DEVELOPMENT OF TB3+DY3+CO-DOPED BORO-PHOSPHATE GLASS FOR COOL WHITE LED AND RADIATION SHIELDING

Abstract

Title oflnvention: Development ofTb3+/Dy3+ Co-Doped Boro-Phosphate Glass for Cool White LED and Radiation Shielding Field of Invention: Material Science, Nanotechnology and Optoelectronics 7. ABSTRACT The Tb3+/Dy3+ co-doped Boro-Phosphate Glass (BPANZDyTb) was synthesized using the melt-quenching method, with the composition: 40% B203, 39% P205, 5%. Al203, 5% NaF, 10% ZnO, 0.5% Tb203, and 0.5% Dy203. The structural properties of the glass were characterized using X-ray diffraction (XRD), Raman spectroscopy, and Fourier Transform Infrared (FTIR) spectroscopy. XRD patterns, recorded in the 10-90° range, confirmed . that the glass is amorphous. FTIR analysis indicated the presence of various structural groups within the network, including BcO-B, B04, BO, P-0, P02, P-0-B; and P04 units. Optical properties were investigated using UV-visible diffuse reflectance spectroscopy, which revealed the photoluminescence excitation peak at 348 nm. The emission spectra exhibited peaks at 484 nm (blue, 4F9/2---> 6Hl5/2), 576 nm (yellow, 4F9/2-+ 6Hl3/2), and 662 nm (red, 4F9/2-+ 6Hll/2). Tb3+ ions-showed characteristic emission peaks at 412 nm (5D3-+ 7F5), 441 nm (5D3---> 7F4), 546 nm (5D4-+ 7FS), and 625 nm (5D4 ---> 7F3). The color coordinates from CIE 1931 chromaticity indicate that the glass is suitable for cold white light-emitting diode (LED) applications, with coordinates of x = 0.3106 andy= 0.3240, and a correlated color temperature (CCT) of approximately 6768 K. Gamma-ray shielding parameters, including the half-value layer O'IVL), mass attenuation coefficient (p/p ), mean free path (MFP), and effective atomic number (Zeff), were calculated using Phy-X software. The results suggest that the Tb3+/Dy3+ co-doped Boro-Phosphate ~. . ...Glass is an effective material for radiation shielding applications.

Specification

1. TITLE OF THE INVENTION
. \1\ I \I\\\ II I II 111\\\1\ II\ \1710083962
Development ofTb3+/Dy3+ Co-Doped Boro-Phosphate Glass for Cool
White LED and Radiation Shielding
2. APPLICANT:
SA VEETHA ENGINEERING COLLEGE
SA VEETHA NAGAR, THANDALAM,
CHENNAI- 602105, TAMILNADU.
3. PREAMBLE TO THE DESCRIPTION
The following specification particularly describes the invention and the
manner in which it is to be performed.
4. DESCRIPTION
4.1 BACKGROUND OF INVENTION
The invention relates to the development of Tb3+/Dy3+ co-doped Bora-Phosphate
Glass (BPANZDyTb) for advanced applications in cool white light-emitting diodes (LEOs)
and radiation shielding. Glasses doped with rare earth ions, such as Tb3+ and Dy3+, are of
significant interest due to their unique luminescent properties, which can be tailored for specific
optical and photo11ic applications. The incorporation ofTb3+ and Dy3+ ions in born-phosphate
glass matrices enhances the glass's luminescence and optical perfom1ance, making it ideal for
LED technology, particularly in the production of cool white light. Furthcnnore, these doped
glasses exhibit promising gamma-ray shielding capabilities, making them suitable for use in
radiation protection devices.
Bora-phosphate glasses arc known for their stability, high transparency, and excellent
thennal properties, while rare earth ions like Tb3+ and Dy3+ offer desirable emission
characteristics that are important for lighting and display applications. By co-doping with both
Tb3+ and Dy3+, this glass achieves a balanced emission spechum that spans multiple
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wavelengths, providing. efficient cool white light emission. Additionally, the combination of
high atomic numbers of these rare earth clements contributes to the glass.'s effectiveness in
attenuating ga=a radiation, thus enhancing its suitability for radiation shielding applications.
This invention represents a novel material with dual functionality, addressing the· growing
demand for advanced materials in both lighting and radiation protection technologies.
