FTO Substrate Research Articles

CuS–CdS@TiO2 multi-heterostructure-based photoelectrode for highly efficient photoelectrochemical water splitting

A three-dimensional hierarchical CuS–CdS@TiO2 multi-heterostructure has been fabricated as a highly promising photoanode for PEC water splitting. The CdS@TiO2 structure was synthesized by a two-step hydrothermal method, therein TiO2 nanorods (TiO2 NRs) were used as the template to grow the CdS branches (CdS BRs). Then the surface of the heterostructure was sequentially coated with a p-type CuS semiconductor via a simple SILAR method. The optimized CuS–CdS@TiO2 photoelectrode exhibits a remarkably high photocurrent density of 12.6 mA cm−2 at 1.23 V vs RHE under standard AM 1.5 light illumination. The enhancement in the PEC performance could attribute to the wide range of solar spectrum absorption in CdS BRs, which can generate more photo charge carriers. Meanwhile, the high conductivity of TiO2 NRs serves as an efficient pathway to transfer photogenerated electrons from the CdS BRs to the FTO substrate. In addition, the p-n junction formed between CuS and CdS@TiO2 heterostructure could improve the separation of electron-hole on the surface of the photoanode. This study demonstrates an efficient pathway to improve the photoelectrochemical performance of TiO2-based photoanodes.

Influence of the Ammonia Concentration in Chemical Bath Deposition and Selenourea Concentration in Hydrothermal Process on the Properties of CdS and Sb2S3−ySey Thin Films and the Photovoltaic Performance of the Corresponding Solar Cells

To explore the feasibility of the flexible Sb2S3−ySey thin‐film solar cell fabrication using polyimide thin films as substrates, CdS thin films are prepared on SnO2:F conducting glass (FTO) substrates by decreasing the ammonia concentration of chemical bath deposition, and Sb2S3−ySey thin films are grown on the FTO/CdS substrate by changing the selenourea concentration of hydrothermal process. The influence of the ammonia and selenourea concentration on properties of CdS and Sb2S3−ySey is systematically investigated and solar cells with the architecture of FTO/CdS/Sb2S3−ySey/spiro‐OMeTAD/Au are fabricated. For CdS thin films on FTO substrate, the thickness decreases and roughness increases with the decrease of ammonia concentration in chemical bath deposition. The compact and full‐coverage CdS thin films with thickness of 50 ± 6 nm are successfully obtained using the low ammonia concentration (0.59 m). For Sb2S3−ySey thin films on FTO/CdS substrate, the Se:S:Sb atomic ratio and thickness increases with the increase of selenourea concentration in hydrothermal process. The optimal selenourea concentration is 6 mM. The solar cells with the 50 ± 6 nm thick CdS thin film and Sb2S2.10Se0.56 thin film achieve photoelectric conversion efficiency of 8.07%. The results can provide an efficient support for further applying polyimide thin films to fabricate flexible Sb2S3−ySey thin film solar cells.

Titanium Dioxide Thin Films Produced on FTO Substrate Using the Sol-Gel Process: The Effect of the Dispersant on Optical, Surface and Electrochemical Features.

In this study, TiO2 thin films formed by dip-coating on an FTO substrate were obtained and characterized using surface, optical and electrochemical techniques. The impact of the dispersant (polyethylene glycol-PEG) on the surface (morphology, wettability, surface energy), optical (band gap and Urbach energy) and electrochemical (charge-transfer resistance, flat band potential) properties were investigated. When PEG was added to the sol-gel solution, the optical gap energy of the resultant films was reduced from 3.25 to 3.12 eV, and the Urbach energy increased from 646 to 709 meV. The dispersant addition in the sol-gel process influences surface features, as evidenced by lower contact-angle values and higher surface energy achieved for a compact film with a homogenous nanoparticle structure and larger crystallinity size. Electrochemical measurements (cycle voltammetry, electrochemical impedance spectroscopy and the Mott-Schottky technique) revealed improved catalytic properties of the TiO2 film, due to a higher insertion/extraction rate of protons into the TiO2 nanostructure, as well as a decrease in charge-transfer resistance from 418 k to 23.4 k and a decrease in flat band potential from 0.055 eV to -0.019 eV. The obtained TiO2 films are a promising alternative for technological applications, due to their advantageous surface, optical and electrochemical features.

