Beyond greening: reflections on the business sustainability imperative
- Authors: Smith, Elroy Eugene
- Subjects: Sustainable development , Environmental economics , f-sa
- Language: English
- Type: text , Lectures
- Identifier: http://hdl.handle.net/10948/20768 , vital:29387
- Description: This paper sets out to reflect that organisations should go beyond greening and embrace the sustainability imperative. The concept of greening and environmentalism reached a ceiling as it focuses only on short-term green issues rather than on long-term sustainability goals. Narrow concerns for the natural environment often dilute the true meaning of sustainability. Yet, the field of sustainability is much broader than just focusing on environmental issues. Most contemporary executives know that their response to the challenges of sustainability could seriously affect the competitiveness and survival of their organisations. Despite this notion, most are failing by launching a few greening initiatives without a clear sustainability vision and plan. The sustainability discourse expanded the manner in which organisational success is measured, using values and criteria from the economic, environmental and social realms – commonly known as the triple bottom line. The idea is to balance the needs of people, the planet and the organisation’s profits to create long-term shareholder value. The concept of sustainability has suffered from a proliferation of definitions, meaning many things to different people. However, consensus is forming that sustainability refers to the process by which sound economic systems operate well within the biophysical constraints of the ecosystem to provide a good quality of life that is socially appropriate for current and future generations. Sustainability is bigger than a publicity stunt, green products or occasional acknowledgement to on-going efforts to save the planet. Although greening will be a central part of the way business is conducted, green alone is not a broad enough platform to sustain a business in the long-run. There is a need to look beyond the green aspects of sustainability and also using the social, economic and cultural aspects to build a successful and sustainable organisation. 2 This paper addresses aspects such as the sustainability paradigm, dimensions and drivers of sustainability, statistical evidence of sustainability, national framework for sustainable development in South Africa, a sustainability case example and challenges of sustainability.
- Full Text:
- Authors: Smith, Elroy Eugene
- Subjects: Sustainable development , Environmental economics , f-sa
- Language: English
- Type: text , Lectures
- Identifier: http://hdl.handle.net/10948/20768 , vital:29387
- Description: This paper sets out to reflect that organisations should go beyond greening and embrace the sustainability imperative. The concept of greening and environmentalism reached a ceiling as it focuses only on short-term green issues rather than on long-term sustainability goals. Narrow concerns for the natural environment often dilute the true meaning of sustainability. Yet, the field of sustainability is much broader than just focusing on environmental issues. Most contemporary executives know that their response to the challenges of sustainability could seriously affect the competitiveness and survival of their organisations. Despite this notion, most are failing by launching a few greening initiatives without a clear sustainability vision and plan. The sustainability discourse expanded the manner in which organisational success is measured, using values and criteria from the economic, environmental and social realms – commonly known as the triple bottom line. The idea is to balance the needs of people, the planet and the organisation’s profits to create long-term shareholder value. The concept of sustainability has suffered from a proliferation of definitions, meaning many things to different people. However, consensus is forming that sustainability refers to the process by which sound economic systems operate well within the biophysical constraints of the ecosystem to provide a good quality of life that is socially appropriate for current and future generations. Sustainability is bigger than a publicity stunt, green products or occasional acknowledgement to on-going efforts to save the planet. Although greening will be a central part of the way business is conducted, green alone is not a broad enough platform to sustain a business in the long-run. There is a need to look beyond the green aspects of sustainability and also using the social, economic and cultural aspects to build a successful and sustainable organisation. 2 This paper addresses aspects such as the sustainability paradigm, dimensions and drivers of sustainability, statistical evidence of sustainability, national framework for sustainable development in South Africa, a sustainability case example and challenges of sustainability.
- Full Text:
Carbon nanotube-enhanced photoelectrochemical properties of metallo-octacarboxyphthalocyanines
- Mphahlele, Nonhlanhla E., Roux, Lukas Le, Jafta, Charl J., Cele, Leskey, Mathe, Mkhulu K., Nyokong, Tebello, Kobayashi, Nagao, Ozoemena, Kenneth I.
- Authors: Mphahlele, Nonhlanhla E. , Roux, Lukas Le , Jafta, Charl J. , Cele, Leskey , Mathe, Mkhulu K. , Nyokong, Tebello , Kobayashi, Nagao , Ozoemena, Kenneth I.
- Language: English
- Type: Article
- Identifier: vital:7312 , http://hdl.handle.net/10962/d1020538
- Description: The photoelectrochemistry of metallo-octacarboxyphthalocyanines (MOCPc, where M = Zn or Si(OH)2) integrated with MWCNTs for the development of dye-sensitized solar cells (DSSCs) is reported. The DSSC performance (obtained from the photo-chronoamperometric and photo-impedimetric data) decreased as ZnOCPc > (OH)2SiOCPc. The incorporation of the MWCNTs on the surface of the TiO2 film (MOCPc–MWCNT systems) gave higher photocurrent density than the bare MOCPc complexes. Also, from the EIS results, the MOCPc–MWCNT hybrids gave faster charge transport kinetics (approximately three times faster) compared to the bare MOCPc complexes. The electron lifetime was slightly longer (ca. 6 ms) at the ZnOCPc systems than at the (OH)2SiOCPc system (ca. 4 ms) meaning that the presence of the MWCNTs on the surface of the TiO2 film did not show any significant improvement on preventing charge recombination process. , Original publication is available at http://dx.doi.org/10.1007/s10853-013-7710-1
- Full Text: false
- Authors: Mphahlele, Nonhlanhla E. , Roux, Lukas Le , Jafta, Charl J. , Cele, Leskey , Mathe, Mkhulu K. , Nyokong, Tebello , Kobayashi, Nagao , Ozoemena, Kenneth I.
