Memristors, as next-generation memory devices, have garnered significant academic interest. Among them, TiO2/TiO2-x based memristors have particularly attracted substantial scholarly attention. Research on the activation and stability of TiO2 based memristor devices through process parameters is essential. Here, to determine the impact of process parameters on the activation of TiO2/TiO2-x based memristor devices, we fabricated the memristor devices using a sputtering system andconducted annealing at 400℃. Additionally, to analyze the electrical characteristics of the devices, we measured the I-V curves and C-V curves. Also, we examined TiO2/TiO2-x based memristor devices surface using SEM. Consequently, it was observed that the devices subjected to annealing exhibited improved hysteresis curves in the I-V characteristics, a reduced bandgap, and changes in resistance compared to the non-annealed devices. The retention test results further demonstrated that the set/reset characteristics of the devices were stable, confirming their potential applicability as memory devices.
Titanium oxide (TiO2) thin films were synthesized on polymer insulator and Si substrates by atomic layer deposition (ALD) method. The surface and electrical properties of TiO2 films synthesized at various ALD cycle numbers were investigated. The synthesized TiO2 films exhibited higher contact angle and smooth surface. The contact angle of TiO2 films was increased with the increase of ALD-cycle number. Also, the rms surface roughness of films was slightly rough with the increase of ALD-cycle number. The leakage current on TiO2 film surface synthesized at various conditions were uniformed, and the values were decreased with the increase of ALD-cycle number. In the results, the performance of TiO2 films for self-cleaning critically depended on a number of ALD-cycle.
Titanium oxide (TiO2) thin films were fabricated by unbalanced magnetron (UBM) sputtering. The fabricated TiO2 films were treated by oxygen plasma under various RF powers. We investigated the characteristics of oxygen plasma treatment on the surface, structural, and physical properties of TiO2 films prepared at various plasma treatment RF powers. UBM sputtered TiO2 films exhibited higher contact angle value, smooth surface, and amorphous structure. However, the rms surface roughness TiO2 films were rough, and the contact angle value was decreased with the increase of the plasma treatment RF power Also, the hardness value of TiO2 film as physical properties was slightly increased with the increase of the plasma treatment RF power. In the results, the performance of TiO2 films for self cleaning critically depended on the with the plasma treatment RF power.
A novel heteroleptic ruthenium(II) complex bearing a 4-picolinic acid unit as anchoring ligands (trans-dithiocyanato bis(4-picolinic acid)ruthenium(II) (trans-H1)) was synthesized and its chemical structure was identified by 1H-NMR, FT-IR and mass spectroscopy. The optical, thermal, electrochemical and dye adsorption properties of trans-H1 dye were investigated and compared with those of the gold standard ruthenium complex, Ru(4,4``-dicarboxy-2,2``-bipyridine)2cis(NCS)2 (N3). DSSCs based on trans-H1 dyes were examined under the illumination of AM 1.5 G, 100 mWcm-2 and exhibited typical photovoltaic properties with an open-circuit voltage (VOC) of 0.46 V, a short-circuit current (JSC) of 4.10 mA·cm-2, a fill factor (FF) of 60.4%, and a conversion efficiency (PCE) of 1.14%.
The photoinduced hydrophilicity of TiO2/WO3 double layer films was fabricated by using a conventional rf-magnetron sputtering method. The photoinduced hydrophilic reaction of the TiO2 surface was enhanced by the presence of WO3 under the TiO2 layer by irradiation of a 10 W cylindrical fluorescent light bulb. However, when the TiO2 and WO3 layers were separated by an insulating layer, the surface did not appeared high hydrophilic,under the same light bulb. The enhanced photoinduced hydrophilic reaction can be explained by the charge transfer between TiO2 and WO3 layers. It was also demonstrated that visible light passing through the TiO2 layer could excite WO3. Thus, visible light can be used for the hydrophilic reaction in the present TiO2/WO3 system.
Rhodamine B (RhB) was utilized as a dye sensitizer for dye-sensitized solar cells (DSSCs) and its photovoltaic property was examined under the illumination of AM 1.5 G, 100 mWcm-2. DSSCs based on RhBexhibited typical photovoltaic properties with an open-circuit voltage (VOC) of 0.34 V, a short-circuit current (JSC) of 1.55 mA·cm-2, a fill factor (FF) of 50%, and a conversion efficiency (PCE) of 0.26%. In order to further improve the photovoltaic properties of RhB-based DSSCs, the effect of (i) incorporating a strong electron-donating NCS unit into the RhB molecular backbone, (ii) combining a bis-negatively charged zinc complex anion (Zn-dmit2, dmit=di-mercapto-dithiol-thione) with the amine cation of RhB, (iii) co-adsorbing RhB dyes with chenodeoxycholic acid (CDCA) molecules onto porous TiO2 electrodes, was investigated and discussed.
