Visible Transmission Spectroscopy Research Articles

Online Detection of Dry Matter in Potatoes Based on Visible Near-Infrared Transmission Spectroscopy Combined with 1D-CNN

More efficient resource utilization and increased crop utilization rate are needed to address the growing demand for food. The efficient quality testing of key agricultural products such as potatoes, especially the rapid testing of key nutritional indicators, has become an important strategy for ensuring their quality and safety. In this study, visible and near infrared (Vis/NIR) transmittance spectroscopy (600–900 nm) was used for the online analysis of multiple quality parameters in potatoes. The study concentrated on comparing three one-dimensional convolutional neural network (1D-CNN) models, specifically, the fine-tuned DeepSpectra, the fine-tuned 1D-AlexNet, and classic CNN, with UVE-PLS (uninformative variable elimination–partial least squares) models. These models utilized spectral data for the real-time detection of dry matter (DM) content in potatoes. To address the challenges posed by limited data from Vis/NIR, this study strategically implemented data augmentation techniques. This approach significantly enhanced the robustness and generalization capabilities of the models. The 1D-AlexNet and DeepSpectra models achieved 0.934 and 0.913 R2P and 0.0603 and 0.0695 g/100 g RMSEP for DM, respectively. Compared to UVE-PLS, the R2P value improved by 21.31% (0.770 to 0.934) for the 1D-AlexNet model and 18.64% (0.770 to 0.913) for the DeepSpectra model. The RMSEP value was reduced by 47.31% (0.114 to 0.0603) for 1D-AlexNet, and 39.30% (0.114 to 0.0695) for the DeepSpectra model. As a result, this study would be helpful for researching the online Vis/NIR transmission determination of potato DM using deep learning. These results highlighted the immense potential of employing specific spectral features in deep-learning models for a more precise and efficient online assessment of agricultural quality. This advancement provided some insight and reference for further contributing to the evolution of more targeted and efficient quality assessment methods in agricultural products.

Transitions of nitrogen optical centers induced by femtosecond laser pulses in treated natural diamond

Diamond is a unique optical material with ultra-hard lattice, which properties can be altered by optically active doping defects combined with carbon interstitials and vacancies. Direct laser writing by focused ultrashort laser pulses enables local modification of color centers in diamonds with excellent three-dimensional positioning accuracy, providing unique capabilities for quantum technologies, magnetometry, laser generation and photoluminescence (PL) micromarking. To shed light on currently unknown underlying atomistic transformations, we exposed electron-irradiated and annealed natural IaAB1-type diamond with an initially high content of various nitrogen-vacancy centers (NV, H3, N3 and H4) to millions of 0.2-ps, 525-nm laser pulses focused inside the sample. The modified areas were characterized by Fourier-transform infrared (FT-IR) and ultraviolet–visible transmission spectroscopy and confocal Raman/PL microspectroscopy with excitation wavelengths of 405 nm and 532 nm. We report on a local decrease in originally strong PL yield of NV, H3 and H4 centers with a monotonic dependence on both pulse energy and exposure time, as well as a rise of H1b and H1c lines in the FT-IR spectra accompanied by a drop in the concentration of H1a center. The results indicate that laser-induced processes make possible both creation and destruction of NV, H3 and H4 centers influenced by their initial concentration and the parameters of laser modification, which can be useful for adjusting of laser writing regimes for PL micromark inscription and other local modification of diamond for photonics applications.

Ag nanoparticle dispersed TiO2 thin films by single step sol gel process: Evaluation of the physical properties and photocatalytic degradation

The photocatalyst must be low cost, high performing, and recyclable for efficient water treatment applications. Herein, we deposited TiO2 and Ag-dispersed TiO2 thin films via sol-gel spin coating and post-deposit annealing at 400 °C for 50 min. The physical properties of TiO2 and Ag: TiO2 thin films were analyzed by X-ray, Raman analysis, Atomic Force Microscope, Scanning Electron Microscopy, Electron Dispersive Spectroscopy, Transmission Electron Microscopy, and UV–visible transmittance spectroscopy. The structural evaluation established that the films were of anatase phase without any peaks related to metallic Ag or Ag oxides. The scanning transmission electron microscopy images demonstrated the presence of Ag nanoparticles with a diameter of ∼8 nm distributed on the film surface. The cross-sectional images from the high-angle annular dark-field scanning transmission electron microscopy confirmed the presence of Ag nanoparticles along the thickness of the Ag: TiO2 thin films. The optical bandgap of the Ag: TiO2 samples red shifted from 3.35 eV to 3.00 eV when the doping concentration reached 8 wt%. Photocatalysis showed by all samples were analyzed following the degradation of methylene blue (MB) with UV-light illumination. The Ag: TiO2 thin films demonstrated a substantial improvement in photocatalytic efficiency. The 4 wt% Ag doped TiO2 sample degraded 98% of MB in 180 min, a degradation efficiency 60% higher than the undoped samples.