- Language: English
- Type: Article
- Identifier: vital:7312 , http://hdl.handle.net/10962/d1020538
- Description: The photoelectrochemistry of metallo-octacarboxyphthalocyanines (MOCPc, where M = Zn or Si(OH)2) integrated with MWCNTs for the development of dye-sensitized solar cells (DSSCs) is reported. The DSSC performance (obtained from the photo-chronoamperometric and photo-impedimetric data) decreased as ZnOCPc > (OH)2SiOCPc. The incorporation of the MWCNTs on the surface of the TiO2 film (MOCPc–MWCNT systems) gave higher photocurrent density than the bare MOCPc complexes. Also, from the EIS results, the MOCPc–MWCNT hybrids gave faster charge transport kinetics (approximately three times faster) compared to the bare MOCPc complexes. The electron lifetime was slightly longer (ca. 6 ms) at the ZnOCPc systems than at the (OH)2SiOCPc system (ca. 4 ms) meaning that the presence of the MWCNTs on the surface of the TiO2 film did not show any significant improvement on preventing charge recombination process. , Original publication is available at http://dx.doi.org/10.1007/s10853-013-7710-1
- Full Text: false
Characterization of electrodes modified by one pot or step by step electro-click reaction and axial ligation of iron tetracarboxyphthalocyanine
- Maringa, Audacity, Mashazi, Philani N, Nyokong, Tebello
- Authors: Maringa, Audacity , Mashazi, Philani N , Nyokong, Tebello
- Language: English
- Type: Article
- Identifier: vital:7307 , http://hdl.handle.net/10962/d1020384
- Description: The modification of the glassy carbon electrode (GCE) was carried out using two methods. The first method is simultaneous electropolymerization and electro-click followed by immersion into a solution of dimethyl formamide (DMF) containing FeTCPc. The second method is step by step whereby electropolymerization is carried out first followed by electro-click and then immersion into a DMF solution containing FeTCPc. From the electrochemical characterization, it was observed that the second route (step by step method) was the best as indicated by the ferricyanide studies (cyclic voltammetry and scanning electrochemical microscopy). In the electrooxidation of hydrazine, we obtained a potential of 0.26 V. Of interest were the detection limit of 6.4 μM and the catalytic rate constant of 2.1 × 109 cm3 mol−1 s−1. This shows that the sensor can be used for the electrooxidation of hydrazine. , Original publication is available at http://dx.doi.org/10.1016/j.electacta.2014.09.011
- Full Text: false
- Authors: Maringa, Audacity , Mashazi, Philani N , Nyokong, Tebello
- Language: English
- Type: Article
- Identifier: vital:7307 , http://hdl.handle.net/10962/d1020384
- Description: The modification of the glassy carbon electrode (GCE) was carried out using two methods. The first method is simultaneous electropolymerization and electro-click followed by immersion into a solution of dimethyl formamide (DMF) containing FeTCPc. The second method is step by step whereby electropolymerization is carried out first followed by electro-click and then immersion into a DMF solution containing FeTCPc. From the electrochemical characterization, it was observed that the second route (step by step method) was the best as indicated by the ferricyanide studies (cyclic voltammetry and scanning electrochemical microscopy). In the electrooxidation of hydrazine, we obtained a potential of 0.26 V. Of interest were the detection limit of 6.4 μM and the catalytic rate constant of 2.1 × 109 cm3 mol−1 s−1. This shows that the sensor can be used for the electrooxidation of hydrazine. , Original publication is available at http://dx.doi.org/10.1016/j.electacta.2014.09.011
- Full Text: false
Consumer health informatics in the information age and beyond
- Authors: Pottas, Dalenca
- Subjects: Medical informatics , Information technology , f-sa
- Language: English
- Type: text , Lectures
- Identifier: http://hdl.handle.net/10948/20757 , vital:29386
- Description: This paper reviews current and future trends and challenges in the field of consumer health informatics. Emergent innovations driving consumer health informatics in the information age include devices, tools and applications supporting personalised healthcare, electronic personal health record (PHR) systems and a plethora of tools in the health social media domain. Within this domain, a new kind of social media citizen, the consumer specialist or patient opinion leader, is taking the lead in online communities of patients. A new generation of personal health records combining PHRs and social media is emerging, even though pervasive adoption and use of PHRs remains elusive. The accuracy of information, security and privacy of personal health information, legislative matters and the digital divide remain recurring challenges of consumer health informatics. In future, PHR vendors will have to address the lack of espousal of PHRs in innovative ways to provide a compelling case for adoption. The continued uptake of health social media necessitates efforts to understand, through longitudinal studies, precisely who the users are, what they use it for and how it contributes to the achievement of both personal and public health outcomes. Health information consumers, of varying levels of techno-literacy, needs and preferences, must be assisted to move from simply accessing information to distilling relevant and credible information and making informed decisions. Further research is required to understand the changing relationships between patients and healthcare providers and how consumer health information technologies can best support these. There is a need to evaluate the effectiveness of consumer health information technologies to inform both public policy and the next generation of tools, technologies and artefacts that could better facilitate improved health outcomes. Lastly, more effort is required to erode digital inequalities. As we move into a future emphasising both the global and the individual, accelerated connectedness and speed of change, consumer health informatics must respond such that it remains germane and amplifies the value that can be gained by all stakeholders.
- Full Text:
- Authors: Pottas, Dalenca
- Subjects: Medical informatics , Information technology , f-sa
- Language: English
- Type: text , Lectures
- Identifier: http://hdl.handle.net/10948/20757 , vital:29386
- Description: This paper reviews current and future trends and challenges in the field of consumer health informatics. Emergent innovations driving consumer health informatics in the information age include devices, tools and applications supporting personalised healthcare, electronic personal health record (PHR) systems and a plethora of tools in the health social media domain. Within this domain, a new kind of social media citizen, the consumer specialist or patient opinion leader, is taking the lead in online communities of patients. A new generation of personal health records combining PHRs and social media is emerging, even though pervasive adoption and use of PHRs remains elusive. The accuracy of information, security and privacy of personal health information, legislative matters and the digital divide remain recurring challenges of consumer health informatics. In future, PHR vendors will have to address the lack of espousal of PHRs in innovative ways to provide a compelling case for adoption. The continued uptake of health social media necessitates efforts to understand, through longitudinal studies, precisely who the users are, what they use it for and how it contributes to the achievement of both personal and public health outcomes. Health information consumers, of varying levels of techno-literacy, needs and preferences, must be assisted to move from simply accessing information to distilling relevant and credible information and making informed decisions. Further research is required to understand the changing relationships between patients and healthcare providers and how consumer health information technologies can best support these. There is a need to evaluate the effectiveness of consumer health information technologies to inform both public policy and the next generation of tools, technologies and artefacts that could better facilitate improved health outcomes. Lastly, more effort is required to erode digital inequalities. As we move into a future emphasising both the global and the individual, accelerated connectedness and speed of change, consumer health informatics must respond such that it remains germane and amplifies the value that can be gained by all stakeholders.
