Y2O3 Host Research Articles

Narrowband-UVB-emitting gadolinium-doped yttrium oxide nanofilm on xenon excimer lamp for phototherapy

The continuous utilization of ultraviolet (UV) light sources within both academic and industrial contexts necessitates the imperative advancement of alternative UV sources to replace hazardous mercury lamps. Herein, we proposed a mercury-free narrowband UVB (NB-UVB)-emitting device from Y2O3:Gd3+ nanofilm on a tubular quartz substrate. The nanofilm is fabricated utilizing the spin-coating sol-gel precursor technique and is subsequently synthesized via a high-annealing temperature solid-state reaction. This synthesis resulted in the formation of a single-phase cubical structure of Y2O3 characterized by a crack-free morphology. The NB-UVB radiative output with a peak at 315 nm is generated through vacuum UV-induced photoluminescence originating from the emission of Xe excimer, which subsequently excites the Gd3+ luminescent centers incorporated within the Y2O3 host matrix. Moreover, in a high-voltage bipolar power system operating at 19 kV and 19 kHz, the device exhibited an NB-UVB radiance output of 1.34 mW, accompanied by a power efficiency of 0.02 %, whilst preserving exceptional temporal performance. Thus, this investigation introduces an innovative perspective on a mercury-free NB-UVB-emitting device, thereby promoting further exploration into the application of UV radiation sources derived from excimer lamp technology.

Exploring Optically Stable Reddish-Orange Fluorescent Magnetic Pigment (0.90)Y2O3:(0.10-x)Eu3+:(x)Bi3+ for Anti-counterfeiting Applications.

The (0.90)Y2O3:(0.10-x)Eu3+:(x)Bi3+ nanophosphors (0.00 ≤ x ≤ 0.06) are synthesised using chemical combustion citrate route and characterized via X-ray diffraction, Raman spectroscopy, Fourier transform infrared spectroscopy, UV- visible and photoluminescence spectroscopy. The scanning electron micrographs indicate that the grain size of the phosphors ranges between 40 to 50nm. The photoluminescence (PL) spectra, acquired under the excitation wavelength of 365nm of ultraviolet light, show emission peaks at wavelengths 580nm, 586-598nm, 610nm, 629-661nm and 686-695nm corresponding to the 5D0 → 7FJ electronic transitions of the Eu3+ ion with J = 0, 1, 2, 3 and 4, respectively. The most intense PL spectra at 611nm (5D0 → 7F2), showcasing reddish-orange emission, indicate a higher concentration of Eu3+ ions in asymmetric sites within the Y2O3 host matrix. The presence of the distinct electronic transitions of Eu3+ in PL spectra acclaims that Bi3+ ions transfer their energy efficiently to Eu3+ ions in the matrix. Physical and chemical tests are being conducted on nanophosphors with Bi3+ substitutional doping of x = 0.02 and x = 0.04, both demonstrating intense PL emission. Magnetisation measurements suggest the soft magnetic nature of the nanophosphors, attributing it to the presence of Eu3+ ions in the 7F2 state. The highest PL intensity is seen in the nanophosphor (x = 0.04) with substitutional doping of 6% of Eu3+ and 4% of Bi3+ in Y2O3. This nanophosphor also demonstrates excellent optical stability in the investigated conditions and exhibits soft magnetic behaviour, positioning it as a promising material for incorporation as a fluorescent magnetic pigment in security ink applications. These features serve to prevent counterfeiting of secured documents both optically and magnetically.

Effect of Y:Zn ratio on microstructure and emission of Er3+/Yb3+ codoped Y2O3–ZnO ceramic phosphors

In this study, Er3+/Yb3+ codoped Y2O3–ZnO ceramic phosphors were prepared by sol–gel method. The samples had two emission bands, namely, green (535 nm) and red (660 nm), which are attributed to Er3+: 2H11/2(4S3/2) → 4I15/2 and Er3+: 4F9/2 → 4I15/2 radiative transitions, respectively. The samples exhibited green- and red-emission intensity enhancement by 1.728 and 2.286 times that of the pure Y2O3 host, respectively and by 514.468 and 214.341 times that of the pure ZnO host. The emission intensities are first enhanced by lattice expansion. With the change of Y:Zn ratio, the high surface energy is converted into low crystal surface resulting in the change of asymmetry crystal field for matrix. When the intensity of the asymmetric crystal field reaches maximum, both emissions are further boosted. When the high surface energy transforms into crystal surface energy, the microstructure changes into a compact mesoporous structure. Consequently, the chemical stability of the samples improves significantly, and the final emission band of the three samples with mesoporous structures is continuously red.