Improving the Photo Electro Catalytic Degradation of Methylene Blue by Modified TiO2/ITO Photo Anodes

TiO2 photoanodes have gained significant attention for the removal of organic pollutants through photoelectrocatalytic processes, with the aim of developing a cost-effective and efficient method for improving the degradation of pollutants in surface water. This study investigated the effects of adding titanium nanooxide (Degussa P25) containing 70% anatase and 30% rutile phases on the properties of nanostructured TiO2 photoanodes prepared on glass substrates (indium tin oxide (ITO)) using sol–gel/dip coating techniques The results obtained from ultraviolet–visible transmittance spectroscopy, electrochemical (EC) impedance spectroscopy, photocurrent, and atomic force microscopy analyses revealed that the addition of Degussa P25 improved the electrical conductivity of the TiO2/ITO anode and reduced the optical bandgap from 3.50 to 3.35 eV, while the size of the titanium oxide particles decreased to about 75 nm. The EC impedance spectra measurement confirms that the addition of titanium nanooxide Degussa P25 improved the electrical conductivity for TiO2/ITO anode. The photoelectrocatalysis (PEC) performance of the TiO2 photoanodes was investigated via the degradation of methylene blue (MB) under UVA light irradiation. The AB photoanode (with the addition of Degussa P25) exhibited excellent PEC performance, with 95.9% color removal efficiency and 63% total organic carbon (TOC) removal efficiency, compared to 92% color removal efficiency and 56% TOC removal efficiency for the A photoanode (without the addition of Degussa P25). The kinetic constants (k) were 134 × 10−4, 110 × 10−4 (min−1) for A and AB anodes, respectively, and the degradation of MB followed first-order kinetics for all anodes. The A and AB anodes were compared as electrodes for the degradation of MB using PEC, photocatalysis (PC), and EC technologies. Subsequently, The A and AB anodes were utilized as electrodes to compare the performance of PEC, PC, and EC technologies for the degradation of MB. The results showed that the AB anode exhibited higher efficiency in all PC technologies, with color removal (%) efficiencies of 95.9% (PEC), 33% (PC), and 21% (EC) compared to 92% (PEC), 28% (PC), and 19% (EC) for the A anode. Additionally, the photooxidation process had a 2.1% effect on the degradation of the initial MB concentration.

Resistive switching characteristics and mechanism of W/TiO2/ITO devices

In recent years, titanium oxide (TiO2)-based memristors have come under widespread investigation due to their compatibility with CMOS technology and their potential use as the forthcoming nonvolatile memories. However, the practical application of these devices requires a detailed understanding of their switching mechanism. This study examined the resistive switching and conduction mechanism of titania films on an Indium tin oxide (ITO) substrate with tungsten (W) serving as the top electrode (TE). The thin film of TiO2 was fabricated by solution processing and spin coating technique. The sol was prepared using titanium tetra isopropoxide (TTIP) and ethanol. Optical characterization was done using UV–Visible transmission spectroscopy. From the tauc plot, the band gap of films treated at 250 °C and 400 °C was found to be 3.37 eV and 3.29 eV, respectively. From the electrical analysis, a pinched hysteresis current–voltage curve was obtained, and the device exhibits stable, reversible, forming-free, and interface type resistance-switching characteristics.The homogeneous switching observed in this device is caused by oxygen vacancy-induced barrier modulation at the metal-oxide interface. The I-V data were fitted to various conduction mechanismsand it was found that ohmic conduction and Schottky emission mechanism (SE) were dominant in the low and high field regions, respectively, for both HRS and LRS.