- Full Text:
Development of Graphene/CdSe Quantum Dots-Co Phthalocyanine Nanocomposite for Oxygen Reduction Reaction
- Nyoni, Stephen, Nyokong, Tebello
- Authors: Nyoni, Stephen , Nyokong, Tebello
- Language: English
- Type: Article
- Identifier: vital:7300 , http://hdl.handle.net/10962/d1020368
- Description: Nanocomposites containing CdSe quantum dots, tetra(4-(4,6-diaminopyrimidin-2-ylthio) phthalocyaninatocobalt(II)) (CoPyPc) and reduced graphene nanosheets (rGNS) were devoloped and used for the modification of a glassy carbon electrode. Characterization of the nanocomposites was done by transmission electron microscopy (TEM) and X-ray diffraction (XRD) analyses. Cyclic voltammetry (CV) was used for electrochemical characterization of the prepared nanocomposite for oxygen reduction reaction. The oxygen reduction activity for rGNS/CdSe-CoPyPc nanocomposite was found to be superior over the individual nanomaterials in this study. The activity of the nanocomposite towards oxygen reduction was also tested for tolerance to methanol crossover effect using chronoamperometry (CA) and electrochemical impedance spectroscopy (EIS) studies. , Original publication is available at http://dx.doi.org/10.1002/elan.201400372
- Full Text: false
- Authors: Nyoni, Stephen , Nyokong, Tebello
- Language: English
- Type: Article
- Identifier: vital:7300 , http://hdl.handle.net/10962/d1020368
- Description: Nanocomposites containing CdSe quantum dots, tetra(4-(4,6-diaminopyrimidin-2-ylthio) phthalocyaninatocobalt(II)) (CoPyPc) and reduced graphene nanosheets (rGNS) were devoloped and used for the modification of a glassy carbon electrode. Characterization of the nanocomposites was done by transmission electron microscopy (TEM) and X-ray diffraction (XRD) analyses. Cyclic voltammetry (CV) was used for electrochemical characterization of the prepared nanocomposite for oxygen reduction reaction. The oxygen reduction activity for rGNS/CdSe-CoPyPc nanocomposite was found to be superior over the individual nanomaterials in this study. The activity of the nanocomposite towards oxygen reduction was also tested for tolerance to methanol crossover effect using chronoamperometry (CA) and electrochemical impedance spectroscopy (EIS) studies. , Original publication is available at http://dx.doi.org/10.1002/elan.201400372
- Full Text: false
Effect of bovine serum albumin and single walled carbon nanotube on the photophysical properties of zinc octacarboxy phthalocyanine
- Ogbodu, Racheal O, Nyokong, Tebello
- Authors: Ogbodu, Racheal O , Nyokong, Tebello
- Language: English
- Type: Article
- Identifier: vital:7321 , http://hdl.handle.net/10962/d1020566
- Description: This work reports on the photophysical parameters of the conjugate between zinc octacarboxy phthalocyanine (ZnOCPc) and bovine serum albumin (BSA) represented as ZnOCPc–BSA (1) which was further adsorbed onto single walled carbon nanotubes (SWCNT) represented as (ZnOCPc–BSA–SWCNT 2). ZnOCPc (without BSA) was also adsorbed on SWCNT represented as ZnOCPc–SWCNT (3). The presence of BSA resulted in the increase in singlet oxygen quantum yield (ΦΔ) for 1 (at ΦΔ = 0.44) and 2 (at ΦΔ = 0.41) compared to ΦΔ = 0.21 for ZnOCPc alone. For complex 3 which did not contain BSA singlet oxygen quantum yield decreased. , Original publication is available at http://dx.doi.org/10.1016/j.saa.2013.10.064
- Full Text: false
- Authors: Ogbodu, Racheal O , Nyokong, Tebello
- Language: English
- Type: Article
- Identifier: vital:7321 , http://hdl.handle.net/10962/d1020566
- Description: This work reports on the photophysical parameters of the conjugate between zinc octacarboxy phthalocyanine (ZnOCPc) and bovine serum albumin (BSA) represented as ZnOCPc–BSA (1) which was further adsorbed onto single walled carbon nanotubes (SWCNT) represented as (ZnOCPc–BSA–SWCNT 2). ZnOCPc (without BSA) was also adsorbed on SWCNT represented as ZnOCPc–SWCNT (3). The presence of BSA resulted in the increase in singlet oxygen quantum yield (ΦΔ) for 1 (at ΦΔ = 0.44) and 2 (at ΦΔ = 0.41) compared to ΦΔ = 0.21 for ZnOCPc alone. For complex 3 which did not contain BSA singlet oxygen quantum yield decreased. , Original publication is available at http://dx.doi.org/10.1016/j.saa.2013.10.064
- Full Text: false
Effects of analytes on the fluorescence properties of CdTe@ZnS quantum dots decorated with cobalt tetraamino-phthalocyanine
- Adegoke, Oluwasesan, Nyokong, Tebello
- Authors: Adegoke, Oluwasesan , Nyokong, Tebello
- Language: English
- Type: Article
- Identifier: vital:7315 , http://hdl.handle.net/10962/d1020541
- Description: In this work, we have carried out an investigation on the effects of different biologically active analytes on the fluorescence response of glutathione-capped CdTe@ZnS quantum dots (QDs)-colbalt tetraamino-phthalocyanine nanoconjugate system. Firstly, fluorescence quenching occurred. Experimental results showed that some analytes either “turned on”, others further quenched or showed no effect on the fluorescence emission of the nanoprobe. , Original publication is available at http://dx.doi.org/10.1016/j.jlumin.2013.09.079
- Full Text: false
- Authors: Adegoke, Oluwasesan , Nyokong, Tebello
- Language: English
- Type: Article
- Identifier: vital:7315 , http://hdl.handle.net/10962/d1020541
- Description: In this work, we have carried out an investigation on the effects of different biologically active analytes on the fluorescence response of glutathione-capped CdTe@ZnS quantum dots (QDs)-colbalt tetraamino-phthalocyanine nanoconjugate system. Firstly, fluorescence quenching occurred. Experimental results showed that some analytes either “turned on”, others further quenched or showed no effect on the fluorescence emission of the nanoprobe. , Original publication is available at http://dx.doi.org/10.1016/j.jlumin.2013.09.079
- Full Text: false
Effects of differently shaped silver nanoparticles on the photophysics of pyridylsulfanyl-substituted phthalocyanines
- D’Souza, Sarah, Mashazi, Philani N, Britton, Jonathan, Nyokong, Tebello
- Authors: D’Souza, Sarah , Mashazi, Philani N , Britton, Jonathan , Nyokong, Tebello
- Language: English
- Type: Article
- Identifier: vital:7290 , http://hdl.handle.net/10962/d1020353
- Description: This paper reports on the photophysical behavior of (2-pyridylsulfanyl)phthalocyaninato zinc(II) and 2,9(10),16(17),23(24)-tetra-(2-pyridylsulfanyl)phthalocyaninato zinc(II) in the presence of differently shaped silver nanoparticles (nanospheres, nanotriangles and nanoflowers). The presence of shaped nanoparticles increased both triplet quantum yields and lifetimes of the tetra-substituted mercaptopyridine zinc phthalocyanine in DMSO. It is apparent from this work that the shape of the silver nanoparticle used is of little consequence in influencing photophysical behavior of the phthalocyanines. , Original publication is available at http://dx.doi.org/10.1016/j.poly.2015.06.038
- Full Text: false
- Authors: D’Souza, Sarah , Mashazi, Philani N , Britton, Jonathan , Nyokong, Tebello
- Language: English
- Type: Article
- Identifier: vital:7290 , http://hdl.handle.net/10962/d1020353
- Description: This paper reports on the photophysical behavior of (2-pyridylsulfanyl)phthalocyaninato zinc(II) and 2,9(10),16(17),23(24)-tetra-(2-pyridylsulfanyl)phthalocyaninato zinc(II) in the presence of differently shaped silver nanoparticles (nanospheres, nanotriangles and nanoflowers). The presence of shaped nanoparticles increased both triplet quantum yields and lifetimes of the tetra-substituted mercaptopyridine zinc phthalocyanine in DMSO. It is apparent from this work that the shape of the silver nanoparticle used is of little consequence in influencing photophysical behavior of the phthalocyanines. , Original publication is available at http://dx.doi.org/10.1016/j.poly.2015.06.038
- Full Text: false