Improving the photoelectrochemical water splitting performance of CuO photocathodes using a protective CuBi2O4 layer

A heterojunction photocathode of CuO and CuBi2O4 grown on an FTO substrate (FTO/CuO/CuBi2O4) was synthesized using hydrothermal method followed by spin coating and annealing to overcome the bottlenecks encountered by CuO in photoelectrochemical (PEC) water splitting application. The synthesis methods, morphological, structural properties, and composition of each sample under each synthesis condition are discussed in detail. The photocathode with 15 coating layers annealed at 450 °C exhibited the best PEC performance. Moreover, its current density reached 1.23 mA/cm2 under an applied voltage of − 0.6 V versus Ag/AgCl in a neutral electrolyte. Additionally, it exhibited higher stability than the bare CuO thin film. The bonding of CuBi2O4 on CuO resulted in close contact between the two semiconductors, helping the semiconductors support each other to increase the PEC efficiency of the photocathode. CuO acted as the electron-generating layer, and the CuBi2O4 layer helped minimize photocorrosion as well as transport the carriers to the electrode/electrolyte interface to accomplish the hydrogen evolution reaction.

Tailoring the deposition of MoSe2 on TiO2 nanorods arrays via radiofrequency magnetron sputtering for enhanced photoelectrochemical water splitting

MoSe2/1 D TiO2 nanorods (NRs) heterojunction assembly was systematically fabricated, and its photoelectrocatalytic properties were investigated. The fabrication process involves the growth of 1D TiO2 NRs arrays on FTO substrates using hydrothermal synthesis followed by the deposition of MoSe2 nanosheets on the TiO2 NRs using radiofrequency magnetron sputtering (RF magnetron sputtering). The photoelectrochemical properties of the heterojunction were explored and optimized as a function of the thickness of the MoSe2 layer, which was controlled by the sputtering time. The MoSe2 grows perpendicularly on TiO2 NRs in a 2D layered structure, maximizing the exposed active edges, an essential aspect that permits maximum exploitation of deposited MoSe2.Compared to pure TiO2 NRs, the heterojunction nanostructured assembly displayed excellent spectral and photoelectrochemical properties, including more surface oxygen vacancies, enhanced visible-light absorption, higher photocurrent response, and decreased charge transfer resistance. In particular, the sample synthesized by sputtering of MoSe2 for 90 s, i.e., MoSe2@TiO2-90 s, depicted the highest current density (1.86 mA cm−2 at 0.5 V vs. Ag/AgCl) compared to other samples.The excellent photoelectrochemical activity of the heterojunction stemmed from the synergy between tailored loading of MoSe2 nanosheets and the 1D structure of TiO2 NRs, which afford a high surface/volume ratio, effective charge separation, fast electron transfer, and easy accessibility to the MoSe2 active edges. These factors boost the catalytic activity.

Enhancement of Structural, Optical and Photoelectrochemical Properties of n−Cu2O Thin Films with K Ions Doping toward Biosensor and Solar Cell Applications

