In2O3 Nanoparticles Research Articles

UV-activated ultrasensitive and fast reversible ppb NO2 sensing based on ZnO nanorod modified by constructing interfacial electric field with In2O3 nanoparticles

The poor recovery characteristic of NO2 sensors operated at room temperature is always a challenge to solve. In order to realize the combination of ultra-high response and fast response and recovery speed, heterogeneous interfacial electric fields are constructed by loading In2O3 nanoparticles on ZnO nanorods, which possess fast charge transfer ability, to improve the separation efficiency of photogenerated carriers. The sensing results show that 10 mol% In2O3-decorated ZnO (In: Zn) exhibits a response of 117.0 to 700 ppb NO2 at room temperature under ultraviolet (UV) illumination. Even when the concentration of NO2 drops down to 50 ppb, the response also can reach 1.5. In addition, the sensor's response time is 100 s when exposed to 700 ppb NO2 and can recover 90 % resistance variation within 31 s. Moreover, the role of photogenerated carriers in NO2 sensing process under UV illumination were described in detail.

The early onset and persistent worsening pulmonary alveolar proteinosis in rats by indium oxide nanoparticles

Workplace inhalation exposure to indium compounds has been reported to produce ‘indium lung disease’ characterized by pulmonary alveolar proteinosis (PAP), granulomas, and pulmonary fibrosis. However, there is little information about the pulmonary toxicity of nano-sized indium oxide (In2O3), which is widely used in various applications such as liquid crystal displays. In this study, we evaluated the time-course and dose-dependent lung injuries by In2O3 nanoparticles (NPs) after a single intratracheal instillation to rats. In2O3 NPs were instilled to female Wistar rats at 7.5, 30, and 90 cm2/rat and lung injuries were evaluated at day 1, 3, 7, 14, 30, 90, and 180 after a single intratracheal instillation. Treatment of In2O3 NPs induced worsening diverse pathological changes including PAP, persistent neutrophilic inflammation, type II cell hyperplasia, foamy macrophages, and granulomas in a time- and dose-dependent manner. PAP was induced from day 3 and worsened throughout the study. The concentrations of interleukin-1β, tumor necrosis factor-α, and monocyte chemoattractant protein-1 in bronchoalveolar lavage fluid (BALF) showed dose- and time-dependent increases and the levels of these inflammatory mediators are consistent with the data of inflammatory cells in BALF and progressive lung damages by In2O3 NPs. This study suggests that a single inhalation exposure to In2O3 NPs can produce worsening lung damages such as PAP, chronic active inflammation, infiltration of foamy macrophages, and granulomas. The early onset and persistent PAP even at the very low dose (7.5 cm2/rat) implies that the re-evaluation of occupational recommended exposure limit for In2O3 NPs is urgently needed to protect workers.

Hydrothermal synthesis of In2O3 nanocubes for highly responsive and selective ethanol gas sensing

Indium oxide nanocubes (NCs) were prepared via a simple, template-free hydrothermal method at low temperature; the so-obtained structures exhibited large surface area (47.67 m2/g) and Barrett−Joyner−Halenda (BJH) adsorption average pore diameter (11.92 nm), both higher than for commercial In2O3 nanoparticles. At the optimal temperature of 300 °C, the In2O3 NCs-based sensor showed a superior response of 85–100 ppm ethanol, 3.4 times higher than that of the commercial one based on In2O3 NPs, and also faster response time (15 s) than the commercial device (60 s). The better sensing performance of the synthesized In2O3 NCs can be attributed to its unique properties that include large BET surface area and BJH adsorption average pore diameter as well as abundance of sharp edges and tips, which result in high surface to volume ratios for the gas adsorption and diffusion processes, facilitating the charge-transfer and sensing reactions at the gas–solid interfaces. In addition, the In2O3 NCs exhibited excellent selectivity to ethanol among other target gases (CO, CH4, CH3CHO, H2, and CH3COCH3). This work provides an effective design pathway for ethanol sensors based on In2O3 NCs.

