Low Temperature Sol-gel Process Research Articles

Ce-TiO2 nanoparticles with surface-confined Ce3+/Ce4+ redox pairs for rapid sunlight-driven elimination of organic contaminants from water

Industrial discharge of organic pollutants poses a severe threat to human health and aquatic life. Elimination of these pollutants from drinking and wastewater is imperative for a sustainable environment. To address this issue, pure and Ce3+-doped TiO2 nanoparticles are designed with stable tetragonal (anatase) lattices by a low-temperature sol–gel process. The spectroscopic and structural analyses reveal the formation of TiO2 and Ce-TiO2 nanocrystals with controlled crystallite size (3–6 nm), high surface areas, and varying surface chemistry. The effect of calcination (thermal (Δ) treatment at 450 °C) on the structure and photocatalytic performance of ΔTiO2 and ΔCe-TiO2 nanoparticles is also investigated. Simultaneous photocatalysis experiments over a 90-min exposure to natural sunlight show 240 % and 191 % improved elimination of methylene blue (MB), an organic pollutant, by Ce-TiO2 and ΔCe-TiO2 nanoparticles compared to their pure TiO2 analogs. Also, Ce-TiO2 and ΔCe-TiO2 nanoparticles exhibit 326 % and 229 % faster kinetics for the photocatalytic elimination of MB primarily due to the surface-confinement of Ce3+ in Ce-TiO2 nanocrystals, where Ce3+ ions play a dual role as reducing agent for adsorbed oxygen species and electron trap sites via Ce3+/Ce4+ interconversion. The mechanism of photocatalytic redox reactions is discussed. The study elaborates on the role of Ce-TiO2 nanoparticles as an effective photocatalyst for the elimination of organic pollutants in wastewater.

Preparation of Low-Temperature Solution-Processed High-κ Gate Dielectrics Using Organic-Inorganic TiO2 Hybrid Nanoparticles.

Organic-inorganic hybrid dielectric nanomaterials are vital for OTFT applications due to their unique combination of organic dielectric and inorganic properties. Despite the challenges in preparing stable titania (TiO2) nanoparticles, we successfully synthesized colloidally stable organic-inorganic (O-I) TiO2 hybrid nanoparticles using an amphiphilic polymer as a stabilizer through a low-temperature sol-gel process. The resulting O-I TiO2 hybrid sols exhibited long-term stability and formed a high-quality dielectric layer with a high dielectric constant (κ) and minimal leakage current density. We also addressed the effect of the ethylene oxide chain within the hydrophilic segment of the amphiphilic polymer on the dielectric properties of the coating film derived from O-I TiO2 hybrid sols. Using the O-I TiO2 hybrid dielectric layer with excellent insulating properties enhanced the electrical performance of the gate dielectrics, including superior field-effect mobility and stable operation in OTFT devices. We believe that this study provides a reliable method for the preparation of O-I hybrid TiO2 dielectric materials designed to enhance the operational stability and electrical performance of OTFTs.

Structural, optical and electrical properties of M0.025Sm0.175Ce0.8O2-δ : an electrolyte for IT-SOFCs

The system of compositions M y Sm x-y Ce1-x O2-δ (M = Al, Ca, Mg & Sr, x = 0.20; y = 0.025) are investigated in the present study as electrolytes for IT-SOFCs. These samples are prepared by a low-temperature sol-gel process modified by sucrose-pectin to obtain a nanocrystalline powder. The synthesized nanocrystalline powder calcined at 600°C. The average crystallite size is in the range of 11–16 nm. The co-dopants Al, Ca, Mg & Sr promote densification of the SDC 20 at relatively lower sintering temperatures (<1300°C). These samples are characterized by XRD, Williamson-Hall plots, UV-Visible, Raman, FESEM, and impedance spectroscopy. The electrical conductivity is measured in the temperature range of 300–700°C. The sample with composition Sr0.025Sm0.175Ce0.80O2-δ (SrSDC) exhibits higher electrical conductivity of 0.03342 S/cm at 700°C. Hence, SrSDC can be used as an electrolyte for IT-SOFC applications.

