 F_2 transition of Eu~(3+)) under the optimal excitation wavelength of 275 nm(~4 f~8-4 f~75 d~1 transition of Tb~(3+),~8 S_(7/2)→6~I_J transition of Gd~(3+)).The presence of Gd~(3+) and Tb~(3+) excitation bands on the PLE spectra monitoring the Eu~(3+) emission directly gives an evidence of Tb~(3+) → Eu~(3+) and Gd~(3+) → Eu~(~(3+)) energy transfer,The emission intensity varies with the Eu~(3+) amount,and the quenching concentration is ～5 at% which is close to the calculated value.The quenching mechanism is determined to be the exchange reaction between Eu~(3+).The temperature-dependent PL analysis indicates that the best(Gd_(0.92)Eu_(0.05)Tb_(0.03))AlO_3 sample possesses good thermally stable properties.All the(Gd_(0.97-x)Eu_xTb_(0.03))AIO_3 phosphors in this work have similar CIE chromaticity coordinates and color temperatures,which are(0.65 ± 0.02,0.35 ± 0.02) and ～2558 K,respectively.Fluorescence decay analysis shows that the lifetime for～617 nm emission decreases with the content of Eu~(3+) and temperature increasing.Owing to the Tb~(3+)→ Eu~(3+) energy transfer,the luminescent properties of the(Gd_(0.92)Eu_(0.05)Tb_(0.03))AlO_3 phosphors are superior to the single Eu~(~(3+)) doped sample(Gd_(0.95)Eu_(0.05))AlO_3.As a result,the prepared phosphors may be widely used in solid-state display and light emitting devices.     

Up-conversion photoluminescence emissions of CaMoO_4:Pr~(3+)/Yb~(3+) powder

CaMoO_4:Pr~(3+)/Yb~(3+) powder was successfully synthesized by a facile hydrothermal method. X-ray diffraction(XRD) patterns of samples confirmed tetragonal structure and morphology and sizes were confirmed by scanning electron microscopy(SEM) analyses. Particles consisted of regular micro-spheres with uniform sizes, the diameter of each sphere lay in the range of 3 to 4 μm. The up-conversion photoluminescence emission and its concentration dependence were investigated under infrared excitation at 980 nm. All the UC micro-particles exhibited the typical blue, green and red emissions. Dominant blue emissions originated from ~3P_0→~3H_4 and intense red emissions originated from ~3P0→~3F_2 transitions, and they both belonged to two-photon excitation processes in CaMoO_4: Yb~(3+)/Pr~(3+) powder. The optimum doping concentrations of Pr~(3+) and Yb~(3+) for the highest UC luminescence were 0.1 mol.% and 16 mol.%, respectively. The possible up-conversion mechanisms were discussed in detail. It was found that the UC emission could be well controlled from blue to green to white color by adjusting the concentration of Pr~(3+) ions in CaMoO_4:Pr~(3+)/Yb~(3+) microcrystal. So it is a candidate material for solid-state lasers, biological imaging, solar cells, and optical communications.     

Improvement of Luminescent Properties of PbWO4 by Doping with Gd3＋ Ions

The luminescent properties of PbW04: Gd3 were studied. The luminescence of Gd3 in PbWO4: Gd3 was quenched. It is possible that the excitation states of Gd3 locate in the conduction band of PbW04 crystal. The luminescent intensity of the green and the blue band of PbW04 emission increases by doping with about 0.005% and 0.01% (molar fraction) Gd3 respectively. Mechanism of this enhancement of PbWO4:Gd3 luminescence is probably due to energy transfer from Gd3 to PbW04 host in the crystal. The PbW04 doped with low concentration of Gd (about 0.005% -0.01% ) is a good scintillating material.     

Enhancement of luminescence intensity and spectroscopic analysis of Eu3+ activated and Li+ charge-compensated Bi2O3 nanophosphors for solid-state lighting

The present work reports the synthesis, characterization, photoluminescence and photocatalytic activity of Eu~(3+)(1 mol%-11 mol%) doped and Li~+(0.5 mol%-5 mol%) co-doped Bi_2 O_3 nanophosphors(NPs) by sonochemical method. The average particle size was estimated using powder X-ray diffraction(PXRD)and transmission electron microscopy(TEM) and is found to be in the range of 30-35 nm. The scanning electron microscopy(SEM) images were highly dependent on sonication time and concentration of epigallocatechin gallate(EGCG) bio-surfactant. The energy gap of doped and co-doped Bi_2 O_3 nanophosphors was estimated using Kubelka-Munk(K-M) function and is found to be in the range of2.9-3.08 eV. The effect of Li+ co-doping on luminescence of optimized Bi_2 O_3:Eu~(3+) was studied and is found about more than 3 fold enhancement of emission intensity. Judd-Ofelt parameters(Ω_2, Ω_4 and Ω_6).transition probabilities(A_T), quantum efficiency(η), luminescence lifetime(τ_(rad)), color chromaticity coordinates(CIE) and correlated color temperature(CCT) values were estimated from the emission spectra and are discussed in detail. The estimated CIE chromaticity co-ordinates are very close to the NTSC(National Television Standard Committee) standard value of red emission. The synthesized NPs show excellent photocatalytic activity of acid red-88 under UV-light irradiation, which can degrade 98.1% in60 min. The decreasing electron-hole pair recombination rate with quick electron transfer ability is predominantly ascribed to the balance between crystallite size, morphology, band gap, defects, surface area, etc. These results show a light for the use of sonochemical route of Bi_2 O_3:Eu~(3+):Li~+ in solid state display and photocatalytic applications.