Acetone sensing characteristics of Fe2O3/In2O3 nanocomposite

Fe2O3 and In2O3 nanoparticles were prepared by a citric sol-gel method and mixed subsequently to form the (x)Fe2O3/(1 − x)In2O3 (x = 0, 0.05, 0.10, 0.15, 0.20, 0.50, 1) nanocomposites. XRD confirmed the separate phases of cubic In2O3 and orthorhombic Fe2O3 in the composites. At the prime working temperature of 200 °C, the 0.15Fe2O3/0.85In2O3 nanocomposite-based sensor showed the best acetone sensing performance among all sensors, including the highest gas response, sensitivity, selectivity and stability. Although the mean grain size was slightly increased upon adding Fe2O3 nanoparticles in larger sizes, which leaded to smaller BET surface area, the electron transfer from Fe2O3 to In2O3 across the heterostructure interface increased the electron concentration in the surface region of In2O3, which resulted in more adsorbed oxygen species on the surface of In2O3 and favored the subsequent acetone sensing process.

Facile synthesis of Pr-doped In2O3 nanoparticles and their high gas sensing performance for ethanol

Excellent sensing performance of a gas sensor includes high responsiveness, good selectivity, short recovery time and relatively mild operating temperature; doping is one of the efficient means to improve the performance of gas sensor. Herein, Pr-doped In2O3 nanoparticles were synthesized using ethanol as solvent by one step solvothermal method. The morphology and structure of the samples were characterized by X-ray powder diffraction, transmission electron microscopy, X-ray photoelectron spectroscopy. The result indicated that the as-obtained Pr-doped In2O3 nanoparticles with a diameter ca. 10 nm and the specific surface area was 65.38 m2/g. Interestingly, the 3 mol% Pr-doped In2O3 nanoparticles based sensor had efficient sensing performance for ethanol with a response value (106 at 50 ppm), a response time was 16.2 s, and a recovery time was 10 s at 240℃, and these properties could maintain long-term stability. In addition, we found that the above sensor had good selectivity for ethanol by detecting including ethanol the six gases, such as formaldehyde, methanol, acetone, benzene and ammonia.

Microbial toxicity of gallium- and indium-based oxide and arsenide nanoparticles

III-V semiconductor materials such as gallium arsenide (GaAs) and indium arsenide (InAs) are increasingly used in the fabrication of electronic devices. There is a growing concern about the potential release of these materials into the environment leading to effects on public and environmental health. The waste effluents from the chemical mechanical planarization process could impact microorganisms in biological wastewater treatment systems. Currently, there is only limited information about the inhibition of gallium- and indium-based nanoparticles (NPs) on microorganisms. This study evaluated the acute toxicity of GaAs, InAs, gallium oxide (Ga2O3), and indium oxide (In2O3) particulates using two microbial inhibition assays targeting methanogenic archaea and the marine bacterium, Aliivibrio fischeri. GaAs and InAs NPs were acutely toxic towards these microorganisms; Ga2O3 and In2O3 NPs were not. The toxic effect was mainly due to the release of soluble arsenic species and it increased with decreasing particle size and with increasing time due to the progressive corrosion of the NPs in the aqueous bioassay medium. Collectively, the results indicate that the toxicity exerted by the arsenide NPs under environmental conditions will vary depending on intrinsic properties of the material such as particle size as well as on the dissolution time and aqueous chemistry.

Humidity-Sensitive Field Effect Transistor with In₂O₃ Nanoparticles as a Sensing Layer.

In this work, we investigate the humidity-sensing performance on a humidity-sensitive p-channel field effect transistor (FET) having a floating-gate (FG) and a control-gate (CG) placing horizontally each other. A sensing layer is formed onto a part of the CG and the O/N/O stack over the FG by inkjet-printing process. The printed ink is composed of indium oxide (In₂O₃. nanoparticles and dimethylformamide (HCON(CH₃)₂) as solvent. DC/Pulsed measurements are carried out by switching chamber ambience between dry and humid N₂ at 25 °C. Pulsed measurement effectively alleviates the ID drift of the device. When the device is exposed to humidity, the |ID| is appreciably decreased in the p-channel FET-type sensor, since H₂O molecules act as an electron donor. The sensitivity of the sensor increases with increasing relative humidity up to about 68% and decreases with further increasing relative humidity.