The effect of thickness on structural, optical, and electrical properties deposited ZnO thin films by PLD

In this paper, the effect of film thickness on structural, electrical, and optical properties of ZnO thin films deposited by Pulsed laser Deposition (PLD) over a quartz substrate has been studied. In PLD the thickness of the deposited thin films varies from 200 nm to 300 nm by increasing the number of laser shots from 9000 shots to 12,000 shots respectively. Deposited thin films were studied by Grazing angle X-ray diffraction (Gi-XRD), Ultraviolet–Visible transmittance spectroscopy (UV–Vis), Lateral I-V measurements, Field emission scanning electron spectroscopy (FESEM), and energy dispersive X-ray spectroscopy (EDX). Gi-XRD result shows that films deposited over quartz are poly-crystalline in nature and are oriented along (002), (102), and (103) planes. FESEM analysis shows that 300 nm thick film is distributed uniformly over the surface and 200 nm ZnO thin film is distributed mainly at the center. EDX results show the presence of Zn and O elements in both deposited thin films. I-V characteristics in the dark show Schottky contact with Vc 2.9 V and 1 V for 200 nm and 300 nm thin films respectively. The optical band gap of ZnO thin films intersects at the same photo energies for both thicknesses. Tauc’s plot of both films reveals the similar optical band gap energies of 3.25 eV in both deposited films.

Studying the effects of processing parameters in the aerosol-assisted chemical vapour deposition of TiO2 coatings on glass for applications in photocatalytic NOx remediation

Herein, we employ an aerosol-assisted method (AA-CVD) to produce TiO2 on window glass and study how the process parameters affect their photocatalytic activity towards NOx (NO + NO2) remediation. A range of process parameters are explored to produce 50 unique TiO2 coatings with wide ranging physicochemical properties. The physicochemical properties were examined using X-ray diffraction (XRD), atomic force microscopy (AFM), UV–visible transmission spectroscopy and transient absorption spectroscopy (TAS), and the photocatalytic activity towards NO gas was measured using protocol akin to the ISO (22197-1:2016). The most active sample showed an NO removal of ∼14.4 ± 1.7 % and NOx removal of ∼5.4 ± 0.77 %, which was ∼40 and ∼25 times higher than that of a commercially available self-cleaning window. The links between the process parameters, physicochemical properties and photocatalytic activity were studied in depth, where it was seen that the three most influential physicochemical properties on the observed activity were surface roughness, charge carrier population and charge carrier lifetime. Therefore, we recommend that these properties be targeted in the rational design of more active coatings for applications in photocatalytic NOx remediation.

Directly Imaging Dynamic Electronic Coupling during Electrochemical Oxidation of Single Silver Nanoparticles.

The electronic coupling between a metal electrode and single nano-entities is of unfading significance which impacts the heterogeneous electron transfer. Herein, we demonstrated a simple optical technique for directly imaging the transient interfacial electronic coupling events during electrochemical oxidation of single Ag nanoparticles on Au electrode. The electronic coupling brings out a dramatic dip behavior of bright field imaging traces, and is conductive to cross the energy barrier of oxidation for single silver nanoparticles. This dip behavior is further verified by in situ vis-transmission spectroscopy, and the heterogeneity of the Au-Ag electronic coupling down to single-nanoparticle level is uncovered by unifying the morphology and size of individual silver nanoparticles. These results suggest the interfacial electronic coupling facilitates electron transfer of single nanoparticles, and provide important insight into understanding detailed mechanism of nanoelectrochemistry.

Effect of sodium doping on characteristics of p-SnOx films prepared by reactive direct current magnetron sputtering

Conventionally, p-type semiconducting oxide films of high optical transmission and good electric conduction are materials of great demand in electronic and optoelectric devices. They can conveniently be integrated with their n-type counterparts for formation of homo or heterojunctions. In this report, Na-doped SnOx films were fabricated by reactively sputtering the Sn + Na alloy targets at substrate temperature of 200 °C. Effect of Na dopant concentration on crystal structure, electric and optical properties of Na-doped SnOx films was investigated with X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, atomic force microscopy, Hall and UV–Visible transmission spectroscopy. The obtained results revealed that when Na + substituted Sn2+, the hole concentration increased but the crystallite size reduced, leading to increased grain boundary and reduced carrier mobility. However, electric resistivity still reduced thanks to the increase of carrier concentration. Averange optical transmission of Na-doped SnOx films in visible range was approximately 65%. In addition, optical bandgap value reduced as Na doping amount in those films increased. The Na-doped SnOx films sputtered from Sn + 3 at% Na alloy targets, corresponding to 1.56 at% Na existing in films, presented the best electric property (nH = 2.75 × 1019cm−3, μ = 2.4 cm2/VS, ρ = 9.35 × 10−2Ωcm). This film proceeded with diode structure of glass/FTO/n-nc-Si:H/p-SnOx:Na/Cu, resulted in the best characteristics (VOC = 0.59 V, n = 3.57, rectifying ratio = 22, Rs = 38.1 Ω).

