ZnO P2O5 Glasses Research Articles

Photoluminescence and radioluminescence properties of MnO-doped SnO–ZnO–P2O5 glasses

In this study, the photoluminescence and radioluminescence properties of MnO-doped SnO–ZnO–P2O5 glasses are examined. We have confirmed that linear dose-dependence and radioluminescence emission decay depend on Mn2+ concentration. Energy transfer from donor Sn2+ center to acceptor Mn2+ center is observed in both photoluminescence and radioluminescence processes, and the energy transfer efficiency is more than 90% when the Mn2+/Sn2+ ratio is 5. Since emission intensity of Mn2+ is higher than that of Sn2+ in radioluminescence compared to photoluminescence, it is suggested that energy transfer from the host matrix to Mn2+ center by X-ray occurred preferentially over energy transfer to Sn2+ center. The present results suggest that the conventional parity rule for photoluminescence is not always adaptable for radioluminescence, although emission-related energy levels are the same for both the processes.

The effect of WO3 dopant on the structural and optical properties of ZnO–P2O5 glass and the effect of gamma irradiation

Zinc phosphate glasses doped with different ratios of tungsten trioxide were prepared. Optical and infrared absorption spectra were investigated before and after subjecting the glasses to 80kGy gamma ray dose. The base undoped zinc phosphate glass shows strong and broad UV absorption band centered at about 240nm but with no visible bands. The WO3-doped glasses reveal the same UV absorption bands beside extra three bands at 330, 380 and 575nm which are related to the presence tungsten ions in the pentavalent state. Infrared absorption spectra show characteristic variable phosphate groups with limited variations when introducing WO3 in the doping level up to 0.75%. Electron spin resonance measurements of the selected high doped tungsten glass indicate that mixed penta- and hexa-valent states of the tungsten ions and on gamma irradiation the pentavalent increases. The result supports the optical absorption after gamma irradiation which involves photochemical reactions in the UV region and the transformation of some W6+ to W5+ by absorbing electrons during the irradiation process.

Multi-wavelength-driven solar spectral conversion in P2O5–ZnO–Li2O glasses for improving greenhouse photosynthetic activity

The highest quantum efficiency among amorphous materials was recently observed in the ns2-type Sn2+ activators doped ZnO–P2O5 glass system, which is comparable to the MgWO4 crystal. In this paper, Mn2+/Sn2+-codoped low-melting 44P2O5–36ZnO–20Li2O (PZL) glasses were prepared by the melt-quenching method to explore blue and red emission materials for greenhouse. Photoluminescence properties of the PZL glasses were investigated systematically by decay curves and absorption, excitation, and emission spectra. The glasses have high optical transparency in the visible region, and can emit intense red light excited at 300, 354, 409, and 505nm. Significantly, upon 300nm excitation, dual blue/red emissions were achieved. Moreover, the ratio of red to blue light could be tuned by adjusting the energy-transfer (ET) of Sn2+→Mn2+ through simply adjusting the content of Mn2+. Our research extends the utilization of solar energy in glass greenhouse for plant cultivation.

Structural and thermochemical study of Na2O–ZnO–P2O5 glasses

Glasses of the (50−x/2)Na2O–xZnO–(50−x/2)P2O5(3≤O/P≤3.49) and (50−x)Na2O–xZnO–50P2O5 (O/P=3) (0≤x≤33mol%) compositions were prepared using the conventional melt quenching technique. The increase of density and glass transition temperature in both series is related to the reticulation of phosphate chains.For the first series of glasses, Fourier-transformed infrared (FTIR), Raman and 31P solid state magic angle spinning nuclear magnetic resonance (MAS-NMR) spectroscopy revealed the decrease of Q2 tetrahedral sites and the increase of phosphate dimers (Q1), indicating the shortening of phosphate chains. For the second series, FTIR and Raman spectroscopy show only the presence of Q2 tetrahedral sites.Dissolution of these series in 4.5% weight of H3PO4 solution has been followed calorimetrically and showed that the dissolution of the first series is endothermic for the low ZnO content and becomes exothermic when x rises. This behavior is correlated to the structural modification. For the second series, the dissolution phenomenon is endothermic confirming the presence of the same structure over the whole composition range.

Energy Transfer from Sn2+ to RE3+ Cations in ZnO–P2O5 Glass

Abstract The photoluminescence (PL) properties of rare earth (RE)-doped SnO–ZnO–P2O5 (RE-SZP) glass were examined in the visible region. RE-SZP glass, except for those doped with Ce3+, exhibited similar optical band edges because of the s–p transition in Sn2+. The RE3+ PL excitation bands in RE-SZP glass were red-shifted compared to the bands in Sn-free glass because of the energy transfer from the Sn2+ center. In addition, the emission intensity in a few RE-SZP glass systems was remarkably enhanced by Sn2+ addition. Emission decays of Sn2+ in the glass were typically independent of the RE3+, and suggest the exchange interaction between Sn2+ and RE3+. This indicated that the RE3+ cation is generally located close to the Sn2+ center in order to allow energy transfer.