n-type Cu2O thin films were grown on conductive FTO substrates using a low-cost electrodeposition method. The doping of the n-Cu2O thin films with K ions was well identified using XRD, Raman, SEM, EDX, UV-vis, PL, photocurrent, Mott-Schottky, and EIS measurements. The results of the XRD show the creation of cubic Cu2O polycrystalline and monoclinic CuO, with the crystallite sizes ranging from 55 to 25.2 nm. The Raman analysis confirmed the presence of functional groups corresponding to the Cu2O and CuO in the fabricated samples. Moreover, the samples' crystallinity and morphology change with the doping concentrations which was confirmed by SEM. The PL results show two characteristic emission peaks at 520 and 690 nm which are due to the interband transitions in the Cu2O as well as the oxygen vacancies in the CuO, respectively. Moreover, the PL strength was quenched at higher doping concentrations which reveals that the dopant K limits e-/h+ pairs recombination by trapped electrons and holes. The optical results show that the absorption edge is positioned between 425 and 460 nm. The computed Eg for the undoped and K-doped n-Cu2O was observed to be between 2.39 and 2.21 eV. The photocurrent measurements displayed that the grown thin films have the characteristic behavior of n-type semiconductors. Furthermore, the photocurrent is enhanced by raising the doped concentration, where the maximum value was achieved with 0.1 M of K ions. The Mott-Schottky measurements revealed that the flat band potential and donor density vary with a doping concentration from -0.87 to -0.71 V and 1.3 × 1017 to 3.2 × 1017 cm-3, respectively. EIS shows that the lowest resistivity to charge transfer (Rct) was attained at a 0.1 M concentration of K ions. The outcomes indicate that doping n-Cu2O thin films are an excellent candidate for biosensor and photovoltaic applications.

Tuning work function and surface-modified AZO films on FTO substrate to improve the efficiency of thin-film silicon solar cells

Tuning work function and surface-modified AZO films on FTO substrate to improve the efficiency of thin-film silicon solar cells

Au/TiO2 nanorod arrays-based electrochemical aptasensor for ultrasensitive detection of adenosine

An electrochemical aptasensor was constructed based on Au/TiO2 nanorod arrays for ultrasensitive detection of adenosine. Specifically, The TiO2 nanorod arrays grown on FTO substrate can attach a large number of Au nanoparticles (AuNPs), which greatly increase the immobilization of aptamers and significantly improve the redox signal of electrostatically adsorbed [Ru(NH3)6]3+. In the presence of adenosine, the number of [Ru(NH3)6]3+ electrostatically adsorbed on the aptamer skeleton decreases, resulting in a decline in the detected square wave voltammetry (SWV) signal. Under the optimal conditions, the peak SWV current values of aptasensor based on five TiO2 nanorod arrays are linear with the logarithmic concentration of adenosine, and the minimum detection limit is 0.42 fM. More importantly, the aptasensor has shown high specificity, extraordinary precision, continuous stability, as well as wonderful applicability for adenosine. Hence, the aptasensor paves the way for developing an effective clinical diagnostic means for adenosine detection.

Remarkable energy storage and photocatalytic remediation potential of novel graphene oxide loaded bi-metal sulphide Ba4Fe2S6-GO nanocomposite thin film

A novel hybrid Barium–Iron sulphide combined with graphene oxide (Ba4Fe2S6-GO) thin film was prepared. The newly synthesized bi-metal composite was synthesized in situ by diethyldithiocarbamate ligand. Deposition of pure BaFe–S and hybrid [BaFe]S-GO on FTO substrate was performed through electron-beam deposition system. The hybrid thin films exhibited enhanced electrical and photocatalytic properties. Characterization was performed by UV–vis spectrophotometry, FTIR, XRD, XPS, SEM-EDX. Direct band gaps 5.48 and 5.8 eV were observed for Ba4Fe2S6-GO and Ba4Fe2S6, respectively, calculated through Tauc's plot. X-ray diffraction revealed anorthic crystal arrangement possessing crystal lattices 9 (a), 6.7 (b) and 24.6 (c) Å. SEM displayed a cloud-like spherical morphology. The energy storage potential of thin film was explored by cyclic voltammetric and linear sweep voltammetric techniques. A specific capacitance of 248 F g−1 presented it as a potential energy storage supercapacitor electrode material. Redox reaction displayed by Ba4Fe2S6-GO electrode exhibited that it is electrochemically active. Thin films were also investigated for their potentiality to remove organic contaminants. Ba4Fe2S6-GO thin films clearly displayed an enhanced photocatalytic activity for the removal of toxic pollutants owing to the presence GO in its structure. The use of films for decontamination presents it to be utilized as a remediation tool.