Effects of number of ring substituents on the physicochemical properties of zinc aminophenoxy phthalocyanine-single walled carbon nanotube conjugate
- Ogbodu, Racheal O, Nyokong, Tebello
- Authors: Ogbodu, Racheal O , Nyokong, Tebello
- Language: English
- Type: Article
- Identifier: vital:7319 , http://hdl.handle.net/10962/d1020564
- Description: This work reports on the linking of zinc monoaminophenoxy (ZnMAPPc) or zinc tetraaminophenoxy phthalocyanine (ZnTAPPc) complexes to single walled carbon nanotubes (SWCNTs) through either covalent or non-covalent (adsorption) bonding. The functionalized complexes showed better thermal stability when compared to the SWCNT-COOH, ZnMAPPc and ZnTAPPc alone as confirmed by thermogravimetric analyses. The covalently linked ZnMAPc-SWCNT showed higher electron transfer rate constant and photoinduced electron efficiency when compared to adsorbed complexes. ZnMAPPc-SWCNT complexes (linked and adsorbed) showed better photophysical and photochemical properties when compared to ZnTAPPc-SWCNT complexes. The triplet, singlet oxygen and florescence quantum yields of ZnMAPPc (or ZnTAPPc) decrease upon linking or adsorption onto SWCNTs. , Original publication is available at http://dx.doi.org/10.1016/j.jphotochem.2013.09.015
- Full Text: false
- Authors: Ogbodu, Racheal O , Nyokong, Tebello
- Language: English
- Type: Article
- Identifier: vital:7319 , http://hdl.handle.net/10962/d1020564
- Description: This work reports on the linking of zinc monoaminophenoxy (ZnMAPPc) or zinc tetraaminophenoxy phthalocyanine (ZnTAPPc) complexes to single walled carbon nanotubes (SWCNTs) through either covalent or non-covalent (adsorption) bonding. The functionalized complexes showed better thermal stability when compared to the SWCNT-COOH, ZnMAPPc and ZnTAPPc alone as confirmed by thermogravimetric analyses. The covalently linked ZnMAPc-SWCNT showed higher electron transfer rate constant and photoinduced electron efficiency when compared to adsorbed complexes. ZnMAPPc-SWCNT complexes (linked and adsorbed) showed better photophysical and photochemical properties when compared to ZnTAPPc-SWCNT complexes. The triplet, singlet oxygen and florescence quantum yields of ZnMAPPc (or ZnTAPPc) decrease upon linking or adsorption onto SWCNTs. , Original publication is available at http://dx.doi.org/10.1016/j.jphotochem.2013.09.015
- Full Text: false
Electrocatalytic behahiour of cobalt tetraamino-phthalocyanine in the presence of a composite of reduced graphene nanosheets and of multi-walled carbon nanotubes
- Nyoni, Stephen, Nyokong, Tebello
- Authors: Nyoni, Stephen , Nyokong, Tebello
- Language: English
- Type: Article
- Identifier: vital:7309 , http://hdl.handle.net/10962/d1020386
- Description: A composite of multi-walled carbon nanotubes (MWCNT) with reduced graphene nanosheets (rGNS-2) was developed in order to minimize the restacking of the latter. The composite was used to modify a glassy carbon electrode (GCE). GCE was further modified with cobalt tetraamino phthalocyanine (CoTAPc). The modified electrode is represented as rGNS-2-MWCNT-CoTAPc-GCE. X-ray photoelectron spectroscopy, transmission electron microscopy, scanning electrochemical microscopy and Raman spectroscopy were used to explore into surface functionalities, morphology and topography of the nanocomposite. The rGNS-2-MWCNT-CoTAPc-GCE had a low limit of detection of 3.32 × 10−8 M towards the detection of paraguat as a test analyte. A mechanism for paraquat detection using an rGNS-2-MWCNT-CoTAPc-GCE is also proposed in this work. , Original publication is available at http://dx.doi.org/10.1016/j.electacta.2014.05.093
- Full Text: false
- Authors: Nyoni, Stephen , Nyokong, Tebello
- Language: English
- Type: Article
- Identifier: vital:7309 , http://hdl.handle.net/10962/d1020386
- Description: A composite of multi-walled carbon nanotubes (MWCNT) with reduced graphene nanosheets (rGNS-2) was developed in order to minimize the restacking of the latter. The composite was used to modify a glassy carbon electrode (GCE). GCE was further modified with cobalt tetraamino phthalocyanine (CoTAPc). The modified electrode is represented as rGNS-2-MWCNT-CoTAPc-GCE. X-ray photoelectron spectroscopy, transmission electron microscopy, scanning electrochemical microscopy and Raman spectroscopy were used to explore into surface functionalities, morphology and topography of the nanocomposite. The rGNS-2-MWCNT-CoTAPc-GCE had a low limit of detection of 3.32 × 10−8 M towards the detection of paraguat as a test analyte. A mechanism for paraquat detection using an rGNS-2-MWCNT-CoTAPc-GCE is also proposed in this work. , Original publication is available at http://dx.doi.org/10.1016/j.electacta.2014.05.093
- Full Text: false
Electrochemical behaviour of gold nanoparticles and Co tetraaminophthalocyanine on glassy carbon electrode
- Maringa, Audacity, Antunes, Edith M, Nyokong, Tebello
- Authors: Maringa, Audacity , Antunes, Edith M , Nyokong, Tebello
- Language: English
- Type: Article
- Identifier: vital:7306 , http://hdl.handle.net/10962/d1020383
- Description: We report on the electrodeposition of gold nanoparticles (AuNPs) onto the glassy carbon electrode (GCE) followed by polymerization of cobalt tetraamino phthalocyanine (CoPc(NH2)4) on top (represented as poly-CoPc(NH2)4-/AuNPs-GCE). The modified electrode where CoPc(NH2)4 is polymerized first followed by deposition of AuNPs is represented as AuNPs/poly-CoPc(NH2)4-GCE. In the absence of AuNPs, the electrode is represented as poly-CoPc(NH2)4-GCE or for AuNPs alone (AuNPs-GCE). The surface coverage was 1.5 × 10−9 mol cm−2 for AuNPs-GCE and 3.0 × 10−9 mol cm−2 for the rest of the modified electrodes. AuNPs/CoPc(NH2)4-GCE exhibited high electrocatalytic activity towards the oxidation of nitrite, with detection potential of 0.76 V. The catalytic rate constant of 3.96 × 107 cm3 mol−1 s−1 was obtained for nitrite oxidation. , Original publication is available at http://dx.doi.org/10.1016/j.electacta.2013.12.132
- Full Text: false
- Authors: Maringa, Audacity , Antunes, Edith M , Nyokong, Tebello
- Language: English
- Type: Article
- Identifier: vital:7306 , http://hdl.handle.net/10962/d1020383
- Description: We report on the electrodeposition of gold nanoparticles (AuNPs) onto the glassy carbon electrode (GCE) followed by polymerization of cobalt tetraamino phthalocyanine (CoPc(NH2)4) on top (represented as poly-CoPc(NH2)4-/AuNPs-GCE). The modified electrode where CoPc(NH2)4 is polymerized first followed by deposition of AuNPs is represented as AuNPs/poly-CoPc(NH2)4-GCE. In the absence of AuNPs, the electrode is represented as poly-CoPc(NH2)4-GCE or for AuNPs alone (AuNPs-GCE). The surface coverage was 1.5 × 10−9 mol cm−2 for AuNPs-GCE and 3.0 × 10−9 mol cm−2 for the rest of the modified electrodes. AuNPs/CoPc(NH2)4-GCE exhibited high electrocatalytic activity towards the oxidation of nitrite, with detection potential of 0.76 V. The catalytic rate constant of 3.96 × 107 cm3 mol−1 s−1 was obtained for nitrite oxidation. , Original publication is available at http://dx.doi.org/10.1016/j.electacta.2013.12.132
- Full Text: false
Enhanced nonlinear optical properties of octa-substituted lead and cadmium phthalocyanines when embedded in poly(bisphenol A carbonate) as thin films
- Mkhize, Colin, Britton, Jonathan, Nyokong, Tebello
- Authors: Mkhize, Colin , Britton, Jonathan , Nyokong, Tebello
- Language: English
- Type: Article
- Identifier: vital:7320 , http://hdl.handle.net/10962/d1020565