Spectroscopic and Magnetic Performance of Cobalt (Co) Incorporated NiMn0.05Fe1.95O4 Nanoferrites: A Potent Antifungal Activity Against Aspergillus niger (MT675916)

We investigated the impact of cobalt (Co) incorporation on the structural, optical, and magnetic properties of ferrite Ni[Formula: see text]CoxMn[Formula: see text]Fe[Formula: see text]O4, also known as NCMF for [Formula: see text], 0.02, and 0.04, which were successfully synthesized using a low-temperature sol-gel combustion process with nitrates as cations and citric acid (C6H8O7) as the combustion/chelating agent. In X-ray diffraction studies, cobalt incorporation resulted in a significant increase in lattice parameter from 8.31 to 8.36, as well as a significant increase in density from 5.42 to 5.52[Formula: see text]g/cm3; crystal size formation was observed in the range of 44.76[Formula: see text]nm to 48.54[Formula: see text]nm for all samples. Raman spectra analysis confirmed that single phase belongs to the Fd3m space group. Fourier transform infrared (FTIR) spectra were used to identify functional clusters and residual groups in all samples. UV–visible spectroscopy showed a redshift of 0.92[Formula: see text]eV for [Formula: see text]. The effect of dopants on nickel ferrites’ magnetization was observed in the range 52–59[Formula: see text]emu/g, indicating that all samples contain soft magnetic content. Antifungal activity of synthesized sample was analyzed against Aspergillus niger (MT675916) species of plant pathogenic fungi isolated from Capsicum during storage. Biological analysis designated that the sample for [Formula: see text] has shown a 100% potent antifungal activity against Aspergillus niger (MT675916) species. For [Formula: see text] treatment completely inhibits the growth of fungus after 7 days. Therefore, NCMF NPs can be used as applicant resources for industrial, medical, and biological applications.

Structure and magnetic behavior of sol-gel grown spinel NixMn3-xO4 nanoparticles: Effect of Ni fraction and induction of superparamagnetism at room temperature

Spinel NixMn3-xO4 nanostructures have attracted a huge research interest due to their applications in catalysis, electrocatalysis, high-performance supercapacitors, lithium-ion batteries, among others. However, those applications strongly depend on the Ni:Mn ratio, valence states and spatial distribution of cations in the spinel lattice. Using a low-temperature sol-gel process, we synthesized NixMn3-xO4 nanoparticles of 14–26 nm average sizes with different Ni contents. Effects of Ni incorporation on the morphology, structure and magnetic properties of the nanostructures were studied by SEM, XRD, XPS, Raman spectroscopy and VSM. While a high Ni content in the spinel nanostructures causes lattice shrinkage, lattice expansion at lower Ni content occurs due to higher occupancy of Mn2+ ions in tetrahedral sites. Structural and magnetic behaviors of the nanostructures were explained by considering the crystal field stabilization energies of the cations. We demonstrate that superparamagnetic behavior can be induced in the NixMn3-xO4 nanostructures by incorporating Ni at x>1.0.

Synthesis of Highly Active Heterostructured Al2TiO5/TiO2 Photocatalyst in a Neutral Medium

