Fluorine-doped Tin Oxide Glass Substrate Research Articles

Nanostructured polyaniline counter electrode for dye-sensitised solar cells: Fabrication and investigation of its electrochemical formation mechanism

Nanostructured polyaniline films with controlled thickness have been successfully grown on fluorine-doped tin oxide (FTO) glass substrates using the cyclic voltammetry (CV) method at room temperature. The formation mechanism of the polyaniline film is monitored by CV techniques, alternating current (AC) impedance spectroscopy, scanning electron microscopy (SEM) and atomic force microscopy (AFM). It is found that the accumulation of nanostructured polyaniline (>70 nm) on both the scattered and compact layers simultaneously increased the reactive interface, which supports charge transfer at the interface and resistance that hinders electronic transport in the film. By optimising the preparation conditions, the short-circuit photocurrent density of a dye-sensitised solar cell (DSSC) with a PANI counter electrode (CE) increased by 11.6% in comparison to a DSSC with an electrodeposited platinum CE.

Synthesis and characterization of Cd 0.7Pb 0.3Se thin films for photoelectrochemical solar cell

Optimum composition Cd 0.7Pb 0.3Se thin films have been deposited using the chemical bath containing cadmium sulfate octahydrate, lead nitrate, tartaric acid, potassium hydroxide, ammonia, and sodium selenosulfate onto fluorine-doped tin oxide glass substrate. The various deposition parameters such as composition of reactive bath, pH of the solution, deposition temperature, deposition time, speed of rotation, etc. have been optimized for obtaining good quality film. X-ray diffraction studies revealed the polycrystalline nature of sample with the solid solution of lead (II) ions in CdSe host lattice, having a hexagonal phase structure. Scanning electron micrograph suggested that the grains were non-uniformly distributed over the substrate surface. Film composition was determined by atomic absorption spectroscopy as well as energy dispersive X-ray atomic spectroscopy. Optical absorption data showed the presence of direct transition with energy band gap 1.80 eV for the deposited thin films. The dark specific conductance of Cd 0.7Pb 0.3Se thin films was found to the order of 10 −6 (Ω cm) −1 having n-type semiconducting nature. Photoelectrochemical characterization was carried out using sulfide/polysulfide electrolyte with 1.401% efficiency.

Facile Fabrication of Hierarchical SnO2 Microspheres Film on Transparent FTO Glass

Hierarchical SnO(2) microspheres consisting of nanosheets on the fluorine-doped tin oxide (FTO) glass substrates are successfully prepared via a facile hydrothermal synthesis process. The as-prepared novel microsphere films were characterized in detail by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), UV-vis diffuse reflectance spectroscopy. Moreover, SnO(2) nanoparticles with 30-80 nm in size covered on the surface of nanosheets/microspheres were also obtained by optimizing the hydrothermal reaction temperature, time, or volume ratio of acetylacetone/H(2)O. The detailed investigations disclose the experimental parameters, such as acetylacetone, NH(4)F, and seed layer play important roles in the morphology of hierarchical SnO(2) microspheres on the FTO glass. The formation process of SnO(2) microspheres is also proposed based on the observations of time dependent samples.

Block copolymer templated nanoporous TiO2for quantum-dot-sensitized solar cells

Nanoporous TiO2 films were prepared on conductive fluorine-doped tin oxide (FTO) glass substrates using polystyrene-block-poly (ethylene oxide) (PS-b-PEO) copolymer as template. By optimizing the ratio of the template to titanium precursor, a TiO2 film with uniform bicontinuous pore structure was obtained. The CdSe quantum dots (QDs) were in situ deposited on the nanoporous TiO2 films by chemical bath deposition. The solar cells based on CdSe QD-sensitized TiO2 films were evaluated by measuring the incident photon to electron conversion efficiency (IPCE) and the photovoltaic performance. The TiO2 film with bicontinuous pore structure showed a higher IPCE value and superior photovoltaic performance. The solar cell based on CdS and CdSe QDs co-sensitized 1.6 μm thick TiO2 films can reach a peak IPCE value of 21% and a power conversion efficiency of 0.358% under the simulated sunlight (AM 1.5, 100 mW cm−2).

