Tin Oxide Semiconductor Research Articles

Influence of support materials on the electroactive behavior, structure and gene expression of wild type and GSU1771-deficient mutant of Geobacter sulfurreducens biofilms.

Geobacter sulfurreducens DL1 is a metal-reducing dissimilatory bacterium frequently used to produce electricity in bioelectrochemical systems (BES). The biofilm formed on electrodes is one of the most important factors for efficient electron transfer; this is possible due to the production of type IV pili and c-type cytochromes that allow it to carry out extracellular electron transfer (EET) to final acceptors. In this study, we analyzed the biofilm formed on different support materials (glass, hematite (Fe2O3) on glass, fluorine-doped tin oxide (FTO) semiconductor glass, Fe2O3 on FTO, graphite, and stainless steel) by G. sulfurreducens DL1 (WT) and GSU1771-deficient strain mutant (Δgsu1771). GSU1771 is a transcriptional regulator that controls the expression of several genes involved in electron transfer. Different approaches and experimental tests were carried out with the biofilms grown on the different support materials including structure analysis by confocal laser scanning microscopy (CLSM), characterization of electrochemical activity, and quantification of relative gene expression by RT-qPCR. The gene expression of selected genes involved in EET was analyzed, observing an overexpression of pgcA, omcS, omcM, and omcF from Δgsu1771 biofilms compared to those from WT, also the overexpression of the epsH gene, which is involved in exopolysaccharide synthesis. Although we observed that for the Δgsu1771 mutant strain, the associated redox processes are similar to the WT strain, and more current is produced, we think that this could be associated with a higher relative expression of certain genes involved in EET and in the production of exopolysaccharides despite the chemical environment where the biofilm develops. This study supports that G. sulfurreducens is capable of adapting to the electrochemical environment where it grows.

A fluorinated greenhouse gas sensor based on N-doped tin oxide materials

A novel N-doped tin oxide semiconductor metal oxide sensor has been successfully fabricated for fluorinated greenhouse gas sensing.

An artificially-intelligent cornea with tactile sensation enables sensory expansion and interaction

We demonstrate an artificially-intelligent cornea that can assume the functions of the native human cornea such as protection, tactile perception, and light refraction, and possesses sensory expansion and interactive functions. These functions are realized by an artificial corneal reflex arc that is constructed to implement mechanical and light information coding, information processing, and the regulation of transmitted light. Digitally-aligned, long and continuous zinc tin oxide (ZTO) semiconductor fabric patterns were fabricated as the active channels of the artificial synapse, which are non-toxic, heavy-metal-free, low-cost, and ensure superior comprehensive optical properties (transmittance >99.89%, haze <0.36%). Precisely-tuned crystal-phase structures of the ZTO fibers enabled reconfigurable synaptic plasticity, which is applicable to encrypted communication and associative learning. This work suggests new strategies for the tuning of synaptic plasticity and the design of visual neuroprosthetics, and has important implications for the development of neuromorphic electronics and for visual restoration.

The hydrothermal synthesis of SNO2 nanoparticles derived from tin chloride precursor for the electron transport layer of perovskite solar cells

Tin oxide (SnO2) semiconductor is recognized as a highly promising material for the electron transport layer (ETL) in perovskite solar cells (PSC) due to their wide band gap energy and high electron mobility. This material has been considered as the potential alternative material for substituting the conventional titanium dioxide (TiO2). In the form of nanostructure material, it is expected that SnO2 as the ETL in PSC device can be significantly improved owing to its high surface area leading to more intensive photon absorption. In this present study, SnO2 nanoparticles were synthesized via the hydrothermal method with temperature variations ranging from 120 °C to 160 °C for 16 hours. The as-synthesized samples were characterized using X-ray diffraction (XRD), scanning electron microscope (SEM), and an ultraviolet–visible (UV-Vis) spectrophotometer. The SnO2 nanoparticles were then integrated into the PSC device as the ETL, and the performance testing was conducted using a semiconductor parameter analyzer to obtain the I-V curve. On the basis of investigation results, it has been found that the temperature used during the hydrothermal process plays a crucial role in determining the crystallinity, morphology, and band gap energy of the SnO2 nanoparticles. The results of the PSC performance test indicate that SnO2 nanoparticles synthesized at a hydrothermal temperature of 150 °C demonstrated the highest power conversion efficiency (PCE) of 3.89 %. This outcome confirms the viability of SnO2 nanoparticles produced through the hydrothermal method

