Structure Of FTO Research Articles

A reversible implantable memristor for health monitoring applications

Conventional implantable electronics based on von Neumann architectures encounter significant limitations in computing and processing vast biological information due to computational bottlenecks. The memristor with integrated memory-computing and low power consumption offer a promising solution to overcome the computational bottleneck and Moore's law limitations of traditional silicon-based implantable devices, making them the most promising candidates for next-generation implantable devices. In this work, a highly stable memristor with an Ag/BaTiO3/MnO2/FTO structure was fabricated, demonstrating retention characteristics exceeding 1200 cycles and endurance above 1000 s. The device successfully exhibited three-stage responses to biological signals after implantation in SD (Sprague-Dawley) rats. Importantly, the memristor perform remarkable reversibility, maintaining over 100 cycles of stable repetition even after extraction from the rat. This study provides a new perspective on the biomedical application of memristors, expanding the potential of implantable memristive devices in intelligent medical fields such as health monitoring and auxiliary diagnostics.

Evolution between RS and NRS behaviors in BiFeO3@egg albumen nanocomposite based memristor

The coupling of resistance switching (RS) behavior and N-type negative differential resistance (NDR) effect provides a promising physical basis for the preparation of low-power and multifunctional electronic devices. N-type NDR effect can be expressed by the relationship between peak voltage (VP), valley voltage (VV) and the homologous current (IP, IV). In this work, a memristive device with Ag/BFO@EA/FTO structure was prepared by inserting BiFeO3 (BFO) nanoparticles into egg albumen (EA) as the functional layer, and observed the evolution between RS and NDR coupled RS (NRS) behaviors with the regulation of applied voltage window. Besides, it can be observed a wide current gap of 18.6 mA between IP and IV in the narrow voltage gap (about 0.4 V) between VP and VV, indicating that the device has low power consumption and fast reading/writing speed when it is applied to information processing. Finally, based on the obtained data, it was deeply analyzed the mechanism of NRS effect in the Ag/BFO@EA/FTO memristive device. Therefore, this work provides a new perspective for realizing multi-level storage and multifunctional advanced applications in the memristive device.

Resistive switching characteristics of Ag2O/TiO2 bilayer film based memristor

With the increasing importance of artificial intelligence (AI), significant effort has been devoted to the development of memory device that seek to emulate the energy-efficient information storage and processing. In this work, a memristive device with Ag/Ag2O/TiO2/FTO structure was fabricated by the sol-gel method. The as-prepared memristive device exhibits bipolar resistive switching characteristics under direct-current-voltage sweep. In particular, this memristive device with Ag2O/TiO2 layer annealing at 450 ℃ has a low switching voltage after 150 successive cycles. At the same time, the switching window of the device with Ag2O/TiO2 layer annealing at 450 ℃ is obvious, and the switching resistances are stable and easy to distinguish. This device exhibits some obvious advantages of low power consumption, remarkable repeatability, excellent endurance, and stable memory state. As a result, this Ag2O/TiO2 bilayer film based memristive device has great potential to be used as information storage and processor device for AI applications.

Enhanced resistive switching uniformity in HfO2/TiO2 NWA memristor for synaptic simulation

In this article, we fabricated a memristive device with a Cu/HfO2/TiO2 nanowire array (NWA)/FTO structure through a hydrothermal method and atomic layer deposition. The devices exhibit good resistive switching properties, including low set voltages (∼1 V), good retention (>104 s), and multilevel storage. Compared with the Cu/TiO2 NWA/FTO device, Cu/HfO2/TiO2 NWA/FTO devices exhibit better uniformity, which could be due to the difference between the dielectric constants of TiO2 and HfO2. Under the application of consecutive voltage pulses, some synaptic functions were mimicked, including long-term potentiation/depression, paired-pulse facilitation, and spike timing dependent plasticity.

