Transparent Fluorine-doped Tin Oxide Research Articles

Characterization of the TCO Layer on a Glass Surface for PV IInd and IIIrd Generation Applications

In the dynamic field of photovoltaic technology, the pursuit of efficiency and sustainability has led to continuous novelty, shaping the landscape of solar energy solutions. One of the key elements affecting the efficiency of photovoltaic cells of IInd and IIIrd generation is the presence of transparent conductive oxide (TCO) layers, which are key elements impacting the efficiency and durability of solar panels, especially for DSSC, CdTe, CIGS (copper indium gallium diselenide) or organic, perovskite and quantum dots. TCO with low electrical resistance, high mobility, and high transmittance in the VIS–NIR region is particularly important in DSSC, CIGS, and CdTe solar cells, working as a window and electron transporting layer. This layer must form an ohmic contact with the adjacent layers, typically the buffer layer (such as CdS or ZnS), to ensure efficient charge collection Furthermore it ensures protection against oxidation and moisture, which is especially important when transporting the active cell structure to further process steps such as lamination, which ensures the final seal. Transparent conductive oxide layers, which typically consist of materials such as indium tin oxide (ITO) or alternatives such as fluorine-doped tin oxide (FTO), serve dual purposes in photovoltaic applications. Primarily located as the topmost layer of solar cells, TCOs play a key role in transmitting sunlight while facilitating the efficient collection and transport of generated electrical charges. This complex balance between transparency and conductivity highlights the strategic importance of TCO layers in maximizing the performance and durability of photovoltaic systems. As the global demand for clean energy increases and the photovoltaic industry rapidly develops, understanding the differential contribution of TCO layers becomes particularly important in the context of using PV modules as building-integrated elements (BIPV). The use of transparent or semi-transparent modules allows the use of building glazing, including windows and skylights. In addition, considering the dominant position of the Asian market in the production of cells and modules based on silicon, the European market is intensifying work aimed at finding a competitive PV technology. In this context, thin-film, organic modules may prove competitive. For this purpose, in this work, we focused on the electrical parameters of two different thicknesses of a transparent FTO layer. First, the influence of the FTO layer thickness on the transmittance over a wide range was verified. Next, the chemical composition was determined, and key electrical parameters, including carrier mobility, resistivity, and the Hall coefficient, were determined.

Reversible Intercalation of Protons in Tungsten Oxide Films for Multi-Transduction Sensor Applications

Tungsten oxide films under electrochemical bias, can form tungsten oxide bronzes (MxWO3 with M being small cations such as H+ or Li+) featuring high electronic conductivity and change in coloration to deep blue1. This doping process occurs through the reduction of W6+, as described by the following equation:WO3 + x H+ + xe- -> HxWO3The bronze phase can also be formed through exposure of tungsten oxide to H2 at high temperatures (> 200 oC) or in presence of catalysts2, as described by the following equation:WO3 + x/2 H2 -> HxWO3 Because of the significant changes in both optical and electrical proprieties of the films, electrochemical control of proton doping can be used as a strategy for the development of ion-gated transistors3,4, hydrogen sensors and smart windows5.In this work, we report the use of thin films prepared by sol-gel synthesis using polyperoxotungstic acid (PPTA) as a precursor. We used three different types of substrates (conductive transparent fluorine-doped tin oxide (FTO) glass, Si/SiO2 patterned with Au source-drain electrodes and Interdigitated electrodes patterned on transparent glass) to study the changes of color and conductivity following the formation of the bronze in both electrochemical and dry environments. In electrochemical environment, we show that gating by ionic liquid in transistor configuration can be used to propose an iontronic sensor to detect H2 and H2O6. In dry environment, we show that simultaneous monitoring of visible light transmittance and electrical conductivity can be used a double transducer for H2 sensors6.1 M. S. Whittingham, in Solid State Ionics, 2004, vol. 168, pp. 255–263.2 C. C. Chan, W. C. Hsu, C. C. Chang and C. S. Hsu, Sensors and Actuators, B: Chemical, 2011, 157, 504–509.3 M. Barbosa, X. Meng, F. Soavi, C. Santato and M. O. Orlandi, J Mater Chem C Mater, 2018, 6, 1980–1987.4 G. V. de Oliveira Silva, A. Subramanian, X. Meng, S. Zhang, M. S. Barbosa, B. Baloukas, D. Chartrand, J. C. Gonzáles, M. O. Orlandi, F. Soavi, F. Cicoira and C. Santato, J Phys D Appl Phys,5 G. Cai, J. Wang and P. S. Lee, Acc Chem Res, 2016, 49, 1469–1476.6 M. S. Barbosa, R. A. da Silva, C. Santato and M. O. Orlandi, Journal of Vacuum Science & Technology A, 2022, 40, 013202.

