3D lithium ion batteries—from fundamentals to fabrication

3D microbatteries are proposed as a step change in the energy and power per footprint of surface mountable rechargeable batteries for microelectromechanical systems (MEMS) and other small electronic devices. Within a battery electrode, a 3D nanoarchitecture gives mesoporosity, increasing power by reducing the length of the diffusion path; in the separator region it can form the basis of a robust but porous solid, isolating the electrodes and immobilising an otherwise fluid electrolyte. 3D microarchitecture of the whole cell allows fabrication of interdigitated or interpenetrating networks that minimise the ionic path length between the electrodes in a thick cell. This article outlines the design principles for 3D microbatteries and estimates the geometrical and physical requirements of the materials. It then gives selected examples of recent progress in the techniques available for fabrication of 3D battery structures by successive deposition of electrodes, electrolytes and current collectors onto microstructured substrates by self-assembly methods

Fabrication of submicron metallic grids with interference and phase-mask holography

Complex, submicron Cu metallic mesh nanostructures are made by electrochemical deposition using polymer templates made from photoresist. The polymer templates are fabricated with photoresist using two-beam interference holography and phase mask holography with three diffracted beams. Freestanding metallic mesh structures are made in two separate electrodepositions with perpendicular photoresist grating templates. Cu mesh square nanostructures having large (52.6%) open areas are also made by single electrodeposition with a photoresist template made with a phase mask. These structures have potential as electrodes in photonic devices

First row transition metal catalysts for solar-driven water oxidation produced by electrodeposition

As our reliance on renewable energy resources increases, so will our need to store this energy in the form of chemical fuels to iron-out peaks and troughs in supply. Sunlight, the most plentiful source of renewable energy, is especially problematic in this regard as it is so diffuse. One way to convert solar irradiation to fuels effectively would be to develop large surface area photo-electrochemical devices that could use sunlight directly to split water into H2 and O2. However, in order to be feasible, such an approach requires that these devices (and their components) are extremely cheap. In this review, we will discuss catalysts for the water oxidation half-reaction of electrochemical water splitting that can be produced by electrodeposition (a technique well suited to large-scale, low-cost applications), and that are based on the comparatively plentiful and inexpensive first row transition metals. Special attention will be paid to the electrodeposition conditions used in the various examples given, and structure-function relationships for electrochemical water oxidation for the materials produced by these techniques will be elucidated

Limits on the use of cobalt sulfide as anode of p-type dye-sensitized solar cells

Thin films of cobalt sulfide (CoS) of thickness l < 10m have been employed as anodes of p-type dye-sensitized solar cells (p-DSCs) when P1-sensitized nickel oxide (NiO) was the photoactive cathode and /I - constituted the redox mediator. In the role of counter electrode for p-DSCs, CoS was preferred over traditional platinized fluorine-doped indium oxide (Pt-FTO) due to the lower cost of the starting materials (Co salts) and the easier procedure of deposition onto large area substrates. The latter process was carried out via direct precipitation of CoS from aqueous solutions. The photoconversion efficiency (η) of the corresponding device was 0.07%. This value is about 35% less than the efficiency that is obtained with the analogous p-DSC employing the Pt-FTO anode (η = 0.11). Unlike p-DSCs based on Pt-FTO anodes, the photoelectrochemical cells employing CoS electrodes showed that this anodic material was not able to sustain the photocurrent densities generated by P1-sensitized NiO at a given photopotential. Illumination of the p-DSCs with CoS anodes and P1-sensitized NiO cathodes actually induced the reverse bias of the photoelectrochemical cell with CoS behaving like a p-type semiconductor with no degeneracy. © 2017 IOP Publishing Ltd

Electroplating of semiconductor Materials for Applications in Large Area Electronics: A Review

The attributes of electroplating as a low-cost, simple, scalable, and manufacturable semiconductor deposition technique for the fabrication of large-area and nanotechnology-based device applications are discussed. These strengths of electrodeposition are buttressed experimentally using techniques such as X-ray diffraction, ultraviolet-visible spectroscopy, scanning electron microscopy, atomic force microscopy, energy-dispersive X-ray spectroscopy, and photoelectrochemical cell studies. Based on the results of structural, morphological, compositional, optical, and electronic properties evaluated, it is evident that electroplating possesses the capabilities of producing high-quality semiconductors usable for producing excellent devices. In this paper we will describe the progress of electroplating techniques mainly for the deposition of semiconductor thin film materials and their treatment processes, and fabrication of solar cells