In this work, heterostructured catalyst Al2TiO5/TiO2 (ATO/Ti) was synthesized by a two-step method: low-temperature sol-gel process along with hydrothermal treatment in a neutral medium. Characteristics of the fabricated catalyst were analyzed by various techniques including X-ray diffraction, Fourier transform infrared spectroscopy, Brunauer-Emmett-Teller adsorption, UV-Vis diffuse reflectance spectroscopy, energy-dispersive X-ray spectroscopy, field emission scanning electron microscopy, transmission electron microscopy, Raman spectroscopy, and the point of zero charges. The content of ATO strongly affected the activity of ATO/Ti catalysts for photocatalytic degradation of cinnamic acid (CA). The catalyst, in which 33% TiO2 was replaced by ATO (33ATO/Ti), exhibited the highest activity for the removal of CA. Compared with the bare titanium oxide synthesized in water (TiO2(w)) as well as Al2TiO5 (ATO), the hybrid 33ATO/Ti catalyst exhibited the enhanced photocatalytic activity in the CA degradation under ultraviolet light. The enhancement in the catalytic activity of ATO/Ti could be related to the increase of the specific surface area and the reduction of bandgap energy obtained from the hybridization of TiO2(w) and ATO. The factors as the catalyst dosage ( C cat ), the airflow rate ( Q air ), and the solution initial pH (pH) affected the CA removal efficiency were studied on 33ATO/Ti catalyst. The optimum condition for photodegradation efficiency of CA was found to be at C cat = 0.75 g L − 1 , Q air = 0.3 Lmi n − 1 , and pH = 3.8 . The highest 60-minute removal efficiency of CA reached 77.1% on 33ATO/Ti compared with 67.1% and 30.4% on TiO2(w) and on ATO, respectively. The recyclability of the 33ATO/Ti was also measured at the optimal parameters. The results showed that, compared with TiO2, the hybrid catalyst was easier to recover and reuse, and its activity decreased by 35% after 6 continuous cycles.

Reinspection of formation of BiFe1-xMnxO3 solid solutions via low temperature sol-gel synthesis route

In this study, BiFe1-xMnxO3 (BiFeMnO; x from 0 to 0.5) solid solutions were prepared by low temperature sol-gel processing. It was demonstrated that structural, magnetic and morphological properties of BiFeMnO samples are dependent on the chemical composition of the synthesized BiFe1-xMnxO3 solid solutions. The thermal behaviour of the Bi–Fe–Mn–O precursor gels was investigated by thermogravimetric and differential scanning calorimetry (TG-DSC) measurements. From X-ray diffraction (XRD) analysis it was observed that monophasic BiFe1-xMnxO3 samples have formed up to 25 mol% of substitution. The Rietveld analysis showed that the structure of BiFeMnO specimens can be indexed by rhombohedral or orthorhombic unit cell depending on Mn3+ content. Scanning electron microscopy (SEM) was used to investigate samples morphology and revealed, that smaller particles form when Mn3+ is present inside the structure. Moreover, magnetic properties of solid solutions were also investigated, and antiferromagnetism and weak ferromagnetism were observed for the samples.

Improved photocatalytic activity of anatase-rutile nanocomposites induced by low-temperature sol-gel Sn-modification of TiO2

The Sn-modified TiO2 photocatalysts are prepared by low-temperature sol-gel processing based on organic titanium and tin precursors with varied Sn concentrations (from 0.1–20 mol .%). The role of Sn dopant as the promotor of the formation of TiO2 rutile crystalline phase is explained and the optimal Sn concentration for preparation of efficient Sn-modified titania photocatalyst is determined. Up to 40 % increase in photocatalytic activity is achieved in Sn-modified TiO2 photocatalytic thin films dried at 150 °C with low Sn concentrations in the range from 0.1 to 1 mol .%. At low Sn concentrations optimal ratio between anatase and rutile (nano)crystals is obtained, which facilitates charge separation at the TiO2 photocatalyst’s surface. When the concentration of Sn increases above 5 mol.% or when the films are calcined at 500 °C, the relative amount of rutile phase with inferior photocatalytic activity, increases and the nanocrystals of titania grow, leading to fewer active sites per unit mass and the reduction of activity in comparison to unmodified TiO2.

Effects of Zr doping to improve ionic conductivity and lithium-diffusion kinetics of β-LiVOPO4 cathode material

We tried to improve the ionic conductivity, lithium-ion diffusion, and cycle capacity of pure β-LiVOPO4 cathode material by Zr doping. Pure and Zr-doped β-LiVOPO4 cathode material was synthesized by a low-temperature sol–gel process. The physiochemical properties of the synthesized materials were analyzed by various characterization techniques. The Zr doping of the β-LiVOPO4 was confirmed by ex situ XANES analysis. The electrochemical behavior of the synthesized material was studied by various electrochemical analyses. The lithium-diffusion coefficient values of pristine and selected Zr-doped β-LiVOPO4 cathode materials were studied and compared using SSCV, EIS, and PITT at different voltages. The calculated values of the diffusion coefficients obtained from CV and EIS are in the range of 10−14–10−13cm2/s. The PITT measurement gives the values of 10−12–10−11cm2/s. All techniques indicated that x=0.03 Zr-doped samples obtained the improved the lithium diffusion coefficient values.