Systematic Exploration of WO3/TiO2 Heterojunction Phase Space for Applications in Photoelectrochemical Water Splitting

Recent work has shown that heterojunction photoelectrodes can achieve synergistically higher water splitting activity than their parent materials. To optimize the performance in such layered systems, it is necessary to develop new methods capable of assessing heterojunction phase space. Herein, we explore WO3/TiO2 heterojunction phase space as a model system. Using chemical vapor deposition, 71 unique photoanodes were grown (15 single-layer; 56 heterojunctions). The materials were physically characterized using X-ray diffraction, Raman spectroscopy, scanning electron microscopy, energy-dispersive X-ray spectroscopy analysis, and ultraviolet–visible transmission spectroscopy. Various key performance indicators were measured. Within this WO3/TiO2 heterojunction phase space, the onset potentials ranged from ∼0.45 to ∼0.81 VRHE; the incident-photon-to-current efficiencies at 350, 375, and 400 nm ranged from ∼0.6 to ∼50.9, ∼0.1 to ∼30.0, and ∼0 to ∼15.6%, respectively; and the theoretical solar photocurrents ranged from ∼0.01 to ∼0.94 mA cm–2. Contour plots allowed us to identify regions of heterojunction phase space with high activity and establish trends. We identified an electronic barrier to charge transfer between the heterojunction layers that required a sufficiently high applied potential (≥1.0 VRHE) to be surpassed for synergetic improvements in activity to be observed. We recommend that the methods developed herein, for assessing the performance of sample libraries of heterojunction photoelectrodes, be used alongside combinatorial synthesis methods and high-throughput photoelectrochemical measurements to optimize promising heterojunction systems more rigorously and rapidly.

Nondestructive Preincubation Sex Determination of Broiler Eggs Using Visible Transmission Spectroscopy Combined with Multivariate Analysis

Nondestructive Preincubation Sex Determination of Broiler Eggs Using Visible Transmission Spectroscopy Combined with Multivariate Analysis

Non-destructive sex-specific monitoring of early embryonic growth rate in light brown broiler eggs using light transmission and its correlation with hatching time and chick weight

ABSTRACT 1. Monitoring early embryonic growth rate (EGR) has significant economic and animal welfare benefits. This study focuses on monitoring sex-specific early EGR using light transmission, and correlating this with hatching time and chick weight. For broiler eggs in particular, spectral masking of the light brown eggshells needed to be addressed. This was done using longitudinal visible transmission spectroscopy combined with eggshell colour image analysis. 2. Prior to incubation, colour images of eggs were captured followed by daily measurements of transmission spectra of eggs from days one to nine of incubation. The sex of the eggs was subsequently verified 2 d after hatching. 3. To accurately and sensitively determine sex differences in EGR using light transmission, while minimising interference from eggshell colour and thickness, the ratio of longitudinal transmissions was determined to be most effective at 575 and 610 nm. 3. Embryonic growth was detectable from d 3 (72 h) of incubation, 24 h earlier than previously reported lateral transmission measurements. However, at this time, low blood levels meant that no significant sex-differences (P > 0.05) for the mean T575/T610 ratio were detectable. This may have been due, in part, to spectral masking from the light brown eggshells. At d 7, female embryos had a significantly lower (P < 0.05) mean T575/T610 ratio than males. 4. Although the T575/T610 ratio had low correlations with hatching time and hatch-weight of chicks, this could be a good starting point for further non-destructive investigations for such predictions. 5. In conclusion, the methodology had the sensitivity to differentiate sex-specific early EGR in broiler eggs, even with pigmented eggshells, and has the potential to advance precision hatchery management and poultry research.