In-situ growth of mesoporous In2O3 nanorod arrays on a porous ceramic substrate for ppb-level NO2 detection at room temperature

Mesoporous In2O3 nanorod arrays were synthesized directly on a porous ceramic substrate via a one-step hydrothermal method. The morphology and structure of the obtained In2O3 nanorod arrays were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and X-ray photoelectron spectroscopy. The results revealed that In2O3 nanorod arrays with cubic phase were densely distributed on the porous ceramic substrate, showing the diameter of 120–200 nm and length of 0.5–1 μm. Especially, the nanorod was assembled by aggregated In2O3 nanoparticles with the diameters of 10–30 nm, and its large specific surface ensured the highly gas sensing performance for ppb-level NO2 detection. The response value of the mesoporous In2O3 nanorod arrays to 800 ppb NO2 was 14.9 at room temperature of 25 °C with a short response time of 14 s, and the ultraviolet light was loaded in the recovery process to shorten the recovery time to about 32 s. The growth and gas sensing mechanisms of the mesoporous In2O3 nanorod arrays were discussed. It demonstrates that this work provides a low-cost route for the fabrication of room-temperature NO2 gas sensor with high performance through in-situ growth of the sensing materials on a porous ceramic substrate.

Structural Evolution and Dynamics of an In2O3 Catalyst for CO2 Hydrogenation to Methanol: An Operando XAS-XRD and In Situ TEM Study.

We report an operando examination of a model nanocrystalline In2O3 catalyst for methanol synthesis via CO2 hydrogenation (300 °C, 20 bar) by combining X-ray absorption spectroscopy (XAS), X-ray powder diffraction (XRD), and in situ transmission electron microscopy (TEM). Three distinct catalytic regimes are identified during CO2 hydrogenation: activation, stable performance, and deactivation. The structural evolution of In2O3 nanoparticles (NPs) with time on stream (TOS) followed by XANES-EXAFS-XRD associates the activation stage with a minor decrease of the In-O coordination number and a partial reduction of In2O3 due to the formation of oxygen vacancy sites (i.e., In2O3-x). As the reaction proceeds, a reductive amorphization of In2O3 NPs takes place, characterized by decreasing In-O and In-In coordination numbers and intensities of the In2O3 Bragg peaks. A multivariate analysis of the XANES data confirms the formation of In2O3-x and, with TOS, metallic In. Notably, the appearance of molten In0 coincides with the onset of catalyst deactivation. This phase transition is also visualized by in situ TEM, acquired under reactive conditions at 800 mbar pressure. In situ TEM revealed an electron beam assisted transformation of In2O3 nanoparticles into a dynamic structure in which crystalline and amorphous phases coexist and continuously interconvert. The regeneration of the deactivated In0/In2O3-x catalyst by reoxidation was critically assessed revealing that the spent catalyst can be reoxidized only partially in a CO2 atmosphere or air yielding an average crystallite size of the resultant In2O3 that is approximately an order of magnitude larger than the initial one.

A label-free photoelectrochemical aptasensing platform base on plasmon Au coupling with MOF-derived In2O3@g-C3N4 nanoarchitectures for tetracycline detection

