Spectroscopic studies of Sm3+/Dy3 + co-doped lithium boro-silicate glasses

https://doi.org/10.1016/j.jnoncrysol.2016.02.010Get rights and content

Highlights

  • Sm3 + + Dy3 + co-doped Li2O–B2O3–SiO2 glasses were prepared by melt quenching.

  • Sm3 + glasses gave a reddish orange emission.

  • Dy3 + glasses gave both blue and yellow emissions.

  • Emission bands of Sm3 + ions along with the Dy3 + ion were obtained.

  • The emission color could be tuned by using different excitation wavelengths.

Abstract

Sm3 + + Dy3 + co-doped lithium boro-silicate glasses were prepared by the melt quenching technique. These glasses were characterized by X-ray diffraction (XRD), field emission scanning electron microscope (FE-SEM) and spectroscopic tools to understand the effect of Sm3 + + Dy3 + ions on various properties of the glasses. XRD confirmed that the prepared glasses were amorphous in nature. The FE-SEM analysis revealed the homogeneity and authenticated the various added glass constituents. On excitation with 403 nm the Sm3 + glasses gave a reddish orange emission (4H9/2) while the Dy3 + glasses gave both blue (6H15/2) and yellow (6H13/2) emissions. The emission spectra of the Sm3 + + Dy3 + co-doped lithium boro-silicate glasses showed the emission bands of Sm3 + ions along with the Dy3 + ions. The detailed analysis confirmed that, there was no energy transfer between the Sm3 + and Dy3 + ions. The emission color could be tuned by using different excitation wavelengths for glasses prepared for the present study.

Introduction

The scientific association approved 2015 as the International Year of Light and Light-based Technologies due to the significance of lighting and display systems in every field of the human civilization. In the history of mankind, light plays a vital role, and it is an essential element of technology in the 21st century. Since the inception of human society to till date, scientific community continuously tries to develop materials or devices that can be useful in everyday life for the light application. When Thomas Edison developed a first incandescent lamp, mankind took a first step in the production of light without any combustion, smell and smoke [1]. The major breakthrough in the production of light was the invention of the light emitting diode (LED). In the beginning, LEDs were only useful in the use as indicators or in children's toys. In the 80's the invention of the blue LED by the Nobel Prize winners of 2014 opened a new window for white light combining blue, green and red light [2], [3]. Currently, LED research is one of the most extensive areas of research. In the recent years, various groups and commercial companies were focused on the development of new LED materials with higher efficiency. Many researchers already succeeded in producing some fascinating results.

Glasses are one of the interesting and widely known materials. Glasses offer a broad range of composition, homogeneity, and easy formability in any shapes and size. Introducing rare earth ions or any other microcrystallites in the glasses, provide materials with tunable properties for specific applications [4], [5]. As there is an absence of crystallinity in the glasses, they are advantageous over crystalline materials due to their unique structure and thermodynamics [5]. Glasses activated with trivalent rare earth (RE3 +) ions possess broad emission bands which are beneficial for laser and optical fibers [6]. Among all the rare earths, Sm2O3 and Dy2O3 are interesting to study since Sm3 + ions offer orange-red fluorescence in the visible region with strong fluorescence intensity [7], [8], [9] on the other hand Dy3 + ions show strong blue and yellow emissions [10], [11], [12]. Various reports on the Sm3 + ion and Dy3 + ions containing glasses showed that with the incorporation of these ions there is a significant improvement in the properties of the glasses [7], [8], [9], [10], [11], [12], [13], [14], [15], [16], [17], [18].

