The role of sulfate ions on distinctive defect emissions in ZnO:Ce3+ nanophosphors - A study on the application in color display systems

Letswalo, M.L.A.; Reddy, Leelakrishna; Balakrishna, A.; Swart, H.C.; Ntwaeaborwa, O.M.

doi:10.1016/j.jlumin.2021.118462

Cited by 10 publications

(3 citation statements)

References 57 publications

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“…Cerium-doped ZnO is widely used due to its unique properties including visible-light-emitting devices [13,14], catalytic characteristic [15][16][17], new diluted magnetic [18], spintronics [19,20] and gas sensor [21]. Various synthesis techniques have been used to prepare ZnO nanoparticles, such spray pyrolysis [22], RF magnetron sputtering [23], solid-state reaction [24], solution method [25,26], electrospinning [27] co-precipitation [28], sol-gel [29,30]. In this study, we report the Ce concentration on structural, morphological, and optical properties of sample films deposited by the sol-gel method combining the spin coating technique and water bath growth.…”

Section: Introductionmentioning

confidence: 99%

Crystal Structure and Optical Properties of ZnO:Ce Nano Film

Xin

2022

Molecules

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ZnO and cerium-doped ZnO on a glass substrate have been prepared by the sol–gel method using the spin coating technique and water bath growth process. Ce-doping concentration on film structure, morphology, and optical properties is investigated. The result indicated that the hexagonal wurtzite ZnO with high crystalline quality formed on the substrate. The crystal parameters a and c decreased, crystal size increased, and the compressive strain formed after Ce-doping. Formed un-, 3%, 6%, 12% Ce-doped ZnO film has a spherical shape with a size between 8.6–31, 14–52, 18–56, and 20–91 nm, respectively. All films had good absorption of 300–400 nm ultraviolet light, in particular, the absorption of near ultraviolet (370–400 nm) increased after doping of Ce. The transmittance of light between 400–800 nm decreased with Ce-doping concentration. The band gap energy increased after Ce-doping reaching better optical behavior for preparing ZnO heterostructured thin-film. All film emitted intense blue emission under 375 nm excitation at room temperature. This indicated the film can have application in optoelectronic devices.

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Section: Introductionmentioning

confidence: 99%

Crystal Structure and Optical Properties of ZnO:Ce Nano Film

Xin

2022

Molecules

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“…The band gap values of PBNSEu glass were altered with the increase in the concentration of Eu 3+ ions due to the structural modification and nonbridging oxygen (NBO) forming in the network. [ 25,26 ] As the band gap value is inversely correlated with the Urbach energy value, this indicates the level of defects in the prepared glass. A tail of energy near the absorption coefficient and optical band edge is known as Urbach's energy band.…”

Section: Resultsmentioning

confidence: 99%

“…In host materials doped with Eu 3+ ions, absorption transitions from both the 7 F 0 (ground state) and 7 of Eu 3+ ions due to the structural modification and nonbridging oxygen (NBO) forming in the network. [25,26] As the band gap value 0.3EuKTTB 3.290 3.134 0.52 [24] 0.5EuKTTB 3.262 3.092 0.54 [24] 1EuKTTB 3.235 3.072 0.60 [24] 2EuKTTB 3.211 3.053 0.80 [24] absorption coefficient and optical band edge is known as Urbach's energy band. [27] Plotting lnα vs photon energy (hʋ) with their inverse slopes gives the ΔE value, and an empirical expression is presented here as α(ν) = α0 exp (hʋ ΔE).…”