Enhanced photocatalytic activity of orientationally grown CQD/TiO2 thin film on FTO substrate

We have studied the enhanced light harvesting capacity and reduced recombination rate of TiO2 thin film by composite with Carbon Quantum Dots (CQDs). The CQD/TiO2 film was synthesized using facile, and low-temperature hydrothermal synthesis approach using CQD derived from sugarcane juice and ethanol. The prepared TiO2 and CQD/TiO2 composite thin films were characterized for structural, functional, optical, morphological and elemental compositions analysis using, X-Ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FT-IR), Raman Spectroscopy, UV–Vis Spectroscopy, Field Emission Scanning Electron Microscopy (FESEM) and X-ray Photoelectron Spectroscopy (XPS). The optical band gap of CQD/TiO2 was calculated to be 2.87 eV fall under the visible region favorable for photocatalytic activity under sunlight. The Methylene Blue (MB) dye degradation studies of TiO2 and CQD/TiO2 thin films were carried out under the noon sunlight radiation which showed 78% and 82.6% degradation with good reusability. Therefore, this CQD/TiO2 composite thin film can be a promising candidate for industrial dye effluent treatment.

Optimization, fabrication, and characterization of anthocyanin and carotenoid derivatives based dye-sensitized solar cells

The bracts of Poinsettia, Tamarillo fruit, Annatto seeds, and Pungent Chillies have been used to extract the dyes using ethanol and deionized water. A cocktail of the dyes has been made with equal concentration and will be used as a sensitizer in the proposed dye-sensitized solar cell. The individual and cocktail of the dyes are subjected to FTIR, UV–Visible spectroscopy for the identification of functional groups, and absorption wavelength to find the effectiveness of the dyes for absorption of energy of the photons. From the study, it is found that the sensitizers in the dyes have shown stronger electronic coupling and rapid electron transfer into the conduction band of the TiO2 semiconductor on the FTO substrate. J-V analysis represents photovoltaic characterization of assembled thin film nano-crystalline solar cells. Anthocyanin derivative of Poinsettia bracts attained a photo-sensitized conversion efficiency of 1.74% achieving an overlong lifespan of electrons. Ethanol was chosen for attaining the best energy conversion efficiency owing to its polarity. The presence of phytoconstituents has an impact on the color of the sensitizers and the degradation in the power conversion efficiencies was also monitored. This research examines the parameters that influence the stability of anthocyanin and carotenoid pigments, as well as the solvents required for effective derivative extraction.

P-n heterojunction constructed by γ-Fe2O3 covering CuO with CuFe2O4 interface for visible-light-driven photoelectrochemical water oxidation

Fe2O3 is a promising n-type semiconductor as the photoanode of photoelectrochemical water-splitting method due to its abundance, low cost, environment-friendly, and high chemical stability. However, the recombination of photogenerated holes and electrons leads to low solar-to-hydrogen efficiency. In this work, to overcome the recombination issue, a p-type semiconductor, CuO, is introduced underneath the γ-Fe2O3 to synthesize γ-Fe2O3/CuO on the FTO substrate. Along with the formation of p-n heterojunction, CuFe2O4 is in situ generated at the interface of γ-Fe2O3 and CuO. The existence of Cu2O in CuO and CuFe2O4 promotes the charge transfer from CuO to γ-Fe2O3 and within CuFe2O4, respectively, resulting in creating an internal electric field in γ-Fe2O3/CuO and leading to the conduction band of CuO bending up and γ-Fe2O3 bending down. Additionally, Cu(II) in CuFe2O4 contributes to fast electron capture. Consequently, the charge transfer efficiency and charge separation efficiency of photo-generated holes are promoted. Hence, γ-Fe2O3/CuO exhibits an enhanced photocurrent density of 13.40 mA cm−2 (1.9 times higher than γ-Fe2O3). The photo corrosion resistance of CuO is dramatically increased with the protection of CuFe2O4, resulting in superior high chemical stability, i.e. 85% of the initial activity remains after a long-term test.