Nano-size BaTiO3 powder was synthesized by relatively simple hydrothermal reaction method. Finely dispersed Ti hydroxide precursor was first precipitated using Ti(SO4)2 and NaOH solution by applying ultrasonic power and washed thoroughly to remove SO4 2- and Na+ ion. Then hydrothermal reaction was done at 160℃ for 6 hrs using solution prepared by washed Ti hydroxide precursor slurry and Ba(OH)2ㆍ8H2O with Ti:Ba mole ratio of 1:1. 200 ~ 500 nm size and uniform size distributed BaTiO3 powder was synthesized by relatively low temperature and simple process.
In this paper, TiO2 based thin-film transistors (TFTs) were fabricated using by an atomic layer deposition with high aspect ratio and excellent step coverage. Ti02 semiconducting layer was deposited showing a rutile phase through the rapid thermal annealing process, and exhibited TFT characteristics with a 200 pm channel length of low-leakage currents (none of current flow during off-state), stable threshold voltages (-10 V - 0 V), and a much higher on/off current ratio (
Photo electrode is an important component of DSSC, so this paper did some research on it. Through the method of adding PEG additive into TiO2 paste, the electrical characteristics and efficienciesof DSSCs with photo electrode surface area were studied. In the case of not adding PEG in TiO2 paste,26 ㎛ thickness TiO2 photo electrode shows 5.081% efficiency. The highest short circuit current densitywas 10.476 mA/cm2. The structure of porous TiO2 film can be controlled through changing the PEGadditive amount in TiO2 paste and the molecular weight of PEG. When the additive amount of PEG20,000 in TiO2 paste reaches 5%, the peak efficiency with 26 ㎛ thickness TiO2 photo electrode was5.387% and its highest current density were 11.084 mA/cm2.
Photo electrode is an important component for DSSC. DSSCs electrical characteristics and efficiencies fabricated with different TiO2 photo electrodes thickness and modified phoro electrode surface area were studied. 11 ㎛ TiO2 photo electrode shows a 4.956% efficiency. The highest short circuit current density was a 9.949 mA/cm2. Efficiencies and short circuit current density increased as tape casting thickness decreased. Modified surface area of the photo electrode by needle stamp processing were studied. 200 times needle stamp processing on photo electrodes shows a highest 5.168% efficiency. Also the short circuit current density was a 10.261 mA/cm2.
In this work, according to temperature and time of hydrothermal synthesis, the electrochemical properties of TiIO2 particle using TTIP based on thanging temperature and time in the hydrothermal synthesis were analyzed and optimized temperature and time were derived. When hydrothermal synthesis were analyzed and optimized temperature and time were derived. When hydrothermal synthesis temperature and time were 200℃ and 1 h, respectively. The fabricated DSSC delivered the best electrochemical properties. In that case, TiO2 particle size was 13.018 nm, electron transport time was 2.34×103s and recombination time was 4.01×102s. The lowest impedance of 13.52 Ω and Voc, Jsc, FF is 0.70 V, 11.50 mAcm2, 65.62%, respectively and corresponding efficiency of 5.34% was considered as the optimal.
Dye-sensitized solar cells (DSSCs) based on titanium dioxide (TiO2) have been extensively studied because of their promising low-cost alternatives to conventional semiconductor based solar cells. DSSCs consist of molecular dye at the interface between a liquid electrolyte and a mesoporous wide-bandgap semiconductor oxide. Most efforts for high conversion efficiencies have focused on dye and liquid electrolytes. However, interface engineering between dye and electrode is also important to reduce recombination and improve efficiency. In this work, for interface engineering, we deposited semiconducting ferroelectric BiFeO3 with bandgap of 2.8 eV on TiO2 nanoparticles and nanotubes. Photovoltaic properties of DSSCs were characterized as a function of thickness of BiFeO3. We showed that ferroelectric BiFeO3-coated TiO2 electrodes enable to increase overall efficiency of DSSCs, which was associated with efficient electron transport due to internal electric field originating from electric polarization. It was suggested that engineering the dye-TiO2 interface using ferroelectric materials as inorganic modifiers can be key parameter for enhanced photovoltaic performance of the cell.
