H. C. Swart

H. C. Swart
University of the Free State | ufs · Department of Physics

PhD

About

1,214
Publications
266,687
Reads
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24,132
Citations
Additional affiliations
January 1985 - present
University of the Free State
Position
  • Sarchi chair

Publications

Publications (1,214)
Article
Full-text available
The fluorescence intensity ratio (FIR) approach, which relies on thermally coupled levels (TCLs), is significantly important for optical thermometry at room tempertaures and above but found impractical for low temperature...
Article
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Er³⁺ and Yb³⁺ doped CaTiO3 phosphors were synthesized via the solution combustion method and analyzed for structural, morphological, and optical properties using X-ray powder diffraction, field emission scanning electron microscopy, and photoluminescence spectroscopy. The Er³⁺ ions showed green and red emissions when excited by a 980 nm infrared so...
Article
The present study reports on the phase formation, spectral, surface, and luminescence properties of the yellowish-white emitting Ba2Mg(BO3)2:Dy3+ phosphors synthesized by the solid-state reaction method. The XRD and Rietveld refinement results confirm the trigonal phase of BaMg(BO3)2:Dy3+ with space group R-3m. The scanning electron microscopy imag...
Article
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The holistic approach of the photoluminescence (PL), thermoluminescence (TL), and persistent luminescence properties at room temperature of BaAl2O4:Tb³⁺ were investigated in detail using a wide range of techniques. Materials were obtained using a solution combustion synthesis. The x-ray powder diffraction patterns of nondoped and Tb³⁺ doped BaAl2O4...
Article
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Nanotechnology has changed and developed all the sectors and working fields. Nanoparticles are one of the important evolutionary materials that have application in almost all the working areas such as catalysis, bioengineering, photoelectricity, antibacterial, anticancer, and medical imaging due to their unique physical and chemical properties. Tra...
Article
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Zinc selenide (ZnSe) thin films were deposited on non-conducting glass substrates at different selenium concentrations using a photo-assisted chemical bath deposition method. The films were deposited for 2.0 h at 80 °C and annealed for 2.0 h at 250 °C. X-ray diffraction (XRD) revealed a hexagonal structure with preferential orientation along the (0...
Article
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Particle-liquid dispersion technique entails a principle analogous to that of an optically thin arrangement of particles, which is applicable in lab-on-a-chip technology, thin coatings for lighting, solar cell sensitization, medical bioimaging, and temperature measurements in fluids. Sr2V2O7:Bi3+ phosphor particles demonstrated the ability to lumin...
Article
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The luminescent properties of Europium (Eu) doped BaAl2O4 phosphors were strongly influenced by post-annealing temperatures for blue-green persistent luminescence and latent fingerprints (LFPs). The X-ray powder diffraction patterns of the...
Article
ZnSe thin films were deposited on nonconducting glass substrates using different Zn[Formula: see text] ion concentrations. The films were deposited at 80[Formula: see text]C for 2.0[Formula: see text]h via photo-assisted chemical bath technique and annealed for 2.0[Formula: see text]h at 250[Formula: see text]C. X-ray diffraction revealed a hexagon...
Preprint
Full-text available
Er ³⁺ and Yb ³⁺ doped CaTiO 3 phosphors were prepared using combustion synthesis. The synthesized samples underwent comprehensive analysis to evaluate their structural, morphological, and optical properties. This analysis encompassed techniques such as X-ray powder diffraction, field emission scanning electron microscopy, and photoluminescence inve...
Article
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A polymer based nanocomposite (NC) material embedded with highly luminescent nanopowders could be promising for replacing traditional luminescent materials from a technological point of view. In this study, we have successfully obtained YPO4: Sm³⁺ /Polymer nanocomposite phosphor films by embedding YPO4: Sm³⁺ luminescent nanoparticles (NPs) for oran...
Chapter
With a vast landscape of material, careful distillation of the most important discoveries helps researchers find the key information. Publications in nanoscience cross conventional boundaries from chemistry to specialised areas of physics and nanomedicine. This volume provides a critical and comprehensive assessment of the most recent research and...
Article