Electrochemical Synthesis of CuIn ( Se , S ) 2 Layer for Thin-Film Solar Cell with a Superstrate Configuration

Copper indium diselenide thin films were grown on a fluorine-doped tin oxide (FTO) glass substrate covered with a thin layer of cadmium sulfide (CdS) by an electrodeposition method. The annealing of the films in a sulfur atmosphere resulted in a partial replacement of selenium with sulfur to form solid solutions. Structural characterizations of the annealed samples by using X-ray diffraction, energy-diffused X-ray analysis, and UV/visible/near-infrared absorption spectra revealed that the sulfur contents and the photoabsorption onsets strongly depended on the annealing temperature. The performance of superstrate-type solar cells was highest when the layer was annealed at in a sulfur atmosphere. A capacitance–voltage analysis of the junctions showed that the hole density in was increased by annealing at a high temperature, contributing to the improvement in the photocurrent. However, annealing at a high temperature led to the interdiffusion of CdS into the layer, resulting in the lowering of the solar cell performance. As a result of the trade-off between these factors, annealing at gave the best result for films made by the electrodeposition method.

Controllable Electrochemical Synthesis of Hierarchical ZnO Nanostructures on FTO Glass

Hierarchical ZnO hexagonal nanorods were successfully synthesized on fluorine-doped tin oxide (FTO) glass substrates via a simple electrodeposition from DMSO−H2O solution. The formation process was studied in detail by observing time-dependent products, and an oriented attachment mechanism is suggested for the growth of these hierarchical hexagonal nanorods. The influence of reaction temperature and solvent on the morphologies of products was also investigated. Interestingly, the optical band gap of hierarchical ZnO nanorods can be tuned by simply changing the reaction temperature during the electrodeposition process.

Fast formation of thick and transparent titania nanotubular films from sputtered Ti

Ti films sputtered on transparent fluorine-doped tin oxide glass substrates were anodized in fluoride-containing organic electrolyte in the presence of H 2O. In this work, anodic TiO 2 nanotubes (ATNs) as long as 9.2 ± 0.3 μm were obtained with high growth rate of 0.64 ± 0.3 μm min −1. We demonstrated the optimum anodization conditions for ATN growth on foreign substrates, were within the range of 0.3–0.5% (wt) NH 4F, with 3–5% (vol) H 2O at 60 V. XPS and ICP-MS were utilized to elucidate the increase of thickness and volume expansion obtained from the sputtered Ti film to their ATN forms. The ATN films exhibited excellent uniformity and adhesion to the substrates.

Large-Scale, Noncurling, and Free-Standing Crystallized TiO2 Nanotube Arrays for Dye-Sensitized Solar Cells

Large-area noncurling crystallized free-standing TiO2 nanotube (TNT) arrays have been fabricated by a two-step anodization process. These free-standing crystallized TNT arrays can be easily transferred to fluorine-doped tin oxide glass substrates without any crack. Furthermore, the investigation of these crystallized free-standing TNT arrays in dye-sensitized solar cells (DSSCs) was carried out and showed a roughly 100% enhanced conversion efficiency compared with that of the TNT array on a Ti substrate.

PV Efficiency Improved Large-area Dye-sensitized Solar Cells

Several techniques including current-collecting metal fingers and double-layer TiO2 electrode were applied to improve the conversion efficiency of large area dye-sensitized solar cells (DSSCs). Silver paste was used to fabricate the current-collecting metal fingers on the fluorine-doped tin oxide (FTO) glass substrate by screen-printing process. Then a single- or double-layer TiO2 electrode was fabricated by using screen-printing process. The double-layer TiO2 electrode consists of a transparent TiO2 layer and a light-scattering TiO2 layer. Results showed that applying the current-collecting metal fingers and double-layer TiO2 electrode could effectively improve the conversion efficiency. The conversion efficiency of 5.89% was achieved in a DSSC module with an area of 50mm×50mm by using the current-collecting metal finger cell of 45mm×3.5mm and double-layer TiO2 electrode under global air mass 1.5 condition.

A high-performance counter electrode based on poly(3,4-alkylenedioxythiophene) for dye-sensitized solar cells

A poly(3,3-diethyl-3,4-dihydro-2H-thieno-[3,4-b][1,4]dioxepine) (PProDOT-Et 2) counter electrode prepared by electrochemical polymerization on a fluorine-doped tin oxide (FTO) glass substrate was incorporated in a platinum-free dye-sensitized solar cell (DSSC). The surface roughness and I −/I 3 − redox reaction behaviors based on PProDOT-Et 2, poly(3,4-propylenedioxythiophene) (PProDOT), poly(3,4-ethylenedioxythiophene) (PEDOT), and sputtered-Pt electrodes were characterized, and their performances as counter electrodes in DSSCs were compared. Cells fabricated with a PProDOT-Et 2 counter electrode showed a higher conversion efficiency of 7.88% compared to cells fabricated with PEDOT (3.93%), PProDOT (7.08%), and sputtered-Pt (7.77%) electrodes. This enhancement was attributed to increases in the effective surface area and good catalytic properties for I 3 − reduction. In terms of the film thickness effect, the fill factor was strongly dependent on the deposition charge capacity of the PProDOT-Et 2 layer, but the aggregation of PProDOT-Et 2 in thicker layers (>80 mC cm −2) resulted in decreases in J SC and the cell conversion efficiency. The charge transfer resistances ( R ct1) of the PProDOT-Et 2 counter electrodes had the lowest value of ∼18 Ω at a deposition charge capacity of 40 mC cm −2. These results indicate that films with high conductivity, high active surface area, and good catalytic properties for I 3 − reduction can potentially be used as the counter electrode in a high-performance DSSC.