Proton conductivities and structures of BaO–ZnO–P2O5 glasses in the ultraphosphate region for intermediate temperature fuel cells

Phosphate glasses are promising materials for electrolytes of intermediate temperature fuel cells, because they have good proton conductivity at 150–250 °C. However, the effects of the glass composition and melting condition on proton conductivities are unclear yet. In this work, the structures of BaO–ZnO–P2O5 glasses were investigated by magic angle spinning-nuclear magnetic resonance (MAS-NMR) and Raman spectroscopy, and the proton conductivities were measured by an AC impedance method. The proton conductivity of 30 mol%ZnO-70 mol%P2O5 glass melted at 800 °C reached 1 × 10−3 S/cm at 250 °C for. The proton transportation number of the ZnO–P2O5 glass was almost unity, confirmed by a hydrogen concentration cell. The power density of 0.4 mW/cm2 was obtained for a fuel cell using the ZnO–P2O5 glass electrolyte at 250 °C. A branching phosphate structure was transformed into a middle phosphate structure by substituting BaO with ZnO, which caused an improvement in proton mobility.

Emission property of Sn2 +-doped ZnO–P2O5 glass

Photoluminescent properties of amorphous zinc phosphate glass, containing Sn2+ as an emission center, were investigated. Varying the chemical composition changed both the excitation and emission properties. The redox reaction that occurred during melting was found to affect both valences of transition metal and Sn cations to change the emission property of the Sn2+-containing glass. We have also examined the emission property of substituted SnO–ZnO–P2O5 glass, and demonstrated that the emission color can be tailored by chemical composition to obtain blue, white, and red. It is notable that the quantum efficiency value of the present RE-free glass is comparable to that of crystal phosphor such as MgWO4. We have, therefore, emphasized that transparent inorganic glass phosphor will be one of the fascinating emitting materials adoptable to future strong LED light source.

Preparation of rare-earth-free oxide glass phosphors

Light emission in rare earth (RE)-free SnO–ZnO–P2O5 glasses is demonstrated. The RE-free transparent phosphate glasses show light emission with high quantum efficiency (QE) values, comparable to conventional crystalline phosphors, by excitation with deep-UV light. The broad emissions of the RE-free transparent glasses can be continuously tuned by both the amount of activator and the composition of the glasses, without reduction of the QE values. For future emitting devices, we believe that the low-melting glasses will constitute one of the most industrially favorable inorganic materials possessing transparency and emitting properties.

Electronic states of SnO-ZnO–P2O5 glasses and photoluminescence properties

SnO–ZnO–P2O5 glasses with 30 and 40mol% P2O5 were prepared by a melting process in an air atmosphere. The glass transition temperature, refractive index, and photoluminescence of the glasses were investigated. The electronic states of Sn(II) and Sn(IV) were determined by Mössbauer spectroscopy. The PO4 units were investigated by Raman spectroscopy. The glass transition temperature was lower than 450°C, and decreased as the Sn concentrations increased, so that the minimum was about 250°C. The refractive index increased as the Sn concentration increased. The emission spectra of the glasses peaked at around 2.0–3.0eV and depended on the glass compositions.

Photoluminescent Properties of Sb‐Doped Phosphate Glass

The authors report on the UV‐excited photoluminescence measured in Sb2O3–ZnO–P2O5 glass. Pre‐heat treatment performed before melting effectively prevented the discoloration caused by precipitation of Sb nanoparticles. Although both Sb3+ and Sn2+ belong to the ns2‐type emission center, the Sb3+‐doped 60ZnO–40P2O5 glass showed an emission with a weaker intensity and a broader band than Sn2+‐doped 60ZnO–40P2O5 glass. The emission decay of 1.0SbO3/2–60ZnO–40P2O5 glass was about 2.5 μs, which was shorter than that of 1.0SnO–60ZnO–40P2O5 glass. The obtained results suggest that the emission properties of ns2‐type emission centers depend on several factors, such as element of emission center, chemical composition, and preparation scheme, which are easily and widely tuned in random amorphous materials.

High efficient white light emission of rare earth-free MnO-SnO-ZnO-P2O5 glass

White light emission of rare earth (RE)-free Mn-doped SnO–ZnO–P2O5 glass is demonstrated. Glass transition temperature of the obtained glass is below 440°C, which assures the application to sealant of solid state light emitting devices. The RE-free transparent glass shows white light emission with a high value of quantum efficiency (QE) comparable to conventional crystalline phosphor by excitation of deep UV light. The broad emission of RE-free transparent glass can be continuously tuned by both the amount of activator and the composition of the glass without decrease of the QE value.

