Antimony-doped Tin Oxide Films Research Articles

High Optical Contrast of Quartet Dual-Band Electrochromic Device for Energy-Efficient Smart Window.

A quartet dual-band electrochromic device (ECD) was developed to selectively control the transmittance from the visible to near-infrared wavelengths for the application of an energy-efficient smart window. The new AgNO3+TBABr+LiClO4 (ATL)-based electrolyte was developed to independently control the redox reaction of lithium and silver ions to demonstrate the quartet mode of an ECD. A dual-band ECD with a sandwich structure was assembled using an ATL-based electrolyte, WO3 electrochromic layer, and antimony-doped tin oxide (ATO) ion storage layer. The employed WO3 and ATO films were fabricated using a nanoparticle deposition system (NPDS), a novel ecofriendly dry deposition method. Four modes, namely, transparent, warm, cool, and all-block modes, were demonstrated via an independent redox reaction of both lithium and silver ions through the simple control of the applied voltage. In the warm mode, the localized surface plasmon resonance effect was exploited by producing silver nanoparticles upon two-step voltage application. Furthermore, since the high surface roughness of the WO3 thin film fabricated by NPDS maximized the light scattering effect, 0% transmittance at all wavelengths was observed in the all-block mode. Dual-band ECD showed high optical contrasts of 73% and long-term durability over 1000 cycles with no degradation. Therefore, the possibility of controlling transmittance at the target wavelength was confirmed using a simple device with a simple process, suggesting a new strategy for the design of dual-band smart windows to reduce the energy consumption of buildings.

Cerium‐Modified Mesoporous Antimony Doped Tin Oxide as Intercalation‐Free Charge Storage Layers for Electrochromic Devices

AbstractCharge storage layers are an important component of electrochromic devices, which are expected to exhibit high storage capacity and transparency as well as fast electron transfer rates. However, these layers often rely on the (de)intercalation of ions into the crystal lattice of the material and therefore require optimization to be compatible with non‐intercalating electrolytes. In this report, the post‐modification of mesoporous antimony‐doped tin oxide (ATO) nanoparticle layers with a redox‐active cerium compound is described. In particular, the switching of the Ce3+/Ce4+ couple on the conductive nanoparticle scaffold is demonstrated using tetrabutylammonium perchlorate as a non‐intercalating electrolyte. Remarkably, high storage capacities of up to 27 mC cm−2 and transmittance values of ≈90% are achieved. Variation of the antimony doping concentration revealed that nanoparticle layers doped with 15% Sb exhibit the highest capacity, which can be attributed to increased conductivity in the potential range where the Ce3+ ions are oxidized. Finally, the cerium‐modified ATO films show promising performance as charge storage layers in an electrochromic device with a viologen‐anchored ATO layer as the electrochromic working electrode. Switching times of ≈0.4 s highlight the fast electron transfer capability of the cerium‐decorated ATO layer, even when a non‐intercalating electrolyte is used.

Evaluation of a surface roughness-dependent trimodal switchable mirror using a dry deposition method

We used a nanoparticle deposition system (NPDS) to fabricate surface roughness-dependent trimodal switchable mirrors using a non-electrochromic antimony-doped tin oxide (ATO) film with dry-deposited micro- and nano-sized ATO particles. The devices switched among transparent, mirror and black states. Reversible Ag electrodeposition onto flat ITO glass and the rough surface of the ATO film obviated the need for an electrochromic material. NPDS creates very rough films by supersonically spraying powder onto a substrate. The roughness of the micro-sized ATO film was greater than that of the nano-sized ATO film. As both films were sufficiently rough, a completely black state could be achieved by both devices (0% transmittance over the entire visible wavelength), attributable to light scattering. In contrast, the electrochemical properties of devices with the micro-sized ATO film were superior to those of devices using the nano-sized ATO film because the greater roughness increased the active surface. The charge transfer resistance of devices with the micro-sized film (38 Ω) was lower than that of devices with the nano-sized film (44 Ω). The charge capacity of devices with the micro-sized film (109.87 mC/cm2) was much higher than that of devices with the nano-sized (95.59 mC/cm2). The cyclic transmittance of the device using the micro-sized ATO film was evaluated over 500 cycles with 0% diminution for its durability. Therefore, a trimodal switchable mirror was demonstrated by controlling the surface roughness of a non-electrochromic film. • Dry deposition of particles can control surface roughness of the film. • Trimodal switchable mirror was achieved successfully without electrochromic film. • The electrode with rough surface forms complete black state by light scattering. • Performance of switchable mirror device was compared depending on surface roughness.