A label-free photoelectrochemical (PEC) aptasensor for tetracycline (Tc) detection was successfully fabricated, and plasmon Au coupling with MOF-derived In2O3@g-C3N4 nanoarchitectures (AuInCN) with excellent PEC performance was employed as matrix for the first time. The homogeneous In2O3 nanoparticles (In2O3 NPs) derived from MIL-68(In) precursor were synthesized via calcination in air. The g-C3N4 nanosheets provided a favorable substrate for the fine distribution of In2O3 NPs. The In2O3@g-C3N4 (InCN) heterojunction with compact interface and matching band structure, facilitated the separation and transfer of electron-hole pairs. The surface plasmon resonance (SPR) of gold nanoparticles (Au NPs) could improve the light absorption and the photoelectron transfer of the modified electrode. Meanwhile, the decorated cysteamine stabilized Au NPs were also adequate to immobilize the SH-terminated aptamer as a biorecognition unit, and Tc molecules could be trapped through the specific interaction with the immobilized aptamer. An enhanced PEC photocurrent was realized under visible light illumination, due to the oxidation of captured Tc by photo-generated holes. Thereby, the concentration of Tc could be detected by observing the changes of photocurrent signals. Under optimized conditions, the PEC aptasensor exhibited the linear range from 0.01 nmol L−1 to 500 nmol L−1, with a detection limit (S/N = 3) of 3.3 pmol L−1. The prepared PEC aptasensor demonstrated acceptable stability, specificity and reproducibility, indicating the potential applications for the detection of Tc.

Ultrasensitive sensor based on Y2O3-In2O3 nanocomposites for the detection of methanol at room temperature

Y2O3-In2O3 nanocomposites (NCs) were prepared via simple co-precipitation and sol-gel processes. Prepared pure Y2O3, In2O3 nanoparticles (NPs) and Y2O3-In2O3 NCs were subjected to their structural, morphological, and compositional characterization via XRD, XPS, FESEM and TEM, and EDS respectively. Results revealed the perfect phase formation and desired composition of the samples. Gas sensing studies of Y2O3, In2O3 NPs and Y2O3-In2O3 NCs were performed under room conditions and observed that the Y2O3-In2O3 sensor has shown excellent response towards methanol at room temperature (RT). The response of ~923 and 3.722 were observed for Y2O3-In2O3 towards 200 ppm and 1 ppm methanol respectively. Response/recovery time of Y2O3-In2O3 sensor was also calculated. Overall Y2O3-In2O3 gas sensor has shown high response, sharp response/recovery time (13/18 s), good selectivity towards methanol and high stability. The mechanism involved in these improved gas sensing properties of Y2O3-In2O3 sensor has been described in detail.

Carrier densities of Sn-doped In2O3 nanoparticles and their effect on X-ray photoelectron emission

Sn-doped In2O3 (ITO) nanoparticles with various Sn doping concentrations were successfully fabricated using a liquid phase coprecipitation method. Similar to sputtered ITO thin films, Sn doping reaches a maximum carrier density (1.52×1021cm−3) at 10 at. % in ITO nanoparticles, which was estimated from the bulk plasmon energy based on a scanning ellipsometry (SE) simulation. Interestingly, the X-ray photoelectron emission spectra (XPS) of In 3d core levels show a clear asymmetric peak with a shoulder on the high-binding-energy side for degenerated ITO nanoparticles, which may be associated with the influence of the surface plasmon or plasmonic coupling. Our results suggest that combining the SE simulation and XPS measurements effectively provides a new way to understand the difference between bulk plasmons and surface plasmons for transparent conductive oxide nanoparticles.

Electrochemical synthesis of In2O3 nanoparticles for fabricating ITO ceramics

In2O3 nanoparticles approximately 50–100 nm in size were successfully synthesised using an electrochemical method utilising aqueous NH4Cl solution as electrolyte followed by calcination at 400 °C for 3 h. Scanning and transmission electron microscopy analyses revealed that the obtained In2O3 nanoparticles were uniform, monodisperse, and near-spherical. The optical performance of the In2O3 nanoparticles was investigated using UV–Vis and photoluminescence spectra. The In2O3 nanoparticles were used to fabricate tin-doped indium oxide (ITO) ceramics using the slip casting method, and the sintering behaviours and microstructures of the ITO ceramics were studied in detail. The results demonstrated that ITO ceramics sintered at 1600 °C for 8 h exhibited high density (7.135 g/cm3) and low resistivity (0.137 mΩ⋅cm), which indicated their great potential for fabricating ITO films featuring excellent properties.