The utilization of a fluoran leuco sensitizer, 2-anilino-6-dibutyl amino-3-methylfluoran (ODB-2), for dye-sensitized solar cells (DSSCs) was investigated through the examination of the adsorption of ODB-2 molecules onto the surfaces of porous titanium dioxide (titania, TiO2) films and the photovoltaic properties of ODB-2-based DSSCs. Despite of the absence of the specific anchoring groups with titania, ODB-2 dye molecules were spontaneously adsorbed onto the titania surfaces because the lactone ring in ODB-2 was opened and changed into the carboxylic acid (-COOH) by releasing protons from the surfaces (TiOH2 +) of titania, which consequently leads to the chemisorption reaction of ODB-2 molecules to the active sites of titania. DSSCs based on ODB-2 exhibited typical photovoltaic properties with an open-circuit voltage (VOC) of 0.19 V, a short-circuit current (JSC) of 0.30 mA·cm-2, a fill factor (FF) of 37%, and a conversion efficiency (PCE) of 0.02%.
This study is explore the photoelectric conversion change of dye-sensitized solar cells with surface treatment of the conductive substrate. gases of FTO surface treatment were N2, and O2. Treatment conditions of surface were gas flux from 25 sccm to 50 sccm and RF power were from 25 W to 50 W. Treatment time and pressure were fixed 5 min and 100 mtoor. The best sheet resistance and surface roughness were obtained by O2 50 sccm and 50 W and that result were 7.643 Ω/㎠ and 17.113 nm, respectively. The best efficiency result was obtained by O2 50 sccm and 50 W and that result of Voc, Jsc, FF and efficiency were 7.03 V, 14.88 mA/㎠, 63.75% and 6.67%, respectively.
Ordered mesoporous oxide films have been focused because of their low density, high interior specific surface area, and high thermal insulation. Specially, the ordered mesoporous oxide films prepared by self-assembly has many advantages due to easy process and high reproducibility. In this work, ordered mesoporous SiO2, Al2O3, and TiO2 films were synthesized by control of composition and processing parameter. Also, their structural, thermal, and mechanical properties were characterized variously. In conclusion, ordered mesoporous oxides will be one of core materials in new technology due to their excellent and unique properties.
The sol-gel method has been widely used to synthesize the TiO2 for dye sensitized solar cells and has advantages of easily fabrication process, controlling the TiO2 phase and getting transparent thin-film composed of the TiO2. In this paper, we synthesized the crystalline TiO2 by sol-gel method controlled by the quantity ratio of Nitric acid and Ammonium hydroxide additives. The best efficiency result was obtained by 0.05 M Ammonium hydroxide and that results of Voc, Jsc, FF, and efficiency were 0.68 V, 3.28 mA/cm2, 58.14 and 5.21%, respectively.
Embossed TiO2 thin films with high surface areas are achieved using soft-templates composed of monolayer polystyrene beads. The form of links between the beads in the templates is controlled by varying the O2 plasma etching time on the templates, resulting in various templates with close-linked, nano-linked, and isolated beads. Room-temperature deposition of TiO2 on the plasma-treated templates and calcination at 550℃ result in embossed films with tailored links between anatase TiO2 hollow hemispheres. Although all the embossed films have similar surface areas, the sensitivity of films with nano-linked TiO2 hollow hemispheres to 500 ppm CO and ethanol gases are much higher than that of films with close-linked and isolated hollow hemispheres, and the detection limits of them are as low as 0.6 ppm for CO and 0.1 ppm for ethanol. The strong correlation of sensitivity with the form of links between hollow hemispheres reveals the critical role of potential barriers formed at the links. The facile, large-scale, and on-chip fabrication of embossed TiO2 films with nano-linked hollow hemispheres on Si substrate and the high sensitivity without the aid of additives give us a sustainable competitive advantage over various methods for the fabrication of highly sensitive TiO2-based sensors.
In this paper, we have theoretically analyzed and designed a dielectric multi-layer sensor with a SPR (surface plasmon resonance) using analytical calculation and FDTD (finite difference time-domain) methods. The proposed structure is composed of periodic layer and thin metal film. It has many advantages. One of that is a high sensitivity of the SPR. Another is a high Q-factor of the characteristics in the PhC (photonic crystals) micro-cavity structure. The incident light has double resonance characteristics, because the filtered light by PhC structure, dielectric multi-layer, is met the thin metal film for SPR effect. We have also observed the change of resonance characteristics according to the variation of effective index on the metal film.