Cobalt-doped double-layer α-Fe2O3 nanorod arrays for enhanced photoelectrochemical reduction of Cr(VI)

Element doping is an important method for improving the performance levels of photoelectrochemical (PEC) cells. Nevertheless, to date, the PEC conversion efficiency and photocurrent characteristics of the available photoanodes remain very low. In this study, cobalt (Co) was selectively doped into the bottom and/or top layers of double-layered α-Fe2O3 nanorod arrays grown on conductive transparent substrates (F:SnO2, FTO) via a two-step hydrothermal method; this process was performed to enhance the charge transfer ability and thus significantly improve the PEC performance. The light response capabilities of all α-Fe2O3 films were evaluated by an electrochemical workstation under dark or visible light irradiation conditions. The sample of Co doped in the bottom layer exhibited a high photoelectrochemical performance, achieving a current density of 1.37 mA/cm2 at + 1.0 V versus saturated calomel electrode (SCE); additionally, the sample exhibited a photoelectric synergistic ability to reduce Cr(VI) in an aqueous solution, with 84.85% reduction in 180 min. Under the influence of the electric field inside the double-layer electrode, the photoexcited electrons and holes are transferred to the surfaces of the FTO substrate and the photoanode, increasing the current density and enhancing Cr(VI) reduction. The results of this study offer an alternative approach for designing novel photoanodes with improved PEC performance levels by engineering the electron density distribution and band structure for efficient carrier separation; the results may provide new solutions in heavy metal reduction and contaminant degradation projects.

Microwave-Assisted Hydrothermal Synthesis of Fe-Doped TiO2 Photoanode for Photocatalytic Hydrogen Evolution

One-dimensional TiO2 nanostructures like nanotubes, nanowires, and nanorods have received huge attention due to their photocatalytic hydrogen-generating ability. However, its wide band gap and high charge carrier recombination rate hampered the efficiency with which it converts solar energy into hydrogen. To improve this application, metallic doping employing a quick and easy synthesis method should be proposed. In this study, we report on the microwave-assisted hydrothermal synthesis of iron-doped TiO2 nanowires on an FTO substrate. The formation of TiO2 nano-wires was validated by structural and morphological analysis carried out using XRD and SEM imaging respectively. EDX was employed to provide a breakdown of their chemical composition to verify the presence of dopants in the samples. The impact of Fe-doping on optical and photoelectrochemical properties was studied. Electrochemical impedance spectroscopy was used to determine the mechanisms behind charge accumulation and charge transfer properties. The Mott-Schottky plot was used to examine the donor density and the flat-band potential of the pristine and Fe-doped TiO2 samples.

Nanobelt and nanoplatelet structured molybdenum disulfide thin film as a saturable absorber under nanopulsed green laser excitation

Demonstration of saturable absorption (SA) in MoS2 thin films with varying NLO coefficients as a function of reaction time of hydrothermal method is made using the open aperture Z-scan technique. Under nanosecond pulsed laser excitation (532 ​nm, 9 ns, 10 HZ), saturable absorption occurred involving the overtone of electron - hole pair state and band edge state of MoS2. Further higher ground state cross-section than excited state cross-section favors SA process in MoS2 thin films. The strong saturable absorption behaviors of nanobelt like structured MoS2 film could be attributed to the coexistence of 1T and 2H crystal phases and lower dimension morphology that allows more photons to transit to the higher energy state. Earlier the fabrication of MoS2 thin film on a FTO substrate with a varying reaction time of the hydrothermal technique such as 24, 36, 48 and 60 ​h was made. Raman spectrum has two sets of characteristics vibration representing the metallic 1T – octahedral coordination Oh phase and the semiconducting 2H – trigonal prismatic D3h phase. XRD and Raman studies confirm the formation of mixed phases of MoS2 with 1T phase dominating over 2H phase in MoS2 thin films. Here the absorbance and band gap of the MoS2 thin film increased with increase in reaction time. The luminescence spectra exhibit prominent peaks at 594 ​nm and 621 ​nm resulting from a direct bandgap transition and they are mostly due to the VBM splitting at the K-point. All the films exhibit maximum absorbance in the UV region (291 ​nm) due to the excitonic features of MoS2 and notable absorbance in the visible region (680 ​nm) due to the overtones of MoS2 ‘s electron-hole pair. SEM images confirm that nanoplatelet and nanobelt structured MoS2 was formed with varying size with respect to reaction time. Furthermore, while the nanoplatelet structure faded, nanobelts were grown for a prolonged reaction time. Thus, MoS2 nanostructure coated thin film would be useful for the design of saturable absorbers for fabricating optical switches and mode locking devices.