Hydroelectric actuator for 3-dimensional analysis of electrophoretic and dielectrophoretic behavior of cancer cells; suitable in diagnosis and invasion studies

Cancer is a cellular-based disease, so cytological diagnosis is one of the main challenges for its early detection. An extensive number of diagnostic methods have been developed to separate cancerous cells from normal ones, in electrical methods attract progressive attention. Identifying and specifying different cells requires understanding their dielectric and electric properties. This study evaluated MDA-MB-231, HUVEC, and MCF-10A cell lines, WBCs isolated from blood, and patient-derived cell samples with a cylindrical body with two transparent FTO (fluorine-doped tin oxide) plate electrodes. Cell mobility rates were recorded in response to these stimuli. It was observed that cancer cells demonstrate drastic changes in their motility in the presence and absence of an electric field (DC/AC). Also, solution viscosity's effect on cancer cells' capturing efficacy was evaluated. This research's main distinguished specification uses a non-microfluidic platform to detect and pathologically evaluate cytological samples with a simple, cheap, and repeatable platform. The capturing procedure was carried out on a cytological slide without any complicated electrode patterning with the ability of cytological staining. Moreover, this platform successfully designed and experimented with the invasion assay (the ability of captured cancer cells to invade normal cells).

Study of dye sensitized solar cell using canna lily sensitizer nanocrystalline titanium dioxide photoanode

In the present work, dye sensitized solar cell is fabricated using canna lily as sensitizer on nanocrystalline TiO2 photoanode. TiO2 photoanode film is deposited on transparent fluorine doped tin oxide (FTO) substrate using doctor blade method. Using UV-Vis spectrometer, SEM, optical absorption analyses and photovoltaic characterization is carried out for Canna lily sensitized photoanode. The DSSC is fabricated by assembling canna lily sensitized photoanode and graphite coated counter electrode. The photoelectrochemical performance of the canna lily flower dye extract showed an open circuit voltage (Voc) of 1.6 mV, short circuit current 18 mA Fill factor, and conversion efficiency 0.20%.

Polycrystalline formamidinium lead bromide (FAPbBr3) perovskite as a self-powered and fast visible-light photodetector

Halide perovskite compounds have become a major research topic in the semiconductor field due to a variety of optoelectronic applications and their advantage of low-cost and simple processing methods, combined with tunable properties. The current work presents the use of (NH2)2CHPbBr3 (FAPbBr3), with a direct band gap of 2.17 eV, as a robust visible-light detector. The polycrystalline material was prepared by fusion of the precursor compounds PbBr2 and (NH2)2CHBr in solid state. It was then pressed in the form of a pellet and two transparent fluorine-doped tin oxide glasses were attached on both sides. The photodetector selectively responds to photon energies exceeding its band gap even without external bias, operating in an energy-efficient, self-powered mode. The response times to pulsed light are orders of magnitude shorter than these of previously reported FAPbBr3-based detectors. Electrochemical impedance spectroscopy determined in depth the electrical characteristics of the semiconducting perovskite with and without illumination. These results provide evidence that polycrystalline FAPbBr3, obtained with low-cost and simple synthetic methods compared to other forms, can be an excellent candidate for fast and self-powered optoelectronics, useful for Visible Light Communication (VLC) and Internet of Things (IoT) systems.

