Optical properties of biosynthesized nanoscaled Eu2O3 for red luminescence applications

Mohamed, Hamza Elsayed Ahmed; Hkiri, Khaoula; Khenfouch, Mohammed; Dhlamini, Simon Mokhotjwa; Henini, M.; Mâaza, M.

doi:10.1364/josaa.396244

Cited by 27 publications

(4 citation statements)

References 44 publications

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“…However, the ν(Eu-O) vibrations were reported at 451 cm -1 in ZnO:Eu nanoparticles [356], while Mohamed et al reported Eu bending vibrations at 446 cm -1 and 586 cm -1 [357]. Therefore, the bands at 540 cm -1 and 470 cm -1 in the present study possibly correspond to the interactions between OA and TTFA with Mg or Eu metal cations present in the nanoparticles.…”

Section: Ligand Exchange By Schematic Addition Of Ttfa On Oa-capped N...contrasting

confidence: 49%

The Luminescence of Lanthanide-doped NaMgF3 Nanoparticles: Radioluminescence, Radiophotoluminescence and Optically Stimulated Luminescence

Nalumaga¹

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NaMgF3 is a host material that has demonstrated luminescent properties suitable for radiation dose measurements when doped with lanthanide (Ln) ions. NaMgF3 has a response to ionising radiation similar to that of tissue, and hence it has potential application in radiotherapy where a high level of accuracy is required. This thesis focused on investigations into the suitability of NaMgF3 nanoparticles for radiation dose measurements. Nanoparticles display advantages that can be exploited to increase spatial resolution in two-dimensional dosimetry. Additionally, nanoparticles exhibit new and different distributions of optically active traps, and their luminescence can be sensitised to increase the signal to noise. Hence, this thesis presents results obtained from the synthesis and characterisation of Ln-doped NaMgF3 nanoparticles. The nanoparticles were synthesised via the hydrothermal, reverse micelle and thermolysis techniques. Structural studies were carried out, followed by investigations on the effect of X-ray irradiation on the luminescent properties of the nanoparticles. It was observed that compared to the bulk materials, the nanoparticles exhibited increased oxygen (O2-)-related defect luminescence and favoured substitution of trivalent ions over the divalent ions. The behaviour was attributed to the stability of trivalent ions in aqueous solutions during nanoparticle synthesis, which encouraged increased incorporation of O2--related defects to create charge neutrality. O2--related defects allowed for O2- → Yb3+ charge transfer process, hence Yb3+ emission in the infrared region. X-ray stimulation resulted in Yb3+ → Yb2+ radiophotoluminescence (RPL), but the increase in Yb-dopant concentration revealed no significant effect on the structural and luminescent properties. Most of the studied materials exhibited multiple luminescence properties for monitoring radiation doses, which would increase the dose accuracy. Ce-doped nanoparticles exhibited the first reported optically stimulated luminescence (OSL) in Ln-doped near tissue-equivalent NaMgF3 nanoparticles suitable for total radiation measurements. OSL occurred through a series of processes, including the creation of F-centres through X-ray irradiation and optical stimulation to release electrons that recombined with holes trapped at Ce4+ sites, followed by Ce3+ emission. In addition, the Ce3+ → Ce4+ RPL effect suitable for cumulative radiation monitoring was observed from isolated and aggregated Ce3+ sites in the Ce-doped nanoparticles, providing an additional method to increase dose accuracy. Furthermore, the Ce,Sm co-doped NaMgF3 nanoparticles demonstrated suitability for real-time and cumulative radiation dose monitoring via Sm radioluminescence after a priming dose and multiple Ce3+ → Ce4+, Sm3+ → Sm2+, and O2- → O- RPL signals through which cumulative radiation doses can be determined. Finally, the applicability of singly doped oleic acid-capped NaMgF3:Eu and NaMgF3:Sm nanoparticles for radiation monitoring via the Eu3+ → Eu2+ and Sm3+ → Sm2+ RPL effects were demonstrated. The studies were followed by investigations of the sensitisation of Eu3+ and Sm3+ luminescence signals using 2-thenoyltrifluoroacetone (TTFA). The first successful sensitisation of NaMgF3 nanoparticles was demonstrated through remarkable TTFA → Eu3+ energy transfer. However, minimal TTFA → Sm3+ sensitisation was observed, attributable to a non-optimal energy difference between the TTFA triplet state and the Sm3+ resonance energy level, encouraging back energy transfer. TTFA → O2- sensitisation was additionally observed in the NaMgF3:Sm nanoparticles. Furthermore, enhancement of Sm3+ luminescence was additionally demonstrated in the Ce,Sm co-doped nanoparticles via energy transfer from the Ce3+ fully allowed 4f → 5d transitions. The studies resulted in a wealth of information, and where possible, detailed schematic models are presented to explain the observations, which will guide future research. Ultimately, nanoparticles display luminescent properties suitable for dosimetry applications, and the results encouraged further research into the application of nanoparticles as dosimeter materials.