- Description: This work presents photophysical and nonlinear optical properties of a novel Cd 2,3-[octakis{4-tert-butylphenoxyphthalocyanine}] (CdOtBPPc) and compare them with those of Pb 2,3-[octakis{4-tert-butylphenoxyphthalocyanine}] (PbOtBPPc). For both the CdOtBPPc and PbOtBPPc, third order imaginary susceptibility and second order hyperpolarizability values were found to be within the limit set for good optical limiters. The Pcs were embedded in poly (methyl methacrylate) (PMMA) and poly(bisphenol A carbonate) (PBC) as thin films. The optical limiting values of the Pcs once embedded in film were found to be greatly improved and the limiting fluence of each film was well below the maximum threshold. Both PbOtBPPc and CdOtBPPc showed better optical limiting when embedded in PBC compared to PMMA. CdOtBPPc shows better nonlinear optical behavior than PbOtBPPc in solution and as thin films, even though the former is aggregated in solution. , Original publication is available at http://dx.doi.org/10.1016/j.poly.2014.07.025
- Full Text: false
- Authors: Mkhize, Colin , Britton, Jonathan , Nyokong, Tebello
- Language: English
- Type: Article
- Identifier: vital:7320 , http://hdl.handle.net/10962/d1020565
- Description: This work presents photophysical and nonlinear optical properties of a novel Cd 2,3-[octakis{4-tert-butylphenoxyphthalocyanine}] (CdOtBPPc) and compare them with those of Pb 2,3-[octakis{4-tert-butylphenoxyphthalocyanine}] (PbOtBPPc). For both the CdOtBPPc and PbOtBPPc, third order imaginary susceptibility and second order hyperpolarizability values were found to be within the limit set for good optical limiters. The Pcs were embedded in poly (methyl methacrylate) (PMMA) and poly(bisphenol A carbonate) (PBC) as thin films. The optical limiting values of the Pcs once embedded in film were found to be greatly improved and the limiting fluence of each film was well below the maximum threshold. Both PbOtBPPc and CdOtBPPc showed better optical limiting when embedded in PBC compared to PMMA. CdOtBPPc shows better nonlinear optical behavior than PbOtBPPc in solution and as thin films, even though the former is aggregated in solution. , Original publication is available at http://dx.doi.org/10.1016/j.poly.2014.07.025
- Full Text: false
Factors contributing to occupational stress in student support staff in a Further Education and Training (FET) College in the Southern Cape
- Authors: De Klerk, Ulricha
- Subjects: Work -- Psychological aspects , Job stress -- South Africa -- Western Cape , College students -- South Africa -- Western Cape
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:10085 , http://hdl.handle.net/10948/d1020806
- Description: The main purpose of this study is to explore the factors that contribute to occupational stress as experienced by the Student Support staff in a Further Education and Training (FET) College in the Southern Cape. The Student Support staff has displayed many symptoms of stress over the past few years. This in turn has led to absenteeism, change in staff temperament, their feelings towards the College, motivation levels and a significant change in the staff’s day to day operations. Although the Head of Department for Student Support Services has engaged with the staff on numerous occasions to discuss the reasons for their experience of stress, no substantial reasons could be established in order to make the necessary changes in the department. No interventions that have been implemented to date have relieved the staff’s experience of stress. The researcher chose to use a qualitative, exploratory, descriptive and contextual research design to gain insight into the situation or phenomenon in order to identify the factors contributing to occupational stress and to identify measures that can be implemented to reduce occupational stress in the Student Support staff. The participants in this research included at least 10 Student Support staff within the Student Support Services Department at a Further Education and Training College in the Southern Cape. Purposive sampling was used in this research study. Interviews will continue until data saturation is achieved. The staff members must have been employed for at least one year in the Student Support Services Department. The researcher will make use of semi-structured interviews, observations and field notes. The data will be systematically collected and meanings, themes and general descriptions of the experience analysed within the specific context (de Vos, Strydom, Fouche & Delport, 2005). The researcher will make use of Tesch’s method of analysis, and use Guba’s strategies for ensuring Trustworthiness. The researcher will apply the ethical considerations of confidentiality, informed consent, ethical approval from relevant institutions, avoidance of harm to participants, truthfulness and the debriefing of participants when conducting this study. The findings were reported as three major themes and subthemes. The three major themes were; Student support staff identified several factors that contributed to occupational stress, Student support staff identified the effect that occupational stress has on them, Student support staff offered suggestions that the college could implement to reduce occupational stress. These themes were discussed and analysed in-depth.
- Full Text:
- Authors: De Klerk, Ulricha
- Subjects: Work -- Psychological aspects , Job stress -- South Africa -- Western Cape , College students -- South Africa -- Western Cape
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:10085 , http://hdl.handle.net/10948/d1020806
- Description: The main purpose of this study is to explore the factors that contribute to occupational stress as experienced by the Student Support staff in a Further Education and Training (FET) College in the Southern Cape. The Student Support staff has displayed many symptoms of stress over the past few years. This in turn has led to absenteeism, change in staff temperament, their feelings towards the College, motivation levels and a significant change in the staff’s day to day operations. Although the Head of Department for Student Support Services has engaged with the staff on numerous occasions to discuss the reasons for their experience of stress, no substantial reasons could be established in order to make the necessary changes in the department. No interventions that have been implemented to date have relieved the staff’s experience of stress. The researcher chose to use a qualitative, exploratory, descriptive and contextual research design to gain insight into the situation or phenomenon in order to identify the factors contributing to occupational stress and to identify measures that can be implemented to reduce occupational stress in the Student Support staff. The participants in this research included at least 10 Student Support staff within the Student Support Services Department at a Further Education and Training College in the Southern Cape. Purposive sampling was used in this research study. Interviews will continue until data saturation is achieved. The staff members must have been employed for at least one year in the Student Support Services Department. The researcher will make use of semi-structured interviews, observations and field notes. The data will be systematically collected and meanings, themes and general descriptions of the experience analysed within the specific context (de Vos, Strydom, Fouche & Delport, 2005). The researcher will make use of Tesch’s method of analysis, and use Guba’s strategies for ensuring Trustworthiness. The researcher will apply the ethical considerations of confidentiality, informed consent, ethical approval from relevant institutions, avoidance of harm to participants, truthfulness and the debriefing of participants when conducting this study. The findings were reported as three major themes and subthemes. The three major themes were; Student support staff identified several factors that contributed to occupational stress, Student support staff identified the effect that occupational stress has on them, Student support staff offered suggestions that the college could implement to reduce occupational stress. These themes were discussed and analysed in-depth.