Preparation and Physicochemical Properties of Nanomaterial/Fullerene Composites

Bismuthene, an exfoliated two-dimensional material obtained from bulk bismuth, has drawn significant attention because of its unique electronic properties. Few-layered bismuthene (FLBi) with an average thickness of 1.0 nm was synthesized by the ball mill and sonication method. The FLBi film was fabricated onto a semiconducting SnO2 electrode by electrophoretic deposition (SnO2/FLBi). In the flash-photolysis time-resolved microwave conductivity measurement, the SnO2/FLBi film showed a rise of conductivity upon photoexcitation, supporting the occurrence of the electron injection from the photoexcited FLBi to the conduction band of SnO2. The SnO2/FLBi on a transparent fluorine-doped tin oxide (FTO) electrode was used for photoelectrochemical devices. Photocurrents produced by the FTO/SnO2/FLBi electrode were larger than those produced by the FTO/SnO2 and FTO/FLBi electrodes because of the efficient electron injection. Moreover, FLBi was noncovalently functionalized with fullerene C60 in a mixed solvent of toluene and acetonitrile. Upon photoexcitation, the composite of FLBi and C60 exclusively led to the occurrence of photoinduced energy transfer from C60 to FLBi without generating the charge-separated state. These results give fundamental insights into the feasibility toward the construction of FLBi-based optoelectronic devices.Supramolecular composites consisting of fullerene C60 and carbon nanodiamond (ND) were prepared through spontaneous complexation of C60 aggregates onto the surface of ND aggregates in N-methylpyrrolidone. The resultant C60-ND composite was fabricated onto a nanostructured SnO2 electrode by an electrophoretic deposition method. Formation of the C60-ND composite was supported by dynamic light scattering and field-emission scanning electron microscopy. The C60-ND composite on the SnO2 electrode revealed high incident photon-to-current efficiencies in the visible region in comparison with the single component system of C60 or ND. The enhanced photocurrent generation of the C60-ND composite may originate from the photoinduced charge separation at the interface between C60 and ND. These results will give important insight into the design of all-nanocarbon optoelectronic devices.[1] T. Umeyama, Y. Okawada, T. Ohara, and H. Imahori, Chem. Asian J., 14, 4042-4047 (2019).[2] T. Umeyama, H. Xu, T. Ohara, Y. Tsutsui, S. Seki, H. Imahori, J. Phys. Chem. C, 125, 13954-13962 (2021).

Nanohollow Titanium Oxide Structures on Ti/FTO Glass Formed by Step-Bias Anodic Oxidation for Photoelectrochemical Enhancement.

In this study, a new anodic oxidation with a step-bias increment is proposed to evaluate oxidized titanium (Ti) nanostructures on transparent fluorine-doped tin oxide (FTO) on glass. The optimal Ti thickness was determined to be 130 nm. Compared to the use of a conventional constant bias of 25 V, a bias ranging from 5 V to 20 V with a step size of 5 V for 3 min per period can be used to prepare a titanium oxide (TiOx) layer with nanohollows that shows a large increase in current of 142% under UV illumination provided by a 365 nm LED at a power of 83 mW. Based on AFM and SEM, the TiOx grains formed in the step-bias anodic oxidation were found to lead to nanohollow generation. Results obtained from EDS mapping, HR-TEM and XPS all verified the TiOx composition and supported nanohollow formation. The nanohollows formed in a thin TiOx layer can lead to a high surface roughness and photon absorbance for photocurrent generation. With this step-bias anodic oxidation methodology, TiOx with nanohollows can be obtained easily without any extra cost for realizing a high current under photoelectrochemical measurements that shows potential for electrochemical-based sensing applications.