Production, characterization, and photocatalytic properties of Eu:Y2O3 nanopowders

AbstractEu:Y2O3 nanophosphors (NPs) with different Eu concentrations (3, 5, and 7 at%) were successfully synthesized via the sol–gel method. All synthesized powders had a cubic bixbyite‐type crystal structure with space group Ia‐3. It was observed they had agglomerated sphere‐like morphologies. In addition, a neck formation between the particles, which was the result of the sintering effect at the increasing calcination temperature, was also observed by scanning electron microscopy analysis. Raman and X‐ray photoelectron spectroscopy (XPS) analyses confirmed that the Eu dopant entered into the Y2O3 host. The XPS peak positions shifted to relatively higher binding energy values with increasing dopant concentration and calcination temperature. Increasing Eu dopant concentration in the host structure also increased the 3+ valence ions. The band gap values of the NPs varied between 4.30 and 4.54 eV. The powders doped with 5 at% Eu was active as photocatalysts and the powders that were synthesized at 800°C exhibited highly photocatalytic activity.

Yb3+ influence on NIR emission from Pr3+-doped spherical yttria nanoparticles for advances in NIR I and NIR II biological windows

Highly intense NIR emissions in the first and second biological windows and a remarkable UV–Vis and NIR to NIR energy conversion were observed for Pr3+, Yb3+ co-doped yttria nanoparticles, synthesized via the homogeneous precipitation method. A single-phase body center cubic Y2O3 structure was formed for all the samples after annealing 900 °C for 2 h. Increasing the dopants content, from 0.5 to 5.0 mol %, the replacement of Y3+ by Pr3+ and Yb3+ ions lead to a lattice expansion, which could be calculated. Spherical monodispersed nanoparticles, constituted of several crystallites, were observed by TEM and SEM images. The particles size ranged from 143 to 272 nm for the as-prepared samples and from 88 to 202 nm for the samples annealed at 900 °C. The crystallite size was estimated by Debye-Scherrer and Williamson-Hall methods and ranged from 6 to 27 nm with an average of 13 nm. Photoluminescent studies evidenced pronounced Pr3+ and Yb3+ near infrared (NIR) emission under ultraviolet, visible, and NIR excitation. How the Yb3+ ions co-doping, as well as, the total rare earth content, affected the luminescence properties, were evaluated, along with the energy transfer process involving UV–Vis and NIR to NIR energy conversion between the doping ions and the host. The energy was transferred between the Y2O3 host and Pr3+, Yb3+ upon CT band excitation at 290 nm. NIR emission at 948, 1080, 1115 nm, and 1.5 μm attributed to the Pr3+ transitions 3P0,1→1G4, 1D2→3F3, 1D2→3F4, and 1D2→1G4, denoting the 1D2 population through a multiphonon relaxation process (3P0+3H4→3H6+1D2). A concentration quenching process was ascertained in the highest concentration of dopants (5.0 mol % in total), which indicated that cross-relaxation took place. Both the Yb3+-doped and Pr3+, Yb3+ co-doped samples presented the Yb3+ emission 2F5/2→2F7/2 at 976 nm. All the structural, morphological, and spectroscopic properties of the materials make these spherical yttria nanoparticles potential NIR emitting probes candidates for advances in biophotonics, especially for deep-tissue imaging using NIR I and NIR II biological windows.

Tunable luminescence from yttrium oxide flowers using asparagine as shape modifier

A series of Eu3+/Nd3+/Yb3+ co-doped Y2O3 flowers with different Nd3+ concentrations are synthesized using asparagine as a complexing ligand by low-temperature hydrothermal synthesis technique. The cubic crystal structure and flower like architecture morphology of the annealed co-doped Y2O3 phosphors at different synthesis temperatures have been confirmed from XRD and FESEM analysis. The photoluminescence study of the developed phosphors has been performed by using excitations at 220 nm, 808 nm and 980 nm, and the responsible mechanisms have been discussed in detail. Dipole-dipole interaction is found responsible for concentration quenching with inter-ionic separation ∼15.27 Å among the Nd3+ ions. Asymmetric ratio is calculated to be 3.01 with respective to Eu3+ ions in co-doped Y2O3 host lattice. The spectral characteristics have been described via nephelauxetic ratio and Judd–Ofelt parameters in co-doped Y2O3 under UV excitation. Two photon process dominates the upconversion luminescence on 808 nm irradiation. CIE color coordinates clearly indicates that co-doped Y2O3 phosphors can be further used for multi-color labeling applications. Moreover, because of the intrinsic magnetic moment of Nd3+ ions, the developed Eu3+/Nd3+/Yb3+ co-doped Y2O3 phosphors exhibit paramagnetic behavior with magnetization value 0.0064 emu/g at 300 K.