Development of a new sol-gel route for the preparation of aluminum oxynitride nano-powders

In the present research, a novel low-temperature sol-gel process was developed for the synthesis of the aluminum oxynitride (AlON) phase using aluminum tri-sec-butoxide, acetonitrile, chloroform, and hydrazinium hydroxide. This straightforward process involves the nitridation of the as-synthesized sols under ultra-high purity nitrogen to form the AlON nano-powders. The effect of various parameters such as pH in the range of 8–11, the solvent to alkoxide molar ratio (30–100), and acetonitrile to chloroform molar ratio (20–100%), and heat treatment temperature (900–1500 °C) and time (4–12 h) on the composition of the prepared powders were studied. The characterization of the powders by X-ray diffraction (XRD), fourier-transform infrared spectroscopy (FTIR), field-emission scanning electron microscopy (FE-SEM), and transmission electron microscopy (TEM) demonstrated that the pure phase of AlON (nano powder) was obtained in the sample having the pH value of 10, the molar ratio of solvent to alkoxide of 100, the molar ratio of acetonitrile to chloroform of 80%, which annealed at 1500 °C for 8 h at nitrogen atmosphere with the heating rate of 3 °C/min. Finally, transparent AlON ceramic was fabricated by the spark plasma sintering of as-synthesized AlON powder at 1600 °C for 30 min with a density of 3.64 gr/cm3 and about 54% IR in-line transmission.

Preparation and characterization of chitosan-boehmite nanocomposite membranes for pervaporative ethanol dehydration

Pervaporative ethanol dehydration was studied using some chitosan-boehmite nanocomposite membranes. Nanocomposite membranes were prepared by incorporation of 1 and 2 Wt. % loading of the boehmite nanoparticles synthesized by the low temperature sol-gel process. The prepared samples were characterized by FTIR, FESEM and XRD analysis. The results showed the filler particles uniform distribution within the chitosan matrix. Pervaporation performance of the prepared pristine and the nanocomposite membranes were evaluated for ethanol dehydration. The 2 Wt. % loaded boehmite nanocomposite membrane exhibited highest ethanol dehydration performance for 20 Wt. % water content feed at 50 °C as 0.513 kg/m2 h and 676 as permeation flux and separation factor revealed ∼50% and 2 times increments, respectively.

Multifunctional TiO2/ormosils organic-inorganic hybrid films derived by a sol-gel process for photonics and UV nanoimprint applications

Multifunctional TiO2/ormosils organic-inorganic hybrid films that contain azobenzene and photosensitive groups are prepared by combining a low temperature sol-gel process and a spin-coating technique. The optical waveguide and the structural properties of the hybrid films are characterized and investigated respectively by different techniques. The photo-responsive properties of the hybrid films are induced by a photo-irradiation under UV light at a wavelength of 365 nm. Finally, micro-lens arrays are built in the hybrid films by using a UV soft imprint technique. These results indicate that the as prepared hybrid films with multifunctional photonic properties are promising candidates for integrated optics and photonic applications, which would allow the direct integration onto a single chip of the optical micro-elements and the optical data storage and optical switching devices.