Binder-free room-temperature synthesis of amorphous-WO3 thin film on FTO, ITO, and stainless steel by electrodeposition for electrochromic application

For electrochromic applications, binders are frequently employed to appropriately affix thin films to transparent conductive substrates like fluorine and indium-doped tin oxide glass plates (FTO and ITO) and stainless steel (SS). The different WO3 nanostructure materials are specifically formed using a variety of chemical and physical processes, but WO3 thin films are not sticky on the substrates without etching. Hence in the present research article, the nanostructured WO3 thin films were effectively deposited using straightforward, affordable anodic electrodeposition procedures on a variety of substrates, including ITO, FTO, and SS, without etching. The XRD analysis confirmed that the nanostructured WO3 materials exhibit amorphous nature (a-WO3). The uniformly deposited a-WO3 film shows the cracked morphological structures. The deposited a-WO3 film was confirmed by FTIR analysis. The nanostructured a-WO3 exhibits excellent electrochromic properties with the highest coloration efficiency (CE) on the FTO 191.4 cm2C-1 at 633 nm wavelength. The fastest electrochromic coloration (1.22 s) and bleaching (1.29 s) response time of nanostructured a-WO3 are observed on FTO substrates, respectively. The cycling stability of electrochromic a-WO3 was shown to be good up to 3000 cycles on FTO substrate.

Nanoporous Mg-doped SiO2 nanoparticles with tunable infrared emissivity toward effective radiative cooling coatings

SiO2 is the hotspot radiative cooling material due to its selective radiation or the Mie resonance effect generated by micro/nanospheres of a specific size. Herein, we demonstrate the modulation of the infrared emissivity of the intrinsic SiO2 at the atmospheric window by doping Mg2+ in nanoporous SiO2 nanoparticles via a modified stöber method. The effects of the Mg-doping on the crystallinity, morphology, infrared emissivity of the nanoparticles and the radiative cooling properties of the corresponding coatings are investigated. Results show that the Mg-doping at a level of 0.226–2.26 % can induce cristobalite nanocrystals after sintering at 1000 ℃, transform the morphology from spheres to irregular nanoporous particles, and improve the infrared emissivity up to 0.96. XPS proves the formation of Mg-O bonds and the change of the binding energy of Si 2p and O 1s, supporting the successful doping of Mg2+ in the lattice of SiO2. All-inorganic Mg-doped SiO2 coatings on FTO substrates are prepared via tape casting, which exhibit rough and porous microstructure and high solar reflectivity up to ∼86 %, with the thickness of ∼90 µm. The Mg-doping improves the radiative cooling capacity of the coatings obviously, and the best temperature reduction of 17.8 ℃ compared with the empty space is achieved, 3–5 ℃ lower than the pure SiO2 coating and 4.5 ℃ lower than the commercial SiO2 coating. Our work offers an effective way to modulate the infrared emission of emitter, enriching the technical measures to improve the overall performance of the sub-ambient radiative cooling devices.