In this study, we have focused on the effect of co-doping of Sm3 + and Dy3 + ions on the spectroscopic properties of lithium borosilicate glasses and to check the energy transfer mechanism if any between these two rare earth ions. For this study, we choose Sm3 + and Dy3 + ions due to their strong luminescence in the visible region. In addition to this on co-doping with other rare earth ions Sm3 + ions act as a sensitizer [19], [20]. Naresh et al. [21] reported on the energy transfer between Sm3 + and Eu3 + ions in 45B2O3–55ZnO (BZn) glasses. They observed that there is a significant increase in the Eu3 + emission with the addition of Sm3 + ions in the glasses. Joshi et al. [22] reported on the non-radiative energy transfer between Sm3 + and Eu3 + ions by the electric dipole–dipole interaction between the donor and acceptor ions in zinc-phosphate glasses. With the increase in the Eu3 + content, there is a decrease in the emission intensity of Dy3 + ions in zinc phosphate glasses. There are currently no reports available on the Sm3 + and Dy3 + co-doped glasses.

Thus, keeping in mind the emission properties of Sm3 + and Dy3 + and their technological importance we are reporting on the spectroscopic properties of Li2O–B2O3–SiO2 glasses. We have chosen this glass system because of its high rare earth solubility, good mechanical strength and easy formability [23]. The variation of the physical properties, absorbance and emission properties of these glasses are reported and discussed in the present work.

Section snippets

Experimental

The Li2O–B2O3–SiO2 (LBS) based glass series was prepared by the melt quenching method. Glasses containing Sm3 +, Dy3 + and Sm3 ++ Dy3 + ions were synthesized separately with general formula as follows:30Li2O:70xSm2O317SiO2:67B2O3wherex=0.5,1,1.5,230Li2O:700.5Sm2O3yDy2O317SiO2:67B2O3wherey=0.25,0.5,0.75,130Li2O:700.5Dy2O317SiO2:67B2O3.

Analytical grade chemical starting materials Li2CO3 (Merck), B2O3 (Merck), SiO2 (Merck), Sm2O3 (Merck) and Dy2O3 (Merck) were weighed in appropriate quantities and

Results and discussions

Table 2, Table 3 depict the values of density measured for singly doped and co-doped glasses. By using the values of density and average molecular weight of glasses different theoretical parameters e.g. concentration of RE ions (N), mean spacing between the RE3 + ion (ri), polaron radius (rp) and field strength (F) of RE–O bond in the glass were further calculated as per the following relations [10].Concentrationofions=mol%ofRENAρglassaveragemolecularweightInternucleardistanceri=1N13Polaronradius

Conclusions

Sm3 + + Dy3 + co-doped glasses were synthesized successfully by the melt quenching method. Detailed characterization of these glasses by XRD, FE-SEM, absorption spectroscopy and emission spectroscopy helped to understand the obtained results. Emission spectra of Sm3 + + Dy3 + co-doped glasses on 403 nm (excitation of Sm3 +) showed the bands belonged to both Sm3 + and Dy3 +. The emission intensity of the Sm3 + ions decreased with the increase in Dy3 + ion concentration. The color co-ordinates for a different

Acknowledgments

This research is supported by the South African Research Chairs Initiative of the Department of Science and Technology and the National Research Foundation of South Africa (grant 84415). The financial support from the University of the Free State is also acknowledged.

References (26)

  • A.G. Souza Filho et al.

    J. Phys. Chem. Solids

    (2000)
  • L. Zhu et al.

    Phys. B Condens. Matter

    (2010)
  • S. Arunkumar et al.

    J. Alloys Compd.

    (2013)
  • S. Shanmuga Sundari et al.

    J. Lumin.

    (2010)
  • Z. Mazurak et al.

    Opt. Mater.

    (2010)
  • V. Naresh et al.

    J. Alloys Compd.

    (2015)
  • G. Venkataiah et al.

    Opt. Mater.

    (2015)
  • D. Zhu et al.

    Displays

    (2014)
  • P. Mottier

    LED for lighting applications

    (2010)
  • J.Y. Tsao et al.

    Ann. Phys.

    (2015)
  • Y. Nanishi

    Nat. Photonics

    (2014)
  • O.V. Mazurin

    Handbook of Glass Data

    (1983)
  • M. Yamane et al.

    Glasses for photonics

    (2000)
  • Cited by (0)

    View full text