Low‐Temperature Processing of Printed Field‐Effect Transistors from Sublimating‐Stabilizer Derived Oxide Nanodispersions

AbstractOxide semiconductors are becoming an increasingly attractive choice for solution processed/printed transistors and circuits, as they possess numerous critical advantages over the other printable semiconductor technologies, such as abundance, low‐cost, environmental/thermal stability, nontoxicity, and most importantly, excellent electronic transport properties. However, on the downside, there are also major challenges, one of which is their high process temperatures, especially when they are processed from oxide precursors. In order to address this limitation, here, a general recipe for low temperature curable nanodispersions/nanoinks is proposed using aromatic surfactants that sublimates near room temperature. In this regard, stable nanoinks from In2O3 nanoparticles, with high particle loading, are developed using an inexpensive, nontoxic aromatic compound thymol as the stabilizer; while, thymol sublimates near room temperature (<40 °C), a quick heating at 100 °C is carried out to ensure its complete removal. The printed field‐effect transistors from thymol‐stabilized nanoinks show an on/off ratio >107, a maximum device mobility of 13.5 cm2 V−1 s−1, and transconductance values as high as 10 µS µm−1. It is believed that this general route to obtain low temperature curable electronic grade nanodispersions may find applications beyond the printed logic electronics demonstrated in the present study.

Metal(loid) oxide (Al2O3, Mn3O4, SiO2 and SnO2) nanoparticles cause cytotoxicity in yeast via intracellular generation of reactive oxygen species.

In this work, the physicochemical characterization of five (Al2O3, In2O3, Mn3O4, SiO2 and SnO2) nanoparticles (NPs) was carried out. In addition, the evaluation of the possible toxic impacts of these NPs and the respective modes of action were performed using the yeast Saccharomyces cerevisiae. In general, in aqueous suspension, metal(loid) oxide (MOx) NPs displayed an overall negative charge and agglomerated; these NPs were practically insoluble (dissolution < 8%) and did not generate detectable amounts of reactive oxygen species (ROS) under abiotic conditions. Except In2O3 NPs, which did not induce an obvious toxic effect on yeast cells (up to 100mg/L), the other NPs induced a loss of cell viability in a dose-dependent manner. The comparative analysis of the loss of cell viability induced by the NPs with the ions released by NPs (NPs supernatant) suggested that SiO2 toxicity was mainly caused by the NPs themselves, Al2O3 and SnO2 toxic effects could be attributed to both the NPs and the respective released ions and Mn3O4 harmfulness could be mainly due to the released ions. Al2O3, Mn3O4, SiO2 and SnO2 NPs induced the loss of metabolic activity and the generation of intracellular ROS without permeabilization of plasma membrane. The co-incubation of yeast cells with MOx NPs and a free radical scavenger (ascorbic acid) quenched intracellular ROS and significantly restored cell viability and metabolic activity. These results evidenced that the intracellular generation of ROS constituted the main cause of the cytotoxicity exhibited by yeasts treated with the MOx NPs. This study highlights the importance of a ROS-mediated mechanism in the toxicity induced by MOx NPs.

Assembled Films of Sn-Doped In2O3 Plasmonic Nanoparticles on High-Permittivity Substrates for Thermal Shielding

This study presents the infrared (IR) plasmonic responses of assembled films consisting of Sn-doped In2O3 nanoparticles (ITO-NP films) placed on different substrates. The reflectance properties of the NP films are found to depend on substrate permittivity that affects the types of solar thermal-shielding. Increasing the substrate permittivity provides high reflectance in the IR range resulting from the plasmon modes and the interference effect in the NP films, as demonstrated through changes in the optical properties by tuning substrate permittivity. In particular, the plasmon modes played an important role in enhancing reflectance in the near-IR range. Induced image charges in the substrates produced field interactions with the plasmon modes in the NP films that are formed along the in-plane and out-of-plane directions, a consideration further verified by the strong image charges induced by metallic substrates consisting of ITO films. On the other hand, the interference effects contributed to the reflect...