Effect of O2/Ar ratio and sputtering power on the photoelectric properties of antimony doped tin oxide films on ZnO layer

Effect of O2/Ar ratio and sputtering power on the photoelectric properties of antimony doped tin oxide films on ZnO layer

UV- and NIR-blocking properties of ZnO/ATO bilayer films prepared by RF magnetron sputtering

Films with ultraviolet (UV) and near-infrared (NIR) blocking properties can be used to protect against UV and heat radiation, thus prolonging the operating life of photovoltaic devices. Being wide band-gap semiconductors, ZnO films can absorb UV light and antimony doped tin oxide (ATO) films can play the role of defending against the NIR light with low electrical resistivities. In this work, the bilayer films of ZnO overlayed by ATO are sputtered by radio-frequent (r.f.) magnetron sputtering, and the growth rules of ATO on ZnO film are studied comprehensively by adjusting parameters including the sputtering power, pressure, gas flow rate ratio of O 2 /Ar and sputtering time. Eventually, a bilayer film with 200 nm thick ZnO layer and 400 nm thick ATO layer is fabricated and shows about 96% UV-blocking (from 280 nm to 380 nm), about 66% NIR-blocking (from 1100 nm to 2500 nm) while maintains about 80% light transmittance (from 380 nm to 1100 nm) after annealing in the nitrogen atmosphere at 500 °C for 1 h. This transparent bilayer film with UV and NIR double blocking functions can be potentially used in organic solar cells. • ZnO/ATO bilayers with UV and near IR double blocking functions were produced. • The bilayers of ZnO overlayed by ATO were deposited by r.f. magnetron sputtering. • 96% UV-blocking (280–380 nm) was got from ZnO (200 nm)/ATO (400 nm) bilayer. • 66% NIR-blocking (1100–2500 nm) and 80% transmission (380–1100 nm) were also gained.

Electrical Tuning of the Fifth‐Order Optical Nonlinearity of Antimony‐Doped Tin Oxide

AbstractIn this work, the electrical tuning of the fifth‐order nonlinear absorption of antimony‐doped tin oxide (ATO) by ionic liquid gating is demonstrated. The pristine ATO film exhibits two‐photon‐induced excited‐state absorption (2PA‐ESA) with laser excitation at 1030 nm. The fifth‐order nonlinear absorption coefficient (γeff) of the ATO film can be monotonically modified in the range of 0.51 to 3.46 cm3 GW−2 by varying the sample bias, with a maximum enhancement factor of 6.8. The fundamental processes occurring during electrical tuning are revealed. The electrostatic and electrochemical capacitance is responsible for the modification in the number of free carriers in the conduction band of ATO. The electrical modulation of the nonlinear absorption of the ATO is ascribed to the voltage‐dependent diameter of the undepleted core of ATO. A smaller voltage results in the charging of ATO and a larger undepleted core, and consequently the size of the active component for 2PA‐ESA is larger. The electrochemical capacitance results from the chemisorption of H+ and OH− on the surface of the ATO, the larger water content in the ionic liquid affording a larger modulation range for the number of free carriers and the γeff.

Substrate Temperature Dependent Physical Properties of Spray Deposited Antimony-Doped SnO2 Thin Films

Antimony doped tin oxide (ATO) thin film has been widely explored as an alternative transparent conducting oxide (TCO) electrode. The ATO thin films are not yet commercialized due to issues in reproducibility and stability of its transparent conducting properties. In this work, properties of spray deposited ATO thin films are explored as a function of substrate temperature. The deposited ATO thin films are investigated using ultraviolet-visible spectrometer, Hall Effect, and temperature-dependent four probe methods. The film deposited at 450°C was found to possess relatively higher transmittance of 89 % with a wide bandgap of 3.81 eV. Furthermore, it also showed good electrical properties such as high carrier concentration (3.12 × 1020 cm−3), high mobility (25.1 cm2/Vs), low sheet resistance (24.9 Ω/□), and an excellent figure of merit value (1.25 × 10−2 Ω−1). The obtained results are correlated with substrate temperature. The activation energies of the ATO thin films are estimated using Arrhenius plot from the temperature-dependent electrical measurement to elucidate the conduction mechanism. The ATO films were also annealed at various temperature to study the stability of the sheet resistance. The results obtained imply the optimized ATO thin films to be a potential alternative TCO candidate.

