dr Njemuwa Njoku Nwaji |
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Ostatnie publikacje
1. | Nwaji N., Hyojin K.♦, Birhanu Bayissa G.♦, Osial M., Vapaavuori J.♦, Lee J.♦, Giersig M., A Stable Perovskite Sensitized Photonic Crystal P, ChemSusChem, ISSN: 1864-5631, DOI: 10.1002/cssc.202400395, pp.2-9, 2024 Streszczenie: The slow photon effect in inverse opal photonic crystals Słowa kluczowe: Hydrogen production, inverse opals, perovskite, quantum dots, photocatalysts, photonic crystals Afiliacje autorów:
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2. | Nwaji N., Juyong G.♦, My‐Chi N.♦, Huu‐Quang N.♦, Hyojin K.♦, Youngeun C.♦, Youngmi K.♦, Hongxia C.♦, Jaebeom L.♦, Emerging potentials of Fe-based nanomaterials for chiral sensing and imaging, Medicinal Research Review, ISSN: 1098-1128, DOI: 10.1002/med.22003, Vol.44, pp.897-918, 2024 Streszczenie: Fe-based nanostructures have possessed promising properties that make it suitable for chiral sensing and imaging applications owing to their ultra-small size, non-toxicity, biocompatibility, excellent photostability, tunable fluorescence, and water solubility. This review summarizes the recent research progress in the field of Fe-based nanostructures and places special emphases on their applications in chiral sensing and imaging. The synthetic strategies to prepare the targeted Fe-based structures were also introduced. The chiral sensing and imaging applications of the nanostructures are discussed in details. Słowa kluczowe: imaging, metasurfaces, quantum dots, sensing, terahertz Afiliacje autorów:
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3. | Birhanu Bayissa G.♦, Teshome Tufa L.♦, Nwaji Njemuwa N., Xiaojun H.♦, Lee J.♦, Advances in All‑Solid‑State Lithium–Sulfur Batteries for Commercialization, Nano-Micro Letters, ISSN: 2150-5551, DOI: 10.1007/s40820-024-01385-6, Vol.16, pp.2-38, 2024 Streszczenie: Solid-state batteries are commonly acknowledged as the forthcoming evolution Afiliacje autorów:
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4. | Nwaji N., Fikadu B.♦, Osial M., Moazzami Goudarzi Z., Asgaran S.♦, Teshome Tufa L.♦, Lee J.♦, Giersig M., Disentangling the catalytic origin in defect engineered 2D NiCoMoS@Ni(CN)2 core-shell heterostructure for energy-saving hydrazine-assisted water oxidation, International Journal of Hydrogen Energy, ISSN: 0360-3199, DOI: 10.1016/j.ijhydene.2024.08.432, Vol.86, pp.554-563, 2024 Streszczenie: The major hindrance to efficient electrocatalytic hydrogen generation from water electrolysis is the sluggish kinetics with corresponding large overvoltage of oxygen evolution reaction. Herein, we report a defective 2D NiCoMoS@Ni(CN)2 core-shell heterostructure derived from Hofmann-type MOF as an efficient and durable high-performance noble metal-free electrocatalyst for hydrazine oxidation reaction (HzOR) in alkaline media. The sluggish oxygen evolution reaction was replaced with a more thermodynamically favourable HzOR, enabling energy-saving electrochemical hydrogen production with 2D NiCoMoS@Ni(CN)2 acting as a bifunctional electrocatalyst for anodic HzOR and cathodic hydrogen generation. Operating at room temperature, the two-electrode electrolyzer delivers 100 mA cm−2 from a cell voltage of just 257 mV, with strong long-term electrochemical durability and nearly 100% Faradaic efficiency for hydrogen evolution in 1.0 M KOH aqueous solution with 0.5 M hydrazine. The density functional theory (DFT) was employed to investigate the origin of catalytic performance and showed that high vacancy creation within the heterointerface endowed NiCoMoS@Ni(CN)2 with favourable functionalities for excellent catalytic performance. Słowa kluczowe: Defect engineering, Core-shell, Electrocatalyst, Hydrazine oxidation, Heterostructure Afiliacje autorów:
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5. | Nwaji N., Fikadu B.♦, Osial M., Gicha B.B.♦, Warczak M.♦, Fan H.♦, Lee J.♦, Giersig M., Atomically dispersed ruthenium in transition metal double layered hydroxide as a bifunctional catalyst for overall water splitting, RENEWABLE ENERGY, ISSN: 0960-1481, DOI: 10.1016/j.renene.2024.121307, Vol.235, pp.1-10, 2024 Streszczenie: Efficient and sustainable energy conversion depends on the rational design of single-atom catalysts. The control of the active sites at the atomic level is vital for electrocatalytic materials in alkaline and acidic electrolytes. Moreover, fabrication of effective catalysts with a well-defined surface structure results in an in-depth understanding of the catalytic mechanism. Herein, a single atom ruthenium dispersed in nickel-cobalt layered hydroxide (Ru-NiCo LDH) is reported. Through the precise controlling of the atomic dispersion and local coordination environment, Ru-NiCo LDH//Ru-NiCo LDH provides an ultra-low overpotential of 1.45 mV at 10 mA cm−2 for the overall water splitting, which surpasses that of the state-of-the-art Pt/C/RuO2 redox couple. Density functional theory calculations show that Ru-NiCo LDH optimizes hydrogen evolution intermediate adsorption energies and promotes O-O coupling at a Ru-O active site for oxygen evolution, while Ni serves as the water dissociation site for effective water splitting. As a potential model, Ru-NiCo LDH shows enhanced water splitting performance with potential for the development of promising water-alkaline catalysts. Afiliacje autorów:
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6. | Nwaji N., Getasew Mulualem Z.♦, Juyong G.♦, Hyojin K.♦, Lemma Tushome T.♦, Yujin C.♦, Mahedra G.♦, Hyeyoung S.♦, Jaebeom L.♦, Dimeric NiCo single-atom anchored on ultrathin N-doped 2D molybdenum carbide boosted performance in solid-state supercapacitor, Journal of Energy Storage, ISSN: 2352-152X, DOI: 10.1016/j.est.2024.110671, Vol.83, pp.1-10, 2024 Streszczenie: Tuning the electronic structure of single-atom catalysts through dimeric single-atom formation could be an innovative approach to increasing their energy storage activity, but the process of achieving this is challenging. In this study, we designed a simple technique to obtain Nisingle bondCo single atom dimers (SADs) anchored on N-doped molybdenum carbide (N-Mo2C) through in-situ encapsulation of Nisingle bondCo into molybdenum polydopamine, followed by annealing with optimal tuning of nitrogen dopant. The Nisingle bondCo atomic level coordination was confirmed with X-ray absorption spectroscopy. When used as energy storage supercapacitor, The NiCo-SADs showed enhanced specific capacity (1004.8 F g−1 at 1 A g−1), enhanced rate capability (75 %), and exceptional cycling stability (93.6 % with 98.5 % coulombic efficiency) via a dominant capacitive charge storage. The augmented charge storage characteristics are attributed to the collaborative features of the active Nisingle bondCo constituents acting as electron reservoir for effective adsorption of HO− ion during the electrochemical process. The DFT study showed thermodynamically favorable OH− adsorption between the three metal bridges that promoted redox reaction kinetics and enhanced conductivity for the NiCo-SADs. When using N-Mo2C as the anode to fabricate hybrid supercapacitors, the device exhibits high energy density of 69.69 Wh kg−1 at power density of 8200 W kg−1, respectively and shows excellent long-term cycling stability (93.42 % after 3000 cycles), which affirms the potential of the assembled device for applications in solid state supercapacitors. Afiliacje autorów:
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7. | Zhang Y.♦, Nwaji N.♦, Wu L.♦, Jin m.♦, Zhou G.♦, Giersig M., Wang X.♦, Qiu T.♦, Akinoglu E.M.♦, MAPbBr3/Bi2WO6 Z-scheme-Heterojunction Photocatalysts for photocatalytic CO2 reduction, JOURNAL OF MATERIALS SCIENCE, ISSN: 0022-2461, DOI: 10.1007/s10853-023-09220-w, Vol.59, pp.1498-1512, 2024 Streszczenie: Photocatalytic CO2 reduction has emerged as a promising strategy for converting solar energy into valuable chemicals, capturing the attention of scientists across various disciplines. Organic and inorganic perovskites, particularly methylammonium lead bromide (MAPbBr3), have demonstrated potential in this field due to their remarkable visible-light response and carrier transport properties. However, the catalytic performance of pristine MAPbBr3 has been limited by severe charge recombination, hindering its applicability in photocatalytic systems. Here, we show that a MAPbBr3/Bi2WO6 (MA/BWO) heterojunction significantly enhances photocatalytic CO2 reduction performance compared to individual pristine MA or BWO. This enhancement is evidenced by the superior performance of the 25% MA/BWO composite, which exhibits CO and CH4 release rates of 1.82 μmol/g/h and 0.08 μmol/g/h, respectively. This improvement is attributed to the direct Z-scheme heterojunction formed between MAPbBr3 and Bi2WO6, which facilitates efficient charge separation and suppresses charge recombination. The results challenge the previous understanding of MAPbBr3-based photocatalysts and demonstrate a novel approach for developing highly active organic and inorganic perovskite photocatalysts. The successful application of the MA/BWO heterojunction in photocatalytic CO2 reduction expands the scope of organic and inorganic perovskites in the field of renewable energy conversion. By providing a broader perspective, our findings contribute to the ongoing efforts towards sustainable energy solutions, appealing Afiliacje autorów:
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8. | Yonas S.♦, Gicha B.B.♦, Adhikari S.♦, Sabir F.K.♦, Tran V.T.♦, Nwaji N., Gonfa B.A.♦, Teshome Tufa L.♦, Electric-Field-Assisted Synthesis of Cu/MoS2 Nanostructures for Efficient Hydrogen Evolution Reaction, Micromachines, ISSN: 2072-666X, DOI: 10.3390/mi15040495, Vol.15, No.495, pp.1-13, 2024 Streszczenie: Molybdenum sulfide–oxide (MoS2, MS) emerges as the prime electrocatalyst candidate demonstrating hydrogen evolution reaction (HER) activity comparable to platinum (Pt). This study presents a facile electrochemical approach for fabricating a hybrid copper (Cu)/MoS2 (CMS) nanos- tructure thin-film electrocatalyst directly onto nickel foam (NF) without a binder or template. The synthesized CMS nanostructures were characterized utilizing energy-ispersive X-ray spectroscopy (EDS), scanning electron microscopy (SEM), X-ray diffraction (XRD), and electrochemical methods. The XRD result revealed that the Cu metal coating on MS results in the creation of an extremely crys-talline CMS nanostructure with a well-defined interface. The hybrid nanostructures demonstrated Słowa kluczowe: electrodeposition, hydrogen evolution reactions, catalytic activity, Cu/MoS2 nanostructures Afiliacje autorów:
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9. | Birhanu Bayissa G.♦, Teshome Tufa L.♦, Mahendra G.♦, Lee Y.♦, Fikadu Banti B.♦, Nwaji Njoku N., You S.♦, Lee J.♦, Oxygen Vacancy Generation and Stabilization in Layered NiFeCo Double Hydroxide Nanosheets for a Highly Efficient Oxygen Evolution Reaction, ACS Applied Nano Materials, ISSN: 2574-0970, DOI: 10.1021/acsanm.4c01840, Vol.8, pp.A-K, 2024 Streszczenie: Oxygen vacancy (Vo) is ubiquitous, playing a critical role in tuning the electronic configuration and optimizing the adsorption of adsorbates in the oxygen evolution reaction (OER) process. However, fine control over the density and stabilization of Vo is a big challenge in the highly oxidizing environment of OER. Herein, we have fabricated bulk NiFeCo (layered double hydroxide) LDHs via the hydrothermal method and exfoliated them into thin sheets rich with Vo using high-energy Ar-plasma. We doped fluoride to simultaneously modulate the charge distribution of surrounding atoms and stabilize Vo by taking advantage of the extremely high electronegativity and similar ion diameter to oxygen of fluoride. The material exhibited OER activity with a low overpotential of 200 mV at 10 mA cm–2 and a Tafel slope of 34.6 mV dec–1. Density functional theory (DFT) calculations support the claim that Vo and fluoride substantially increase NiFeCo LDH OER activity by modifying the electronic structures of the catalytically active sites. Słowa kluczowe: Electrocatalyst, Double layered hydroxide, oxygen evolution reaction, oxygen vacancy, stabilization Afiliacje autorów:
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10. | Nwaji Njemuwa N.♦, Juyong G.♦, Mahendra G.♦, Hyojin K., Adewale Hammed P.♦, Sharan A.♦, Singh N.♦, Lee J.♦, Defect engineered Fe3C@NiCo2S4 trojan nanospike derived from Metal Organic framework as Advanced electrode material for Hybrid supercapacitor., ACS Applied Materials and Interfaces, ISSN: 1944-8244, DOI: 10.1021/acsami.3c04635, Vol.15, No.29, pp.34779-34788, 2023 Streszczenie: The rational synthesis and tailoring of metal-organic frameworks (MOFs) with multifunctional micro/nanoarchitectures have emerged as a subject of significant academic interest owing to their promising potential for utilization in advanced energy storage devices. Herein, we explored a category of three-dimensional (3D) NiCo2S4 nanospikes that have been integrated into a 1D Fe3C microarchitecture using a chemical surface transformation process. The resulting electrode materials, i.e., Fe3C@NiCo2S4 nanospikes, exhibit immense potential for utilization in high-performance hybrid supercapacitors. The nanospikes exhibit an elevated specific capacity (1894.2 F g-1 at 1 A g-1), enhanced rate capability (59%), and exceptional cycling stability (92.5% with 98.7% Coulombic efficiency) via a charge storage mechanism reminiscent of a battery. The augmented charge storage characteristics are attributed to the collaborative features of the active constituents, amplified availability of active sites inherent in the nanospikes, and the proficient redox chemical reactions of multi-metallic guest species. When using nitrogen-doped carbon nanofibers as the anode to fabricate hybrid supercapacitors, the device exhibits high energy and power densities of 62.98 Wh kg-1 and 6834 W kg-1, respectively, and shows excellent long-term cycling stability (95.4% after 5000 cycles), which affirms the significant potential of the proposed design for applications in hybrid supercapacitors. The DFT study showed the strong coupling of the oxygen from the electrolyte OH- with the metal atom of the nanostructures, resulting in high adsorption properties that facilitate the redox reaction kinetics. Słowa kluczowe: defect engineering,Nanospike,advanced electrode,hybrid,MOF,Supercapacitor Afiliacje autorów:
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11. | Mahendra G.♦, Huu-Quang N.♦, Sohyun K.♦, Birhanu Bayissa G.♦, Teshome Tufa L.♦, Nwaji Njemuwa N., My-Chi Thi N.♦, Juyong G.♦, Lee J.♦, Rugged forest morphology of magnetoplasmonic nanorods that collect maximum light for photoelectrochemical water splitting, Nano Micro Small Journal, ISSN: 1613-6829, DOI: 10.1002/smll.202302980, Vol.19, pp.1-14, 2023 Streszczenie: A feasible nanoscale framework of heterogeneous plasmonic materials and Afiliacje autorów:
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12. | Nwaji N.♦, Akinoglu E.M.♦, Lin Q.♦, Teshome Tufa L.♦, Sharan A.♦, Singh N.♦, Wang X.♦, Giersig M., Lee J.♦, Surface Modulation of Fe3O4 Confined in Porous Molybdenum-Based Nanoplatform for Enhanced Hydrogen Production, Energy Technology, ISSN: 2194-4296, DOI: 10.1002/ente.202201061, Vol.11, No.2, pp.2201061-1-9, 2023 Streszczenie: The integration of different precursor components to form single nanostructures via one-step synthesis process is mostly restricted by the compatibility and complexity of components. Herein, a highly uniform, spherical, hollowed, and hierarchical iron oxide-wrapped Mo–polydopamine is synthesized using a one-pot liquid-phase reaction at room temperature. Mo2C is doped with Fe3O4 to harness the rich electrons in Fe dopants for effective lowering of the unoccupied d-orbitals in Mo. The surface conductivity of the as-prepared nanostructures is enhanced by decorating them with gold nanoparticles utilizing strong interaction of Au and amine. The nanocomposites are converted into carbidic hollowed structures via an annealing process without any distortion in morphology. The well-organized structure and nanosize of the particles provide efficient catalytic performance for hydrogen evolution reaction in acidic media. MoFe–C@Au exhibits a very positive onset potential of 2 mV, low Tafel slope of 50.1 mV dec^-1, and remarkable long- term stability. Słowa kluczowe: electrocatalysts,hierarchical syntheses,hydrogen evolution,molybdenum,polydopamine Afiliacje autorów:
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13. | Cheru Fekadu M.♦, Bedasa Abdisa G.♦, Fedlu Kedir S.♦, Birhanu Bayissa G.♦, Nwaji N., Lemma Teshome T.♦, Jaebeom L.♦, Ni-Based Ultrathin Nanostructures for Overall Electrochemical Water Splitting, Material Chemistry Frontiers, ISSN: 2052-1537, DOI: 10.1039/D2QM00964A, Vol.7, pp.194-215, 2023 Streszczenie: Hydrogen produced by electrochemical water splitting is considered to be a sustainable fuel source, an Afiliacje autorów:
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14. | Nwaji Njemuwa N.♦, Hyojin K.♦, Mahendra G.♦, Teshome Tufa L.♦, Juyong G.♦, Sharan A.♦, Singh N.♦, Lee J.♦, Sulfur vacancy induced Co3S4@CoMo2S4 nanocomposite as functional electrode for high performance supercapacitor, Journal of Materials Chemistry A, ISSN: 2050-7488, DOI: 10.1039/d2ta08820g, Vol.11, pp.3640-3652, 2023 Streszczenie: Vacancy engineering offers an attractive approach to improving the surface properties and electronic Afiliacje autorów:
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15. | Achadu Ojodomo J.♦, Nwaji N.♦, Lee D.♦, Lee J.♦, Akinoglu E.M.♦, Giersig M., Park Enoch Y.♦, 3D hierarchically porous magnetic molybdenum trioxide@gold nanospheres as a nanogap-enhanced Raman scattering biosensor for SARS-CoV-2, Nanoscale Advances, ISSN: 2516-0230, DOI: 10.1039/d1na00746g, Vol.4, pp.871-883, 2022 Streszczenie: The global pandemic of COVID-19 is an example of how quickly a disease-causing virus can take root and threaten our civilization. Nowadays, ultrasensitive and rapid detection of contagious pathogens is in high demand. Here, we present a novel hierarchically porous 3-dimensional magnetic molybdenum trioxide–polydopamine-gold functionalized nanosphere (3D mag-MoO3–PDA@Au NS) composed of plasmonic, semiconductor, and magnetic nanoparticles as a multifunctional nanosculptured hybrid. Based on the synthesized 3D mag-MoO3–PDA@Au NS, a universal “plug and play” biosensor for pathogens is proposed. Specifically, a magnetically-induced nanogap-enhanced Raman scattering (MINERS) detection platform was developed using the 3D nanostructure. Through a magnetic actuation process, the MINERS system overcomes Raman signal stability and reproducibility challenges for the ultrasensitive detection of SARS-CoV-2 spike protein over a wide dynamic range up to a detection limit of 10−15 g mL−1. The proposed MINERS platform will facilitate the broader use of Raman spectroscopy as a powerful analytical detection tool in diverse fields. Afiliacje autorów:
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16. | Refilwe M.♦, Nwaji Njemuwa N., Muthumuni M.♦, Zhi-Long C.♦, Tebello N.♦, Photodynamic therapy characteristics of phthalocyanines in the presence of boron doped detonation nanodiamonds: Effect of symmetry and charge, Phothodygnosis, ISSN: 1873-1597, DOI: 10.1016/j.pdpdt.2021.102705, Vol.37, pp.1-9, 2022 Streszczenie: The synthesis, photophysicochemical and photodynamic therapy (PDT) activities of benzothiazole substituted zinc phthalocyanine (Pc): 1 (asymmetrically substituted and composed of no charges), 2 (asymmetrically substituted and composed of three positive charges), and 3 (symmetrically substituted and composed of four positive charges), are presented. The triplet and singlet oxygen quantum yields were highest for complex 2 showing the importance of asymmetry and charge. The complexes are covalently and non-covalently linked to B doped detonation nanodiamonds (B@DNDs) to yield nanohybrids (B@DNDs-1, B@DNDs-2, B@DNDs-3). The presence of B@DNDs, asymmetry and positive charge resulted in improved PDT with the lowest cell viability being observed for B@DNDs-2 at 5%. The cell viability ranged from 5% to 7% for the nanohybrids compared to 19–26% for Pcs alone. Afiliacje autorów:
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17. | Nwaji N., Akinoglu E.M.♦, Biyun L.♦, Xin W.♦, Michael G., One-Pot Synthesis of One-Dimensional Multijunction Semiconductor Nanochains from Cu1.94S, CdS, and ZnS for Photocatalytic Hydrogen Generation., ACS Applied Materials and Interfaces, ISSN: 1944-8244, DOI: 10.1021/acsami.1c18020, Vol.49, pp.58630-58639, 2021 Streszczenie: Chains of alternating semiconductor nanocrystals are complex nanostructures that can offer control over photogenerated charge carriers dynamics and quantized electronic states. We develop a simple one-pot colloidal synthesis of complex Cu1.94S-CdS and Cu1.94S-ZnS nanochains exploiting an equilibrium driving ion exchange mechanism. The chain length of the heterostructures can be tuned using a concentration dependent cation exchange mechanism controlled by the precursor concentrations, which enables the synthesis of monodisperse and uniform Cu1.94S-CdS-Cu1.94S nanochains featuring three epitaxial junctions. These seamless junctions enable efficient separation of photogenerated charge carriers, which can be harvested for photocatalytic applications. We demonstrate the superior photocatalytic activity of these noble metal free materials through solar hydrogen generation at a hydrogen evolution rate of 22.01 mmol g–1 h–1, which is 1.5-fold that of Pt/CdS heterostructure photocatalyst particles. Afiliacje autorów:
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18. | Nwaji N.♦, Akinoglu E.M.♦, Giersig M., Gold nanoparticle-decorated Bi2S3 nanorods and nanoflowers for photocatalytic wastewater treatment, Catalysts, ISSN: 2073-4344, DOI: 10.3390/catal11030355, Vol.11, No.3, pp.355-1-12, 2021 Streszczenie: Colloidal synthesis of photocatalysts with potential to overcome the drawback of low photocatalytic efficiency brought by charge recombination and narrow photo-response has been a challenge. Herein, a general and facile colloidal approach to synthesize orthorhombic phase Bi2S3 particles with rod and flower-like morphology is reported. We elucidate the formation and growth process mechanisms of these synthesized nanocrystals in detail and cooperate these Bi2S3 particles with metallic gold nanoparticles (AuNPs) to construct heterostructured photocatalysts. The unique properties of AuNPs featuring tunable surface plasmon resonance and large field enhancement are used to sensitize the photocatalytic activity of the Bi2S3 semiconductor particles. The morphology, structure, elemental composition, and light absorption ability of the prepared catalysts are characterized by (high-resolution) transmission electron microscopy, scanning electron microscopy, X-ray diffraction spectroscopy, X-ray photoelectron spectroscopy, and UV–vis absorption spectroscopy. The catalysts exhibit high and stable photocatalytic activity for the degradation of organic pollutants demonstrated using rhodamine B and methyl orange dyes under solar light irradiation. We show that the incorporation of the AuNPs with the Bi2S3 particles increases the photocatalytic activity 1.2 to 3-fold. Radical trapping analysis indicates that the production of hydroxyl and superoxide radicals are the dominant active species responsible for the photodegradation activity. The photocatalysts exhibit good stability and recyclability. Słowa kluczowe: Bi2S3, nanoflower, nanorod, photocatalysis, heterostructures, AuNPs Afiliacje autorów:
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19. | Gabriele V.R.♦, Mazhabi R.M.♦, Alexander N.♦, Mukherjee P.♦, Seyfried T.N.♦, Nwaji N.♦, Akinoglu E.M.♦, Mackiewicz A.♦, Zhou G.♦, Giersig M., Naughton M.J.♦, Kempa K.♦, Light- and melanin nanoparticle-induced cytotoxicity in metastatic cancer cells, Pharmaceutics, ISSN: 1999-4923, DOI: 10.3390/pharmaceutics13070965, Vol.13, No.7, pp.965-1-14, 2021 Streszczenie: Melanin nanoparticles are known to be biologically benign to human cells for a wide range of concentrations in a high glucose culture nutrition. Here, we show cytotoxic behavior at high nanoparticle and low glucose concentrations, as well as at low nanoparticle concentration under exposure to (nonionizing) visible radiation. To study these effects in detail, we developed highly monodispersed melanin nanoparticles (both uncoated and glucose-coated). In order to study the effect of significant cellular uptake of these nanoparticles, we employed three cancer cell lines: VM-M3, A375 (derived from melanoma), and HeLa, all known to exhibit strong macrophagic character, i.e., strong nanoparticle uptake through phagocytic ingestion. Our main observations are: (i) metastatic VM-M3 cancer cells massively ingest melanin nanoparticles (mNPs); (ii) the observed ingestion is enhanced by coating mNPs with glucose; (iii) after a certain level of mNP ingestion, the metastatic cancer cells studied here are observed to die—glucose coating appears to slow that process; (iv) cells that accumulate mNPs are much more susceptible to killing by laser illumination than cells that do not accumulate mNPs; and (v) non-metastatic VM-NM1 cancer cells also studied in this work do not ingest the mNPs, and remain unaffected after receiving identical optical energy levels and doses. Results of this study could lead to the development of a therapy for control of metastatic stages of cancer. Słowa kluczowe: melanoma, melanin nanoparticles, cytotoxicity, laser medical applications, hyperthermia Afiliacje autorów:
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20. | Nwaji N., Akinoglu E.M.♦, Synthesis of ZnS-CuS-Bi nanonail heterostructures and funnel mechanism of their photocatalytic activity, Journal of Environmental Chemical Engineering, ISSN: 2213-2929, DOI: 10.1016/j.jece.2021.106066, Vol.9, pp.1-7, 2021 Streszczenie: Nanonail shaped ZnS-CuS-Bi three component nanoparticles are synthesized via a simple one-pot colloidal Afiliacje autorów:
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21. | Nnaemeka N.♦, Nwaji N., John M.♦, Tebello N.♦, Ball-type phthalocyanines and reduced graphene oxide nanoparticles as separate and combined corrosion inhibitors of aluminium in HCl, Journal of molecular structure, ISSN: 0022-2860, DOI: 10.1016/j.molstruc.2021.130279, Vol.1236, pp.1-12, 2021 Streszczenie: Corrosion inhibition performances and adsorption behaviour at the aluminum-HCl solution interface were Afiliacje autorów:
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22. | Anthony C. E.♦, Dickson N. U.♦, Nwaji Njemuwa N., Olawale J. O.♦, Obianuju L. N.♦, Miracle E.♦, Christopher U. S.♦, Obinna O. O.♦, David O. I.♦, Green synthesis of silver nanoparticles using leaf extract of Euphorbia sanguine: an in vitro study of its photocatalytic and melanogenesis inhibition activity, Inorganic nano-metal chemistry, ISSN: 2470-1564, DOI: 10.1080/24701556.2021.1891100, Vol.49, pp.1-8, 2020 Streszczenie: We report on biosynthesis of silver nanoparticles using aqueous leaf extract of Euphorbia sanguinea and its photocatalytic degradation of Congo red dye and melanogenesis inhibition activity of mushroom tyrosine enzyme. Surface Plasmon resonance bands obtained from UV-Vis spectra were within the range 430–436 nm. FT-IR studies reveal the presence of functional groups of the plant metabolites used as stabilizing agents of nanoparticles. The shape of silver nanoparticles is spherical with size ranges about 20–28.8 nm as confirmed by SEM. XRD patterns displayed well-defined crystalline peaks corresponding to the face-centred cubic structures of metallic silver nanoparticles. The results of photocatalysis showed high photocatalytic efficiency of 86% and 90% within 5 min and 60 min, respectively at a rate of solar radiation of in the degradation of Congo red dye. The AgNPs gave dose dependent melanogenesis inhibition activity with IC50 of 71.96 µg/ml, showing non competitive mode of inhibition Afiliacje autorów:
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23. | Anthony C. E.♦, Dickson N. U.♦, Nwaji N., Obinna O. O.♦, Chimerem O. E.♦, Sandra I. M.♦, Olawale J. O.♦, Obianuju L. N.♦, Green Synthesis of Biogenic Zinc Oxide Nanoflower as Dual Agent for Photodegradation of an Organic Dye and Tyrosinase Inhibitor, Journal of Inorganic and Organometallic Polymers and Materials, ISSN: 1574-1451, DOI: 10.1007/s10904-020-01729-w, Vol.31, pp.886-896, 2020 Streszczenie: In the study, metabolites of Euphorbia sanguinea were used as benign reducing and stabilizing agents to obtain zinc oxide Afiliacje autorów:
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24. | Refilwe M.♦, Tendamudzimu T.♦, Muthumuni M.♦, Nwaji N.♦, Kevin L.♦, Tebello N.♦, Theoretical and photodynamic therapy characteristics of heteroatom doped detonation nanodiamonds linked to asymmetrical phthalocyanine for eradication of breast cancer cells, Journal of Luminescence, ISSN: 0022-2313, DOI: 10.1016/j.jlumin.2020.117465, Vol.227, pp.1-13, 2020 Streszczenie: An amide mono substituted benzothiozole phthalocyanine: zinc(II) 3-(4-((3,17,23-tris(4-(benzo [d]thiazol-2-yl) Afiliacje autorów:
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25. | Shereen A. M.♦, Nwaji N., John M.♦, Tebello N.♦, Saad M.♦, Nonlinear optical responses of carbazole-substituted phthalocyanines conjugated to graphene quantum dots and in thin films , Journal of Luminescence, ISSN: 0022-2313, DOI: 10.1016/j.jlumin.2019.04.034, Vol.213, pp.88-97, 2019 Streszczenie: hree different phthalocyanine complexes substituted with carbazoles were conjugated to graphene quantum dots (GQDs) through π–π stacking. The morphologies, sizes, and crystallinities of the nanoconjugates were determined using Raman spectroscopy, energy dispersive X-ray spectroscopy, transmission electron microscopy, and X-ray diffraction. The nonlinear optical (NLO) properties of the metallophthalocyanines alone and when conjugated to the GQD nanomaterial in different solvents, as well as after having been embedded in thin films, were studied. The effects of the different substituents and solvents on the NLO properties of the metallophthalocyanines were evaluated. Enhancements in the photophysical properties of the complexes upon conjugation with the nanomaterial were observed. Fluorescence quantum yields, fluorescence lifetimes, triplet quantum yields, and triplet lifetimes were measured for the complexes, and for their conjugates in DMSO. Afiliacje autorów:
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26. | Edith D.♦, David O. O.♦, Nwaji N.♦, Earl P.♦, Tebello N.♦, Photophysicochemical and photodynamic therapy properties of metallophthalocyanines linked to gold speckled silica nanoparticles., Photodiagnosis and Photodynamic Therapy, ISSN: 1572-1000, DOI: 10.1016/j.pdpdt.2019.01.019, Vol.25, pp.325-333, 2019 Streszczenie: This work reports on the linkage of 2(3),9(10),16(17),23(24) tetrakis [(benzo[d]thiazol-2-yl phenoxy) phthalocyaninato] zinc(II) (1) and indium(III) chloride (2) to gold speckled silica (GSS) nanoparticles via gold to Afiliacje autorów:
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27. | Nnaemeka N.♦, Nwaji N., Gertrude F.♦, John M.♦, Tebello N.♦, Inhibition of Aluminium Corrosion Using Benzothiazole and Its Phthalocyanine Derivative, Electrocatlysis, ISSN: 1868-5994, DOI: 10.1007/s12678-019-00538-1, Vol.10, pp.445-458, 2019 Streszczenie: Cyclic voltammetry and potentiodynamic polarization techniques were used to study the effects of 4-[4-(1,3-benzothiazol- Afiliacje autorów:
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28. | Adachukwu Nwaka N.♦, Pius Oziri U.♦, William Robert W.♦, Nwaji N., Karl F.♦, Fatty acid profile and production of fatliquor from Canarium schweinfurthii mesocarp oil. Pertanika , Pertanika Journal of Science and Technology, ISSN: 0128-7680, Vol.27, pp.2221-2243, 2019 Streszczenie: Fatty acid profile of Canarium schweinfurthii mesocarp oil was determined by GC-MS. Afiliacje autorów:
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29. | Nnaemeka N.♦, Nwaji N., John M.♦, Tebello N.♦, Corrosion Resistance of Aluminum against Acid Activation: Impact of Benzothiazole-Substituted Gallium Phthalocyanine, Molecules, ISSN: 1420-3049, DOI: 10.3390/molecules24010207, Vol.24, pp.4-22, 2019 Streszczenie: This study describes the adsorption behavior of organic inhibitors at the aluminum-HCl Afiliacje autorów:
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30. | Gertrude F.♦, Nwaji N., Tebello N.♦, Low symmetric metallophthalocyanine modified electrode via click chemistry for simultaneous detection of heavy metals, Journal of Electroanalytical Chemistry, ISSN: 1572-6657, DOI: 10.1016/j.jelechem.2018.02.016, Vol.813, pp.58-66, 2018 Streszczenie: Beside different methods and materials used to develop electrochemical sensors, the modification of the electrode using click reaction based on metallophthalocyanine (MPc) compounds are shown to improve the stability and sensitivity of the sensor. This work reported the development of electrochemical sensor for mercury (II), Lead (II), copper (II) and cadmium (II) ions detection based on the synthesized novel low symmetry alkyne terminated cobalt Phthalocyanine (CoPc) derivative. Differential pulse stripping voltammetry (DPSV) technique was employed for the first time in simultaneous determination of trace levels of the above metal ions using modified glassy carbon electrode (GCE) via click chemistry. Under the optimum experimental conditions, the anodic peak current is proportional to the concentrations of metal ions over a wide range of 0 to 0.1 mM with nanolevel detection limit of 81.94, 327.71, 55.87 and 347.06 nM and the sensitivity of 866.23 ± 5.48, 215.82 ± 2.16, 1979.48 ± 11.47 and 204.50 ± 1.10 μA/mM for Hg(II), Cu(II), Pb(II) and Cd(II), respectively. The selectivity of the clicked-CoPc modified GCE toward Hg(II), Cu(II), Pb(II), Cd(II) present no interference from these metals ions. The fabricated electrochemical sensor exhibited very good electrochemical properties such as good reproducibility, stability, reusability and is suitable for the detection of heavy metal ions in tap water in our laboratory. Afiliacje autorów:
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31. | Nwaji N., John M.♦, Tebello N.♦, An optical limiting study in aminophenoxy substituted phthalocyanine in the presence of semiconductor quantum dots, Journal of Luminescence, ISSN: 0022-2313, Vol.203, pp.247-256, 2018 Streszczenie: The synthesis of 4-bis(4-aminophenoxy)phenoxy derivatized phthalocyanine containing In (complex 2), and Ga Afiliacje autorów:
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32. | Nwaji N., Ojodomo A.♦, Tebello N.♦, Photo-induced resonance energy transfer and nonlinear optical response in ball-type phthalocyanine conjugated to semiconductor and graphene quantum dots, New Journal of chemistry, ISSN: 1144-0546, DOI: 10.1039/C7NJ05196D, pp.1-13, 2018 Streszczenie: The synthesis of ball-type zinc and gallium phthalocyanines (complexes 2 and 3) and their covalent linkage to glutathione Afiliacje autorów:
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33. | David O. O.♦, Nwaji N., Lindokhuhle C. N.♦, Lesedi M.♦, Edith D.♦, Tebello N.♦, Novel nano-dyad of homoleptic sandwich-type phthalocyanines with nitrogen doped graphene quantum dots for nonlinear optics, New Journal of chemistry, ISSN: 1144-0546, Vol.42, pp.10124-10133, 2018 Streszczenie: The syntheses of neodymium(III) 2,9,16,23-tetrakis-(2,6-di-tert-butyl-4-methylphenoxy)phthalocyanine (2), Afiliacje autorów:
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34. | Edith D.♦, Nwaji N., John M.♦, Tebello N.♦, the photophysicochemical behavior of symmetric and asymmetric zinc phthalocyanine surface assembled onto gold nanotriangles , New Journal of chemistry, ISSN: 1144-0546, DOI: 10.1039/C8NJ02746C, Vol.42, pp.14290-14299, 2018 Streszczenie: The synthesis of a novel asymmetric phthalocyanine, (4-(4-(benzo[d]thiazol-2-yl)phenoxy)-2,10,17-tris(4-(2-carboxyethyl)phenoxy)phthalocyaninatol)zinc(II), complex 3, is reported. Complex 3 together with the previously reported complexes tetrakis[(benzo[d]thiazol-2-yl phenoxy)phthalocyaninato]zinc(II) (4) and 3-(4-((3,17,23-tris(4-(benzo[d]thiazol-2-yl)phenoxy)phthalocyaninatol)oxy)phenyl)propanoic acid zinc(II) (5), were linked to gold nanotriangles (AuNTs) through S–Au/Au–N self-assembly to afford the conjugates (3-AuNTs, 4-AuNTs and 5-AuNTs). The photophysicochemical behaviour of the complexes and their conjugates were studied. The asymmetric complexes 3 and 5, displayed improved triplet and singlet oxygen quantum yields compared to the symmetric complex 4, while all conjugates displayed improved triplet and singlet oxygen quantum yields compared to their respective complexes alone. The complexes and their conjugates could serve as good candidates for photodynamic therapy. Afiliacje autorów:
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35. | Nwaji N., Somila D.♦, John M.♦, Tebello N.♦, Phototophysical and enhanced nonlinear optical response in asymetric benzothiazole substituted phthalocyanine covalently linked to semiconductor quantum dots, Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, ISSN: 1386-1425, DOI: 10.1016/j.saa.2018.06.098, Vol.204, pp.629-639, 2018 Streszczenie: The synthesis of asymmetric benzothiazole substituted phthalocyanines (complexes 3 to 5) and their covalent Afiliacje autorów:
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36. | Edith D.♦, David O. O.♦, Nwaji N., Tebello N.♦, Gylcosylated phthalocyanine-gold nanoparticles for photodynamic therapy, effect of nanoparticles shape, Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, ISSN: 1386-1425, Vol.203, pp.85-95, 2018 Streszczenie: In this work, we report on the synthesis of tris-[(2,2,7,7-tetramethyltetrahydro-3aH-bis([1,3]dioxolo)[4,5-b:4′,5′-d]pyran-5-yl)methoxy)-2-(4-benzo[d]thiazol-2-ylphenoxyphthalocyaninato] zinc(II) (complex 3) and its linkage to gold nanoparticles (AuNPs) of different shapes through S-Au/N-Au self-assembly. The conjugates of complex 3 (with both gold nanorods (AuNR) and nanospheres (AuNS)), displayed decreased fluorescence quantum yield with corresponding improved triplet and singlet quantum yields compared to complex 3 alone, however 3-AuNR showed improved properties than 3-AuNS. Complex 3 showed relatively low in vitro dark cytotoxicity against the epithelial breast cancer cells with cell survival ≥ 85% at concentration ≤ 160 μg/mL but afforded reduced photodynamic therapy activity which may be due to aggregation. 3-AuNR afforded superior PDT activity with <50% viable cells at concentration ≥ 40 μg/mL in comparison to 3-AuNS with <50% viable cells at concentration ≥ 80 μg/mL. The superior activity of 3-AuNR is attributed to the photothermal therapy effect since nanorods absorb more light at 680 nm than nanospheres Afiliacje autorów:
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37. | Nwaji N., John M.♦, Tebello N.♦, Photophysical and strong optical limiting properties of ball-type phthalocyanines dimers and their monomeric analogues, Journal of Photochemistry and Photobiology A, ISSN: 1010-6030, DOI: 10.1016/j.jphotochem.2017.10.045, Vol.352, pp.73-85, 2018 Streszczenie: The nonlinear optical behaviors of ball-type phthalocyanine complexes: 10,11,’150,250-tetrakis-[4,40-((4- Afiliacje autorów:
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38. | Refilwe M.♦, Nwaji N., Muthumuni M.♦, Earl P.♦, Tebello N.♦, Effect of number of positive charges on the photophysical and photodynamic therapy activities of quarternary benzothiazole substituted zinc phthalocyanine, Journal of Photochemistry and Photobiology A, ISSN: 1010-6030, Vol.367, pp.253-260, 2018 Streszczenie: The synthesis, photophysicochemical and photodynamic therapy (PDT) activity of quaternary benzothiazole substituted zinc phthalocyanine (2, containing two charges, and 3, containing four charges) are reported in this work. Furthermore, the activity of the synthesized complex was compared to non-quaternary derivative (1). Higher triplet and singlet oxygen quantum yields of 0.92 and 0.85, respectively, for quaternized complexes 2 and 3 compared to complex 1 alone. Complexes 1, 2 and 3 showed relatively no dark toxicity against the epithelial breast cancer cells with cell survival of above 90 ± 3%. The quaternary derivatives (2 and 3) showed superior PDT activity with 30% or less of viable cells at concentration of 50.0 μg/mL in comparison to complex 1 alone which further lay credence to the importance of quaternization in the enhancement of PDT activit Afiliacje autorów:
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39. | Bokolombe P. N.♦, Zweli H.♦, Nwaji N.♦, Gertrude F.♦, John M.♦, Tebello N.♦, Photophysical and optical limiting properties at 532 nm of BODIPY dyes with p-benzyloxystyryl groups at the 3,5-positions, Journal of Porphyrins and Phthalocyanines, ISSN: 1088-4246, DOI: 10.1142/S1088424617500857, Vol.22, pp.413-422, 2018 Streszczenie: The synthesis and characterization of a series of 3,5-di-p Afiliacje autorów:
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40. | Omaka N. O.♦, Anthony C. E.♦, Nwaji Njemuwa N., Damian C. O.♦, Nickel(II) and copper(II) complexes of 2,2‐bibenzo[d] thiazole: Synthesis, characterisation and biological studies , Applied Organometallic Chemistry, ISSN: 1099-0739, DOI: 10.1002/aoc.4241, Vol.32, pp.1-10, 2018 Streszczenie: Benzothiazole moiety has gained a lot of attention because of its importance as essential pharmacophore in the development of metal based drugs. Nickel(II) and copper(II) complexes of a benzothiazole based ligand, 2,2’-bibenzo[d]thiazole (L1), synthesized by the reaction of benzothiazole-2-carbonylchloride and o-aminothiophenol, is reported. The compounds were characterised by elemental and percentage metal analyses, spectroscopic (FTIR and UV–vis), 1H and 13C NMR, Mass spectra, thermal, magnetic moment and molar conductance analyses. The mass spectra, elemental and percentage metal composition of the metal complexes gave a 2:1 ligand to metal stoichiometric mole ratio. The spectral data showed that the ligand was coordinated to the metal ions through the nitrogen atoms of the benzothiazole moiety. The electronic spectra and magnetic susceptibility measurements showed that the nickel and copper complexes adopted square planar geometries. The ligand and its metal(II) complexes were screened against some drug resistant microbes and were found to exhibit varied degree of antimicrobial activities. The nickel complex was more active compared to ciprofloxacin against Staphylococcus aureus and Bacillus cereus. Similarly, the antioxidant potential of the ligand was evaluated. The ligand is a better ferrous ion chelating agent compared to 1,10-phenanthroline and 2,2-bipyridine. The ligand and its complexes exhibited good antimicrobial and Fe2+ chelating properties making them probable compounds of interest in antibiotic and antioxidant drug researches. Afiliacje autorów:
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41. | Nwaji N., Tebello N.♦, Nanosecond optical nonlinearities in low symmetry phthalocyanine nanoconjugates studied using the Z- scan technique, Journal of Luminescence, ISSN: 0022-2313, DOI: 10.1016/j.jlumin.2017.08.053, Vol.192, pp.247-256, 2017 Streszczenie: In this study, the photophysical, and nonlinear optical limiting properties of low symmetry tris[(4-benzo[d] thiazol-2-ylphenoxy)-2-phenoxyl acetic acid phthalocyaninato] zinc (II) (3) conjugated to metallic nanoparticles have been investigated using open aperture Z-scan techniques at 532 nm. The nonlinear optical response demonstrated that the studied complex and the nanoconjugates exhibits higher excited state absorption cross-section resulting from S1 and T1 compared to ground state absorption. Enhanced optical limiting performance was observed when the complex was conjugated to nanoparticles with 3SA-AuNPs showing the best optical limiting threshold of 0.39 J/cm2. Afiliacje autorów:
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42. | Nwaji N., John M.♦, Jonathan B.♦, Tebello N.♦, Synthesis, photophysical and nonlinear optical properties of a series of ball-type phthalocyanines in solution and thin films, New Journal of chemistry, ISSN: 1144-0546, DOI: 10.1039/C6NJ03662G, Vol.41, pp.1-15, 2017 Streszczenie: In this study, we report on the enhanced nonlinear optical properties of novel tetrakis-4-(hexadecane-1,2-dioxyl)-bis(phthalocyaninato zinc(II)) (4), tetrakis-4-(hexadecane-1,2-dioxyl)-bis(phthalocyaninato gallium chloride) (5) and tetrakis-4-(hexadecane-1,2-dioxyl)-bis(phthalocyaninato indium chloride) (6) both in solution and when embedded in polymer thin films. Complexes 5 and 6 bearing heavy atoms showed enhanced triplet quantum yield and nonlinear optical response. The nonlinear third-order susceptibility and second-order hyperpolarizability values are also reported. Time dependent density functional theory (TD-DFT) calculations were performed in order to explain the origin of the observed UV-vis and magnetic circular dichroism (MCD) spectra of the complexes. Afiliacje autorów:
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43. | Nwaji N., John M.♦, Tebello N.♦, 4-Bis (4-aminophenoxy)phenoxy derivitized phthalocyanine conjugated to metallic nanoparticles: searching for enhanced optical limiting materials, New Journal of chemistry, ISSN: 1144-0546, DOI: 10.1039/C7NJ02718D, Vol.41, pp.1-15, 2017 Streszczenie: n this study, the photophysical, nonlinear absorption and nonlinear optical limiting properties of 4-(2,4-bis(4-aminophenoxy)phenoxy) phthalocyinato zinc(II) phthalocyanine (6) conjugated to metallic nanoparticles have been investigated using open aperture Z-scan techniques using 532 nm nanosecond pulses. The nonlinear optical response demonstrated that the studied complex and the nanoconjugates exhibit higher excited state absorption cross-section compared to ground state absorption. Enhanced optical limiting performance was observed when complex 6 was conjugated to nanoparticles with 6CB-AuNPs (CB = covalent bond) showing the highest optical limiting threshold of 0.36 J cm−2. Afiliacje autorów:
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44. | Nwaji N., Benjamin J.♦, John M.♦, David O. O.♦, Tebello N.♦, Nonlinear optical dynamics of benzothiazole derivatized phthalocyanines in solution, thin films and when conjugated to nanoparticles, Journal of Photochemistry and Photobiology A, ISSN: 1010-6030, DOI: 10.1016/j.jphotochem.2017.05.042, Vol.346, pp.73-85, 2017 Streszczenie: Benzothiazole phthalocynines complexes: tetrakis[(benzo[d]thiazol-2-ylphenoxy)phthalocyaninato] indium(III) chloride (1) and tetrakis[(benzo[d]thiazol-2-ylthio)phthalocyaninato] indium(III) chloride (2) were synthesisized and their nanosecond nonlinear optical behaviours in solution, solid state and when conjugated to metallic nanoparticles were examined and compared to those of the corresponding ZnPc and GaPc which are designated as: tetrakis[(4-benzo[d]thiazol-2-ylphenoxy)phthalocyaninato] zinc(II) (3), tetrakis[(4-benzo[d]thiazol-2-ylphenoxy)phthalocyaninato] gallium(III) chloride (4), tetrakis[(4-benzo[d]thiazol-2-ylthio)phthalocyaninato] zinc(II) (5) and tetrakis[(4-benzo[d]thiazol-2-ylthio)phthalocyaninato] gallium(III) chloride (6). Trends in the electronic structures were identified through a comparison of the UV–vis absorption and magnetic circular dichroism (MCD) spectroscopy of the complexes and calculated spectra predicted by time dependent density functional theory (TD-DFT). Of all the complexes and nanoconjugates, complex 2 (containing sulphur linkages and In as a central metal) gave the best optical limiting behaviour. Afiliacje autorów:
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45. | Edith D.♦, Nwaji N., David O. O.♦, John M.♦, Tebello N.♦, Investigation of photophysicochemical properties of zinc phthalocyanines conjugated to metallic nanoparticles , Journal of Photochemistry and Photobiology A, ISSN: 1010-6030, DOI: 10.1016/j.jphotochem.2017.09.020, Vol.349, pp.148-161, 2017 Streszczenie: The syntheses of zinc(II) tetra–[3–(4–phenoxy) (propanoic acid) phthalocyanine] (2) and zinc(II) mono–[3–(4–phenoxy) (propanoic acid) phthalocyanine (3) are reported in this work. Compounds 2 and 3 were covalently linked to glutathione capped silver (AgNPs–GSH), gold (AuNPs–GSH) and silver-gold alloy (Ag3Au1NPs–GSH) nanoparticles (NPs) via an amide bond formation to afford the conjugates: 2–AgNPs–GSH, 3–AgNPs–GSH, 2–AuNPs–GSH, 3–AuNPs–GSH, 2-Ag3Au1NPs–GSH and 3-Ag3Au1NPs–GSH. The photophysicochemical behaviours of the compounds and their conjugates with NPs were assessed in solution. The conjugates afforded a decrease in fluorescence quantum yields and lifetimes with improved triplet quantum yields in comparison to the compounds. Accordingly, the AgNPs and AuNPs conjugates with the compounds afforded high singlet quantum yields. On the contrary, the conjugates of the alloy afforded decreased singlet quantum yields probably due to the screening effect. The compounds and their conjugates with NPs could serve as a viable and efficacious photosensitizer for photodynamic therapy. Afiliacje autorów:
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46. | Nwaji N., Owolabi M. B.♦, Jonathan B.♦, Tebello N.♦, Photophysical and nonlinear optical study of benzothiazole substituted phthalocyanines in solution and thin films , Journal of Porphyrins and Phthalocyanines, ISSN: 1088-4246, DOI: 10.1142/S1088424617500079, Vol.21, pp.1-10, 2017 Streszczenie: In this study, the photophysical, nonlinear absorption and nonlinear optical limiting properties of zinc and gallium phthalocyanine complexes: tetrakis[(benzo[d]thiazol-2-yl phenoxy)phthalocyaninato]zinc(II) (3), tetrakis[(benzo[d]thiazol-2-yl phenoxy)phthalocyaninato] gallium(III) chloride (4), tetrakis[(benzo[d]thiazol-2-ylthio)phthalocyaninato] zinc(II) (5), tetrakis[(benzo[d]thiazol-2-ylthio)phthalocyaninato] gallium(III) chloride (6), were investigated both in solution and when embedded in polystyrene thin films using 532 nm laser excitation at 10 ns pulses. It was also observed that complexes that have higher triplet state absorption also possessed enhanced nonlinear and optical limiting behavior. Superior optical performance was observed when the complexes were embedded in thin films compared to when they are in solution. Complex 6 in thin films gave the highest imaginary third-order susceptibility (Im Afiliacje autorów:
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47. | Nwaji N., David O. O.♦, John M.♦, Marcel L.♦, Samson K.♦, Jonathan B.♦, Tebello N.♦, Improved nonlinear optical behaviour of ball type indium (III) phthalocyanine linked to glutathione capped nanoparticles, Dyes and Pigments, ISSN: 1873-3743, DOI: 10.1016/j.dyepig.2017.01.066, Vol.140, pp.417-430, 2017 Streszczenie: The synthesis of ball–type indium phthalocyanine (complex 4) and its covalent attachment to glutathione (GSH–) capped (Ag, Au, CdTeSe, CdTeSe/ZnO) nanoparticles are reported in this work. Furthermore, their photophysical and nonlinear optical behaviour were investigated. We observed a decrease in the fluorescence quantum yield with corresponding increase in the triplet quantum yield of the nanoconjugates in comparison to complex 4 alone. The reverse saturable absorption was found to be dependent on excited state absorption. The optical limiting threshold ranges from 0.40–0.78 (J/cm2). The nanoconjugate of the complex 4 with GSH–CdTeSe/ZnO (QD1) accounted for the most improved triplet state parameters and nonlinear optical behaviour in comparison to complex 4 and the other nanoconjugates studied in this work. Afiliacje autorów:
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Abstrakty konferencyjne
1. | Nwaji N., Achadu O.♦, Giersig M., Porous magnetic nanostructures for sensing SARS-CoV-2, AMBRA 2024, 2nd International Conference on Advanced Materials for Bio-Related Applications , 2024-05-19/05-23, Wrocław (PL), pp.50, 2024 |