Properties and structures of TiO2-ZnO-P2O5 glasses

The glass forming region of TiO2–ZnO–P2O5 glasses was investigated at 1400°C, which is lower than the melting temperature of general titanophosphete glasses. TiO2 could be added up to 15 mol% in the TiO2–ZnO–P2O5 glasses. The glass forming region of 15TiO2–ZnO–P2O5 was quite smaller than that of ZnO–P2O5, and the glasses with TiO2 were colorized by the formation of Ti3+. The refractive index of the glasses increased with increases in the TiO2 concentrations, and the maximum was 1.656. The glass transition temperature, Tg, of the glasses increased with increased TiO2 concentrations, although Tg decreased with increases in the ratio of ZnO to P2O5. Raman spectra of the glasses suggested that P–O–Ti bonds were formed by the addition of TiO2. The increase in Tg and the narrow glass forming region were caused by the formation of strong chemical bonds, P–O–Ti.

The Influence of Sb2O3Addition on the Properties of Low‐melting ZnO–P2O5Glasses

The influence of 0–16 mol% Sb2O3substitution for P2O5on the properties of ZnO–P2O5glasses has been investigated. It was shown that Sb2O3could participate in the glass network and thermal stability of the glasses decreased with increasing Sb2O3content. Glass transition temperatureTg, softening temperatureTs, and water durability all decreased firstly (up to 6 mol% Sb2O3added) and then increased. Substitution of 12 mol% Sb2O3led to a 16°C decrease inTgand 30°C decrease inTs, and weight loss of the glass was only 0.42 mg/cm2, which is ∼11 times lower than that of the glass without Sb2O3after immersion in deionized water at 90°C for 1 day. The glass containing 12 mol% Sb2O3might be a substitute for Pb‐based glasses in some applications.

Dissolution behavior of ZnO–P2O5 glasses in water

Bulk binary ZnO–P2O5 glasses with 50–70mol% ZnO were immersed in distilled water at 30–90°C for up to 72h. The immersed samples were characterized by weight loss, the change in solution pH, X-ray diffraction (XRD) analysis, scanning electron microscopy and Raman spectroscopy. Weight loss decreased with ZnO concentration for all immersion temperatures. Dissolution behavior was classified into two types in terms of weight loss and macroscopic appearance. Type I was primarily recognized in 50–60mol% ZnO glasses. In type I, the weight loss for 72h was relatively large (>1.0×10−7kgmm−2, >10% of initial sample weight). Raman spectra of the type I glasses indicated that the depolymerization of phosphate glass network occurred during the dissolution process. Crystalline Zn2P2O7·3H2O was precipitated in the water solution after immersion. Type II dissolution behavior was recognized in the 65 and 70mol% ZnO glasses except for the 65ZnO–35P2O5 glass immersed at 90°C. In the type II behavior, the weight loss for 72h was relatively-small (<1.0×10−8kgmm−2, <1% of initial sample weight). The microstructure of the type II glass indicated selective dissolution. The dissolution process of the type II glass is discussed.

Gamma-ray dosimetry using zinc phosphate glasses

A series of ZnO-P2O5 glass systems has been prepared by melting ZnO with anhydrous P2O5 in an open crucible. The temperature dependence on the d.c. electrical conductivity measurements for these glasses is studied over the temperature range from room temperature to 573 K. It was found that the d.c. conductivity decreases with increasing mol% ZnO. The induced changes in the d.c. electrical conductivity caused by different doses of gamma irradiations were also studied. Gamma doses up to 5.O Mrad were used, results were explained and discussed in terms of the interaction of gamma rays with the glass compositions. Results of the present work have shown that the effect ofγ-ray on the d.c. conductivity of the glass system is composition dependent and the low ZnO concentration specimen is more sensitive to theγ-irradiations.

37 Evaluation of the technicon immunoglobulin kits on RA-1000

In order to study the influence of rubidium (Rb) addition on the phase composition, microstructure, mechanical properties and cell response of bioactive glass-ceramics, CaO–SiO2–Na2O–B2O3–MgO–ZnO–P2O5 glass system was designed with and without addition of Rb. The results show that hydroxyapatite (HA) and Mg–whitelockite (Ca18Mg2H2(PO4)14) crystalline phases are formed in the glass matrix without Rb. After the addition of Rb, only HA phase is detected. The grain size of the crystals in the glass-ceramics is larger with the addition of Rb than that of samples without Rb. Rb addition can improve the bending strength of glass-ceramics. The cultivation of human bone marrow mesenchymal stem cells (hBMSCs) on Rb-containing glass-ceramics demonstrates enhanced cell adhesion, proliferation and ALP activity. In conclusion, Rb-modified glass-ceramics exhibit good mechanical property, excellent bioactivity and biocompatibility, which have potential for bone regeneration application.