Growth of hexagonal shape nanostructured Sb2O3 thin films by spray pyrolysis and their structural, morphological, electrical and optical properties

In recent past decades, various oxide’s thin films were synthesized successfully by chemical spray pyrolysis technique (CSPT), but little work has been dedicated to the synthesis of Sb2O3 thin films. In this investigation, we report the synthesis of nanostructured antimony trioxide (Sb2O3) thin films using the simple and low-cost CSPT. The deposited films were characterized in detailed by means of x-ray diffraction (XRD), field emission scanning electron microscope (FESEM) and energy dispersive x-ray analysis (EDAX), UV–Visible absorption and transmission spectroscopy, Raman spectroscopy. The electrical resistivity was measured using two-point probe method. The XRD analysis shows that the deposited films possess good crystalline nature, senarmonite cubic phase, with average crystallites size of 58.73 nm. FESEM–EDAX analysis revealed that nano-dimensional hexagonal cubic crystal morphology grown-up on the surface with excellent elemental composition of Sb2O3. The deposited Sb2O3 films exhibit semiconducting behaviour, with the calculated band gap, activation energy and resistivity were found to be the order of 3.43 eV, 0.764 eV and 26.16 × 102 Ω cm respectively. Raman spectra analysis verifies the homogeneity of the deposited material.

Prediction of infertile chicken eggs before hatching by the Naïve-Bayes method combined with visible near infrared transmission spectroscopy

The traditional candling methods are very hard to discriminate the infertile chicken eggs from the fertile ones before hatching on the poultry farm. The purpose of this study was to detect infertile chicken eggs before hatching by use of the nondestructive technique of visible near infrared transmission spectroscopy. The Naïve-Bayes method was adopted to link spectral data and qualitative observation values of chicken eggs to build a model. Five preprocessing methods were applied to spectral data to improve the robustness of the models. The internal test method of leave one cross validation and an external test method were employed to test the predictive ability of the established models. Naïve-Bayes with a second derivative by the Savitzky-Golay preprocessing method was selected as the optimal prediction model by comparing with four evaluation parameters of other models. The overall accuracy of the model using the second derivative—Savitzky-Golay preprocessing method was 91.67%, while the sensitivity and the specificity were 95% and 100%, respectively. The prediction ability of the optimal model was assessed by use of unknown new egg samples. The average overall prediction accuracy of the prediction set containing 111 eggs was 89.12%, while the sensitivity and specificity were 88.14 and 90.38%, respectively. Results showed that the prediction model had good predictability and stability. Therefore, visible near infrared transmission spectroscopy would be an appropriate technology to detect infertile chicken eggs before hatching.HighlightsThe infertile chicken eggs from the fertile ones before hatching were discriminatedVisible near infrared spectroscopy first detected infertile chicken eggs before hatching.Naive bayes classifier with five different pre-processing methods were compared.The unknown eggs were predicted by the optimal Naive bayes prediction model.

Impact of annealing temperature on structural, morphological and optical properties of GO-TiO2 thin films prepared by spin coating technique

Abstract Thin films of graphene oxide – titanium dioxide were synthesized by spin coated on glass substrates. Annealing in air from room temperature to 300, 400 and 500 °C and at heating rate of about 0.16 °C/s affected the film structure, surface morphology and optical properties as studied by X-ray diffractometry, scanning electron microscopy, atomic force microscopy, and ultraviolet–visible transmittance spectroscopy. The film structure changed from amorphous to crystalline state with an increased annealing temperature. A crystalline TiO2 (i.e. anatase) formed at 500 °C. At a higher annealing temperature, the surface roughness and grain size of the films increased. The film transmittance reached a maximum of 80% in the visible region and the optical band-gap energy was changed from 3.00 to 3.71 eV. Therefore, these films could be applied in perovskite solar cells for energy harvesting.

Morphological and Kinetic Insights into Cu2O–CuO Oxidation

The conversion of Cu2O to CuO thin films is probed in situ with UV–vis transmission spectroscopy at various thermodynamic conditions. The obtained spectral series are simulated with different CuO/Cu2O growth models, using the transfer‐matrix method and Bruggeman's mean‐field approach to account for Cu residuals in the oxide matrix. The analysis reveals that Cu2O oxidation proceeds via a flat and homogeneous reaction front, in contrast to polycrystalline copper that preferentially oxidizes along the grain boundaries. The conclusion is supported by the measured activation energy for Cu2O oxidation, which is compatible with Cu diffusion via the bulk oxide and not via line defects. The kinetics of CuO growth is found to follow logarithmic and exponential rate laws at low and high temperature, respectively. While the logarithmic regime is governed by CuO nucleation within the Cu2O phase, the exponential dependence results from self‐heating of the sample in the exothermic reaction. In both cases, traces of unreacted copper are detected in the oxide matrix, giving rise to a characteristic tail in the transmission response.