Low temperature processing of Al2O3-GPTMS-PMMA hybrid films with applications to high-performance ZnO thin-film transistors

In this work we evaluate the synthesis of inorganic-organic Al2O3-GPTMS-PMMA hybrid films using a low temperature sol-gel process and their use as gate dielectric for thin film transistors (TFTs). The hybrid films were deposited by dip coating process and then annealed at 150 °C in air. The analysis of the hybrid films was performed by UV–VIS spectroscopy, FTIR, AFM, SEM, C-V and I-V measurements. The optical transparency above 85% in the visible range and homogeneity of the hybrid films support the proper link between inorganic and organic phases with strong bonds. At microscopic level, the hybrid films have uniform surface roughness lower than 1 nm. The C-V and I-V measurements performed on MIM structures showed leakage current density in the order of 10−7 A/cm2 at 104 kV/cm electric field. Capacitance and dielectric constant measured at 1 kHz were 20.4 pF and of 6.2, respectively. TFTs were fabricated using bottom gate and aluminium top contacts to obtain mobilities of 4.5 cm2/Vs, threshold voltage of 0.7 V and Ion/Ioff ratio of 107, while mantaining operating voltage under 8 V.

Transparent Photocatalytic Thin Films on Flexible Polymer Substrates

Self-cleaning and/or photocatalytic films on polymer substrates have found numerous applications during the past decades. However, the common demand for high-temperature post synthesis treatment limits the application to temperature resistant substrates only. Herein, we prepared self-cleaning photocatalytic films on four thermosensitive polymeric substrates: polyvinyl chloride (PVC), polymethyl methacrylate (PMMA), and acryl coated polyester (PES) fabric (D2) with poly(vinylidene fluoride) (PVDF) containing lacquer (D1). TiO2 was prepared via a low-temperature sol-gel process using titanium(IV) isopropoxide and zirconium(IV) butoxide as precursors with various loading levels of Zr; 0, 5, 10, and 20 mol.%, and deposited on the substrates by using a SiO2 binder in form of thin films (ca. 200 nm thick) via dip-coating. The films were characterized by SEM, hardness test, UV-Vis, photothermal beam deflection spectroscopy, and IR spectroscopy, while photocatalytic activity was measured by the fluorescence-based method of the terephthalic acid probe and wetting by contact angle measurements. Films containing 10 mol.% of Zr showed the best compromise regarding photocatalytic activity and mechanical stability while from substrates point of view PVC performed the best, followed by PMMA, D1, and D2. The beneficial role of SiO2 binder was not only guaranteeing excellent mechanical stability, but also to prevent the D1 polymer from deterioration; the latter was found to be labile to long-term solar-light exposure due to degradation of the top PVDF layer.