Section: Ft-tr Spectra Analysismentioning

confidence: 99%

Optical, emission, and excitation dynamics of Eu³⁺‐doped bismuth‐based phosphate glass for visible display laser applications

et al. 2022

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Eu3+‐doped‐bismuth‐based phosphate glasses with chemical equation (60 − x)P2O5–20Bi2O3−10Na2CO3–10SrF2–xEu2O3 (PBNSEu), (where x = 0, 0.1, 0.5, 1.0, 1.5 and 2 mol%) were fabricated using the melt‐quenching method. Obtain X‐ray diffraction (XRD), energy‐dispersive X‐ray (EDAX), and Fourier transform infrared (FTIR) spectra were used to characterize the structure of the prepared PBNSEu glass. The J–O (Judd–Ofelt) intensity parameters (Ω2, Ω4) were estimated using photoluminescence emission spectra. When excited with a xenon lamp at λexc = 394 nm, the most intense red‐emission transition occurred at ~612 nm (5D0→7F2). J–O intensity parameters were used to calculate radiative properties, whereas the radiative branching ratio (βR), radiative transition probability (AR), radiative lifetime (τR), and total radiative transition rate (Aτ) were calculated for the transitions 5D0→7FJ (where J = 0–4) and were obtained in the emission spectra for europium ion‐doped in the current glass. Using the CIE1931 chromaticity coordinates axes, the colours of various concentrations of Eu3+ ion‐doped PBNS glass were evaluated using the emission spectra. Temperature‐dependent luminescence spectra were recorded for the optimized PBNSEu20 glass to calculate the activation energy. These results strongly suggested red components in w‐LEDs and visible display laser applications.

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The Role of Anions in Rare-earth Activated Inorganic Host Materials for its Luminescence Characteristics

Reddy

2024

J Fluoresc

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This work is inspired from the comprehensive work done by our research team aimed at improving the efficiency of white light emitting diodes (LEDs) through improvements in the colour rendering index of the red light (CRI), one of the primary colours of white light. Such work is triggered through the incorporation of anions (BO33−, PO43−, SO42−), either individually or as an integral part of dopant activated inorganic phosphor host materials. Numerous host materials such as ZnO, Y2O3, Ca3(PO4)2, CaMoO4, ABPO4, ABSO4 (where A represents alkali metals and B alkaline earth metals) have been considered ideal hosts materials for studying luminescence properties of materials (including other phosphors). In addition, red emitting dopants such as Sm3+, Eu3+ and Ce3+ have been incorporated into these host materials to achieve a higher CRI of red colour, an essential component of white light. The role anions in various materials is multifaceted; firstly, it acts as sensitizer whereby it absorbs excitation energy and transfers it non-radiatively to the dopants, secondly, it acts as a charge compensator to dopants with a charge of + 3, thirdly, it creates crystal fields that affects the electronic transitions of the dopants and fourthly, it creates a stable crystal structure that allows for dopant embedding. By understanding the exact role of these anions and their interactions with the host lattice and dopant ions, we could further optimize the luminescent properties of these activated host materials, which leads to higher efficiencies and performances in white light-emitting diodes and other lighting technologies. This work is a comprehensive review of the work undertaken by our research team aimed at enhancing the luminescent properties of WLEDs.

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The role of sulfate ions on distinctive defect emissions in ZnO:Ce3+ nanophosphors - A study on the application in color display systems

Cited by 10 publications

References 57 publications

Crystal Structure and Optical Properties of ZnO:Ce Nano Film

Crystal Structure and Optical Properties of ZnO:Ce Nano Film

Optical, emission, and excitation dynamics of Eu³⁺‐doped bismuth‐based phosphate glass for visible display laser applications

The Role of Anions in Rare-earth Activated Inorganic Host Materials for its Luminescence Characteristics

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The role of sulfate ions on distinctive defect emissions in ZnO:Ce3+ nanophosphors - A study on the application in color display systems

Cited by 10 publications

References 57 publications

Crystal Structure and Optical Properties of ZnO:Ce Nano Film

Crystal Structure and Optical Properties of ZnO:Ce Nano Film

Optical, emission, and excitation dynamics of Eu3+‐doped bismuth‐based phosphate glass for visible display laser applications

The Role of Anions in Rare-earth Activated Inorganic Host Materials for its Luminescence Characteristics

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Optical, emission, and excitation dynamics of Eu³⁺‐doped bismuth‐based phosphate glass for visible display laser applications