Flame-made Y2O3:Yb3+/Er3+ upconversion nanoparticles: Mass production synthesis, multicolor tuning and thermal sensing studies

Developing a rapid and continuous synthesis method for scalable production of upconversion nanoparticles (UCNPs) plays an important role in the applications of advanced color display, high-resolution biomedical imaging and precise optical thermometry. Here, for the first time, we report the multicolor tunable upconversion luminescence (UCL) in Y2O3:Yb3+/Er3+ (x/1 mol%) UCNPs with the average size of ∼14 nm, which were successfully fabricated by liquid-fed flame aerosol synthesis with a high production rate of ∼40 g h−1. Under the excitation of 980 nm continuous-wave (CW) laser, the UCL color can be efficiently modulated from green to red and the red-to-green (R/G) UCL intensity ratio is enhanced dramatically as the doping concentration of Yb3+ ions increases from 1 to 15 mol%. The UCL color manipulation can be ascribed to the cross-relaxation (CR) and the energy back transfer (EBT) processes between Yb3+ and Er3+ ions, and it was proved by investigating the dependence of UCL on the pump power and the decay lifetimes of 4S3/2 and 4F9/2 states. Moreover, the coefficients of CR and EBT processes were also calculated by a rate equation model, and the results suggest that they are efficient in Y2O3 host. In addition, the optical thermal sensing performance was also evaluated by analyzing fluorescence intensity ratio (FIR) of the thermally coupled levels (2H11/2, 4S3/2) of Er3+ ions in Y2O3:Yb3+/Er3+ (1/1 mol%) UCNPs, achieving an excellent thermal sensitivity of 0.0196 K−1 at 543 K.

The Microstructure and Electronic Properties of Yttrium Oxide Doped With Cerium: A Theoretical Insight.

Trivalent Cerium (Ce3+) doped Yttrium Oxide (Y2O3) host crystal has drawn considerable interest due to its popular optical 5d-4f transition. The outstanding optical properties of Y2O3:Ce system have been demonstrated by previous studies but the microstructures still remain unclear. The lacks of Y2O3:Ce microstructures could constitute a problem to further exploit its potential applications. In this sense, we have comprehensively investigated the structural evolutions of Y2O3:Ce crystals based on the CALYPSO structure search method in conjunction with density functional theory calculations. Our result uncovers a new rhombohedral phase of Y2O3:Ce with R-3 group symmetry. In the host crystal, the Y3+ ion at central site can be naturally replaced by the doped Ce3+, resulting in a perfect cage-like configuration. We find an interesting phase transition that the crystallographic symmetry of Y2O3 changes from cubic to rhombohedral when the impurity Ce3+ is doped into the host crystal. With the nominal concentration of Ce3+ at 3.125%, many metastable structures are also identified due to the different occupying points in the host crystal. The X-ray diffraction patterns of Y2O3:Ce are simulated and the theoretical result is comparable to experimental data, thus demonstrating the validity of the lowest energy structure. The result of phonon dispersions shows that the ground state structure is dynamically stable. The analysis of electronic properties indicate that the Y2O3:Ce possesses a band gap of 4.20 eV which suggests that the incorporation of impurity Ce3+ ion into Y2O3 host crystal leads to an insulator to semiconductor transition. Meanwhile, the strong covalent bonds of O atoms in the crystal, which may greatly contribute to the stability of ground state structure, are evidenced by electron localization function. These obtained results elucidate the structural and bonding characters of Y2O3:Ce and could also provide useful insights for understanding the experimental phenomena.