Expanded solar absorption spectrum to improve photoelectrochemical oxygen evolution reaction: Synergistic effect of upconversion nanoparticles and ZnFe2O4/TiO2

The key to increasing photocatalytic activity is to maximize solar spectrum utilization and minimize the recombination of photosynthetic carriers. Along with ZnFe2O4 for visible light absorption, we designed a novel heterojunction photoelectrode using upconversion nanoparticles (UCNPs) with near-infrared (NIR) light absorption to improve solar absorption efficiency. We fabricated a UCNP-decorated ZnFe2O4/TiO2 photocatalyst (UCNPs-ZFO/TiO2) by sequentially drop-casting ZFO nanoparticles and UCNPs onto TiO2 nanopillars grown on a transparent fluorine-doped tin oxide (FTO) substrate. The UCNP-ZFO/TiO2 exhibited a significantly higher photocurrent density of 0.795 mA cm−2 compared to that of the pristine TiO2 (0.260 mA cm−2). The applied bias photon-to-current efficiency of UCNP-ZFO/TiO2 was 4.1 times higher than that of TiO2, and its photoanode had the lowest charge transfer resistance and highest charge density among the prepared photoelectrodes. This implies that the combination of UCNPs and ZFO on the TiO2 photoanode can be an effective strategy to significantly improve photoelectrochemical performance owing to the synergetic utilization of NIR light by UCNPs and that of visible light by the ZFO nanoparticles.

Unrevealing the effect of transparent fluorine-doped tin oxide (FTO) substrate and irradiance configuration to unmask the activity of FTO-BiVO4 heterojunction

Three FTO-BiVO4 photoelectrodes are fabricated modifying the BiVO4 thickness, and systematically evaluating the influence of FTO substrate on the optical, electrical properties, and photoelectrochemical performance of BiVO4 semiconductor. The catalysts are characterized using two light sources with back-side or front-side irradiations, to investigate the impacts of different energy sources and configuration illumination on the FTO-BiVO4 photoactivity. This analysis reveals the existence of an additional charge transfer resistance increasing with thickness film subjected to front-side illumination, while the resistance remarkably diminishes when this interface is directly irradiated under back-side illumination. The highest photocurrent is achieved with the LED lamp under back-side illumination, condition selected to compare the degradation of 20 mg L−1 ciprofloxacin (CIP) in 0.05 M NaCl through electrocatalysis, photocatalysis, and photoelectrocatalysis using front-side or back-side illuminations. In these evaluations, modified FTO contributes to the photogeneration of reactive chlorine species, whence it cannot be considered as a simple substrate. Back-side illumination presents a higher CIP elimination in comparison with front-irradiation. A schematic energy band diagram relying on Tauc and Mott-Schottky plots, and incorporating FTO as a photoactive semiconductor is established to rationalize the formation of oxidant species in the system. A degradation mechanism is established based on HPLC measurements of the different treatment methods.

Microwave radiation induced performance modifications of dye-sensitized solar cells

Natural dye from Argemone mexicana flower is used as the photosensitizer for fabricating dye-sensitized solar cells (DSSCs). The cells were fabricated using TiO2 as the semiconducting layer deposited on the transparent fluorine-doped tin oxide (FTO) conductive glass. Microwave processing is used for annealing the TiO2-coated FTO glass. The UV–Vis absorption spectra, FTIR and Raman Spectral studies were carried out to check the suitability of the dyes. The I–V characteristic curves of all the fabricated DSSCs were measured and analyzed. The photovoltaic parameters, short-circuit current (I sc), open-circuit voltage (V oc), fill factor (FF) and efficiency (η) of microwave annealed DSSCs are calculated and reported in this paper. Optimum values were observed for solar cells prepared with blocking layer and irradiated with microwave for 7 min, short-circuit current = 2.71 mA, open-circuit voltage = 0.47 mV, fill factor=0.54 and efficiency = 0.69.

Spectroelectrochemical and electrochromic behavior of poly(methylene blue) and poly(thionine)-modified multi-walled carbon nanotubes

The increasing efforts devoted to fabricating electrochromic (EC) devices have motivated a lot of studies to develop new EC materials. Herein, we introduce two poly(phenothiazine)-type redox active polymer films as new EC materials. Poly(methylene blue) (PMB) and poly(thionine) (PTH) films were electrochemically deposited onto the transparent fluorine-doped tin oxide (FTO) electrode modified with multi-walled carbon nanotubes (MWCNTs), which are named as FTO/MWCNTs/PMB and FTO/MWCNTs/PTH, respectively. The as-prepared polymer films were characterized using field emission scanning electron microscopy (FESEM), Fourier transform infrared (FT-IR), cyclic voltammetry (CV), and spectroelectrochemical techniques. Both polymer films exhibited EC behavior at approximately 600 nm. PMB and PTH films are blue and pale purple, respectively, in the oxidized state and change their color to colorless, if reduced at − 0.6 V. In particular, FTO/MWCNTs/PMB showed a satisfactory ΔT (24%) at 600 nm. The obtained results demonstrate that PMB and PTH, as derivatives of phenothiazine dyes, can be introduced as novel EC materials.