- Full Text:
Grounds & gardens : adding value to the living space : "Enabling the Academic Project" : 26 years on the greenside
- Authors: Hazell, M
- Language: English
- Type: Text
- Identifier: vital:7959 , http://hdl.handle.net/10962/d1008354
- Description: [A presentation given by Mark Hazell, Manager: Grounds & Gardens at Rhodes University, to the Rhodes University Environmental Committee on the occasion of his retirement from Rhodes University]
- Full Text:
- Authors: Hazell, M
- Language: English
- Type: Text
- Identifier: vital:7959 , http://hdl.handle.net/10962/d1008354
- Description: [A presentation given by Mark Hazell, Manager: Grounds & Gardens at Rhodes University, to the Rhodes University Environmental Committee on the occasion of his retirement from Rhodes University]
- Full Text:
Improved l-cysteine electrocatalysis through a sequential drop dry technique using multi-walled carbon nanotubes and cobalt tetraaminophthalocyanine conjugates
- Nyoni, Stephen, Mugadza, Tawanda, Nyokong, Tebello
- Authors: Nyoni, Stephen , Mugadza, Tawanda , Nyokong, Tebello
- Language: English
- Type: Article
- Identifier: vital:7308 , http://hdl.handle.net/10962/d1020385
- Description: Voltammetry, chronoamperometry, scanning electrochemical microscopy and electrochemical impedance spectroscopy methods are used for characterization of a glassy carbon electrode modified with multi-walled carbon nanotubes (MWCNTs)–cobalt tetraaminophthalocyanine (CoTAPc) mixture or sequential drop dry modification technique whereby the MWCNTs are first placed on to the electrode followed by CoTAPc. The sequential drop dry CoTAPc–MWCNTs modified surface gave better catalytic responses with a catalytic rate constant of 2.2 × 105 M−1 s−1, apparent electron transfer rate constant of 0.073 cm s−1, and a limit of detection of 2.8 × 10−7 M. Scanning electrochemical microscopy (SECM) surface characterization (topography and reactivity) further gave proof the better catalytic perfomance of the sequential drop dry CoTAPc–MWCNTs modified surface. , Original publication is available at http://dx.doi.org/10.1016/j.electacta.2013.10.023
- Full Text: false
- Authors: Nyoni, Stephen , Mugadza, Tawanda , Nyokong, Tebello
- Language: English
- Type: Article
- Identifier: vital:7308 , http://hdl.handle.net/10962/d1020385
- Description: Voltammetry, chronoamperometry, scanning electrochemical microscopy and electrochemical impedance spectroscopy methods are used for characterization of a glassy carbon electrode modified with multi-walled carbon nanotubes (MWCNTs)–cobalt tetraaminophthalocyanine (CoTAPc) mixture or sequential drop dry modification technique whereby the MWCNTs are first placed on to the electrode followed by CoTAPc. The sequential drop dry CoTAPc–MWCNTs modified surface gave better catalytic responses with a catalytic rate constant of 2.2 × 105 M−1 s−1, apparent electron transfer rate constant of 0.073 cm s−1, and a limit of detection of 2.8 × 10−7 M. Scanning electrochemical microscopy (SECM) surface characterization (topography and reactivity) further gave proof the better catalytic perfomance of the sequential drop dry CoTAPc–MWCNTs modified surface. , Original publication is available at http://dx.doi.org/10.1016/j.electacta.2013.10.023
- Full Text: false
Job satisfaction amongst middle managers of Department of Health
- Authors: Mawonga, Mzukisi Edward
- Subjects: Job satisfaction -- South Africa -- Eastern Cape , Job stress -- South Africa -- Eastern Cape. , Middle managers -- Job satisfaction , Public health administration -- South Africa
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:10082 , http://hdl.handle.net/10948/d1020197
- Description: Job satisfaction studies are an essential element for ensuring improvement in service delivery. The researcher was committed to assist top management with important information that can make them aware of the causes and consequences of job satisfaction (Nel, Van Dyk, Haasbroek, Schultz, Sono and Werner, 2006:52). Job satisfaction is not only concerned with feeling good at work, it also encompasses job content, the work environment and interaction with all people. The study was conducted at the Department of Health in the Province of the Eastern Cape. This study aimed to describe the level of job satisfaction amongst middle managers of the Department of Health (DoH) at the Head Office, in terms of remuneration, interpersonal relationships, development, support, recognition, extent of supervision, their attitude to the work itself and working conditions.
- Full Text:
- Authors: Mawonga, Mzukisi Edward
- Subjects: Job satisfaction -- South Africa -- Eastern Cape , Job stress -- South Africa -- Eastern Cape. , Middle managers -- Job satisfaction , Public health administration -- South Africa
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:10082 , http://hdl.handle.net/10948/d1020197
- Description: Job satisfaction studies are an essential element for ensuring improvement in service delivery. The researcher was committed to assist top management with important information that can make them aware of the causes and consequences of job satisfaction (Nel, Van Dyk, Haasbroek, Schultz, Sono and Werner, 2006:52). Job satisfaction is not only concerned with feeling good at work, it also encompasses job content, the work environment and interaction with all people. The study was conducted at the Department of Health in the Province of the Eastern Cape. This study aimed to describe the level of job satisfaction amongst middle managers of the Department of Health (DoH) at the Head Office, in terms of remuneration, interpersonal relationships, development, support, recognition, extent of supervision, their attitude to the work itself and working conditions.
- Full Text:
Local economic development: disseminating global best practices to affect futuristic thinking in SA
- Authors: Perks, Sandra
- Subjects: Economic development , Economic development -- South Africa , f-sa
- Language: English
- Type: text , Lectures
- Identifier: http://hdl.handle.net/10948/20966 , vital:29423
- Description: The aim of Local Economic Development (LED) is to ensure that the economy of a community, region or country grows faster than the population, so that there can be surplus resources for future expansion (Rucker, Kinnett & Barbash 2012). This suggests that LED is more than economic development at local level. LED is often not viewed from an economic perspective but from a political perspective. Birkhölzer (2005:3) outlines four possible political LED viewpoints. The first perspective is “development from above” with an authoritarian state dictating to regional government and local authorities. This perspective has been proven flawed when political or economic turbulences occur. The second perspective is “development from outside” with reliance on outside investors to bring into the country the necessary resources, mostly funding. This perspective is risky from a sustainability point of view. The third perspective is the “wait and see” where migration occurs if there are problems. This perspective is equally flawed as it is becoming increasingly difficult to migrate because it is so costly, and also finding the right place to go can prove to be problematic. The last perspective is the “development from within” where people play a key role, and do not rely on government or the economy to serve their needs or solve their problems; this points to self-sufficiency.