4.2 FIELD OF INVENTION
The field of this invention lies in the development of novel luminescent materials for
optical and radiation shielding applications. Specifically, it pertains to the design of rare earthdoped
boro-phosphate glasses with dual functionality, combining cool white light emission for
LED technology and gamma-ray shielding properties. The invention focuses on the co-doping
of Tb3+ (Terbium) and Dy3+ (Dysprosium) ions into a boro-phosphate glass matrix, which
enhances the glass's .optical characteristics, particularly its ability to emit white light across
multiple wavelengths. This makes the material suitable for use in solid-state lighting devices
sucli as cool white LEOs.
In addition to its optical applications, the doped glass exhibits excellent radiation
shielding properties, making it' valuable in nuclear, medical, and space applications where
protection from gamma radiation is critical. The combination of high atomic number elements
like Tb3+ and Dy3+ provides effective attenuation of gamma rays .. This invention thus
straddles the fields of photonics, materials science, and radiation protection, offering
innovative solutions for both energy-efficient lighting and radiation safety .
4.3 DISCUSSION OF THE RELATED ART
Recent studies have explored the potential of Tb3+10y3+ co-doped boro-phosphatc
glasses for both liuninescent applications, such as cool white LEOs, and radiation shielding.
Sharma et al. (20 19) investigated the luminescent and thennal propCI1ies of Tb3+ and Dy3+
doped boro-phosphate glasses, highlighting their efficiency for lighting applications,
particularly for solid-state lighting systems in the visible spectmm [ 1). Rao et al. (2020)
examined these glasses for radiation shielding, noting their effectiveness in gamma-ray
attenuation, which makes them suitable for applications in radiation protection technologies
[2). Similarly, Kumar et al. (2021) focused on the photoluminescent properties of Tb3+/Dy3+
co-doped boro-phosphatc glass systems, demonstrating their suitability for cool white LED
applications with optimal emission spectra and color coordinates [3).
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Bai ct al. (2020) addressed the radiation shielding performance, showing that these
doped glasses effectively attenuate gamma radiation, further confinning their potential in
radiation shielding applications [4]. Singh et al. (2022) highlighted the energy efficiency and
optical performance of these glasses, specifically their enhanced luminescence for LED
lighting systems [5]. Zhou et al. (2021) also emphasized the dual functionality ofTb3+/Dy3+
co-doped glasses, noting their role in both luminescence and radiation shielding [6]. Gao et al.
(2020) explored the combined role of Tb3+ and Dy3+ ions in improving both light emission
and gamma-ray attenuation, demonstrating the practical value of these materials in both
photonics and radiation protection [7]. Basha et al. (2023) conducted a detailed spectroscopic
analysis of these glasses, confirming their potential for use in optoelectronic devices, including
LED applications (8]. Ahmed et al. (2022) further investigated their structural and shielding
properties, confirming that these matetials offer effective gamma radiation protection, making
them suitable for use in medical and industrial settings [9]. Finally, Verma et al. (2023)
provided an extensive review on the synthesis, characterization, and multifunctional
applications of these co-doped boro-phosphate glasses, summarizing their promising potential
in both lighting and radiation shielding technologies [I 0]. These studies highlight the
advancements in the development ofTb3+/Dy3t co-doped boro-phosphate glasses as versatile
materials for usc in both photonic and radiation protection applications.
References:
I. Shanna, A., et al. (20 19). "Lwninescence and thermal stability of Tb3+ and Dy3+ doped
boro-phosphate glasses." Journal of Luminescence, 212, 144-150.
2. Rao, K. M., et al. (2020). "Rare-earth doped boro-phosphate glasses for radiation shielding
and luminescence." Materials Science and Engineering B, 262, 114649.
3. Kumar, V., et al. (2021). "Optical characterization ofTb3+/Dy3+ co-doped bora-phosphate
glass systems for white LED applications." Journal ofNon-Crystallinc Solids, 561, 120725.
4. Bai, R., ct al. (2020). "Gamma radiation shielding performance of Dy3+ and Tb3+ doped
glass ceramics." Joumal of Materials Scicnc~: Materials in Electronics, 31, I 0325-10334 .
5. Singh, P., et al. (2022). "Design and characterization of boro-phospbate glass doped with
Tb3+ and Dy3+ for energy-efficient lighting." Energy Repmts, 8, 2647-2654.