Study the Optical Properties of Undoped and Antimony Doped Tin Oxide Films Prepared by APCVD Technique

In the present study, antimony doped tin oxide (SnO2:Sb) thin films are prepared by atmospheric pressure chemical vapor deposition (APCVD) technique by varying the doping concentration in very small range, 1- 1.4 wt.% at a constant substrate temperature of 480 oC. The effect of Sb-doping concentration on the optical behavior of SnO2 film deposited on glass substrates are analyzed and discussed. Optical measurements showed that the average optical transmittance decreased with increased Sb concentration, and each of absorbance, absorption coefficient and extinction factor were increased in same way and regularly with increasing the concentration of Sb. However the optical reflectance and the refractive index were irregularly increased in same way with increasing the concentration of Sb. A little decrease of energy gap from 3.96 to 4.015 eV with increasing Sb concentration is observed.

Characterization of Sb doped SnO2 films prepared by spray technique and their application to photocurrent generation

Pure and antimony doped tin oxide films (SnO2:Sb) have been prepared by a chemical spray technique on silica glass substrates. X-ray diffraction (XRD), atomic force microscopy (AFM), UV–Vis spectroscopy, Fourier transform infrared spectroscopy (FTIR), electrochemical impedances spectroscopy (EIS) and electrochemical photocurrent (ECP) measurements were used to characterize the obtained films. The results of XRD indicated that all films exhibited tetragonal cassiterite SnO2 structure. The Sb-doped films showed a transparency more than 70% in the visible region and the Sb inclusion in the cassiterite lattice reduced the transparency in this region. EIS spectra have a single semi-circle in the high frequency region and the diameter of half-circle was found to decrease in the presence of small amount of Sb doping (2%). Electrochemical photocurrent test showed that the maximum increasing current under ultraviolet light was obtained for a doping level of 4%.

Synthesis, characterization and properties of ATO/potassium silicate film prepared by twice spray pyrolysis

Hydrophilic coatings have received considerable attentions in recent years. This study investigates an ATO/potassium silicate hydrophilic film based on antimony doped tin oxide (ATO) and potassium silicate (PS) which deposited on aluminum sheets by twice spray pyrolysis. For comparison, four groups of samples including aluminum sheets (Al), aluminum sheets deposited with ATO film (Al/ATO), aluminum sheets deposited with potassium silicate film (Al/PS) and aluminum sheets deposited with both ATO and potassium silicate films (Al/ATO/PS) have been used for experiments. The morphologies, phase structures and chemical compositions of four samples have been characterized using FE-SEM, AFM, XRD and XPS. The hydrophilic, anticorrosive, thermal conductive and electrical resistive properties of the four samples have been studied in detail. The results show clearly that smooth PS film possesses good hydrophilicity and the water contact angle of ATO/PS film maintains below 17° after being exposed in air for 1 month. Moreover, the ATO/PS film shows lower corrosion current density comparing with other samples, revealing its excellent corrosion resistance property. The difference in the thermal conductivity values of the four samples is not significant. And the thermal conductivity is slightly increased by 4.0% for Al/ATO/PS, compared to Al/PS. These results indicate that ATO/PS film has superior hydrophilic performance, corrosion resistance and thermal conductivity than the individual potassium silicate film and ATO film.

Investigation of sensing properties of sol–gel processed 4 at%Sb:SnO2/TiO2 thin films

In this work we investigate the gas and photo sensing properties of the antimony doped tin oxide and titanium oxide (4 at%Sb:SnO2/TiO2) nanocrystalline thin films deposited by sol–gel dip-coating. Photoconductivity measurements are carried out under solar light spectra irradiation at different powers. These results show a photo sensitivity of the films in a lateral junction due to interfacial defects. Gas sensitivity was studied at different pressures, and higher conductivity is presented at lower pressure compared to oxygen-rich atmosphere. It occurs due to absence of oxygen adsorption on the semiconductors surface. TiO2 films are also investigated concerning its properties to gas sensing under photo-excitation with InGaN LED light source with wavelength centered in 450 nm. The decay of photo-induced current evaluated under O2 and vacuum atmospheres shows that the sample illumination may contribute to higher gas-sensitivity. This measurement allows determining the charge carrier capture energy, that is related to trapping dominated by distinct defects in each atmosphere.