SIMULATION AND IMPROVEMENT OF THE PERFORMANCE OF CdTe SOLAR CELL WITH ULTRATHIN ABSORBER LAYER

In the few past years, the usage of CdTe thin-film solar cells has increased considerably due to their high efficiency, performance stability and cost effectiveness. In this work, a conventional structure of FTO–[Formula: see text]-SnO2–CdS–CdTe was simulated initially to verify the simulation process. An ultrathin absorber layer was considered to make the device more economical. A [Formula: see text]-type copper oxide thin film was employed at the back contact as a hole transport–electron blocking layer (HT–EBL). Besides, the use of a bilayer ZnS–CdS compound and a monolayer CdS:Zn compound as the electron transport layer was also studied. The proposed modeled cell parameters then were optimized to increase the efficiency.

Fabrication of a light-emitting device based on the CdS/ZnS spherical quantum dots

In this work, we focus on the colloidal quantum dot based light-emitting diodes (QD-LEDs) performance. First, we synthesize the spherical QDs with a CdS core that covered with a wider band gap II–VI semiconductor acting as a shell (ZnS). In order to synthesize this nano crystal QDs with structure of CdS/ZnS/CdS/ZnS, we use a reverse micelle process. These four-layer quantum well quantum dots (QWQDs) can generate the white light emission. The positional design of different layers i.e., core/shell QD emitters is a critical factor for white emissive devices. The blue emission generated by CdS core mixes with green/orange components originating from ZnS inner shell and creates an efficiency white light emission. Then, we fabricate a white-QDLED with a device structure of FTO/ ZnO / QD / CBP/ MoO3 / Al films. A thin film of CdS/ZnS/CdS/ZnS QDs is deposited by electrostatically assembled colloidal QD solutions. The experimental results show that the emission spectra of QDs and current density through the LED are controlled by varying the particle sizes. The peaks of absorbance and Photoluminescence (PL) spectrums for core/shell structures get the red shifted as the dot size increases. Furthermore, this QD-LED with a smaller nano particle layer has a higher current density.

The effect of the top electrode on the switching behavior of bipolar Al2O3/ZnO RRAM

In this letter, the atomic layer deposited (ALD) resistive random access memory(RRAM) device with Au/Al2O3/ZnO/FTO structure (ox-RRAM) exhibiting bipolar characteristics is proposed to compare with Ag/Al2O3/ZnO/FTO (conduction bridge RRAM(CBRAM)) device to demonstrate the effect of electrode material on device behavior. Although both devices have undergone similar processes during the fabrication, the proposed device with Au top electrode shows oxygen vacancy-based valance change mechanism (VCM) of switching with two stable states. The latter follows conductive metallic bridge-based switching (CBRAM) with multilevel storage. However, both devices have shown self-compliance feature, with a maximum current settled to 10–20 mA. Also, they have distinguishable memory window (Roff/Ron) > 102. The current conduction mechanism in both devices follows ohmic conduction and space charge limited conduction (SCLC) at low resistance state (LRS) and high resistance state (HRS), respectively. It reveals that the stacking of oxide layers and deposition method influence the electronic conduction mechanism, whereas the top electrode has a prominent role in the switching mechanism. It is also reported that the endurance and retention of the proposed ox-RRAM are better than its CBRAM counterpart.

Simple and green route for fabrication of a nanostructured of the graphene‐Fe3O4@PANI for the photovoltaic activity

In this work, for the first time, Gr (graphene)|Fe3O4@PANI nanocomposite was synthesized from graphite, aniline-HCl and FeCl3.6H2O via a simple in-situ and green route as the active layer for photovoltaic application. The proposed nanocomposite was characterized by FT-IR, SEM, TEM, UV-vis spectroscopy, XRD technique, and then the thermal, magnetic, electrochemical, and photovoltaic properties investigated. The energy gap was calculated, and it is noticed that the optical band gap of nanocomposite fallows an indirect transition, arising from a strong spin-orbit coupling created by Fe3O4 in the Gr|Fe3O4@PANI nanocomposite. Next, polymer solar cell (PSC) based on this nanocomposite was fabricated with a simple device structure of FTO│TiO2│Gr|Fe3O4@PANI│Al. The photovoltaic properties of the cells have been evaluated under AM 1.5G illumination at 60 mW/cm2 with a solar simulator. A power conversion efficiency (PCE) of 1.81% was observed with a short circuit current (Jsc) of 4.14 mA/cm2, an open-circuit voltage (Voc) of 0.71 V, which indicates this kind of conjugated polymer should be a promising material in the application of polymer solar cells.