DSSCs efficiency by thickness of TiO2 photoelectrode and thickness differences between two substrates studied. DSSCs is made of the doctor blade method and photoelectrode annealing temperature elevated in a different ways. In addition, cells efficiencies of according to the different thickness between TiO2 photoelectrode substrate and Pt counter electrode was measured. Efficiency of DSSCs made with TiO2 photoelectrode of 18 ㎛thickness and the gap difference between the substrate 28 ㎛shows a highest 4.805% efficiency.
As an alternative energy, Dye-sensitized solar cells (DSSCs) have received much attention due to low cost manufacturing procedure and high energy consumption rate. Incorporating scattering centers in the nanocrystalline photoanode or additional scattering layers on the nanocrystalline photoanode is an effective way to enhance the light harvest efficiency of the photoanode and the performance of dye-sensitized solar cells (DSSCs). The light scattering abilities of these scattering layers also depend on the relative sizes and phase of the particles in the layers. A higher surface area is normally obtained using large particle sizes. Therefore, transparent high surface area TiO2 layers and an additional scattering layer consisting of TiO2 -Rutile 500 ㎚paste with relatively larger particles are attractive. In this work, we investigates the applicability of a hybrid TiO2 electrode (or a working electrode with a light scattering layer) in a DSSCs. We fabrication various thin film using TiO2 paste 20 ㎚and TiO2 paste 500 ㎚. As a result, the efficiency of the a single structure thin film was 3.35% and the efficiency as scattering layer of hybrid structure thin film was 4.36%, 4.73%.
In general, a photoelectrode in DSSC(dye sensitized solar cell) are fabricated by using the TiO2 (Titanium dioxide) to realize high efficiency and the efficiency of DSSC is affected by the size, the shape and the property of TiO2. We synthesized the crystalline TiO2 by sol-gel method. In spite of many merits, only weakness for the sol-gel method is taking many process times. To solve this problem, we reduced the fabricating processes. The reduced process is the making process that is TiO2 sol to TiO2 powder with including of two heat treatment and two mixing. We could simplify the process by preparing TiO2 sol to TiO2 paste directly. As a result, DSSC fabrication process is simplified and we have obtained the efficiency best result 3.88% with VOC=0.71 V, JSC=8.70 mA/cm-2, and FF=62.37%, respectively.
The TiO2/Si3N4/Ag/Si3N4/TiO2 multi layered structure was designed for the possible application of transparent electrodes in PDP (Plasma Display Panel). Multi layered film was deposited on a glass substrate at room temperature by DC/RF magnetron sputtering system and EMP (Essential Macleod Program) was adopted to optimize the optical characteristics of film. During the deposition process, the Ag layer in TiO2/Ag/TiO2 became heavily oxidized and the filter characteristic was degraded easily. In thus study, Si3N4 layer was used as a diffusion buffer layer between TiO2 and Ag. in order to prevent the oxidation of Ag layer in TiO2/Si3N4/Ag/Si3N4/TiO2 structure. It was confirmed that Si3N4 layer is one of candidate materials acting as diffusin barrier between TiO2/Ag/TiO2.
The adsorption kinetic study of ruthenium complex, N3, onto nanoporous titanium dioxide (TiO2) photoanodes has been carried out by measuring dye uptake in-situ. Three simplified kinetic models including a pseudo first-order equation, pseudo second-order equation and intraparticle diffusion equation were chosen to follow the adsorption process. Kinetic parameters, rate constant, equilibrium adsorption capacities and related coefficient coefficients for each kinetic model were calculated and discussed. It was shown that the adsorption kinetics of N3 dye molecules onto porous TiO2 obeys pseudo second-order kinetics with chemisorption being the rate determining step. Additionally the heterogeneous surface and the pore size distribution of porous TiO2 adsorbents were also discussed.
The TiO2/ZnS/Ag/ZnS/TiO2 multilayered structure for the transparent electrodes in plasma display panel was designed by essential macleod program (EMP) and the multilayered film was deposited on a glass substrate by direct-current (DC)/radio-frequency (RF) magnetron sputtering system. During film deposition process, the Ag layer in TiO2/Ag/TiO2 structure became oxidized and the filter characteristic was degraded easily. In this study, ZnS layer was adopted as a diffusion blocking layer between TiO2 and Ag to prevent the oxidation of Ag layer efficiently in TiO2/ZnS/Ag/ZnS/TiO2 structure. Based on the AES depth profiling analysis, the Ag layer was effectively protected by the ZnS layer as compared with the TiO2/Ag/TiO2 multilayered films without ZnS as an antioxidant layer. The 3 times stacked TiO2/ZnS/Ag/ZnS/TiO2 films have low sheet resistance of 1.22 Ω/□ and luminous transmittance was as high as 62% in the visible ranges.
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