Spray coated multi-wall carbon nanotube counter electrode for tri-iodide [formula omitted] reduction in dye-sensitized solar cells

Spray coated multi-wall carbon nanotube (CNT) film on fluorine-doped tin oxide glass substrate has been investigated as a counter electrode for tri-iodide reduction in dye-sensitized solar cells. The photovoltaic parameters, in particular, the fill factor shows a strong dependency on the spraying time of multi-wall CNTs. Under one sun illumination (100 mW cm −2, AM 1.5 G), the device shows a maximum energy conversion efficiency of 7.59%. Electrochemical impedance spectroscopy analysis reveals a decrease in the charge transfer resistance of multi-wall CNT counter electrode with increase of spraying time; leads to an improvement in the photovoltaic parameters.

Portable, parallel grid dye-sensitized solar cell module prepared by screen printing

Screen-printing technology is used to fabricate large dye-sensitized solar cells (DSSCs). The high series-resistance associated with transparent conductive oxide glass substrates causes poor performance in large DSSCs especially at an exposure of 1 sun. The DSSC design has an embedded silver grid; a fluorine-doped tin oxide (FTO) glass substrate and stripe type titanium dioxide (TiO2) active layers introduced by screen-printing. The counter electrode is prepared from a screen printable paste based on hexachloro platinic acid. A DSSC module, which consists of five stripe-type working electrodes on a 5 cm × 5 cm, embedded silver grid FTO glass substrate, shows stable performance with an energy conversion efficiency of 5.45% under standard test conditions. © 2006 Elsevier B.V. All rights reserved.

Electrosynthesis and characterization of iron selenide thin films

Iron selenide thin films have been deposited onto stainless steel and fluorine-doped tin oxide (FTO) glass substrates by the electrodeposition process, in potentiostatic mode using ferric chloride ( FeCl 3 ) and selenium dioxide ( SeO 2 ) salts. The deposition mechanism and growth of the films were investigated by cyclic voltammetry and chronoamperometry. The structural, morphological, compositional and optical properties of the deposited films have been studied using X-ray diffraction (XRD), scanning electron microscopy (SEM), EDAX and optical absorption techniques, respectively. XRD studies reveal that the films are polycrystalline with monoclinic crystal structure. The surface morphology study shows that grains are uniformly distributed over the entire surface of the substrate. EDAX study reveals that the iron selenide films are rich in iron. Optical absorption study shows the presence of direct transition with bandgap energy of 1.23 eV.

Highly Efficient Dye-Sensitized Solar Cells Based on Carbon Black Counter Electrodes

Carbon black was employed as the catalyst for triiodide reduction on fluorine-doped tin oxide glass substrates (FTO-glass) used as counter electrodes in platinum-free dye-sensitized solar cells. The fill factors were strongly dependent on the thickness of the carbon layer, and the light energy conversion efficiency also increased up to a thickness of . The charge-transfer resistance of the carbon counter electrode decreased with the thickness of the carbon layer. The for the thicker carbon layer is less than three times that for the platinized FTO-glass. The highest cell efficiency was 9.1% under light intensity (1 sun AM 1.5 light, , , fill ).

Effect of temperature on photo-electrochemical properties of n-Fe2O3/KOH/C cells

n-Fe2O3 films were prepared by pyrolytic decomposition of ferric chloride solution onto fluorine-doped tin oxide (20 Omega Square Operator -1) glass substrates. The conventional three-electrode system was employed to study the effect of temperature on the performance of the cell. The temperature of the cell was varied from 0-60 degrees C. The optimum operating temperature for the n-Fe2O3/KOH/C cell was found to be 35 degrees C. The flat band potential was found to shift in the anodic direction with increasing temperature. Studies of the decay of the open circuit voltage VOC showed that the decay time decreases with increasing temperature.