Effect of Posttranslational Modifications on the Structure and Activity of FTO Demethylase.

The FTO protein is involved in a wide range of physiological processes, including adipogenesis and osteogenesis. This two-domain protein belongs to the AlkB family of 2-oxoglutarate (2-OG)- and Fe(II)-dependent dioxygenases, displaying N6-methyladenosine (N6-meA) demethylase activity. The aim of the study was to characterize the relationships between the structure and activity of FTO. The effect of cofactors (Fe2+/Mn2+ and 2-OG), Ca2+ that do not bind at the catalytic site, and protein concentration on FTO properties expressed in either E. coli (ECFTO) or baculovirus (BESFTO) system were determined using biophysical methods (DSF, MST, SAXS) and biochemical techniques (size-exclusion chromatography, enzymatic assay). We found that BESFTO carries three phosphoserines (S184, S256, S260), while there were no such modifications in ECFTO. The S256D mutation mimicking the S256 phosphorylation moderately decreased FTO catalytic activity. In the presence of Ca2+, a slight stabilization of the FTO structure was observed, accompanied by a decrease in catalytic activity. Size exclusion chromatography and MST data confirmed the ability of FTO from both expression systems to form homodimers. The MST-determined dissociation constant of the FTO homodimer was consistent with their in vivo formation in human cells. Finally, a low-resolution structure of the FTO homodimer was built based on SAXS data.

The FTO Gene and Diseases: The Role of Genetic Polymorphism, Epigenetic Modifications, and Environmental Factors

The review provides information on the function of the FTO gene (known as the fat mass and obesity-associated gene) and the encoded enzyme, on the functional role of single nucleotide polymorphisms (SNPs) in coding and noncoding gene regions and the range of their competences, and on association of the FTO polymorphisms with diseases and traits. Factors that have modifying effect on the contribution of polymorphisms to the risk of disease development and trait variability are discussed. The FTO gene encodes alpha-ketoglutarate-dependent dioxygenase, which has a wide range of competences (including demethylation of RNA and single-stranded DNA), which are important for the functioning of the body. Nonsynonymous substitutions in the FTO gene lead to the development of orphan autosomal recessive disease (OMIM 612938). In the FTO noncoding regions, a wide range of variants has been detected, including those of regulatory importance (eQTL, sQTL, etc.). The competence of these variants extends to both FTO and neighboring genes (IRX3, IRX5, RPGRIP1L). Intronic polymorphisms of the FTO gene have been found to be associated with a wide range of multifactorial diseases and traits (obesity and related anthropometric traits, lipid metabolism markers, diabetes mellitus (type 2), coronary heart disease, metabolic syndrome, and other diseases). In the overwhelming majority of studies, the same allele variants are classified as risk ones; however, previously established associations of the FTO polymorphisms with diseases (traits) are demonstrated not in all populations. It is demonstrated that the effects of the FTO gene SNPs can be modified by exogenous and endogenous environmental factors, as well as lifestyle (including the type of diet, consumption of certain nutrients and medications, physical activity, etc.). Epigenetic factors (DNA methylation at CpG sites) are also important for regulating the level of FTO expression and the effects of individual SNPs. The accumulated data on the FTO structure and function, as well as the functional role of the encoded enzyme, make this gene attractive from the point of view of developing personalized approaches to healthcare.

Electrodeposition of CdTe Thin Films for Solar Energy Water Splitting.

CdTe thin films have been prepared by electrochemical deposition. The morphological, structural, and optical properties of CdTe thin films deposited with different deposition time were investigated, and the influence of film thickness on the photoelectric characteristics of CdTe thin films was studied. At the deposition time of 1.5 h, CdTe thin films had good optical properties and the photocurrent reached 20 μAcm−2. Furthermore, the Pt/CdS/CdTe/FTO structure was prepared to improve its PEC stability and the photocurrent of 240 μAcm−2 had been achieved.

Efficient PbSe Colloidal Quantum Dot Solar Cells Using SnO2 as a Buffer Layer.