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Section: Ligand Exchange By Schematic Addition Of Ttfa On Oa-capped N...contrasting

confidence: 49%

The Luminescence of Lanthanide-doped NaMgF3 Nanoparticles: Radioluminescence, Radiophotoluminescence and Optically Stimulated Luminescence

Nalumaga¹

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“…However, the popular usage modern QDs as hue changers is hampered by a number of problems: (i) Cd-based compounds are harmful to the environment, and the amount of substitute, greener hosts with elevated quantum effectiveness, which is required for transformation-based LEDs, is restricted. (ii) When QDs are utilized for green and red radiation, the modest Stokes shift causes significant reabsorption [20]- [22]. To reduce some of the reabsorption, distinct ways of QDs has been considered.…”

Section: Results and Analysismentioning

confidence: 99%

Study of phosphor Ba2Si3O8:Eu2+ to produce WLED devices with support from ZnCdSe/ZnSe quantum dot

Huu

Hien

Thai

2022

IJEECS

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We created the blue-green Ba2Si3O8:Eu2+ (or BaE) phosphor treated with Eu2+ using the standard solid-state method with the concentration of Eu as well as heating temperature properly adjusted for the maximum luminescence efficacy. It is possible to excite the said phosphor using near-UV (n-UV) wavelengths and to display its wide emission band, which is the 5d => 4f shift for Eu2+, caused by the combination of the Eu activator and the nearby host. We integrated the said phosphor with the n-UV LED to create the pc-LED (short for diodes based on conversion phosphor). For the task of creating the WLED device that yields significant color rendering index, we combined the orange ZnCdSe/ZnSe quantum dot with a distinctive sheet structure for the pc-LED made with phosphor BaE. This research demonstrates the electroluminescence features of the said elements.

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“…The washed precipitates were finally dried in an oven for 2 h at 70°C and finally annealed in a ceramic boat at 500°C for 2 h in a glass tube furnace. The annealed materials, assumed as HT‐La 2 O 3 NPs, were characterized for investigating their structural, optical, and vibrational properties using multiple techniques 21,26 …”

Section: Methodsmentioning

confidence: 99%

“…The annealed materials, assumed as HT-La 2 O 3 NPs, were characterized for investigating their structural, optical, and vibrational properties using multiple techniques. 21,26…”

Section: Biosynthesis Of Ht-la 2 O 3 Npsmentioning

confidence: 99%

Structural, vibrational, optical, and anticancer properties of Hyphaene thebaica‐reduced nano‐lanthanum oxide (La₂O₃)

Mohamed

Khalil

Hkiri

et al. 2023

Applied Organom Chemis

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Phytoextracts modulated synthesis of nano‐scaled spherical lanthanum oxide nanoparticles (La2O3 NPs) are reported using the aqueous extracts of Hyphaene thebaica as a bioreducing and chelating agent. X‐ray diffraction (XRD) pattern revealed sharp peaks and single‐phase purity. The Debye–Scherrer approximation indicated an average crystallite size of 37 nm, whereas W‐H plot revealed a crystallite size of 59 nm, complemented by the high‐resolution transmission electron microscopy (HR‐TEM). The infrared spectroscopy revealed characteristic La‐O band at 426 and 648 cm−1. K‐M function revealed the bandgap of 5.6 eV, whereas broad intense emission peaks between 345 and 750 nm. The Raman spectra revealed peaks at 182, 325, 384, and 491 cm−1. Elemental composition was confirmed using energy‐dispersive X‐ray spectroscopy (EDS) spectrum, and the spotty rings from selected area electron diffraction (SAED) indicated the crystalline nature of the HT‐La2O3 NPs. In addition, the HT‐La2O3 NPs were investigated for in vitro antioxidant, anticancer, antiangiogenic, and cytotoxic potentials. DPPH free radical scavenging activity was highest, that is, 49.54 ± 0.88% at 1000 μg/mL. MTT assay on MCF‐7 and 3T3 cell lines revealed a median lethal concentration of 114 and 43 μg/mL, respectively. The antiangiogenic effect examined by chick chorioallantoic membrane (CAM) assay indicated inhibition of 57.14 ± 0.96% at 1000‐μg/mL concentration with an IC50 of 551 μg/mL. IC50 for the brine shrimp lethality assay was 314.2 μg/mL. Our study indicates cytotoxicity of HT‐La2O3 NPs, and it further concluded that HT‐La2O3 NPs were more potent against 3T3 cells as compared with MCF‐7 cells. Further research on the biological synthesis and anticancer studies are recommended for the large‐scale applications of the La2O3 NPs.

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Optical properties of biosynthesized nanoscaled Eu₂O₃ for red luminescence applications

Cited by 27 publications

References 44 publications

The Luminescence of Lanthanide-doped NaMgF3 Nanoparticles: Radioluminescence, Radiophotoluminescence and Optically Stimulated Luminescence

The Luminescence of Lanthanide-doped NaMgF3 Nanoparticles: Radioluminescence, Radiophotoluminescence and Optically Stimulated Luminescence

Study of phosphor Ba2Si3O8:Eu2+ to produce WLED devices with support from ZnCdSe/ZnSe quantum dot

Structural, vibrational, optical, and anticancer properties of Hyphaene thebaica‐reduced nano‐lanthanum oxide (La₂O₃)

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Optical properties of biosynthesized nanoscaled Eu2O3 for red luminescence applications

Cited by 27 publications

References 44 publications

The Luminescence of Lanthanide-doped NaMgF3 Nanoparticles: Radioluminescence, Radiophotoluminescence and Optically Stimulated Luminescence

The Luminescence of Lanthanide-doped NaMgF3 Nanoparticles: Radioluminescence, Radiophotoluminescence and Optically Stimulated Luminescence

Study of phosphor Ba2Si3O8:Eu2+ to produce WLED devices with support from ZnCdSe/ZnSe quantum dot

Structural, vibrational, optical, and anticancer properties of Hyphaene thebaica‐reduced nano‐lanthanum oxide (La2O3)

Contact Info

Product

Resources

About

Optical properties of biosynthesized nanoscaled Eu₂O₃ for red luminescence applications

Structural, vibrational, optical, and anticancer properties of Hyphaene thebaica‐reduced nano‐lanthanum oxide (La₂O₃)