- Full Text:
- Authors: Perks, Sandra
- Subjects: Economic development , Economic development -- South Africa , f-sa
- Language: English
- Type: text , Lectures
- Identifier: http://hdl.handle.net/10948/20966 , vital:29423
- Description: The aim of Local Economic Development (LED) is to ensure that the economy of a community, region or country grows faster than the population, so that there can be surplus resources for future expansion (Rucker, Kinnett & Barbash 2012). This suggests that LED is more than economic development at local level. LED is often not viewed from an economic perspective but from a political perspective. Birkhölzer (2005:3) outlines four possible political LED viewpoints. The first perspective is “development from above” with an authoritarian state dictating to regional government and local authorities. This perspective has been proven flawed when political or economic turbulences occur. The second perspective is “development from outside” with reliance on outside investors to bring into the country the necessary resources, mostly funding. This perspective is risky from a sustainability point of view. The third perspective is the “wait and see” where migration occurs if there are problems. This perspective is equally flawed as it is becoming increasingly difficult to migrate because it is so costly, and also finding the right place to go can prove to be problematic. The last perspective is the “development from within” where people play a key role, and do not rely on government or the economy to serve their needs or solve their problems; this points to self-sufficiency.
- Full Text:
Nurse managers' perceptions of the Eastern Cape department of health employee assistance programme
- Authors: Stenge, Nyameka
- Subjects: Employee assistance programs -- South Africa -- Eastern Cape , Nurse administrators -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:10088 , http://hdl.handle.net/10948/d1021203
- Description: Organizations assist employees to deal effectively with demanding work and the work environment, including their personal problems, through an Employee Assistance Programme (EAP). The essence of the EAP is the application of knowledge about behaviour and behavioural health to make accurate assessments, followed by appropriate action to improve the productivity and healthy functioning of the employees. According to the report from the Employee Wellness Directorate of the Eastern Cape, the Employee Assistance Programme Practitioners saw 576 employees in 2010. These statistics only represent a few districts in the Eastern Cape as some districts do not have Employee Assistance Practitioners offering employee assistance, hence this number could be higher. In some instances employees do self-referral, which may increase the number without the managers knowing who is utilizing the EAP. This makes it difficult for the managers to monitor such employees and the effectiveness of the intervention rendered. Managers refer employees but do not have control over whether employees made use of the EAP and on the progress in sessions as they do not always receive the feedback. The Employee Assistance counsellor may receive a written referral from the nursing manager and then consults the referred employee in private. The employee gives consent and then the EAP counsellor addresses the problem at hand. If it is a complex case needing expert intervention arrangements are made. If the intervention requires follow up sessions, the EAP counsellor makes the necessary arrangements through the referring manager until the problem is resolved. The EAP counsellor monitors the employee and asks the manager to support the employee without divulging details of the problem that was being addressed. However, the Nursing Managers do not know how effective the programme is and whether the employees benefit from the use. The above-mentioned problem led the researcher to ask the following questions: • What are the perceptions that Nurse Managers in the Department of Health in the Eastern Cape Province have of the effectiveness of the Employee Assistance Programme? • How can Nurse Managers optimize employees’ use of the EAP? The goal of this study was to identify the perceptions of Nurse Managers of the Employee Assistance Programme in order to determine how the programme’s use can be optimized. The researcher used a qualitative, explorative, descriptive and contextual design. The research population was selected purposively and included the Nursing Managers in the Department of Health in the Chris Hani District, Eastern Cape, who have referred employees to the Employee Assistance Programme. Semi-structured interviews were used during the data gathering process. Interviews were conducted at a venue convenient to the participants. Open-ended questions were asked to enable participants to express their perceptions on the topic. The researcher also used observation and field-notes to ensure that the data gathering provided rich information. The data was analysed using Tesch’s method of data analysis. Trustworthiness was ensured by using Guba’s model of trustworthiness. The ethical strategies of informed consent, confidentiality and anonymity, avoidance of harm and voluntary participation were ensured. Two themes emerged from the data analysis. Theme one showed that the participants had contrasting perceptions regarding the effectiveness of the current Employee Assistance Programme. Some felt that they have benefitted from the programme while others felt differently. Theme two described the participants’ views elated to improving the utilization of the EAP. Positive and negative factors that impacted on the implementation of EAP have been identified. Results show that both the employer and the employees could benefit if EAP is well implemented. Decentralization of EAP could be very cost effective and could save the employer thousands of rands because resources would be utilized better.
- Full Text:
- Authors: Stenge, Nyameka
- Subjects: Employee assistance programs -- South Africa -- Eastern Cape , Nurse administrators -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:10088 , http://hdl.handle.net/10948/d1021203
- Description: Organizations assist employees to deal effectively with demanding work and the work environment, including their personal problems, through an Employee Assistance Programme (EAP). The essence of the EAP is the application of knowledge about behaviour and behavioural health to make accurate assessments, followed by appropriate action to improve the productivity and healthy functioning of the employees. According to the report from the Employee Wellness Directorate of the Eastern Cape, the Employee Assistance Programme Practitioners saw 576 employees in 2010. These statistics only represent a few districts in the Eastern Cape as some districts do not have Employee Assistance Practitioners offering employee assistance, hence this number could be higher. In some instances employees do self-referral, which may increase the number without the managers knowing who is utilizing the EAP. This makes it difficult for the managers to monitor such employees and the effectiveness of the intervention rendered. Managers refer employees but do not have control over whether employees made use of the EAP and on the progress in sessions as they do not always receive the feedback. The Employee Assistance counsellor may receive a written referral from the nursing manager and then consults the referred employee in private. The employee gives consent and then the EAP counsellor addresses the problem at hand. If it is a complex case needing expert intervention arrangements are made. If the intervention requires follow up sessions, the EAP counsellor makes the necessary arrangements through the referring manager until the problem is resolved. The EAP counsellor monitors the employee and asks the manager to support the employee without divulging details of the problem that was being addressed. However, the Nursing Managers do not know how effective the programme is and whether the employees benefit from the use. The above-mentioned problem led the researcher to ask the following questions: • What are the perceptions that Nurse Managers in the Department of Health in the Eastern Cape Province have of the effectiveness of the Employee Assistance Programme? • How can Nurse Managers optimize employees’ use of the EAP? The goal of this study was to identify the perceptions of Nurse Managers of the Employee Assistance Programme in order to determine how the programme’s use can be optimized. The researcher used a qualitative, explorative, descriptive and contextual design. The research population was selected purposively and included the Nursing Managers in the Department of Health in the Chris Hani District, Eastern Cape, who have referred employees to the Employee Assistance Programme. Semi-structured interviews were used during the data gathering process. Interviews were conducted at a venue convenient to the participants. Open-ended questions were asked to enable participants to express their perceptions on the topic. The researcher also used observation and field-notes to ensure that the data gathering provided rich information. The data was analysed using Tesch’s method of data analysis. Trustworthiness was ensured by using Guba’s model of trustworthiness. The ethical strategies of informed consent, confidentiality and anonymity, avoidance of harm and voluntary participation were ensured. Two themes emerged from the data analysis. Theme one showed that the participants had contrasting perceptions regarding the effectiveness of the current Employee Assistance Programme. Some felt that they have benefitted from the programme while others felt differently. Theme two described the participants’ views elated to improving the utilization of the EAP. Positive and negative factors that impacted on the implementation of EAP have been identified. Results show that both the employer and the employees could benefit if EAP is well implemented. Decentralization of EAP could be very cost effective and could save the employer thousands of rands because resources would be utilized better.