PbSe colloidal quantum dots (CQDs) are widely used in solar cells because of their tunable band gap, solution processability, and efficient multiple exciton generation effect. The most efficient PbSe CQD solar cells use high-temperature-processed ZnO as the electron transport layer (ETL), limiting their applications in flexible photovoltaics. Currently, low-temperature solution-processed SnO2 has been demonstrated as an efficient ETL for high-efficient PbS CQD and perovskite solar cells because of less parasitic light absorption and higher electron mobility. Herein, we introduce low-temperature solution-processed SnO2 as ETL for PbSe CQD solar cells, and fabricate the PbSe CQD absorber layer with a one-step spin-coating method. The champion device with the structure of FTO (SnO2:F)/SnO2/PbSe-PbI2/PbS-EDT (1,2-ethanedithiol)/Au achieves a high open-circuit voltage of 577.1 mV, a short-circuit current density of 24.87 mA cm-2, a fill factor of 67%, and an impressive power conversion efficiency of 9.67%. Our results pave the way for the development of low-temperature flexible PbSe CQD solar cells.

Photoelectrochemical water splitting by engineered multilayer TiO2/GQDs photoanode with cascade charge transfer structure

Herein, for the first time, an efficient photoanode engineered with the cascade structure of FTO|c-TiO2|few graphene layers|TiO2/GQDs|Ni(OH)2 assembly (Ni(OH)2 photoanode) is designed. This photoanode exhibited much lower electron–hole recombination, fast charge transport, higher visible light harvesting, and excellent performance with respect to FTO|c-TiO2|TiO2 assembly (TiO2 photoanode) in the photoelectrocatalytic oxygen evolution process. The photocurrent density of Ni(OH)2 photoanode is 7 times (0.35 mA cm−2 at 1.23 V vs. RHE) greater than that of TiO2 photoanode (0.045 mA cm−2 at 1.23 V vs. RHE). The compact TiO2 (c-TiO2) layer in Ni(OH)2 photoanode plays a role of an effective hole-blocking layer. Few-layer graphene layer could speed up the transport of the photogenerated electrons from the conduction band of the TiO2/GQDs to FTO. Ni(OH)2 layer could transfer rapidly holes into electrolyte solution.

Performance of natural chlorophyll Amaranthus and Carica Papaya dye on TiO2 coating in the making of dye sensitized solar cell (DSSC) through the spin coating method

<p>The natural dye extracted from Amaranthus dye and Carica Papaya dye which has been prepared in ethanol solution as a sensitizer on DSSC. The Spin coating method is used so that the deposition on TiO<sub>2</sub> gets a homogeneous thin layer on the active area of the FTO substrate. The dye solution was tested for characterization using the Elkahfi I-V Meter and UV-Vis 1601 while the FTO structure substrate that had been prepared as a sandwich was tested using Keithley I-V type 2602A. The result of absorbance of dye is at a wavelength of 400 nm - 800 nm and there is also a shift in wavelength and peak absorption of the dye. The greatest efficiency was obtained from chlorophyll amaranthus which is 0.730% while chlorophyll Carica papaya obtained an efficiency of 0.432%. In the combination of Amaranthus dye and Carica papaya dye, the efficiency was 0.526%. High efficiency on TiO<sub>2</sub> electrodes shows good performance on Dye-sensitized solar cells.</p>

Study of carbon-based hole-conductor-free perovskite solar cells

In this paper, the perovskite solar cells (PSCs) with the structure of FTO glass/compact TiO2/mesoporous TiO2/CH3NH3PbI3/carbon electrode were designed and fabricated. The CH3NH3PbI3 absorption layers were prepared using one-step solvent-engineering method. The effects of volume ratios of dimethyl sulfoxide (DMSO) to N, N-dimethylformamide (DMF) and molar ratios of PbI2 to CH3NH3I (MAI) on structure and morphology of CH3NH3PbI3 absorption layers, as well as photovoltaic performance of PSCs were studied. The results show that the PSCs based on a specific ratio of PbI2:MAI = 1:1.4 and DMSO:DMF = 1:3 exhibited an optimal photovoltaic performance, yielding an open-circuit voltage (Voc) of 0.72 V, short-circuit current density (Jsc) of 25.98 mA/cm2, fill factor (FF) of 0.46, and power conversion efficiency (PCE) of 8.45%. And the incident photon-to-electron conversion efficiency (IPCE) is close to 85% between 400 and 600 nm visible region.