Near-infrared luminescence spectroscopy in yttrium oxide phosphor activated with Er3+, Li+ and Yb3+ ions for application in photovoltaic systems

Near-infrared emission from phosphors Y2O3 doped with Er3+, Li+ and Yb3+ ions under continuous excitation at 523 nm is reported. The downshifting emissions from 950 to 1090 nm correspond to transitions 4I11/2 → 4I15/2 of Er3+ ions and 2F5/2 → 2F7/2 of Yb3+ ions; the emissions from 1500 to 1600 nm correspond to transitions 4I13/2 → 4I15/2 of Er3+. The role of Yb3+ ions in phosphors of Y2O3 doped with 4 at.% of Er, 2 at.% of Li and 2 at.% of Yb was to enhance the 950–1090 nm emissions around 3.5 times in comparison with Yb3+ free samples, through an energy transfer from the erbium 4I11/2 level to the ytterbium 2F5/2 level. Li+ plays an important role in such energy transfer process. With addition of Li+ an erbium 4I13/2 and ytterbium 2F5/2 level decay time increasing is also observed. A peak intensity increase in XRD patterns of the sample tri-doped revealed that the incorporation of lithium increases the phosphor crystallinity. FT-IR and SIMS studies confirmed that Li+ ions are incorporated into the Y2O3 host. According to the optical and structural properties of these phosphors, they could be used to increase the photon absorption in photovoltaic systems.

Color‐Tunable Eu3+ and Tb3+ Co‐Doped Nanophosphors Synthesis by Plasma‐Assisted Method

AbstractWith increasing health consciousness, Y2O3‐based rare earth nanophosphors are considered as promising luminescent complexes for bio‐applications. In the present study, an atmospheric pressure plasma‐electrochemical technique is demonstrated for the synthesis of Eu3+/Tb3+ single‐doped or co‐doped Y2O3 nanophosphors from merely an aqueous solution of the corresponding rare earth nitrite salts. Systematic experiments were performed to prepare (Y1‐x‐yEuxTby)2O3 nanophosphors of various Tb3+ and Eu3+ ratios (x:y = 1:0, 2:1, 1:1, 1:2, and 0:1), with the ultimate goal to achieve the colour tunability by simply adjusting the dopant compositions. Results indicated successfulness synthesis of crystalline Eu/Tb single‐doped and co‐doped Y2O3 nanophosphors with Tb3+ and Eu3+ ions being uniformly incorporated into the Y2O3 host matrix. The generated products showed apparent downshift behaviour under ultraviolet irradiation, and characteristic spectral excitation and emission bands were detected by the photoluminescence measurement. Furthermore, by adjusting the relative composition ratios of the terbium and europium ions, the emission colours were shown to be regulated to a large extent. The demonstrated process can be characterized as simple, versatile and environmentally‐friendly, featuring great flexibility in colour tunability, and therefore can present a considerable interest for emerging nanofabrication applications.

The effect of pH on the luminescence properties of Y2O3:Bi phosphor powders synthesised using co-precipitation

This article focuses on studying how the pH, during the synthesis procedure, effects the luminescence properties of Y2O3:Bi2.0 mol% phosphor material. The x-ray diffraction pattern showed that the phosphor material crystallised as a single phase cubic structure with a Ia-3 space group. The photoluminescence spectrum revealed two Bi3+ emission bands, a narrow band centred at 409 nm and a broad band centred at 490 nm originating from S6 and C2 sites that Bi3+ ions may occupy with in the Y2O3 host lattice. The emission at 409 nm showed two excitation bands one centred at 330 nm and another at 390 nm. For the 490 nm emission two excitation bands were also observed centred at 330 nm and 345 nm. X-ray photoelectron spectroscopy showed that the Y 3 d spectrum consisted of ten sub peaks, two peaks for each of the two different sites that both Y3+and Bi3+ occupy within the Y2O3 lattice and last two peaks for the Y-OH bond. The O 1s spectrum consisted of eight peaks, one peak for each of the two different sites that O2− ions occupy within the Y2O3 and Bi2O3 lattice and the remaining four peaks relates to the hydroxy and carbon oxygen bonds. Energy dispersive x-ray spectroscopy confirmed qualitatively the presence of Y, O and Bi ions and indicated that it was not a change in Bi concentration that was responsible for the PL intensity changes.

The role of Li+ in the upconversion emission enhancement of (YYbEr)2O3 nanoparticles.

The mechanism of upconversion enhancement for Li+-doped materials is still contentious. Attempting to settle the debate, here the upconversion emission enhancement of (Y0.97-xYb0.02Er0.01Lix)2O3, x = 0.000-0.123, nanoparticles is studied. Li+ incorporation in the Y2O3 host lattice is achieved via co-precipitation and solid-state reaction routes. In contrast to numerous reports, elemental analysis reveals that the former method does not afford Li+-bearing nanoparticles. The solid-state reaction route accomplishes an effective Li+ doping, as witnessed by inductively coupled plasma atomic emission spectroscopy and X-ray photoelectron spectroscopy (XPS). Transmission electron microscopy and powder X-ray diffraction showed an increase in nanoparticle size with increasing Li+ concentration. Rietveld refinement of powder X-ray diffraction data shows that the cubic lattice parameter decreases with increasing Li+ content. The emission quantum yield increases tenfold with increasing Li+ content up to x = 0.123, reaching a maximal value of 0.04% at x = 0.031. XPS and infrared spectroscopy show that the carbonate groups increase with increasing Li+ content, thus not supporting the prevailing view that the upconversion luminescence enhancement observed upon Li+ nanoparticle's doping is due to the decrease of the number of quenching carbonate groups present. Rather, the particle size increment and the decrease in the lattice parameter of the host crystals are shown to be the prime sources of quantum yield enhancement.