Thickness-dependent hole-blocking capability of RF-sputtered nickel oxide compact layers in dye-sensitized solar cells

Photo-generated charge carrier recombination in dye-sensitized solar cells (DSSCs) is observed to be suppressed significantly at the interface between transparent fluorine-doped tin oxide (FTO) and titanium dioxide (TiO2) by coating nickel oxide (NiO) thin film by RF sputtering. UV-Visible optical absorption spectroscopic measurements performed in the wavelength window of 300–800 nm showed ~ 60% average transmittance for NiO thin films coated for 10 min. The calculated optical bandgap value for NiO was 3.4 eV. The RF-sputtered NiO films were thoroughly characterized by X-ray photo-electron spectroscopy to examine Ni 2p3/2 and Ni 2p1/2 along with O 1s. The present study assessed the effect of 5, 10, and 15 min RF-sputtered NiO thin films at the interface between FTO and mesoporous TiO2. Results showed that charge transport in DSSCs is highly sensitive to NiO thickness at the interface between FTO and TiO2. It was specifically noticed that 10 min coating of NiO on FTO yielded DSSCs with photo-conversion efficiency (η) of ~ 6.8% while DSSCs with no NiO on FTO showed only 4.9%. Further increase in NiO thickness affected the performance of DSSCs due to the significant reduction in tunneling probability from TiO2 to FTO.

Hierarchical Growth of CoO Nanoflower Thin Films Influencing the Electrocatalytic Oxygen Evolution Reaction

The 3D architecture of Co(II) oxide (CoO) having oxygen defects has been recognized as a highly functional characteristic towards efficient electrocatalysis of water. Herein, different surface structures of CoO in the form of chemically deposited films were fabricated via AACVD technique, directly over the transparent fluorine-doped tin oxide (FTO) electrodes just by varying the deposition times. The as-prepared films were characterized by scanning electron microscopy (SEM), energy-dispersive X-ray (EDX), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). As the deposition time is varied, the surface structure of the CoO changes from nanoparticles that are formed just in 15 min to nanobuds at 30-min deposition, and finally to a homogeneously distributed dense population of nanoflowers in 45 min. The evolution of these structures was also accompanied by a preferential exposure of (111) facets and an increasing number of oxygen defects which resulted in an enhancement of electrocatalytic activity towards water oxidation. The CoO nanoflowers (CoO-NFs) with highest number of these active oxygen vacancies showed the best performance with an overpotential of 325 mV vs RHE for a current density of 10 mA/cm2 while having a Taefl slope of 98 mV/dec, a mass activity of 35.2 A/g, and the electrochemically active surface area (ECSA) of 1069 μF. However, more importantly, the current density for CoO-NF jumped sharply to the values above 200 mA/cm2 with potential less than 1.8 V vs RHE, thereby meeting the commercialization standards while still providing high stabilities of oxygen generation, current densities, and repeated cycling. Such a performance can be considered remarkable for a material fabricated via a rapid and facile synthetic route and is directly deposited on a low cost and relatively less conductive FTO substrate which can be attributed to the synergistic effect of the larger specific surface area of 3D structure and the high distribution of oxygen defects.

