Fluorescence Behaviour and Singlet Oxygen Production of Aluminium Phthalocyanine in the Presence of Upconversion Nanoparticles
- Watkins, Zane, Taylor, Jessica, D’Souza, Sarah, Britton, Jonathan, Nyokong, Tebello
- Authors: Watkins, Zane , Taylor, Jessica , D’Souza, Sarah , Britton, Jonathan , Nyokong, Tebello
- Language: English
- Type: Article
- Identifier: vital:7288 , http://hdl.handle.net/10962/d1020337
- Description: NaYF4:Yb/Er/Gd upconversion nanoparticles (UCNP) were synthesised and the photoemission stabilised by embedding them in electrospun fibers. The photophysical behaviour of chloro aluminium tetrasulfo phthalocyanine (ClAlTSPc) was studied in the presence of UCNPs when the two are mixed in solution. The fluorescence quantum yield value of ClAlTSPc decreased in the presence of UCNPs due to the heavy atom effect of UCNPs. This effect also resulted in increase in triplet quantum yields for ClAlTSPc in the presence of UCNPs. The fluorescence lifetimes for UCNPs were shortened at 658 nm in the presence of ClAlTSPc when the former was embedded in fiber and suspended in a dimethyl sulfoxide solution of the latter. A clear singlet oxygen generation by ClAlTSPc though Förster resonance energy transfer was demonstrated using a singlet oxygen quencher, 1,3-diphenylisobenzofuran. , Original publication is available at http://dx.doi.org/10.1007/s10895-015-1632-z
- Full Text: false
- Authors: Watkins, Zane , Taylor, Jessica , D’Souza, Sarah , Britton, Jonathan , Nyokong, Tebello
- Language: English
- Type: Article
- Identifier: vital:7288 , http://hdl.handle.net/10962/d1020337
- Description: NaYF4:Yb/Er/Gd upconversion nanoparticles (UCNP) were synthesised and the photoemission stabilised by embedding them in electrospun fibers. The photophysical behaviour of chloro aluminium tetrasulfo phthalocyanine (ClAlTSPc) was studied in the presence of UCNPs when the two are mixed in solution. The fluorescence quantum yield value of ClAlTSPc decreased in the presence of UCNPs due to the heavy atom effect of UCNPs. This effect also resulted in increase in triplet quantum yields for ClAlTSPc in the presence of UCNPs. The fluorescence lifetimes for UCNPs were shortened at 658 nm in the presence of ClAlTSPc when the former was embedded in fiber and suspended in a dimethyl sulfoxide solution of the latter. A clear singlet oxygen generation by ClAlTSPc though Förster resonance energy transfer was demonstrated using a singlet oxygen quencher, 1,3-diphenylisobenzofuran. , Original publication is available at http://dx.doi.org/10.1007/s10895-015-1632-z
- Full Text: false
Fluorescence Behaviour of an Aluminium Octacarboxy Phthalocyanine - NaYGdF4:Yb/Er Nanoparticle Conjugate
- Taylor, Jessica, Litwinski, Christian, Nyokong, Tebello, Antunes, Edith M
- Authors: Taylor, Jessica , Litwinski, Christian , Nyokong, Tebello , Antunes, Edith M
- Language: English
- Type: Article
- Identifier: vital:7247 , http://hdl.handle.net/10962/d1020252
- Description: Using a methanol assisted thermal decomposition approach, sphere shaped NaYGdF4:Yb/Er upconversion nanoparticles (UCNPs) were successfully synthesized. The chemical, spectroscopic and fluorescence properties of the UCNPs were fully characterized. Characteristic upconversion fluorescence emissions were produced by the NPs in the green, red and NIR regions and the NPs were also shown to possess paramagnetic properties. The influence of the UCNPs on the spectroscopic and fluorescence properties of an aluminium octacarboxy phthalocyanine AlOCPc was investigated. Covalent conjugation to an AlOCPc resulted in a large blue shift of the phthalocyanine’s Q band, which was accompanied by a decrease in the Pc’s fluorescence lifetime in DMSO. By combining the phthalocyanine and upconversion nanoparticle, we present a system capable of multimodal imaging, using both the upconversion nanoparticle’s and phthalocyanine’s emission, and magnetic resonance imaging (as a result of doping the upconversion nanoparticles with Gd3+ ions). , Original publication is available at http://dx.doi.org/10.1007/s10895-015-1539-8
- Full Text: false
- Authors: Taylor, Jessica , Litwinski, Christian , Nyokong, Tebello , Antunes, Edith M
- Language: English
- Type: Article
- Identifier: vital:7247 , http://hdl.handle.net/10962/d1020252