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6. Zhou, W., ct al. (2021). "Fabrication ofTb3+/Dy3+ co-doped bora-phosphate glasses with
high luminescence and radiation shielding capability." Optical Materials, 113, II 0726 ..
7. Gao, X., et al. (2020). "Luminescent properties ofDy3+ and Tb3+ co-doped glasses for light
emission and gamma radiation shielding." Journal of Applied Physics, 128(12), 124504.
8. Basha, R., ct al. (2023). "Spectroscopic analysis of Tb3+/Dy3+ doped bora-phosphate
glasses for optoelectronic applications." Materials Chemistry and Physics, 279, 125788.
9. Al1mcd, R., ct al. (2022). "Radiation shielding performance and structural properties of rareearth
doped bora-phosphate glasses." Radiation Physics and Chemistry, 181, I 09268.
10. Verma, R., et al. (2023). "Tb3+/Dy3+ co-doped bora-phosphate glasses: synthesis,
characterization, and potential applications." Journal of Solid State Chemistry, 315, 123957.
4.4 SUMMARY OF INVENTION
The invention relates to the development of Tb3+/Dy3+ co-doped bora-phosphate
glasses with enhanced luminescent properties for cool white LED applications and superior
gamma-ray shielding capabilities. These glasses are synthesized using the melt-quenching
technique, incorporating a specific composition of B203, P205, Al203, NaF, ZnO, and rareearth
oxides (Tb203 and Dy203). The resulting glass exhibits unique structural features, as
confirmed by X-ray diffraction (XRD), Raman spectroscopy, and Fourier Transfonn Infrared
(FTIR) analysis, revealing an amorphous network containing various structural units such as
B-0-B, P-0, P02, and P04 groups .
Optically, the co-doped glasses demonstrate excellent photoluminescence, with
excitation peaks at 348 nm and distinct emission peaks across blue, yellow, and red regions,
corresponding to transitions in Tb3+ and Dy3+ ions. The chromaticity coordinates (x = 0.3106,
y = 0.3240) and correlated color temperature (6768 K) confirm the suitability of the material
for cool white LED applications. Additionally, gamma-ray shielding properties, including halfvalue
layer (HVL), mass attenuation coefficient (~tip), and effective atomic number (Zeft),
indicate that these glasses are highly effective in radiation attenuation, making them ideal for
use in radiation shielding applications, such as in medical and industrial settings. This invention
provides a versatile material with dual functionality in both photonic and radiation protection
domains.
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4.4 DETAILED DESCRIPTION OF THE INVENTION
Powder X-Ray Diffraction (XRD) Analysis
X-ray diffraction (XRD) studies were performed on the synthesized Tb3+/Dy3+ co-doped
boro-phosphate glass (BPANZDyTb) using a Bruker D8 Advance instrument, with the
diffraction angles ranging from 0° to 90°. The XRD spectra of the glass samples revealed no
crystalline peaks, suggesting that the synthesized material is amorphous. The absence of
crystalline diffraction patterns confirms the non-crystalline nature of the glass matrix, which is
a significant characteristic for glass materials that arc often preferred for their optical and
radiation shielding properties due to their amorphous structure. The amorphous nature of the
BPANZDyTb glass was thus confirmed, distinguishing it from crystalline materials, which
may exhibit unwanted scattering or diffraction phenomena.
Fourier Transform Infrared (FTJR) Analysis
The FTIR spectra of Tb3+/Dy3+ co-doped boro-phosphate glass (BPANZDyTb) were
recorded to investigate the vibrational modes associated with the structural groups in the glass
matrix. In the mid-IR region,· three distinct band groupings were observed. The first group
corresponds to the bending vibrations of B03 units at approximately 650-700 cm-1. The
second band is related to the stretching vibrations of the B04 tetrahedral units at around 850-
1050 cm-1. The third group corresponds to the vibrations of B03 trigonal units, observed in
the range of 1200-1300 cm-1. Additionally, the FTLR spectrwn shows a band centered at 579
cm-1, which is attributed to the bending vibrations of P-0 bonds in P04 units and P-0-B
groups. Another significant band appears at 707 em-I, indicative of the B-0-B bending and
symmetric stretching vibrations in P-0-B linkages. The presence of several other bands, such
as those at 1004 em~] and 1380 cm-1, ftuther supports the formation ofP-0-B connections
between B04 and P04 groups. Vibrational features at 1277 cm-1 and 1380 cm-1 con finn the
existence of pyroborate structures and stretching vibrations of B-0 bonds in B03 units. The
FTIR analysis also reveals the presence of hydroxyl groups (OH), evidenced by the bands at
1744 cm-1 and 3848 em-I, which are attributed to 1'-0H and B-OH vibrations, respectively.