- Full Text:
Optical nonlinearities and photophysicochemical behaviour of green and blue forms of lutetium bisphthalocyanines
- Sekhosana, Kutloano Edward, Amuhaya, Edith, Mack, John, Nyokong, Tebello
- Authors: Sekhosana, Kutloano Edward , Amuhaya, Edith , Mack, John , Nyokong, Tebello
- Language: English
- Type: Article
- Identifier: vital:7316 , http://hdl.handle.net/10962/d1020543
- Description: A rare earth sandwich-type phthalocyanine: bis-{2,3,9,10,16,17,23,24-octa(4-tert-butylphenoxy) phthalocyaninato} lutetium(III) has been synthesized. The photophysical and nonlinear optical behavior of both the “green” and “blue” forms ([LuIIIPc2] and [LuIIIPc2]−, respectively) of the complex have been investigated. High triplet state and singlet oxygen quantum yield values were obtained for the neutral blue form which contains no unpaired electrons. Relatively high third order susceptibility and hyperpolarizability values of the order of 10−10 and 10−28 esu were obtained for both the green and blue forms, respectively. A very low threshold intensity of 0.00051 J cm−2 was obtained for the blue form. Hence the complex shows promise for non-linear optical applications. , Original publication is available at http://dx.doi.org/10.1039/C4TC00505H
- Full Text:
- Authors: Sekhosana, Kutloano Edward , Amuhaya, Edith , Mack, John , Nyokong, Tebello
- Language: English
- Type: Article
- Identifier: vital:7316 , http://hdl.handle.net/10962/d1020543
- Description: A rare earth sandwich-type phthalocyanine: bis-{2,3,9,10,16,17,23,24-octa(4-tert-butylphenoxy) phthalocyaninato} lutetium(III) has been synthesized. The photophysical and nonlinear optical behavior of both the “green” and “blue” forms ([LuIIIPc2] and [LuIIIPc2]−, respectively) of the complex have been investigated. High triplet state and singlet oxygen quantum yield values were obtained for the neutral blue form which contains no unpaired electrons. Relatively high third order susceptibility and hyperpolarizability values of the order of 10−10 and 10−28 esu were obtained for both the green and blue forms, respectively. A very low threshold intensity of 0.00051 J cm−2 was obtained for the blue form. Hence the complex shows promise for non-linear optical applications. , Original publication is available at http://dx.doi.org/10.1039/C4TC00505H
- Full Text:
Optical nonlinearities in non-peripherally substituted pyridyloxy phthalocyanines: a combined effect of symmetry, ring-strain and demetallation
- Sanusi, Kayode, Antunes, Edith M, Nyokong, Tebello
- Authors: Sanusi, Kayode , Antunes, Edith M , Nyokong, Tebello
- Language: English
- Type: Article
- Identifier: vital:7301 , http://hdl.handle.net/10962/d1020375
- Description: The optical nonlinearities of six non-peripherally-substituted pyridyloxy phthalocyanines have been studied at 532 nm using a nanosecond Z-scan technique in a dimethyl sulphoxide solution. Ring-strain effects and the absence of a metal center were found to greatly reduce the inherent high nonlinearities expected of some of these phthalocyanine complexes. Of the six molecules investigated, 1(4),8(11),15(18),22(25)-tetrakis-(2-pyridyloxy)phthalocyaninato lead(II) 3, 1(4),8(11),15(18),22(25)-tetrakis-(2-pyridyloxy)phthalocyanine 5, and 1(4),8(11),15(18),22(25)-tetrakis-(4-pyridyloxy)phthalocyanine 6 were found to exhibit negligible nonlinear optical behavior, due to either the absence of asymmetry or central metal and/or the presence of a ring-strain effect. A two-photon absorption process was found to be the major contributor to the observed reverse saturable absorption (RSA) in 1(4),8(11),15(18),22(25)-tetrakis-(4-pyridyloxy)phthalocyaninato lead(II) 4, 1(4)-mono-(2-pyridyloxy)phthalocyaninato lead(II) 7, and 1(4)-mono-(4-pyridyloxy)phthalocyaninato lead(II) 8, with large two-photon absorption cross-section, high hyperpolarizability and high third-order susceptibility values in the range of 4.53 × 10−43–5.33 × 10−42 cm4 s per photon, 1.61 × 10−28–1.89 × 10−27 esu and 9.73 × 10−12–7.05 × 10−11 esu respectively. , Original publication is available at http://dx.doi.org/10.1039/C3DT52462K , Arbortext Advanced Print Publisher 9.1.520/W Unicode , Acrobat Distiller 10.0.0 (Windows); modified using iText� 5.3.3 �2000-2012 1T3XT BVBA (AGPL-version)
- Full Text:
- Authors: Sanusi, Kayode , Antunes, Edith M , Nyokong, Tebello
- Language: English
- Type: Article
- Identifier: vital:7301 , http://hdl.handle.net/10962/d1020375
- Description: The optical nonlinearities of six non-peripherally-substituted pyridyloxy phthalocyanines have been studied at 532 nm using a nanosecond Z-scan technique in a dimethyl sulphoxide solution. Ring-strain effects and the absence of a metal center were found to greatly reduce the inherent high nonlinearities expected of some of these phthalocyanine complexes. Of the six molecules investigated, 1(4),8(11),15(18),22(25)-tetrakis-(2-pyridyloxy)phthalocyaninato lead(II) 3, 1(4),8(11),15(18),22(25)-tetrakis-(2-pyridyloxy)phthalocyanine 5, and 1(4),8(11),15(18),22(25)-tetrakis-(4-pyridyloxy)phthalocyanine 6 were found to exhibit negligible nonlinear optical behavior, due to either the absence of asymmetry or central metal and/or the presence of a ring-strain effect. A two-photon absorption process was found to be the major contributor to the observed reverse saturable absorption (RSA) in 1(4),8(11),15(18),22(25)-tetrakis-(4-pyridyloxy)phthalocyaninato lead(II) 4, 1(4)-mono-(2-pyridyloxy)phthalocyaninato lead(II) 7, and 1(4)-mono-(4-pyridyloxy)phthalocyaninato lead(II) 8, with large two-photon absorption cross-section, high hyperpolarizability and high third-order susceptibility values in the range of 4.53 × 10−43–5.33 × 10−42 cm4 s per photon, 1.61 × 10−28–1.89 × 10−27 esu and 9.73 × 10−12–7.05 × 10−11 esu respectively. , Original publication is available at http://dx.doi.org/10.1039/C3DT52462K , Arbortext Advanced Print Publisher 9.1.520/W Unicode , Acrobat Distiller 10.0.0 (Windows); modified using iText� 5.3.3 �2000-2012 1T3XT BVBA (AGPL-version)
- Full Text: