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Adewinbi, S, Busari R, Animasahun LO, OMOTOSO E, Taleatu B.  2021.  Effective pseudocapacitive performance of binder free transparent α-V2O5 thin film electrode: Electrochemical and some surface probing, 2021/11/01. 621:413260. Abstract

Vanadium oxide nanomaterial was successfully prepared on conductive substrate via a simple and facile chemical route with no binder or additive. The film was characterized to investigate its microstructural, optical, electrical and electrochemical properties. The SEM micrographs of the annealed film presented enabling environment that is required for effective photocatalysis. It also demonstrated enhanced interaction between the film and the substrate and adequate pore size distribution that can allow free electrolytic ion intercalation/deintercalation for efficient supercapacitive response. EDX confirmed the elemental composition of the film. XRD and Raman spectroscopy showed substantial characteristic peaks that are attributes of orthorhombic crystal structure of V2O5 powder. Optical studies showed that the film exhibited high visible light transmittance and its energy band gap was found to be 2.77 eV. Pseudocapacitive performance of the V2O5 electrode was investigated via a three-electrode cell configuration. The film electrode exhibited highest areal capacity of 1.18 μAh cm⁻², energy density of 0.485 μWhcm⁻² at a power density of 107.71 μWcm⁻² and current density 0.25 mAcm⁻², moderate charge transfer resistance and superior cycling stability. The study demonstrated the viability of V2O5 film as electrode material for the development of high-performance supercapacitors.

Animasahun, L, Taleatu B, Adewinbi S, Bolarinwa HS, Fasasi A.  2021.  Synthesis of SnO2/CuO/SnO2 Multi-layered Structure for Photoabsorption: Compositional and Some Interfacial Structural Studies, 2021/05/29. 3:74-81. Abstract

Many metal oxide heterostructures have been synthesized as mixed oxides or layered structures for photocatalytic, photodegradation of pollutants and light-harvesting applications. However, in the layered structures the effects of interfacial properties and composition have largely not been explored. Hence, the effects of interfacial mixing and diffusion of sandwiched thin CuO layer on optical absorption of as-deposited and heat-treated multi-layered structured SnO2/CuO/SnO2 films were studied. The RBS analysis of the as-deposited films showed the presence of a minute amount of Cu in the surface and bottom SnO2 layers of the structure. We attributed this to inhomogeneous layer thickness evidenced by very low Sn/Cu atoms ratio of the CuO layer. However, the thermal treatment of the layered structure led to pronounced interlayer mixing and consequent formation of SnO2-CuO solid solutions throughout the layered structure. The layer integrity of the inserted CuO of the as-deposited films was very high and the as-deposited structure was far more optically absorbing. However, the annealed structure showed lesser optical absorption because of the onset of interfacial mixing and improved crystallization. This reflected in the optical bandgap variations of the as-deposited and annealed multilayered structures. The significance of this result is that the multi-layered films possess band narrowing – evidence of increased photon absorption - making it a better candidate than pure SnO2 oxide for photocatalysis, photodegradation and photodetection applications. It also pointed to the fact that attention must be paid to effects of heat treatments or annealing when inserting an absorbing layer into a photocatalyst or a material meant for photodegradation or any light-harvesting material.

S.A.Adewinbi, B.A.Taleatu, V.M.Maphiri, O.Fasakin, E.Omotoso, K.O.Oyedotun, N.Manyala.  2021.  Characterization of two-way fabricated hybrid metal-oxide nanostructured electrode materials for photovoltaic and miniaturized supercapacitor applications. Solid State Sciences. 119:106699.
Adewinbi, SA, Buremoh W, Owoeye VA, Ajayeoba YA, Salau AO, Busari HK, Tijani MA, Taleatu BA.  2021.  Preparation and characterization of TiO2 thin film electrode for optoelectronic and energy storage Potentials: Effects of Co incorporation. Chemical Physics Letters . 779:138854.
Adewinbi, SA, Taleatu BA, Busari RA, Maphiri VM, Oyedotun KO, Manyala N.  2021.  Synthesis and electrochemical characterization of pseudocapacitive α-MoO3 thin film as transparent electrode material in optoelectronic and energy storage devices. Materials Chemistry and Physics. 264:124468.
Adewinbi, S, Taleatu B, Busari R, Adewumi O, OMOTOSO E, Oyedotun K, Manyala N.  2020.  Preparation and Surface Characterization of Nanostructured MoO3/CoxOy and V2O5/CoxOy Interfacial Layers as Transparent Oxide Structures for Photoabsorption, 2020/04/02. 49 Abstract

A simple low-cost electrochemical deposition technique has been used to grow molybdenum oxide (MoO3) and vanadium oxide (V2O5) nanostructures separately on cobalt oxide (CoxOy) thin film to form two different bilayer films. The samples were characterized by some surface probing techniques. Morphological and crystal structural studies revealed that the deposited α-MoO3 and V2O5 layers completely laminated the underlying cubic CoxOy film to form compact structures without any significant lattice distortion. The average particle sizes were estimated to be between 34 nm and 41 nm. Optical studies revealed the presence of two energy band transitions in the spinel CoxOy structure which can be attributed to the occurrence of ligand-to-metal charge transfer (LMCT). The electrical studies showed a trap-filled limit voltage (VTFL) in the CoxOy layer which was explained on the basis of space charge limited current (SCLC) behavior of porous film, and it was corrected with lamination by the overlayer. This study also reaffirmed the role of transition metal oxides as a recipe for window and buffer layers capable of minimizing photon absorption loss and recombination of charge carriers between absorber and the contact electrodes in optoelectronic devices.

Busari, R, Taleatu B, Adewinbi S, Adewumi O, OMOTOSO E, Oyedotun K, Fasasi A.  2020.  Synthesis and surface characterization of electrodeposited quaternary chalcogenide Cu2ZnxSnyS1+x+2y thin film as transparent contact electrode, 2020/02/25. 43 Abstract

A low-cost technique, electrochemical deposition has been used to grow nanocrystalline quaternary Cu–Zn–Sn–S (CZTS) on indium tin oxide (ITO)-coated glass substrate. Effects of variations in deposition potentials and sulphur content on the chemical composition, optical, morphological, structural and electrical properties of the deposited films have been investigated. The morphologies showed and confirmed the results from XRD analysis that the films are of polycrystalline grains. Average interplanar spacing of the films is 3.376 Å. The average film’s thickness as estimated from Rutherford back-scattered spectroscopy studies was 34 nm. The estimated stoichiometry was found to be that of Cu2ZnSnS4 tetragonal kesterite structure. Optical studies showed that the absorption characteristic of the deposited CZTS film across the wavelength region is significantly dependent on growth deposition potentials and electrolyte concentration. Estimated band gap is between 1.75 and 1.81 eV. The electrical studies showed that the deposited films exhibit ohmic characteristics. This study demonstrated successful deposition of tetragonal kesterite structures of CZTS using a two-electrode cell approach. It also revealed the novel route of growing CZTS thin film over the conventional three electrode cells.

Busari, R, Taleatu B, Adewinbi S, Adewumi O, Fasasi A.  2020.  Surface Characterisation of Spin Coated Quaternary Chalcogenide CZT(S, O) Thin Film for Optoelectronic Applications, 2020/01/07. 5:38-45. Abstract

Thin films of copper zinc tin sulphide (CZTS) have been deposited on glass substrate at various solution concentration and angular speed using sol-gel spin coating technique. Surface morphology showed that the deposited layers are continuous and pinhole free. The film's particles are evenly distributed and adhered firmly to the substrates. X-ray diffraction studies revealed that the films are polycrystalline with tetragonal kesterite structure. Interplanar spacing and average crystallite size were estimated as 3.732 Å and 56.53 nm. Film's thickness and stoichiometry were determined from Rutherford Backscattering Spectroscopy (RBS) as127 nm and Cu 1.5 Zn 1.0 Sn 1.1 S 4.4 O 3.3. Optical studies showed that the deposited films exhibit direct band transition. The values of the energy gap were found between 1.30 and 1.60 eV. The result of the study suggested that the deposited CZTS thin films can perform as a good absorber material in nanostructured optoelectronic devices.

Taleatu, B, Cozzarini L, Olofinjana B, Bertolini G, Adewinbi S, Behrendt S.  2018.  Preparation of nanocrystalline ZnO/CoxOy and CNT/CoxOy bilayers for photoabsorption potential: XPS and some surface structural characterization, 2018/11/15. 87:155-161. Abstract
Igumbor, E, OMOTOSO E, Khaleed A, Taleatu B.  2018.  Ab initio study of transition metals impurities and stability of complexes in germanium (Ge), 2018/08/13. 20:433. Abstract
Omotoso, E, Auret FD, Igumbor E, Tunhuma S, Danga H, Ngoepe P, Taleatu B, Meyer W.  2018.  The influence of thermal annealing on the characteristics of Au/Ni Schottky contacts on n-type 4H-SiC, 2018/04/28. 124 Abstract

The effects of isochronal annealing on the electrical, morphological and structural characteristics of Au/Ni/4H-SiC Schottky barrier diodes (SBDs) have been studied. Current–voltage (I–V), capacitance–voltage (C–V), deep-level transient spectroscopy, scanning electron microscope (SEM) and X-ray diffraction measurements were employed to study the thermal effect on the characteristics of the SBDs. Prior to thermal annealing of Schottky contacts, the I–V measurements results confirmed the good rectification behaviour with ideality factor of 1.06, Schottky barrier height of 1.20 eV and series resistance of 7 Ω. The rectification properties after annealing was maintained up to an annealing temperature of 500 °C, but deviated slightly above 500 °C. The uncompensated ionized donor concentration decreased with annealing temperature, which could be attributed to out-diffusion of the 4H-SiC into the Au/Ni contacts and decrease in bonding due to formation of nickel silicides. We observed the presence of four deep-level defects with energies 0.09, 0.11, 0.16 and 0.65 eV below the conduction band before and after the isochronal annealing up to 600 °C. The conclusion drawn was that annealing did not affect the number of deep-level defects present in Au/Ni/4H-SiC contacts. The variations in electrical properties of the devices were attributed to the phase transformations and interfacial reactions that occurred after isochronal annealing.

Eyi, A, Ajenifuja E, Taleatu B, Ogunmola E, Omotoso E, Adeyemi O, Babatunde OG.  2017.  Surface microstructure, optical and electrical properties of spray pyrolyzed PbS and Zn-PbS thin films for optoelectronic applications, 2017/01/26. Materials Science- Poland. 35 Abstract

Lead sulphide (PbS) and zinc- doped lead sulphide (Zn-PbS) thin films were prepared by chemical spray pyrolysis on soda lime glass substrates at a temperature of 250 °C. Precursors were prepared from chemical reagents including zinc acetate, lead acetate and thiourea. The deposited films thicknesses and elemental composition were studied by Rutherford backscattering spectroscopy (RBS); the percentages of Pb and S were estimated as 40.58 % and 59.42 %, respectively, while for the Zn-doped sample, the percentages of Zn, Pb and S were respectively 4.84 %, 44.57 % and 50.59 %. Morphological studies revealed that the films were continuous and the particles were uniformly distributed across the substrate surface. AFM probe revealed nanostructured films with particles densely distributed across the substrates surfaces with incorporation of Zn

Mola, GT, Arbab E, Taleatu B, Ahmad I, Maaza M.  2016.  Growth and characterization of V2O5 thin film on conductive electrode, 2016/09/01. Journal of Microscopy. 265(2):214-221. Abstract

Vanadium pentoxide V2O5 thin films were grown at room temperature on ITO coated glass substrates by electrochemical deposition. The resulting films were annealed at 300, 400 and 500°C for 1 h in ambient environment. The effect of heat treatment on the films properties such as surface morphology, crystal structure, optical absorption and photoluminescence were investigated. The x-ray diffraction study showed that the films are well crystallized with temperatures. Strong reflection from plane (400) indicated the film's preferred growth orientation. The V2O5 films are found to be highly transparent across the visible spectrum and the measured photoluminescence quenching suggested the film's potential application in OPV device fabrication.

Arbab, E, Taleatu B, Mola GT.  2014.  Environmental stability of PTB7:PCBM bulk heterojunction solar cell, 2014/12/15. 61 Abstract

The short life span of organic photovoltaic (OPV) cell in an ambient laboratory condition is one of the challenges hindering the realization of organic-based devices. The presence of moisture and oxygen in conjugated polymer matrix is the major factor responsible for the degradation of organic molecules. The chemical degradation of OPV cell generally depends on the nature of the semiconductor polymer used in the preparation of the devices. However, the lifespan of unprotected OPV cells often ranges in the order of few hours in simple laboratory environment. We are reporting here the lifetime of organic photovoltaic cell in ambient laboratory condition whose active layer is composed of PTB7:PCBM blend.

Taleatu, BA, OMOTOSO E, Lal C, Makinde WO, Ogundele KT, Ajenifuja E, Lasisi AR, Eleruja MA, Mola GT.  2014.  XPS and some surface characterizations of electrodeposited MgO nanostructure. Surface and Interface Analysis . 46:372–377.
Lal, C, DiSanto G, Caputo M, Panighel M, Taleatu BA, Goldoni A, Jain IP.  2014.  XPS studies of the adsorption characteristics of 2H-TPP at Fe/Si interface. Optoelectronics and Advanced materials-Rapid Communications. 8(5-6):465-469.
Taleatu, BA, Makinde WA, Eleruja MA, Fasasi AY.  2013.  Band Alignment and Charge Transport Characteristics of TPP/ZnO Hybrid for Photovoltaic Cell Potential. current applied physics. 13:97-102.
Panighel, M, DiSanto G, Caputo M, Lal C, Taleatu BA, Goldoni A.  2013.  Review of 2H-Tetraphenylporphyrins Metalation in Ultra-high Vacuum on Metal Surfaces. IOP Conference Series. :1088-1742., England: Journal of Physics
OMOTOSO, E, ADEGBOYEGA GA, Eleruja MA, Olofinjana B, Akinwunmi OO, ILORI OO, Taleatu BA, Ajayi EOB.  2013.  Synthesis and Some Properties of MOCVD Lead Sulphide and Lead Cadmium Sulphide Thin Films. Journal of Non Oxide Glasses. 5(1):9-19.
Adekoya, SO, Eleruja MA, Olofinjana B, Akinwunmi OO, Taleatu BA, Ajayi EOB.  2012.  Enhanced Light Absorption in Textured Metal Organic Chemical Vapour Deposited (MOCVD) CdO Thin Films. Materials Research Society. :1432., San Fransisco, USA: Cambridge University Press
Caputo, M, DiSanto G, Parisse P, Petaccia L, Floreano L, Verdini A, Panighel M, Struzzi C, Taleatu B, Lal C, Goldoni A.  2012.  Experimental Study of Pristine and Alkali Metal Doped Picene Layers: Confirmation of the Insulating Phase in Multilayer Doped Compounds. Journal of Physical Chemistry C. 116:19902-19908.
Inyang EP, Taleatu BA, Oketayo OO, Mokobia CE, Adenodi RA, Balogun FA.  2011.  Characterizing Thermoluminescence Properties of calcium halophosphate fluorescent coating powder for radiation dosimetry. Journal of Environment Science & Engineering. 53(1):1-6.