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Fourier Transform Raman (FT -Raman) Analysis
Raman spectroscopy was used to probe the vibrational modes of the structural unit~ within the
BPANZDyTb glass. The Raman spectra, recorded in the range of 0-1600 cm-1, exhibit
characteristic vibrations from both phosphate and .borate structural units. Phosphate units,
having larger ionic radii and higher scattering cross-sections than borate groups, dominate the
Raman spectra. TI1e spectra show prominent bands at 99 cm-1, which correspond to the Boson
peak, indicative of the local collective vibrations of B03 units. This peak reflects the
interaction between the vibrational states at low frequencies. The bending vibration of 0-P-0
units is observed at 473 cm-1, while the band at 550 cm-1 corresponds to the bending of P02
groups. The presence of a band at 717 cm-1 confirms the formation of P-F bonds in the glass
stmcture. Other Raman bands at 993 cm-1 and I 004 em-I are attributed to the symmetric
stretching vibrations ofP04 and B04 tetrahedral units. Higher frequency bands at 1284 cm-1
and 1373 em-I are linked to B-0 stretching vibrations in B03 units, present in metaborate,
pyroborate, and orthoborate groups. These Raman features indicate the presence of various
structural motifs within the bora-phosphate glass matrix, including B-0 bonds, P=O linkages,
and P-0-B connections.
UV-Vis Diffuse Reflectance Spectroscopy (DRS)
The UV-Vis diffuse reflectance spectroscopy (DRS) of the Tb3+/Dy3+ co-doped boraphosphate
·glass (BP ANZDyTb) was carried out across the wavelength range of 200-800 nm.
The spectra display characteristic absorption features due to the intra-4f transitions of the
trivalent rare-earth ions (Dy3+ and Tb3+). A broad absorption band was observed at lower
wavelengths around 220 nm, which is associated with the glass host material. The intra-ionic
transitions of Dy3+ and Tb3+ appear as narrower absorption bands superimposed on this broad
host-related absorption. These absorption lines, primarily arising from Dy3+, indicate· the
presence of characteristic transitions within the 4f electron configuration of the Dy3+ ion, while
some lines in the ultraviolet range are likely due to overlapping absorption features from both
Dy3+ and Tb3+ ions. This suggests that Dy3+ contributes more significantly to the absorption
at these wavelengths compared to Tb3+.
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Figure l Photon energy versus EABF of the Tb3+/ Dy3+ co-doped Bora-Phosphate Glass {BPANZDyTb}
Photoluminescence Analysis
Photoluminescence (PL) measurements of the Tb3+/Dy3+ co-doped boro-phosphate glass
(BPANZDyTb) were conducted to explore its luminescent properties. Excitation spectra were
recorded in the 300-500 run range using a 576 nm light source. The emission spectra were
measured at room temperature in the 400-700 nm range, and several distinct emission bands
were observed, corresponding to differen"t electronic transitions of Tb3+ and Dy3+ ions. The
excitation spectrum showed prominent peaks at 317, 348, 383, 421, 445, and 469 run. The
emission spectra, when excited at 348 nm, exhibited discrete emission bands at 412 nm, 441
nm, 484 run, 546 nm, 576 run, 625 nm, and 662 nm. These emission bands can be attributed to
the electronic transitions from various metastable states of the Tb3+ and Dy3+ ions. The
characteristic blue, yellow, and red emission peaks are indicative of the Tb3+ and Dy3+ ions'
transitions, confirming the potential of this material for cool white LED applications.
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5. CLAIMS:
I. High Quality :
Cool white light emission for LED lighting with a high-quality color temperature
(6768 K).
2. Radiation Protection:·
Superior gamma-ray shielding properties suitable for radiation protection in medical
and industrial environments.
3. Enhanced luminescent applications.
Efficient energy transfer between Tb'• and Dy''· ions for enhanced luminescent
applications.
4. Versatility
Amorphous structure provides versatility for moulding into various forms for optical
and shielding purposes.
5. Multifunctional usc
It can be used for both an optical and radiation shielding material in advanced
applications.

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