Efficiently adsorption and degradation of Blue 133 and Reactive Red 66 dyes under UV and visible light using Tin(II) oxide/chitosan in ethyl pyridinium iodide ionic liquid

ABSTRACT The expansion of dye pollutants overburdened the environment and consequently increased pollution. Photodegradation and adsorption are one of the most efficient processes for water treatment. Metal oxides have been studied for this application. Amongst of metal oxides, Tin(II) oxide semiconductor and its modification are interesting. In this work, Tin(II) oxide nanoplates/chitosan in an ionic liquid media was prepared. This mild method was done in ethyl pyridinium iodide ionic liquid. The structural character of this composite was examined by XRD, TEM, AFM, and DRS techniques. The TEM results showed that this composite consisted of plate morphology. The photocatalysis experiments were carried out by irradiating in ultraviolet and visible light of dyes containing Blue 133 (B133), and Reactive Red 66 (R66). By combining the good semiconductor properties of Tin(II) oxide and the high adsorption of chitosan, the composite is promising for the photocatalytic removal of organic dyes. The Langmuir adsorption isotherm model was used to study the adsorption-photodegradation process of dye molecules on this composite. The results revealed that the highest removal efficiency of Blue 133 under visible light was 45.48%, whereas achieved under ultraviolet light 98.41%. Also, the degradation percentage of Reactive Red 66 by composite remained 98.85%, under ultraviolet light, the removal efficiency decreased to 46.12%, while visible light. The presence of chitosan enhanced the photodegradation-adsorption properties directed towards visible light.

Cu-doped flower-like SnO2 architecture toward promoting SO2 detection: Fast equilibrium and low trace monitoring

Design of practical tin oxide (SnO2) semiconductor gas sensors is fundamental strategy to detect hazardous gases such as SO2. However, challenges remain in the detection of SO2 gas at low concentration and slow equilibrium between gas adsorption and desorption. Herein, the superior performance of nanostructured of Cu-doped flower-like SnO2 architecture via feasible hydrothermal method demonstrated for the detection of SO2 gas at low concentration (1–20 ppm) and fast gas adsorption and desorption equilibrium (14 s) towards 5 ppm SO2. Furthermore, the as fabricated 3 mol% Cu-doped SnO2 shows an outstanding gas response (∼ 4.05–20 ppm SO2) at the working temperature of 300 ℃. The Cu-doping strategy may pave the way to ultrasensitive SO2 gas sensor possessing low trace monitoring and fast equilibrium ability to satisfy the increasing demand for toxic SO2 gas detection.

Large-lateral-area SnO2 nanosheets with a loose structure for high-performance acetone sensor at the ppt level

Gas sensors with high sensitivity and high selectivity are required in practical applications to distinguish between target molecules in the detection of volatile organic compounds, real-time security alerts, and clinical diagnostics. Semiconducting tin oxide (SnO2) is highly regarded as a gas-sensing material due to its exceptional responsiveness to changes in gaseous environments and outstanding chemical stability. Herein, we successfully synthesized a large-lateral-area SnO2 nanosheet with a loose structure as a gas sensing material by a one-step facile aqueous solution process without a surfactant or template. The SnO2 sensor exhibited a remarkable sensitivity (Ra/Rg = 1.33) at 40 ppt for acetone, with a theoretical limit of detection of 1.37 ppt, which is the lowest among metal oxide semiconductor-based gas sensors. The anti-interference ability of acetone was higher than those of pristine SnO2 and commercial sensors. These sensors also demonstrated perfect reproducibility and long-term stability of 100 days. The ultrasensitive response of the SnO2 nanosheets toward acetone was attributed to the specific loose large lateral area structure, small grain size, and metastable (101) crystal facets. Considering these advantages, SnO2 nanosheets with larger lateral area sensors have great potential for the detection and monitoring of acetone.