Luminescence properties of Y2O3:Bi3+, Yb3+ co-doped phosphor for application in solar cells

Bismuth (Bi3+) and ytterbium (Yb3+) co-doped yttrium oxide (Y2O3) phosphor powder was successfully synthesised using the co-precipitation technique. The X-ray diffraction (XRD) patterns confirmed that a single phase cubic structure with a Ia-3 space group was formed. The visible emission confirmed the two symmetry sites, C2 and S6, found in the Y2O3 host material and revealed that Bi3+ ions preferred the S6 site as seen the stronger emission intensity. The near-infrared (NIR) emission of Yb3+ increased significantly by the presence of the Bi3+ ions when compared to the singly doped Y2O3:Yb3+ phosphor with the same Yb3+ concentration. An increase in the NIR emission intensity was also observed by simply increasing the Yb3+ concentration in the Y2O3:Bi3+, Yb3+ phosphor material where the intensity increased up to x = 5.0mol% of Yb3+ before decreasing due to concentration quenching.

Eu:Y2O3 highly dispersed fluorescent PVA film as turn off luminescent probe for enzyme free detection of H2O2

In this work, a novel sensing scaffold consisting highly dispersed Eu:Y2O3 fluorescent flexible film of poly vinyl alcohol (EYCP) was synthesized by simple mixing method and applied to facilitate non-enzymatic detection of hydrogen peroxide (H2O2) by turn off probe of fluorescence. The fluorescence spectra of EYCP consisting number of emission sharp transitions from excited, 5D0→7Fj (j=0, 1, 2, 3, 4) energy levels of doped Eu3+ ion in Y2O3 host. In the presence of H2O2, the fluorescence intensity of the EYCP film was quenched due to the reduction of electron–hole pair recombination in Eu centers by electron transfer from Eu–O excited state to H2O2 energy level rather than 5D0 state of Eu3+, which reduces the number of electron in 5D0 state. The EYCP film shows excellent fluorescence quenching in presence of H2O2 by significantly increasing concentration of H2O2 and completely quenched at ∼150μM. A linear relationship is observed between 0.0 and 60μM with a correlation coefficient of 0.989. H2O2 sensing is also compared with the EYC nanoparticles. This study is expected to have a significant impact on further study of the Eu:Y2O3 fluorescent flexible film for wide range applications.

Screening of Er3+/Yb3+Codoped RE–Ta–O and RE–Nb–O (RE = Y, La, or Gd) Upconversion Phosphors

Upconversion (UC) phosphors comprising Er3+/Yb3+ codoped rare-earth complex oxides, RExTayOz and RExNbyOz (RE = Y, La, or Gd), were synthesized via the gelable citrate complex method, and their UC emission properties were compared. This led to the discovery of an intense green-emitting UC phosphor, YTa7O19:Er3+/Yb3+, which is the first example of a YTa7O19 UC phosphor host material. Green UC emission obtained using optimum Er3+ and Yb3+ content was 20 times stronger than that obtained using a Y2O3 host.

Eu3+ ions imminence impact on its photoluminescence in Y2O3 host

A systematic photoluminescence study on 2% Eu-doped Y2O3 particles has been carried out. It is observed that 1300°C annealed samples show higher non-radiative contributions, poor lifetime and quantum efficiency in comparison to the samples annealed at lower temperatures (700°C and 900°C), even though the structural symmetry and emission profile remains almost unaffected by the increasing annealing temperature. Based on empirical exploration it has been established that annealing at 1300°C, reduces the average distance between Eu ions to ~6.7Å on. Odd behavior of 1300°C heated Y2O3:Eu sample has been attributed to the decreased interatomic separation i.e. increased proximity and associated increase in interaction between Eu ions. The inferences has been further supported by luminescence investigation of Y2O3 sampled co-doped with Yb–Er.