Growth and characterisation of n- and p-type ZnTe thin films for applications in electronic devices

Growth and characterisation of n- and p-type ZnTe thin films forapplications in electronic devicesO.I. Olusolaa,b,*, M.L. Madugua, N.A. Abdul-Manafa, I.M. DharmadasaaaElectronic Materials and Sensors Group, Materials and Engineering Research Institute, Sheffield Hallam University, Sheffield S1 1WB, United KingdombDepartment of Physics, School of Science, The Federal University of Technology, FUTA, Akure P.M.B. 704, Nigeriaarticle infoArticle history:Received 8 July 2015Received in revised form16 October 2015Accepted 4 November 2015Available online 7 November 2015Keywords:Electrodepositionn-type ZnTep-type ZnTeIntrinsic dopingZnTe homo-junction diodeabstractThe growth of n- and p-type ZnTe thin films have been achieved intrinsically by potentiostatic elec-trodeposition method using a 2-electrode system. Cyclic voltammogram have been used to obtain rangeof growth voltages required to form stoichiometric thin films of ZnTe. The ZnTe thin films have beenelectrodeposited (ED) on glass/fluorine-doped tin oxide (FTO) conducting substrates in aqueous solutionsof ZnSO4$7H2O and TeO2. The films have been characterised for their structural, electrical, morphological,compositional and optical properties by using X-ray diffraction (XRD), Raman spectroscopy, Photo-electrochemical (PEC) cell measurements, DC conductivity measurements, Scanning electron microscopy(SEM), Atomic force microscopy (AFM), energy-dispersive X-ray analysis (EDX) and Optical absorptiontechniques. The XRD results reveal that the electroplated films are polycrystalline and have hexagonalcrystal structure with the preferred orientation along (002) plane. UVeVisible spectrophotometer hasbeen used for the bandgap determination of as-deposited and heat-treated ZnTe layers. The bandgap ofthe heat-treated ZnTe films are in the range (1.90e2.60) eV depending on the deposition potential. PECcell measurements show that the ED-ZnTe films have both n- and p-type electrical conductivity. The DCconductivity measurements revealed that the average resistivity of n-ZnTe and p-ZnTe layers of equalthickness is of the order of 104Ucm; the magnitude of the electrical resistivity of p-ZnTe is almost fivetimes greater than that of the n-ZnTe layer. Using the n- and p-type ZnTe layers, p-n homo-junctiondiodes with device structure of glass/FTO/n-ZnTe/p-ZnTe/Au were fabricated. The fabricated diodesshowed rectification factor of 102, reverse saturation current of ~10.0 nA and potential barrier heightgreater than 0.77 eV indicating electronic device quality of these layer

The effects of anode material type on the optoelectronic properties of electroplated CdTe thin films and the implications for photovoltaic application

The effects of the type of anode material on the properties of electrodeposited CdTe thin films for photovoltaic application have been studied. Cathodic electrodeposition of two sets of CdTe thin films on glass/fluorine-doped tin oxide (FTO) was carried out in two-electrode configuration using graphite and platinum anodes. Optical absorption spectra of films grown with graphite anode displayed significant spread across the deposition potentials compared to those grown with platinum anode. Photoelectrochemical cell result shows that the CdTe grown with graphite anode became p-type after post-deposition annealing with prior CdCl2 treatment, as a result of carbon incorporation into the films, while those grown with platinum anode remained n-type after annealing. A review of recent photoluminescence characterization of some of these CdTe films reveals the persistence of a defect level at (0.97–0.99) eV below the conduction band in the bandgap of CdTe grown with graphite anode after annealing while films grown with platinum anode showed the absence of this defect level. This confirms the impact of carbon incorporation into CdTe. Solar cell made with CdTe grown with platinum anode produced better conversion efficiency compared to that made with CdTe grown using graphite anode, underlining the impact of anode type in electrodeposition