Investigation of Reduced Graphene Oxide with F-Doped SnO2 as Catalyst Support in Fuel Cells

A main challenge in commercialisation of fuel cells is the performance loss with time of operation. The platinum catalyst is subjected to electrochemical instability, and carbon black as commonly used catalyst support suffers from corrosion.[1,2] To improve the fuel cell stability, alternative support materials can be used. Application of graphene-based carbon in low temperature PEMFCs has demonstrated higher durability than conventional carbon black.[3] The combination with corrosion resistant metal oxides provides additional binding sites for Pt nanoparticles[4,5] and can prevent graphene materials from restacking causing mass transport limitations in fuel cells.[6] In this study, reduced graphene oxide (rGO) is synthesised in two steps. Graphene oxide is received via Hummer’s method[7] and then thermally reduced to rGO. In the following synthesis, fluorine-doped tin (IV) oxide (FTO) nanoparticles are deposited on rGO sheets. Therefore, a sol-gel method using tin tetrachloride precursor followed by addition of NH4F and hydrothermal treatment is carried out on rGO.[8,9] Figure 1a shows the achieved crystalline FTO structure which is similar to cassiterite tin (IV) oxide. Using Scherrer equation an average FTO particle size of 4.8±0.4 nm is calculated. Transmission electron microscopy (TEM) in Figure 1b reveals successful deposition of the FTO nanoparticles on rGO. In the last synthesis step, Pt is precipitated on FTO-rGO via chemical reduction of chloroplatinic acid with ethylene glycol.[4] Then, Pt/FTO-rGO catalyst is intensively investigated for electrochemical stability under fuel cell operation conditions by the use of an accelerated stress test (AST). Within an electrochemical cell the catalyst is exposed to 1,000 potential cycles between -0.02 and 1.40 VRHE at a scan rate of 500 mV s-1under oxygen saturation. To ensure a holistic analysis of possible catalyst and support degradation, this AST is performed twice. During the first test, a rotating disk electrode allows the study of the oxygen reduction reaction (ORR) mechanism and activity at different rotation speeds (400, 900, 1200, 1600, 2000 and 2500 rpm). The electrochemical active surface area (EASA) is carefully determined by hydrogen underpotential deposition as well as carbon monoxide stripping voltammetry. In the second test run, the rotating disk electrode as working electrode is replaced by a catalyst coated grid for identical location TEM analysis. First, the untested Pt/FTO-rGO catalyst on the grid is analysed by TEM and then the catalyst on grid is stressed by exactly the same potential cycling. After performing AST, the same Pt/FTO-rGO particles are investigated again under the microscope. Thus, possible Pt degradation processes like agglomeration can be revealed which allows the supplementation of electrochemical investigations. Fig. 1: XRD pattern of FTO-rGO with comparison to crystalline structure of cassiterite SnO2 (ICDD 98-000-9463) (a) and TEM image of deposited FTO particles on rGO (b). [1] D. Schonvogel, M. Rastedt, P. Wagner, M. Wark, A. Dyck, Fuel Cells 2016, 16, 480-489. [2] Y. Shao-Horn, W. C. Sheng, S. Chen, P. J. Ferreira, E. F. Holby, D. Morgan, Top. Catal. 2007, 46, 285-305. [3] Y. Shao, S. Zhang, C. Wang, Z. Nie, J. Liu, Y. Wang, Y. Lin, J. Power Sources 2010, 195, 4600-4605. [4] R. Kou, Y. Shao, D. Mei, Z. Nie, D. Wang, C. Wang, V. V. Viswanathan, S. Park, I. A. Aksay, Y. Lin, Y. Wang, J. Liu, J. Am. Chem. Soc. 2011, 133, 2541-2547. [5] Y. Liu, W. E. Mustain, J. Am. Chem. Soc. 2013, 135, 530-533. [6] S. Park, Y. Shao, H. Wan, P. C. Rieke, V. V. Viswanathan, S. A. Towne, L. V. Saraf, J. Liu, Y. Lin, Y. Wang, Electrochem. Commun. 2011, 13, 258-261. [7] S. Ratso, I. Kruusenberg, M. Vikkisk, U. Joost, E. Shulga, I. Kink, T. Kallio, K. Tammeveski, Carbon 2014, 73, 361-370. [8] D.-J. Guo, Z.-H. Jing, J. Colloid Interface Sci. 2011, 359, 257-260. [9] H. Xu, L. Shi, Z. Wang, J. Liu, J. Zhu, Y. Zhao, M. Zhang, S. Yuan, ACS Appl. Mater. Interfaces 2015, 7, 27486-27493. Figure 1