- Description: Using a methanol assisted thermal decomposition approach, sphere shaped NaYGdF4:Yb/Er upconversion nanoparticles (UCNPs) were successfully synthesized. The chemical, spectroscopic and fluorescence properties of the UCNPs were fully characterized. Characteristic upconversion fluorescence emissions were produced by the NPs in the green, red and NIR regions and the NPs were also shown to possess paramagnetic properties. The influence of the UCNPs on the spectroscopic and fluorescence properties of an aluminium octacarboxy phthalocyanine AlOCPc was investigated. Covalent conjugation to an AlOCPc resulted in a large blue shift of the phthalocyanine’s Q band, which was accompanied by a decrease in the Pc’s fluorescence lifetime in DMSO. By combining the phthalocyanine and upconversion nanoparticle, we present a system capable of multimodal imaging, using both the upconversion nanoparticle’s and phthalocyanine’s emission, and magnetic resonance imaging (as a result of doping the upconversion nanoparticles with Gd3+ ions). , Original publication is available at http://dx.doi.org/10.1007/s10895-015-1539-8
- Full Text: false
Nonlinear optical behaviour of indium-phthalocyanine tethered to magnetite or silica nanoparticles
- Sanusi, Kayode, Stone, Justin M., Nyokong, Tebello
- Authors: Sanusi, Kayode , Stone, Justin M. , Nyokong, Tebello
- Language: English
- Type: Article
- Identifier: vital:7259 , http://hdl.handle.net/10962/d1020268
- Description: Nonlinear absorption and optical limiting properties of indium phthalocyanine (complex 1) tethered to magnetite (SiMNP-1) or silica (SiNP-1) nanoparticles have been investigated using 10 ns pulses at 532 nm laser excitation. The optical limiting behaviours of the nanocomposites and the bare phthalocyanine are compared. Investigation of the triplet state dynamics revealed highly efficient triplet state absorption in the SiMNP-1 dyad. A large nonlinear absorption (βeff) that increased with decrease in the peak input fluence was observed for SiMNP-1. The SiNP-1 composite showed a slight increase in βeff with decreasing peak input fluence. The nonlinear optical data obtained for the SiNP-1 are within the same range of those of the indium phthalocyanine alone. The nanosecond nonlinear absorption and the optical limiting of the nanocomposites are shown to be dominated by a strong excited state absorption from a two-photon pumped state. Nonlinear scattering effects and strong excited state absorption from a two-photon pumped state account for the enhanced optical limiting behaviour of SiMNP-1 relative to the phthalocyanine alone. , Original publication is available at http://dx.doi.org/10.1039/C4NJ01619J
- Full Text: false
- Authors: Sanusi, Kayode , Stone, Justin M. , Nyokong, Tebello
- Language: English
- Type: Article
- Identifier: vital:7259 , http://hdl.handle.net/10962/d1020268
- Description: Nonlinear absorption and optical limiting properties of indium phthalocyanine (complex 1) tethered to magnetite (SiMNP-1) or silica (SiNP-1) nanoparticles have been investigated using 10 ns pulses at 532 nm laser excitation. The optical limiting behaviours of the nanocomposites and the bare phthalocyanine are compared. Investigation of the triplet state dynamics revealed highly efficient triplet state absorption in the SiMNP-1 dyad. A large nonlinear absorption (βeff) that increased with decrease in the peak input fluence was observed for SiMNP-1. The SiNP-1 composite showed a slight increase in βeff with decreasing peak input fluence. The nonlinear optical data obtained for the SiNP-1 are within the same range of those of the indium phthalocyanine alone. The nanosecond nonlinear absorption and the optical limiting of the nanocomposites are shown to be dominated by a strong excited state absorption from a two-photon pumped state. Nonlinear scattering effects and strong excited state absorption from a two-photon pumped state account for the enhanced optical limiting behaviour of SiMNP-1 relative to the phthalocyanine alone. , Original publication is available at http://dx.doi.org/10.1039/C4NJ01619J
- Full Text: false
Spectral properties and photophysical behaviour of water soluble cationic Mg(II) and Al(III) phthalocyanines
- Idowu, Mopelola A, Arslanoglu, Yasin, Nyokong, Tebello
- Authors: Idowu, Mopelola A , Arslanoglu, Yasin , Nyokong, Tebello
- Language: English
- Type: Article