As a potential upconverting layer for solar cell applications, the effect of substrate temperature on the structural, surface, and upconversion (UC) properties of Y2O3:Ho3+,Yb3+ thin films was studied. On soda-lime glass substrates, pulsed laser deposition was used to generate the films. The structural and compositional analyses were performed usin...
Chapter
This chapter presents the reader with a brief overview of the theoretical aspect of persistent luminescence, instead of presenting an extensive review of literature. The chapter focuses on the pathway of the theory of calculating the continuous trap distributions. The persistent luminescence of ultraviolet, red, white, and over 1000 nm were also di...
Article
To investigate the impact of PO 4 ³⁻ anionic groups, the trivalent europium ion‐doped calcium molybdate (CaMoO 3 ‐PO 4 : x Eu ³⁺ , where x = 0.5, 1.0, 1.5, 2.0, and 2.5 mol%) phosphors were synthesized using the solid‐state reaction method. The detailed study of the phosphor materials was carried out by X‐ray diffraction (XRD), field emission scann...
Article
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SiO 2 :x% Cr ³⁺ (0 ≤ x ≤ 8) nanopowder samples were synthesized using the sol-gel method. The effect of Cr ³⁺ doping concentration on the SiO 2 nanoparticles was studied for possible application in light-emitting diodes (LEDs). Structure and optical properties of undoped and Cr ³⁺ doped SiO 2 nanoparticles were investigated in detail. X-ray diffrac...
Article
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The hydroxyapatite (HAp) nanoparticles were effectively engineered through a combination of ultrasonication and microwave techniques. This process significantly enhances the adsorbent’s specific surface area and particle size compared to microwave and other combinational techniques. The particle size of the adsorbent was effectively reduced to 30 ±...
Article
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This work has demonstrated upconversion luminescence in Er³⁺ doped Gd(OH)3 nanocrystals and luminescence quenching arising from the utilization of hexamethylenetetramine (HMTA) for the formation of rod-like morphologies. The synthesis was carried out via the precipitation technique. TG/DTA results show Gd(OH)3 phase is formed and stabilized in the...
Article
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The structural, surface, and upconversion (UC) luminescence properties of Y2O3:Ho³⁺,Yb³⁺ films grown by pulsed laser deposition, for different numbers of laser pulses, were studied. The crystallinity, surface, and UC luminescence properties of the thin films were found to be highly dependent on the number of laser pulses. The X-ray powder diffracti...
Article
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Lanthanide (Ln³⁺) based luminescent materials, with their distinctive emission spectra, offer opportunities to develop novel coding patterns for various applications, including Tracer Based Sorting (TBS). TBS uses trace amounts of inorganic phosphors and is a promising method for sorting plastics based on criteria beyond plastic type. This study in...
Article
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Visualization of latent fingerprints (LFPs) using conventional powders has faced challenges on multicolor surfaces. However, these challenges are addressed by the advent of fluorescent powders in LFP detection, and they...
Article
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This study reports enhancing the emission intensity of Dy³⁺ doped zinc gallate phosphor via Li⁺ monovalent co-doping. 2–12 mol% Li⁺ co-doped samples and a 0.05 mol% Dy³⁺ doped sample were synthesized using a solid-state synthesis technique. X-ray powder diffraction was used to analyze the phase of the synthesized phosphors. By recording the reflect...
Article
A nanocomposite matrix of covellite–polyvinylpyrrolidone (CuS–PVP) was synthesized through a solution processing method and applied via spin coating onto hydrothermally grown zinc oxide (ZnO) nanorods. Characterization techniques, including X‐ray powder diffraction and scanning electron microscopy, confirmed the successful decoration of chain‐like...
Preprint
This work is a study on the photophysical properties of Er3+ doped and Er3+/ Nd3+ co-doped Gd(OH)3 nanocrystals. It also demonstrated up-conversion luminescence quenching arising from utilization of hexamethylenetetramine (HMTA) for the formation of rod-like morphologies. The synthesis was carried out via the precipitation technique. TG/DTA results...
Preprint
Full-text available
This work is a study on the photophysical properties of Er3+ doped and Er3+/ Nd3+ co-doped Gd(OH)3 nanocrystals. It also demonstrated up-conversion luminescence quenching arising from utilization of hexamethylenetetramine (HMTA) for the formation of rod-like morphologies. The synthesis was carried out via the precipitation technique. TG/DTA results...