Polyacrylate/silica hybrid materials: A step towards multifunctional properties

Organic/Inorganic hybrid systems present a promising alternative for the creation of high-performance materials due to their biphasic structure that imparts multifunctional properties. The sol-gel process which initiated with the synthesis of inorganic glasses has now become a synthetic route for organic-inorganic assemblies due to several advantages such as mild processing conditions and the freedom to play with the structures of precursors. This versatility of the low-temperature sol-gel process provides an opportunity to engineer both the phases resulting in a synergistic combination or entirely new set of properties fruitful for different applications. This review highlights the several pathways for synthesis of silica particles, the interfacial modification and the classification of hybrid materials based on the method of incorporation of an inorganic moiety in the organic matrix along with the structure-property relationship, and the characterization to develop a fundamental understanding of the process. The nature of bonding between the two different species greatly affects the hybrid nanostructure and thus, the bulk properties of the system. In particular, acrylate/silica system has been focused due to its distinctive properties such as transparency, gloss, and strength that find large-scale application in the field of coatings, plastics and rubbers.Abbreviations: °: Degree; °C: Degree Celsius; 1H NMR: Proton nuclear magnetic resonance; A°: Angstrom; AHAS: N-(3-acryloxy-2-hydroxyl propyl)-3-amino-propyltriethoxysilane; AIBA: 2,2′-Azobis(2-methylpropionamidine) dihydrochloride; AIBN: 2,2′-Azobis(2-methylpropionitrile); Al: Aluminium; APDMES: Aminopropyldimethylethoxysilane; APTES: 3-Aminopropyltriethoxysilane; ATRP: Atom transfer radical polymerization; CERAMERS: Ceramically Modified Monomers; CTAB: Cetyltrimethylammonium bromide; DFMA: Dodecafluoroheptyl methacrylate; DMF: Dimethylformamide; DPSD: Diphenylsilanediol; FESEM: Field Emission Scanning Electron Microscope; FTIR: Fourier-transform infrared spectroscopy; GPTMS: 3-Glycidoxypropyltrimethoxysilane; HDTMS: Hexadecyltrimethoxysilane; HEMA: 2-Hydroxyethyl methacrylate; HLB: Hydrophilic-Lyophilic Balance; HMDS: Hexamethyldisilazane; HPC: Hydroxypropyl Cellulose; IPN: Interpenetrating Network; KPS: Potassium persulfate; LCST: Lower critical solution temperature; McPTMS: 3-Mercaptopropyltrimethoxysilane; MOI: 2-(methacryloyloxy)ethyl isocyanate; MPEGMA: Monomethoxy-capped poly(ethylene glycol) methacrylate; MPTMS: 3-methacryloxypropyltrimethoxysilane; MTC: 2-(methacryloyl) ethyltrimethylammonium chloride; MTES: Methyltriethoxysilane; MTMS: Methyltrimethoxysilane; NMP: Nitroxide-Mediated Polymerization; ORMOCERs: Organically Modified Ceramics; ORMOSILs: Organically Modified Silica; OTES: Octyltriethoxysilane; OTMS: Octadecyltrimethoxysilane; PAA: Poly(acrylic acid); PDMS: Polydimethylsiloxane; PEO-PPO-PEO: Poly (ethylene oxides)-b-poly (propylene oxides)-b-poly (ethylene oxides); PHPS: Perhydropolysilazane; PMMA: Poly(methyl methacrylate); POSS: Polyhedral Oligomeric Silsesquioxane; PTMO: Poly(tetramethylene oxide); PTMS: Phenyltrimethoxysilane; PTMS: Phenyltrimethoxysilane; PVP: Poly (vinylpyrrolidone); RAFT: Reversible addition- fragmentation chain transfer; Si: Silicon; Sn: Tin; Ta: Tantalum; TBN: 4-(triethoxysilyl)butyronitrile; TEM: Transmission Electron Microscopy; TEMED: N,N,N′,N′-tetramethylethylenediamine; TEOS: Tetraethoxysilane; Tg: Glass-Transition Temperature; THF: Tetrahydrofuran; Ti: Titanium; TMOS: Tetramethoxysilane; UV: Ultraviolet; VTES: Vinyltriethoxysilane; VTMS: Vinyltrimethoxysilane; Zr: ZirconiumHighlightsAdvantages of hybrid systems over the conventional materialsDiscusses the fundamental aspects of sol-gel chemistryFocusses on a detailed classification of hybrid polymersCovers different synthetic strategies, properties, and applications in diverse fields

Photodegradation of herbicide Metsulfuron-methyl with TiO2 supported on magnetite particles coated with SiO2

Natural watercourses may be significantly contaminated due to the increase of agricultural activities, making it necessary to develop new methodologies for the remediation of agrochemicals, including herbicides. To this effect, photodegradation with TiO2 is a very effective process. However, this semiconductor cannot be easily removed from the treated aqueous medium. Supporting the photocatalyst on different materials facilitates its removal by several methods, including magnetic attraction. According to this goal, this work reports the synthesis of TiO2 photocatalysts supported on SiO2-coated magnetite particles (Fe3O4) by a low-temperature sol-gel process (75 °C). By varying the aging time of the TiO2 sol, materials with different structural properties and combinations of anatase-brookite phases were obtained. Of all the synthesized solids, the one with the highest photocatalytic activity in the degradation of model compounds was the TiO2/SiO2/Fe3O4 catalyst with a 47.4/13.6/39.0 wt % respectively. Under optimal working conditions and at a pH value close to neutrality (conditions in which Metsulfuron-methyl is persistent in an aqueous medium) this catalyst degraded 70% of the herbicide initial concentration in three and a half hours of artificial irradiation with an activity similar to the mass TiO2. The aging time significantly influenced on structural properties of supported TiO2. With its increase, the degree of crystallinity of the samples also increased but its specific surface decreased. The catalyst with higher photoactivity blends the best combination of both factors and is, therefore, a good alternative for the remediation of contaminated effluents with commercial formulations of this herbicide. Also, its magnetic support facilitates its subsequent removal from treated water samples.