Hydrothermal synthesis, structural analysis and room-temperature ferromagnetism of Y2O3:Co2+ nanorods

Co2+-doped Y2O3 nanorods of 70–100nm diameters and 0.3–2µm lengths with different compositions (x=0.00, 0.04, 0.08) in Y2−xCoxO3 were synthesized by an easy hydrothermal method. The X-ray diffraction, Raman spectra, X-ray photoelectron spectroscopy and transmission electron microscopy (TEM) results indicated the formation of a pure cubic phase structure of Y2O3 doped with Co2+ ions without any secondary phase formation. The TEM analysis indicated that the nanorods were grown along the [100] axis. The pure Y2O3 nanorods showed diamagnetism whereas the Co2+-doped ones exhibited room-temperature ferromagnetism. The existence of such room-temperature ferromagnetic behavior in Co2+-doped Y2O3 nanorods is due mainly to the existence of oxygen vacancies originating after the doping of transition metal ions in the Y2O3 host lattice. Oxygen vacancies act as defect centers in the bound magnetic polaron model to account for this dilute magnetic oxide of medium band gap with low transition-metal-ion concentration. The presence of defect-related oxygen vacancies was further confirmed by photoluminescence spectra analysis of our studied materials.

Investigation of luminescence mechanism in La0.2Y1.8O3 scintillator

La0.2Y1.8O3 is a new and promising scintillator which is based on the host material without doping. Here the time gated X-ray excited optical luminescence is measured by using the excitation energy below, above and at the La L3-edge. A relatively slow and broad emission with peak at 415nm has been observed as the dominant emission. Also, a weak emission at 360nm is observed at the fast window, associated with the recombination of trapped excitons in Y2O3 host. The observations show that the broad emission at 415nm is most likely due to the recombination of trapped excitons associated with the La3+ doping into Y2O3 sites.

Microwave synthesis of Y2O3:Eu3+ nanophosphors: A study on the influence of dopant concentration and calcination temperature on structural and photoluminescence properties

Red fluorescent emitting monodispersed spherical Y2O3 nanophosphors with different Eu3+ doping concentrations (0–13mol%) are synthesized by a novel microwave assisted urea precipitation, which is recognized as a green, fast and reproducible synthesis method. The effect of Eu3+ doping and calcination temperature on the structural characteristics and luminescence properties of particles is investigated in detail. The as prepared powders have (Y,Eu)(OH)(CO3) structure which converts to Y2O3:Eu3+ from 500°C and become crystalline at higher temperatures. The crystallite size of nanophosphors increased from 15nm to 25nm as the calcination temperature increased from 700°C to 1050°C. The efficient incorporation of Eu3+ ions in cubic Y2O3 host matrix is confirmed by the calculated X-ray Powder diffraction (XRPD) structural parameters. The scanning electron microscopy (SEM) and transmission electron microscopy (TEM) micrographs show that the as obtained and calcined particles are spherical, monodispersed and non-agglomerated. The overall size of particles increases from 61±8nm to 86±9nm by increasing Eu3+ concentration from 0mol% to 13mol%. High resolution TEM revealed polycrystalline nature of calcined particles. The particles exhibit a strong red emission under ultraviolet (UV) excitation. The photoluminescence (PL) intensity of the peaks increases proportionally with Eu3+ concentration and the calcination temperature with no luminescence quenching phenomenon observed even for Y2O3:13%Eu3+. The fluorescent emission properties combined with the monodispersity and narrow size distribution characteristics make the Y2O3:Eu3+ heavy metal free nanophosphors applicable in fluorescence cell imaging and as fluorescence biolabels.

Synthesis of Y2O3 phosphor by a hydrolysis and oxidation method

A novel and convenient hydrolysis and oxidation method was first used in preparation of carbon contained Y2O3 phosphor powders. The alloy was hydrolyzed in deionized water and the obtained Y(OH)3 powders were heat treated in air atmosphere. The final products - Y2O3 powders were micron clusters which were aggregated by hundreds of nanoparticles with the size of about 5 nm. The chemical composition, structural and morphological features of the samples were characterized by means of X-ray powder diffraction (XRD) analysis, transmission electron microscopy (TEM), Fourier-transform infrared (FT-IR) spectra, X-ray photoelectron spectra (XPS) and carbon sulfur analyzer. The obtained powders showed good bluish-white photoluminescence (PL) emissions (ranging from 430 to 600 nm, peaking at 468 nm and 578 nm) under the xenon light excitation. The luminescent mechanism was ascribed to the carbon impurities in the Y2O3 host.