Effect of different stabilizers on dispersion of gold nanoparticles in bismuth borosilicate glass and their intensity dependent nonlinear behaviour

Here, we report the role of different stabilizers (Eu2O3, EuF3 and KSCN) in stabilizing gold nanoparticles (AuNPs) embedded in Bismuth-Borosilicate glasses. The prepared nanocomposites are characterized by X-ray diffraction (XRD), differential thermal analysis (DTA), UV–Visible transmission spectroscopy, field emission scanning electron microscopy (FESEM), high resolution transmission electron microscopy (HRTEM), ellipsometery and Z-scan. From FESEM, it has been observed that the morphology of AuNPs is highly dependent on the type of stabilizer. Also HRTEM confirms the covering of AuNPs by stabilizer that prevents the coagulation of NPs. The localized surface plasmon resonance related transmission dip is observed around 585 nm for glass containing Eu2O3 as a stabilizer. The linear and nonlinear refractive index of the prepared glasses is obtained from ellipsometery and Z-scan measurements, respectively. All the Z-scan measurements have been carried out at different input peak intensities varying from 1.9 to 14.38 GW/cm2. Nonlinear optical studies with open aperture Z-Scan shows the switching between saturable absorption and two photon absorption as the laser intensity is increased. The existence of third order nonlinearity has been detected using closed aperture Z-scan in the prepared glasses.

Structural, optical, and photoluminescence properties of erbium doped TiO2 films

TiO2 thin films doped with low percentages (3, 7, and 10 at.%) of Er3+ have been synthesized by sol gel spin coating technique. The influence of erbium concentration on the physical properties was analyzed using different characterization techniques such as X-ray diffraction, Raman spectroscopy, TEM analysis, EDS-SEM, AFM, UV–Visible transmittance spectroscopy, photoresponse and photoluminescence. The doped films exhibited significant modifications on the structural, optical and electrical properties due to the incorporation of erbium ions. The band gap energy was red shifted by Er doping indicating an improvement in visible light absorption. Intense Er3+-based emission peaks in the range 520–560 nm were observed for all samples. It was observed that Er-dopant concentration had direct impact on photoluminescence intensity.

Nondestructive discrimination of internal defects in jujube (Huizao) of Xinjiang based on visible and near-infrared spectroscopy

During harvest and transport, defects are most likely to affect the interior of jujubes and thus shorten their storage period. This study applied visible and near-infrared transmission spectroscopy to detect such internal defects. Spectra were acquired on the equator area at 0, 90, 180, and 270 degrees of each sample, and a model was constructed to obtain three-dimensional damage and defect detection model. The first derivative, multiplicative scatter correction, standard normal variate, and median filtering were used for preprocessing. Modeling by mean spectra achieved a better effect than using unidirectional spectra. Then, naive Bayes classifier and support vector machine were employed for the model establishment at 600–950 nm and 680–950 nm bands, respectively, using mean spectra. Median filtering effectively improved the signal to noise ratio and the discrimination accuracy of the support vector machine model at 600–950 nm reached 96.77%, which was the best value among all models. This result indicates that the support vector machine model was the optimum model and 600–950 nm was a suitable data range for the detection of internal defects. This research confirms the feasibility of implementing visible and near-infrared spectroscopy for the detection of internal defects in jujubes.

Influence of base pressure on property of sputtering deposited ITO film

To systematically investigate the effect of base pressure on photoelectric properties of indium tin oxide (ITO) films, ITO films were prepared on glass substrates by RF magnetron sputtering with base pressures varying from 0.42 × 10−6 to 10 × 10−6 Torr in this work. Microstructure and photoelectric properties of ITO films were characterized by atomic force microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, Hall-effect measurements and UV–vis transmission spectroscopy. It concluded that base pressure has an important influence on the properties of sputtering ITO films. As base pressure decreased, In2O3 was more easily decomposed into free oxygen and In2O3−x, the adhesion coefficient of oxygen reduced, and the oxygen vacancy content in ITO films increased. Therefore, with the decrease of the base pressure, the carrier concentration of ITO films increased, the resistivity of ITO films decreased, and the figure of merit of ITO films improved.