- Identifier: vital:7277 , http://hdl.handle.net/10962/d1020292
- Description: Peripherally and non-peripherally tetrasubstituted-[(N-methyl-2-pyridylthio)]phthalocyaninato magnesium (II) (5 and 6) and chloro aluminium (III) (7 and 8) tetraiodide have been synthesized and characterized. The photophysical properties of the complexes in dimethyl sulfoxide (DMSO) and aqueous medium in the presence and absence of cremophore EL have been studied. These complexes show high solubility in aqueous medium though they were aggregated. The triplet state quantum yields (FT) and the triplet lifetimes (tT) were found to be higher in DMSO with ΦT ranging from 0.32 to 0.51, while tT ranged from 282 to 622 ms in DMSO, compared to aqueous medium (pH 7.4 buffer) where ΦT ranged from 0.15 to 0.19 and tT from 26 to 35 ms. Addition of cremophore EL in aqueous solution resulted in partial disaggregation and increased photoactivity. The fluorescence lifetimes of the complexes showed strong dependence on their immediate environment. The ionic magnesium(II) and aluminium(III) phthalocyanines strongly bind to bovine serum albumin (BSA). , Original publication is available at http://dx.doi.org/10.2478/s11532-013-0388-z
- Full Text: false
- Authors: Idowu, Mopelola A , Arslanoglu, Yasin , Nyokong, Tebello
- Language: English
- Type: Article
- Identifier: vital:7277 , http://hdl.handle.net/10962/d1020292
- Description: Peripherally and non-peripherally tetrasubstituted-[(N-methyl-2-pyridylthio)]phthalocyaninato magnesium (II) (5 and 6) and chloro aluminium (III) (7 and 8) tetraiodide have been synthesized and characterized. The photophysical properties of the complexes in dimethyl sulfoxide (DMSO) and aqueous medium in the presence and absence of cremophore EL have been studied. These complexes show high solubility in aqueous medium though they were aggregated. The triplet state quantum yields (FT) and the triplet lifetimes (tT) were found to be higher in DMSO with ΦT ranging from 0.32 to 0.51, while tT ranged from 282 to 622 ms in DMSO, compared to aqueous medium (pH 7.4 buffer) where ΦT ranged from 0.15 to 0.19 and tT from 26 to 35 ms. Addition of cremophore EL in aqueous solution resulted in partial disaggregation and increased photoactivity. The fluorescence lifetimes of the complexes showed strong dependence on their immediate environment. The ionic magnesium(II) and aluminium(III) phthalocyanines strongly bind to bovine serum albumin (BSA). , Original publication is available at http://dx.doi.org/10.2478/s11532-013-0388-z
- Full Text: false
Surface modification of silica-coated gadolinium oxide nanoparticles with zinc tetracarboxyphenoxy phthalocyanine for the photodegradation of Orange G
- Ledwaba, Mpho, Masilela, Nkosiphile, Nyokong, Tebello, Antunes, Edith M
- Authors: Ledwaba, Mpho , Masilela, Nkosiphile , Nyokong, Tebello , Antunes, Edith M
- Language: English
- Type: Article
- Identifier: vital:7249 , http://hdl.handle.net/10962/d1020255
- Description: Zinc tetracarboxyphenoxy phthalocyanine was covalently linked to Gd2O3 nanoparticles for the photocatalytic degradation of Orange G. Characterization of the composite was carried out using XRD, TEM, XPS, UV–vis spectroscopy and FT-IR spectroscopy. The composite showed improved photophysical properties over the phthalocyanine alone and the catalyst was found to be reusable. Analyses of the photodegradation rates of the azo dye indicated pseudo first-order kinetics. , Original publication is available at http://dx.doi.org/10.1016/j.molcata.2015.03.023
- Full Text: false
- Authors: Ledwaba, Mpho , Masilela, Nkosiphile , Nyokong, Tebello , Antunes, Edith M
- Language: English
- Type: Article
- Identifier: vital:7249 , http://hdl.handle.net/10962/d1020255
- Description: Zinc tetracarboxyphenoxy phthalocyanine was covalently linked to Gd2O3 nanoparticles for the photocatalytic degradation of Orange G. Characterization of the composite was carried out using XRD, TEM, XPS, UV–vis spectroscopy and FT-IR spectroscopy. The composite showed improved photophysical properties over the phthalocyanine alone and the catalyst was found to be reusable. Analyses of the photodegradation rates of the azo dye indicated pseudo first-order kinetics. , Original publication is available at http://dx.doi.org/10.1016/j.molcata.2015.03.023
- Full Text: false
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