Photocatalytically Active Cotton Fabrics Produced with Anatase Synthesized Using a Low-Temperature Sol-Gel Process

In this work two different hydrosols were used to impregnate a commercially available cotton fabric with anatase nanoparticles to give it photocatalytic activity. To increase the activity, different pre-treatment methods were applied. The nanoparticle size was determined using dynamic light scattering and x-ray diffraction and the fabrics were examined using scanning electron microscopy. Photocatalytic activity was measured using the degradation of methyl-orange while irradiating the samples with UV light. The synthesis method allowed to produce anatase with an average particle size of 32 to 37 nm depending on the synthesis method used.

Spontaneous growth by sol-gel process of low temperature ZnO as cathode buffer layer in flexible inverted organic solar cells

In this study, the sol–gel method was employed to prepare zinc oxide (ZnO) thin films as cathode buffer layers for inverted organic solar cells (IOSCs). We used a low temperature sol-gel process for the synthesis of ZnO thin films, in which the molar ratio of zinc acetate dihydrate (ZAD) to ethanolamine (MEA) was varied; subsequently, using the thin films, we successfully fabricated inverted solar cells on flexible plastic substrates. A ZnO sol–gel was first prepared by dissolving ZAD and MEA in ethylene glycol monomethyl ether (EGME). The molar ratios of ZAD to MEA were set as 1:1.2, 1:1, and 1:0.8, and we investigated the characteristics of the resulting ZnO thin films. We investigated the optical transmittance, surface roughness, and surface morphology of the films. Then, we discussed the reasons about the improvement of the device efficiency. The devices were fabricated using the ZnO thin films as cathode buffer layers. The results indicated that the morphology of the thin films prepared using the ZAD to MEA ratios of 1:1 and 1:0.8 changed to a rippled nanostructure after two-step annealing. The PCE was enhanced because of the higher light absorption in the active layer caused by the nanostructure. The structure of the inverted device was ITO/ZnO/P3HT:PC61BM/MoO3/Ag. The short-circuit current densities (8.59 mA/cm2 and 8.34 mA/cm2) of the devices with films prepared using the ZAD to MEA ratios of 1:1 and 1:0.8 ratios, respectively, and annealed at 125 °C were higher than that of the device containing the ZnO thin film that was annealed at 150 °C. Inverted solar cells with ZnO films that were prepared using the ZAD to MEA ratios of 1:1 and 1:0.8 and annealed at 125 °C exhibited PCEs of 3.38% and 3.30%, respectively. More than that, PCEs of the flexible device can reach up to 1.53%.

Memristive behavior of the SnO2/TiO2 interface deposited by sol–gel

A novel and cheap Resistive Random Access Memory (RRAM) device is proposed within this work, based on the interface between antimony doped Tin Oxide (4%at Sb:SnO2) and Titanium Oxide (TiO2) thin films, entirely prepared through a low-temperature sol–gel process. The device was fabricated on glass slides using evaporated aluminum electrodes. Typical bipolar memristive behavior under cyclic voltage sweeping and square wave voltages, with well-defined high and low resistance states (HRS and LRS), and set and reset voltages are shown in our samples. The switching mechanism, explained by charges trapping/de-trapping by defects in the SnO2/TiO2 interface, is mainly driven by the external electric field. The calculated on/off ratio was about 8×102 in best conditions with good reproducibility over repeated measurement cycles under cyclic voltammetry and about 102 under applied square wave voltage.

Mechanically robust, thermally stable, highly transparent superhydrophobic coating with low-temperature sol–gel process

The wetting behavior of transparent superhydrophobic surfaces has attracted much attention in our daily life as well as in engineering applications.