Photocatalytic evaluation of ATO/TiO2 heterojunction films fabricated by a nanoparticle deposition system

Antimony-doped tin oxide (ATO), titanium dioxide (TiO2) and ATO/TiO2 mixtures (30:70, 50:50, 70:30 vol%) powders were deposited using a nanoparticle deposition system (NPDS). X-ray diffraction (XRD) data and field-emission scanning electron microscope (FE-SEM) images confirmed that the phases and morphologies of the deposited ATO and TiO2 were similar to those of their pristine structures. Photoelectrochemical (PEC) measurements showed the highest photocurrent of 1.5 mA for the 50:50 vol% ATO/TiO2 film, which compared with 1.2 mA for the other (30:70 and 70:30 vol% ATO/TiO2) hybrid samples, and 0.35 and 0.04 mA for pure TiO2 and ATO, respectively. Methylene blue (MB) dye was degraded in the presence of the 50:50 vol% ATO/TiO2 film, which had the best photocatalytic activity after 7 h of ultraviolet (UV) irradiation. The kinetic rate constant of this film was 0.15 h−1, which was double that of the TiO2 film (0.06 h−1). The photoluminescence intensity of the 50:50 vol% ATO/TiO2 film was low over a wide range of wavelengths, which indicated that its recombination rate was less than that of the ATO and TiO2 films. Finally, the recycle results demonstrated that the 50:50 vol% ATO/TiO2 film was stable to photodegradation for up to six cycles. These heterojunction films containing ATO and TiO2 thus had better photocatalytic properties than the pure TiO2 and ATO films due to the reduction in recombination. Our facile method of preparing heterojunction films by a dry deposition method provided films with good photocatalytic properties.

High figure of merit transparent conducting Sb-doped SnO2 thin films prepared via ultrasonic spray pyrolysis

Doped tin oxide has been studied extensively because of its potential as a replacement for indium tin oxide in transparent conducting oxide layers. Antimony-doped tin oxide (ATO) is one of the most promising materials in this regard, due to its superior transparency in the visible region and broad scope for electrical property improvements. In this paper, we report the fabrication of highly conductive transparent ATO thin films using a simple, low-cost ultrasonic spray pyrolysis method. A film with a resistivity of 5.8×10−5 Ω cm, transmittance of 88% at 550 nm, and figure of merit as high as 47.22×10−2 (Ω/cm2)−1 was produced by tuning the deposition time. The ATO films produced in this experiment may be used as transparent conducting films with performance comparable to that of indium tin oxide.

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.

Preparation and properties of antimony doped tin oxide nanopowders and their conductivity

Antimony doped tin oxide (ATO) nanopowders were prepared by solid-liquid heterogeneous coprecipitation reaction, using SnCl4·5H2O and SbCl3 as the raw materials, NH4HCO3 as the neutralizing agent, CH3COOH as the cosolvent, and C2H5OH as the reaction medium. The ATO nanopowders were prepared into waterborne transparent antistatic coatings. The structure and properties of ATO powders were characterized by X-ray diffraction (XRD), energy dispersive spectrometer (EDS), transmission electron microscopy (TEM), Brunauer-Emmett-Teller (BET) surface area measurement and resistance tester. The results show that ATO nanopowders, whose primary particle size is about 5⿿8nm and specific surface area is 92.75m2g⿿1, have a structure of tetrahedral rutile and a uniform shape of approximately sphere, and the resistivity of ATO nanopowders reaches 1.0Ωcm. The ATO coating is applied on the surface of polyethylene terephthalate (PET) film by roller coating method, the test shows that the ATO film has excellent physical properties. When the visible light transmission rate is more than 80%, the surface resistance of coating film is about 105Ω, which is completely satisfied with the requirement of the anti-static electricity field.

Characteristics of SnO2:Sb Films as Transparent Conductive Electrodes of Flexible Inverted Organic Solar Cells.