Photoelectrocatalytic production of hydrogen peroxide using a photo(catalytic) fuel cell

Photoelectrochemical production of hydrogen peroxide has been studied by using a two-compartment photoelectrochemical cell operating in the Photo(catalytic) Fuel Cell mode, i.e. it run without any external bias, simply by shining light and generating current. The photoanode was made of CdS quantum dots deposited on nanocrystalline titania, which was first formed on a transparent fluorine doped tin oxide electrode. The photoanode operated in an alkaline environment with added ethanol as model fuel. An air-breathing cathode was made by depositing carbon black on carbon cloth, without any additives of particular functionalities. Best results were obtained by using a neutral electrolyte (Na2SO4) in the cathode compartment. Hydrogen peroxide was produced during cell operation in a cumulative manner adding up to 1400 mg/l (41 mM) in three hours of operation. The rate of hydrogen peroxide production during this period of time remained practically constant and was 5.7 μmole/min, which corresponds to an average Faradaic efficiency of 74%. These data characterize a system with satisfactory performance that may be used for solar fuel production.

Synthesis and characterization of ZnO nanoparticles using sol gel technique for dye sensitized solar cells applications

ZnO nanoparticles were synthesized using sol gel technique at different calcination temperature. The effect of calcination temperature on the structure and optical properties of ZnO NPs were studied in detail by using different techniques, X-ray diffraction, high-resolution transmission electron microscope, UV-VIS spectroscopy and photoluminescence spectroscopy. X-ray diffraction analysis revealed that the ZnO NPs were crystalized in a wurtzite structure and the estimated average particle size increased from 24.7 to 40.4 nm with increasing calcination temperature. In addition, the d spacing increased from 0.28196 nm to 0.28213 nm. High-resolution transmission electron microscopy analysis image showed spherical ZnO NPs were formed. UV-VIS absorption measurement was employed to evaluate the absorption edge and the optical band gap using Tauc plot. Energy gap revealed a red shift from 3.15 to 2.96 eV when the calcination temperature was increased. Dye sensitized solar cells were fabricated using synthesized ZnO NPs as a semiconducting layer that were dyed with different Xanthene (CH2[C6H4]2O) dyes separately; (Eosin B, Eosin Y and Rhodamine B) which are low cost dyes. Thin layer of ZnO were deposited on transparent fluorine doped tin oxide conductive glass using doctor blade method. Eosin Y exhibited the best photosensitizing. The conversion efficiency showed a significant improvement from 0.1% to 1.08%.

Tuning of the electrochemical properties of transparent fluorine-doped tin oxide electrodes by microwave pulsed-plasma polymerized allylamine

We report here the dry, one-step, and low-temperature modification of FTO surfaces using pulsed plasma polymerization of allylamine (PPAAm). PPAAm/FTO surfaces were characterized by X-ray photoelectron spectroscopy, spectroscopic ellipsometry, and contact angles to understand the morphological, structural, and optical properties. FTO were coated with a very thin layer of adherent cross-linked, pinhole-, and additive-free allylamine plasma polymer resistant to hydrolysis and delamination, and characterized by a high density of positively charged amino groups. Electrochemical studies revealed that PPAAm/FTO electrodes show wide range pH stability and reaction rates tuned by the duration of plasma treatment. We show how the modification of plasma treatment duration between 72 s and 288 s affects the chemical structure and thickness of the obtained modification, having a strong influence on the charge transfer kinetics. In particular, XPS revealed the occurrence of the reduction processes under long-term plasma exposure proving the need for monitoring of this key factor. This covalent immobilization of amine compounds on FTO surface using rapid process in microwave pulsed-plasma makes it a promising electrode for future applications in electrochemical biosensors and optoelectronic devices.

Precise control the microstructural, optical, photocatalytic, and photoelectrochemical properties of TiO2 nanoarrays through changing with growth substrate via hydrothermal method

A series of TiO2 nanostructures with rutile phase were synthesized on arbitrary substrates of conductive transparent fluorine-doped tin oxide (FTO), tin-doped indium oxide (ITO), and glass at the low temperature of 150 °C by the hydrothermal method. The samples were characterized by XRD, SEM, TEM, XPS, UV–Vis absorption, and micro-Raman spectroscopy. The effects of growth substrates on the morphologies and optical properties of nanostructures were investigated. TiO2 nanorods were grown on the FTO substrate, while TiO2 nanoflowers were grown on the ITO and glass substrates, and the growth mechanism for these different nanostructures is discussed in detail. The results show that the TiO2 nanorods can improve photocatalytic properties and photoelctrochemical (PEC) performance for its unique structure and optical properties. The TiO2 nanorods exhibited a maximal photocatalytic rate of 4.42 min−1 and photocurrent density of 0.049 mA/cm2, which is about 1.52 and 3.03 times higher than those of TiO2 nanoflowers grown on the ITO substrates, respectively. These findings are quite promising and encouraging for the use of TiO2 nanoarrays in photocatalysis and energy applications.