Facile synthesis of In2O3 nanoparticles with high response to formaldehyde at low temperature

AbstractIn2O3 nanoparticles with uniform particle size (10‐25 nm) were obtained using the facile precipitation strategy at room temperature with following calcined treatment. The gas‐sensing performance of In2O3 nanoparticles with different calcined temperatures was investigated. The results demonstrated that the In2O3 nanoparticles calcined at 500°C exhibited highest sensing response (Ra/Rg = 68.1) to 10 ppm HCHO at 100°C with good selectivity, stability, reproducibility, and ultra‐low limit of detection (1 ppm). The results of XPS, UV, and other characterizations indicated that In2O3‐500 possessed the most absorbed oxygen species, the highest carrier mobility, and lowest band gap energies. Our work offers new insights into the development of sensing materials to the detection of volatile organic compounds (VOCs).

Effect of the indium myristate precursor concentration on the structural, optical, chemical surface, and electronic properties of InP quantum dots passivated with ZnS

In this work, we present results on the synthesis and characterization of InP and InP@ZnS quantum dots (QDs), grown using a single-step chemical synthesis method without injection of hot precursors, varying the concentration of indium myristate in both cases. It was found a color variation of the QDs in solution due to the quantum confinement effects when the nanoparticle sizes are smaller than the exciton Bohr radius. The band-gap energy of the samples was determined from the absorption spectra. From the photoluminescence (PL) spectra, emission peaks located in the range from 2.1 to 3.0 eV were observed. Furthermore, an enhanced PL emission due to a passivation effect in the ZnS-covered InP QDs was obtained. From X-ray diffraction (XRD), it was shown the presence of crystalline phases of the InP, ZnS, and In2O3 nanoparticles, with sizes ranging from 8 to 10 nm as determined by high resolution transmission electron microscopy (HR-TEM). From X-ray photoelectron spectroscopy (XPS) analysis, it was confirmed the formation of InP, ZnS, and In2O3; moreover, by means of a valence band analysis, the electronic structure of the samples was further investigated. The effect of the indium myristate precursor concentration on the optical, structural, surface chemical, and electronic properties of InP and InP@ZnS QDs will be discussed.

Rationally Designed Double-Shell Dodecahedral Microreactors with Efficient Photoelectron Transfer: N-Doped-C-Encapsulated Ultrafine In2 O3 Nanoparticles.

It is desirable but challenging to design efficient micro-/nanoreactors for chemical reactions. In this study, we have fabricated mesoporous double-shelled hollow microreactors composed of N-doped-C-coated ultrafine In2 O3 nanoparticles [N-C/In2 O3 HD (hollow dodecahedron)] by the thermolysis of a dodecahedral In-based framework in Ar atmosphere. The obtained N-C/In2 O3 HD exhibited excellent activity in the photocatalytic oxidative hydroxylation of a series of arylboronic acid substrates. This property can be attributed to its enhanced optical absorption and efficient separation of photo-generated electron-hole pairs, imparted by the unique structure and uniformly coated N-doped C layers. Furthermore, we found O2 .- to be the critical active species in the process of photocatalytic oxidative hydroxylation of arylboronic acids, and the formation mechanism of this radical is also proposed. Theoretical calculations further confirmed that the N-doped C layer serves as an electron acceptor and revealed the microscopic charge-carrier migration path through the In2 O3 /N-doped graphite interfaces. Thus, photo-generated electrons from hybrid states of In2 O3 , composed of In 5s and 2p orbitals, are transferred into the hybrid states of N-doped graphite, composed of C 2p and N 2p orbitals. The present study may be helpful for understanding and designing carbon-based micro-/nanoreactors for photocatalytic reactions, and may also be useful for investigating related micro-/nanoreactors.

Significantly enhanced photocatalytic performance of In2O3 hollow spheres via the coating effect of an N,S-codoped carbon layer

Hollow spheres assembled from N,S-codoped carbon layer coated In2O3 nanoparticles are developed to conduct efficient photocatalysis for oxidative hydroxylation of arylboronic acids.