Preprint
Full-text available
The hydroxyapatite (HAp) nanoparticle was effectively engineered through a combination of ultrasonication followed by microwave techniques. This modification significantly enhances the adsorbent's characteristics compared to microwave and other combinational techniques. The particle size of the adsorbent was effectively reduced to 30×10 ± 3 nm, wit...
Article
Full-text available
Fungal pathogens are a major health issue that threatens the era of antifungal drugs commonly used in the treatment of infections. An effective approach of biosynthetic nanoparticles can be used as antifungal agents owing to their intrinsic features such as their simplicity, non-toxic, and physicochemical properties. Therefore, this study was aimed...
Article
Cadmium telluride (CdTe) thin films were synthesized by using a two-electrode electrodeposition method on a conductive glass fluorine-doped tin oxide (FTO) substrate. The structural analysis revealed that the deposited CdTe thin films have mixed-phase cubic zinc blends and hexagonal structures in as-prepared and annealed forms with pH depositions o...
Article
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The growing need for efficient energy storage has spurred advancements in supercapacitors (SCs), aiming to offer high power and energy density simultaneously. While SCs offer longer cycles and higher power density values, their low energy densities limit practical applications. In response, pseudocapacitive materials have emerged, leveraging revers...
Article
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Cadmium-selenide thin films have been deposited on a glass/fluorine-doped thin oxide substrate using a simple potentiostatic two-electrode electrodeposition configuration. The results of the structural analysis showed that CdSe is nanocrystalline with a cubic zinc blend structure. The energy band gap values of as-deposited CdSe thin films were foun...
Article
Surface-enhanced Raman scattering is a practical, noninvasive spectroscopic technique that measures chemical fingerprints for varieties of molecules in multiple applications. However, synthesizing appropriate substrates for practical, long-term applications of this method has always been a challenging task. In the present study, we show that ZnO/Ag...
Article
Eu3+ ion doped CaF2 thin film was successfully prepared using the hydrothermal method and coated by a spin coating technique. A thin layer of ZnO was deposited on the Eu3+ doped CaF2 thin film by pulsed laser technique. Incorporation of the dopant into the CaF2 crystal was confirmed by x-ray powder diffraction and x-ray photoelectron spectroscopy (...
Article
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Thin films of Bi³⁺ doped LaOCl and LaOF phosphors prepared via the pulsed laser deposition (PLD) technique in vacuum and different argon (Ar) pressures were compared in order to assess their luminescence properties. All peaks of the X-ray diffraction patterns of the films were consistent with the tetragonal structure of the LaOCl and LaOF, but in t...
Article
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ZnO nanorods (ZNRs) were grown on Ga-doped ZnO (GZO) through a two-step procedure, involving pre-treatment to form the seed layer followed by growth of the nanorods through chemical bath deposition (CBD) method
Article
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Divalent europium emission from distinct sites in the Sr 3 Al 2 O 5 Cl 2 host results in two emission bands. The ratio of intensities of these bands is strongly temperature sensitive and can be exploited for two colour ratio-based luminescence thermometry.
Article
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Solar heat management & green air-conditioning are among the major technologies that could mitigate heat islands phenomenon while minimizing significantly the CO2 global foot-print within the building & automotive sectors. Chromogenic materials in general, and thermochromic smart coatings especially are promising candidates that consent a noteworth...
Article
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Although most semiconductor metal oxides including In2O3 show acceptable sensitivity to volatile organic compounds, it is difficult to detect ethanol effectively at low operating temperatures and detection levels. In this study, pure and Co-, Ni-, and Cu-doped In2O3 products with their doping content maintained at 1 mol % were successfully produced...
Chapter
Perovskite solar cells (PSCs) have recently received much attention in photovoltaics research due to their excellent performance. The PSCs have attained 25.2% power conversion efficiency (PCE) and more developments have been carried out to improve their PCE and functional stability. The PCE and stability of PSCs are controlled by each functional la...