Photoelectrocatalytic H2 and H2O2 Production Using Visible-Light-Absorbing Photoanodes

Hydrogen and hydrogen peroxide have been photoelectrocatalytically produced by electrocatalytic reduction using simple carbon electrodes made by depositing a mesoporous carbon film on carbon cloth. Visible-light-absorbing photoanodes have been constructed by depositing mesoporous CdS/TiO2 or WO3 films on transparent fluorine-doped tin oxide (FTO) electrodes. Both produced substantial photocurrents of up to 50 mA in the case of CdS/TiO2 and 25 mA in the case of WO3 photoanodes, and resulting in the production of substantial quantities of H2 gas or aqueous H2O2. Maximum hydrogen production rate was 7.8 µmol/min, and maximum hydrogen peroxide production rate was equivalent, i.e., 7.5 µmol/min. The same reactor was employed for the production of both solar fuels, with the difference being that hydrogen was produced under anaerobic and hydrogen peroxide under aerated conditions. The present data promote the photoelectrochemical production of solar fuels by using simple inexpensive materials for the synthesis of catalysts and the construction of electrodes.

COMPARATIVE STUDY OF TiO2 AND ZnO APPLICATION IN HYBRID SOLAR CELLS USING COPOLYMER P3OT/P3MT

Hybrid inorganic-organic solar cells are an attractive alternative energy source because of their low-cost production and ability to make use of a large amount of solar radiation available. This work aims to evaluate different solar cells composed of TiO2 and ZnO with P3OT/P3MT copolymer. Layers of semiconductor oxides were deposited on transparent fluorine-doped tin oxide (FTO) by spin coating and adsorption in the polymer solution. X-ray diffraction (XRD), scanning electron microscopy (SEM), were used to characterize the fabricated semiconductors and curves of current density vs. potential (j-V), photochronoamperometry (j-t) and electrochemical impedance spectroscopy (EIS) were used to determine their electrical characteristics. The XRD analyses confirmed the crystalline nature of the oxide materials. SEM micrographs showed the spherical morphology of ZnO and the poorly defined agglomerate morphology of TiO2. The electrochemical measurements proved that the best cell was produced with P3OT/P3MT copolymer and TiO2, owing to its lower charge transfer resistance, with the following photovoltaic parameters: Voc = 0.615 V ± 0.004, jsc = 1.545 mA cm-2 ± 0.240, FF = 0.637 ± 0.003, and η = 0.617% ± 0.117.

Preparation and Characterization of Transparent Conducting FTO Thin Films by Chemical Spray Pyrolysis Method

Fluorine doped tin oxide (FTO) thin films were synthesized by chemical spray pyrolysis method on glass substrates for 10 at.%, 15 at.%, 20 at.% of fluorine doping concentrations. Their structural, optical and electrical properties were investigated. X-ray diffraction (XRD) study shows polycrystalline nature of the films with orthorhombic crystal structure. The grain size (D) was observed in the range of 14 nm to 30 nm. The FESEM images of the FTO thin films reveals that the films have smooth and homogeneous surface morphology with thin granular grains distributed throughout the surface. EDX analysis confirms the presence of Sn, O and F elements in the prepared FTO thin films. Photoluminescence (PL) spectrum shows a broad emission which covers near band edge (NBE) as well as deep level emissions (DLE) in the region 380 nm and 620 nm. From the hall effect measurements, it was observed that all the films exhibit n-type conductivity. The sample grown with 10 at. % of fluorine showed the highest transmission percentage (80%) with high mobility and conductivity, which are basic requirements for a TCO.