Antimony-doped tin oxide (ATO) films were deposited on polyethersulfone (PES) substrates by means of a radio frequency (RF) magnetron sputtering method, using a SnO2 target mixed with 6 wt% Sb at room temperature and using various RF powers; these films were used as transparent electrodes in inverted organic solar cells (IOSC). We investigated the structural, optical, and electrical properties of the resulting films by means of various analyses, including X-ray diffraction (XRD), UV-visible spectroscopy, and Hall effect measurements. The crystallinity and conductivity of the ATO films were increased by increasing the RF power used. Based on the experimental data acquired, we fabricated IOSCs based on ATO electrodes deposited by using various conditions. Each IOSC device was composed of an ATO electrode, a ZnO buffer layer, a photoactive layer (P3HT:PCBM), and an Al cathode. The IOSC based on an ATO electrode fabricated at the RF power of 160 W exhibited good device performance due to the electrode's high conductivity and crystallinity.

Novel fabrication of an electrochromic antimony-doped tin oxide film using a nanoparticle deposition system

Novel deposition method of Antimony-doped tin oxide (ATO) thin films was introduced using a nanoparticle deposition system (NPDS) to fabricate an electrochromic (EC) device. NPDS is a dry deposition method that simplifies the ATO deposition process by eliminating the need for solvents or binders. In this study, an ATO EC layer was deposited using NPDS. The surface morphology and electrochemical and optical transmittance properties were characterized. The optical transmittance change in the ATO EC device was ∼35% over the wavelength range of 350–800nm, and the cyclic transmittance was stable. The ATO film deposited using NPDS, exhibited a coloration efficiency of 15.5cm2C−1. Therefore, our results suggest that ATO EC devices can be fabricated using a simple, cost-effective NPDS, which allows nanoparticles to be deposited directly without pre- or post-processing.

Comprehensive optimization of electrical and optical properties for ATO films prepared by pulsed laser deposition

Antimony doped tin oxide (ATO) thin films have been prepared by pulsed laser deposition (PLD) method. The intrinsic effect of Sb dopant, including the Sb content, transition degree between Sb3+ and Sb5+ and crystallinity on the electrical and optical properties of the ATO thin films is mainly investigated. It is suggested that the transition degree of Sb3+ towards Sb5+ (Sb5+/Sb3+ ratio) is determined by Sb content. When the Sb content is increased to 12 at%, the Sb5+/Sb3+ ratio reaches the highest value of 2.05, corresponding to the resistivity of 2.70×10-3 Ω·cm. Meanwhile, the Burstein-Moss effect caused by the increase of carrier concentration is observed and the band gap of the ATO thin films is broadened to 4.0 eV when the Sb content is increased to 12 at%, corresponding to the highest average optical transmittance of 92%. Comprehensively considering the combination of electrical and optical properties, the ATO thin films deposited with Sb content of 12 at% exhibit the best properties with the highest “figure of merit” of 3.85×10-3 Ω-1. Finally, an antimony selenide (Sb2Se3) heterojunction solar cell prototype with the ATO thin film as the anode has been prepared, and a power conversion efficiency of 0.83% has been achieved.

Photoelectrocatalytic properties of TiO2/ATO composite films

Mesoporous composite films of titania (TiO2) and antimony-doped tin oxide (ATO) were prepared on titanium plate substrates from pastes by the doctor-blade method. The photoelectrochemical properties of the samples with different ATO contents were investigated by the degradation of methylene blue under UV light irradiation. It was found that the photocatalytic activity of TiO2 was significantly improved with the help of the introduction of ATO nanocrystals and a forward bias. The synergetic effect of ATO and bias was analyzed by electrochemical impedance spectra (EIS). The EIS analysis results demonstrated that the separation of photogenerated electron–hole pairs can be efficiently enhanced by introducing ATO nanoparticles and applying an external bias.

Influences of defects and Sb valence states on the temperature dependent conductivity of Sb doped SnO2 thin films

Temperature dependent conductivities, surface morphologies, defects and antimony valence state of antimony doped tin oxide (ATO) films were investigated. Much higher conductivity is found for the film calcined at 600 °C than 400 °C due to enhancement of Sb5+ ratio and removal of grain boundaries, vacancies and interstitial dopants; the conductivity increases slightly for the film calcined at 800 °C because of further elimination of vacancy clusters and grain boundaries. A strong temperature dependent conductivity is merely observed in the film calcined at 400 °C Positron annihilation parameter W is well correlated with the conductivity for ATO films.