Facile synthesis of ZnCo2O4@NiMoO4 with porous coated structures on carbon paper as stable and efficient Pt-free counter electrode materials for advanced dye-sensitized solar cells

A porous coating structure transition metal oxide ZnCo2O4@NiMoO4 composite was successfully synthesized on the surface of carbon paper (CP) by a simple two-step hydrothermal method as a Pt-free material for titanium mesh substrate counter electrodes (CEs) in dye-sensitized solar cells (DSSCs). According to BET test results, the material has a high specific surface area, which can provide abundant active sites for the redox reaction of electrolytes to enhance the utilization rate of sunlight by DSSCs, and the composite materials show remarkable electrocatalytic performance in reducing iodine electrolytes and improving the photoelectric conversion efficiency (PCE) of DSSCs. Therefore, the DSSCs equipped with ZnCo2O4@NiMoO4/CP material CEs achieve a PCE of 9.30 % (with Jsc of 20.51 mA·cm−2, Voc of 0.763 V, and FF is 0.60), which is much higher than that of Pt CEs (7.36 %) under the same light conditions. This is due to the excellent catalytic ability and good electrical conductivity of the composite material. On the other hand, because the titanium mesh can increase the contact area between the electrode material and the substrate compared with the FTO substrate, and the titanium mesh has good electrical conductivity, it can enhance the diffusion ability of I-/I3- to accelerate electron transmission.

Clustered tubular S-scheme ZnO/CdS heterojunctions for enhanced photocatalytic hydrogen production

Herein, a cluster-like ZnO/CdS nanotube heterojunction photocatalyst was prepared on an FTO conductive glass substrate by a two-step hydrothermal method. The photocatalytic performance and electron transfer mechanism of ZnO and ZnO/CdS composite structures were analyzed through comparing the hydrogen production efficiency of ZnO and ZnO/CdS. The photocatalytic hydrogen production activity of ZnO/CdS (molar ratio 1:1) achieved 7669 μmol/g/h with the AQE of 55.25 %. Unique clustered tubular structure, wider light absorption range and higher carrier transfer rate endowed the composite with marvellous photocatalytic hydrogen production activity. In addition, the measurement of hydroxyl radicals and ESR verified that the electron transfer mechanism followed the S-scheme, which improved the separation efficiency of electron-hole pairs. The residual ratio of catalysts on the FTO substrate remained above 99 % after two cycles, which was remarkably higher than that of the powder catalyst (63 %). This work provides terrific potential for high-efficient, low-cost and recyclable photocatalysts of hydrogen production in the future.

Electrical and optical properties of electro chemical luminescence device with quasi solid electrolyte and ZnO/TiO2 electrode

In this work, a quasi-solid electrolyte process that can be simply manufactured for an electrochemical luminescence (ECL) device with a ZnO/TiO2 electrode was proposed, and the electro-optical characteristics of the fabricated ECL cells were investigated. The electrolyte was prepared by adding poly (vinylidene fluoride-co-hexa-fluoropropylen) with the Ru(bpy)3(PF6)2 as a luminescence material in 1:4 weigh ratio in 1 g of Acetonitrile (ACN). The ZnO/TiO2 films as an electrode were prepared by RF sputtering system. The ZnO and TiO2 targets were set up in co-sputtered system and FTO glass size 2 × 2 cm2 was used as a substrate. Argon gas flow rating as the working gas was fixed at 30 sccm. First, the ZnO layer is deposited on the FTO substrate at 100 W of RF power and at 10 mTorr of Argon gas pressure. TiO2 layer is deposited on the ZnO layer while increasing the sputtering time by 10 min. The morphological and optical properties of the thin films as electrode were confirmed using scanning electron microscope (SEM, Hitachi Su70), X-ray diffraction (XRD, Rigaku D/max 2100H) and UV–vis spectrometer (DH-2000-BAL Ocean Optics). The performance of proposed ECL devices were evaluated by varying operation voltage of 0.5 V from 2 V to 5 V. As the result, we can achieve high performance of device having a wide operating voltage margin and improved luminance intensity.