Novel Er3+ doped heavy metals-oxyuorophosphate glass as a blue emitter

7 Developed P 2 O 5 -ZnO-PbO-WO 3 -NaF glasses containing Er 3+ ions were prepared by the 8 melt/casting procedures. X-ray diffraction patterns confirmed the amorphicity of the prepared 9 materials. The density and Fourier Transform Infrared FTIR spectroscopy showed that Er 3+ ions 10 play a modifier role and the studied glasses have low phonon energy. The observed decrease in 11 the measured glass transition temperature indicates that the decrease in the bonding strength of the 12 studied glass structure. The studied glass has a high thermal stability. Vickers microhardness 13 results showed the weakening of the glass network. Measured UV-Vis absorption spectra exhibited 14 several bands in the ultraviolet and visible regions. The studied glass has a high refractive index. 15 The metallization criterion showed that the studied glasses have an insulating behavior. The 16 metallization criterion values of the present glasses are in the range of nonlinear optical materials. 17 Under 320 nm excitation wavelength, the studied glass generates three blue bands at 446, 457, and 18 473 nm. The CIE-1931 chromaticity diagram coordinates confirmed the blue emission of the 19 prepared glass. According to the obtained results, the produced glasses have a high potential for 20 using as efficient luminescence materials for photonic devices in the blue region.


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Recently, photonic materials play a tremendous role in several modern devices. A high- applications. Trivalent erbium ion Er 3+ is used as a dopant in various host glasses due to its unique 48 optical properties. The erbium ion is an ideal candidate to be used widely in photonic applications 49 due to its rich energy levels in near infrared, visible, and ultraviolet range [17][18][19] .

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The motivation of the present work is to develop a low phonon energy of glass system 51 incorporated with Er 3+ ions for photonic applications. X-ray diffraction, density, FTIR, DSC, 52 Vickers microhardness, optical absorption were measured. Many structural, thermal, and optical 53 parameters such as mean phosphor-phosphor separation, glass stability, optical band gap, 54 refractive index. Proper amounts of high purity oxides and fluoride were synthesized and melted to get 58 heavy metal oxyfluorophosphate glass containing Er 3+ ion in the chemical formula 45P2O5-25ZnO-59 (20-x)PbO-5WO3-5NaF-xEr2O3, where x in mol% is equal to 0, 1, and 2. The raw materials in the 60 powder form were mixed thoroughly in the agate mortar and placed in a porcelain crucible for 61 melting it in an electric furnace at 1100 °C for 2 h to obtain a homogenous bubble free liquid.

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During the melting period, the molten was intermittent stirring at regular intervals then quenched 63 on a preheated stainless steel mold. The obtained glasses were annealed below the glass transition 64 temperature to eliminate internal thermal stresses.

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The structural phase of the prepared materials was examined using X-ray diffraction  The results revealed diminution in density and growth in molar volume with Er 3+ ions increment.

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The noticeable decrease in the density and augmentation in molar volume indicate that the 105 inclusion of Er 3+ ions to the proposed glass matrix create more interstitial space in the glass 106 network. This space occurs due to the formation of non-bridging oxygens NBOs. The tangible 107 augment of molar volume refers to Er 3+ ions occupy the interstitial space in the present glass 108 network, which meaning the Er 3+ ions enter as a modifier in the studied glass network. This 109 behavior of Er 3+ is responsible for creating the NBOs inside the present glass structure. The mean phosphorphosphor separation − was calculated using standard formula [21] .
where the volume corresponds to the volume that contains one mole of phosphor within 117 the given structure and molar fraction of P2O5, and Avogadro's number. The observed increase in mean phosphorphosphor separation as shown in Figure 3 121 asserts that the expansion in the glass network i.e., the insertion of Er 3+ open the glass network.     . Figure 8 shows the relation between of ( ℎ ) 1/2 versus photon energy ℎ for the 188 sample 3+ free sample as a representative figure, the other samples show the same trend.   The emission band at 457 nm is produced by radiative relaxation from 4 F5/2 level to the ground 241 state 4 I15/2 level. The emission peak at 473 nm is produced through rapid decay of radiative 242 relaxation from 4 F7/2 level to the ground state 4 I15/2. The CIE chromaticity coordinates for 1 and 2 243 mol % of Er 3+ ion are (0.135, 0.045) and (0.133, 0.047), respectively as shown in Figure 12. These        The obtained results of density and molar volume of the studied glasses The mean phosphor-phosphor separation of the studied glasses   Absorption spectra of studied glasses  Optical band gap and Urbach energy as a function in Er3+ of the studied glasses Figure 10 Variation of refractive index and metallization criterion of the studied glasses Figure 11 a) The emission spectra and b) Transition mechanisms of Er3+ in the studied glass network