A novel intermediate layer for Au/CdZnTe/FTO photoconductive structure

In this work, graphene is tried to use to improve the performance of polycrystalline CdZnTe high-energy radiation and photon detectors. A graphene intermediate layer is prepared by spin-coating process on the surface of polycrystalline CdZnTe film, which forms a photoconductive Au/graphene/CdZnTe/FTO structure. XRD, Raman, photoelectric response and other characterisation methods are adopted to investigate the effect of graphene layer on the electrical characteristics and UV photo-response performance of CdZnTe photoconductive structure. It is demonstrated that graphene layer can significantly improve the contact property of Au/CdZnTe structure, and obviously enhance its UV photo-response and the UV sensitivity increased with one order of magnitude.

Resistive Switching Behavior in Organic–Inorganic Hybrid CH3NH3PbI3−xClx Perovskite for Resistive Random Access Memory Devices

The CH3 NH3 PbI3- x Clx organic-inorganic hybrid perovskite material demonstrates remarkable resistive switching behavior, which can be applicable in resistive random access memory devices. The simply designed Au/CH3 NH3 PbI3- x Clx /FTO structure is fabricated by a low-temperature, solution-processable method, which exhibits remarkable bipolar resistive switching and nonvolatile properties.

Characteristic evaluation on spray-deposited WFTO thin films as a function of W doping ratio

In this work, F and F + W simultaneously doped SnO2 highly transparent conducting thin films were deposited on glass substrates at (500 ± 5) °C temperature by the spray pyrolysis method. Microstructural, morphological, electrical and optical properties of FTO films were investigated as a function of tungsten (W) doping, in the range from 0 to 5 at%. X-ray diffraction patterns show that the films exhibit a tetragonal cassiterite structure and (200) preferential orientation of FTO film, and the relative strength of these peaks changes with altering the W doping ratio. The preferred growth of (211) changed to (200) plane with 2 at% W doping level and 3 at% W-doped film had (200) orientation and with further doping, this changed to (110) orientation. The scanning electron microscopy and atomic force microscopy images of the films indicate that the films are made up of dense small particles of a pyramidal shape and have a smooth surface. It was observed that the surface morphology of the films did not change much when the W element was inserted to the FTO structure. It was found that the sheet resistance values of the films varied with W doping ratio, and 2 at% W-doped FTO thin film exhibited the lowest values of sheet resistance (1.12 Ω). Also, the highest figure of merit, infrared reflectivity and optical band gap values were calculated for 2 at% W-doped FTO film as 50.9 × 10−2 Ω−1, 98.82 % and 4.13 eV, respectively. These results make the films an effective candidate for usage in many optoelectronic applications and photo-thermal conversion of solar energy.

나노 다공질 FTO 제작 및 광전변환특성 고찰

In this work, a new type of DSCs based on nanoporous FTO structure is being developed for research aimed at low-cost high-efficiency solar cell application. The nanoporous FTO materials have been prepared through the sol-gel combustion method followed by thermal treatment at . The properties of the nanoporous FTO materials were investigated by IR spectra, BET and TEM analyses, and the photovoltaic performance of the prepared DSCs were examined. It can be seen from the result that the nanoporous FTO exhibited good transparent conductive properties, well suited for DSCs application.