Resistive switching characteristics of interfacial device based on Bi2Ti2O7 film

To solve the problem of information storage and explore a new generation of memory, Au/Bi2Ti2O7/NiO/ITO (Indium tin oxide semiconductor) resistive variable memory is fabricated and its resistive switching characteristics are studied. The device has diode-like rectifier characteristics and shows good durability and stability under 100 cycles of read−and−write tests. At the reading voltage of 0.44 V, the resistive switching ratio of the device reaches 102. Combining the O 1 s spectrum of XPS and further analyzing the I − V double logarithmic curve, it is found that the conduction mechanism of the device is mainly related to the ohmic conduction mechanism and the space charge limiting current mechanism, and its resistive switching behavior is related to the migration of oxygen vacancies to change the interface barrier.

Dielectric constant enhancement of poly 4-vinylphenol (PVPh) via graphene flakes incorporation through electrospray atomization for energy storage.

We report on the fabrication of hybrid composite poly 4-vinlyphenol (PVPh)/graphene thin film via cost-effective electrospray atomization deposition technique. Thin films fabricated through manipulating deposition technique in two different ways which are blending and layer by layer (LBL). For investigation of PVPh/graphene hybrid composite dielectric behavior in comparison to PVPh; three asymmetric MIS thin film capacitors were fabricated, where dielectric thin films (i) PVPh and (ii & iii) hybrid composite thin films PVPh/graphene (blended and LBL) were sandwiched between electrodes i.e. indium tin oxide (ITO) and p-type semiconductor poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS). The dielectric properties of the thin films were characterized for frequencies 1 to 100 kHz while utilizing the MIS thin film capacitors. The capacitance obtained at 1 kHz frequency for PVPh/graphene (LBL) dielectric layer at the voltage range ±10 volts was 8.5 mF cm-2 while for blended PVPh/graphene thin film the capacitance at the voltage range ±3 volts was 0.40 μF cm-2 and for pristine PVPh as dielectric layer the capacitance at voltage range ±1 volts was 1.45 μF cm-2. Similarly, even at higher frequencies up to 100 kHz, the PVPh/graphene (LBL) showed stable behavior. Thus, the composite PVPh/graphene (LBL) thin film has a better dielectric nature compared to the composite PVPh/graphene (blended) thin film, even at higher frequencies with larger operational voltage window. This distinguishing nature of the composite PVP/graphene (LBL) is attributed to increase in dielectric constant due to graphene flakes in between PVPh. For the thin films LBL and blended PVPh/graphene, the calculated dielectric constant at 10 kHz is 6.7 and 0.023 while at 100 kHz it is 2 and 0.0167, respectively.

Noise spectroscopy based numerical modelling of chemisorption on SnO2 surface for CO gas sensing applications

The gas sensor response of the tin oxide (SnO2) semiconductor toward carbon monoxide (CO) gas has been simulated using the noise spectroscopy technique. The Wolkenstein gas adsorption model is used to calculate the surface coverage of environmental oxygen ions and target gas molecules. The interaction of CO gas molecules with the negatively charged oxygen ions has been incorporated in the numerical model. The equilibrium charge neutrality condition of the semiconductor material has been solved as a function of gas adsorption parameters like surface coverage, temperature, pressure and surface potential. Eventually, the power density spectrum (PDS) of the electrical conductance of the sensing layer was calculated before and after the gas adsorption conditions. It has been observed that the semiconductor band bending increases sharply at a certain concentration of environmental oxygen gas concentration (10−4 to 10−3 atm). At a temperature of 480 K, a steep decrease in surface potential was observed. This temperature range of maximum sensor response was optimized for calculating noise spectrum of electrical conductivity fluctuations at equilibrium condition of adsorption-desorption. The cutoff frequency (109 Hz) was calculated using normalized PDS of electrical conductance. The gas sensor response was calculated as a ratio of film conductance before and after the gas adsorption as a function of gas pressure and surface temperature at the calculated cutoff frequency. The increase in sensor response was observed with the increase in CO partial pressure as a function of temperature for a specific cut off frequency. The comparison of sensor response of the presented model has been demonstrated with another published numerical model. The presented model shows improved sensor response for higher (>10−8 atm) CO partial pressure.

P-type conversion of distorted SnOx thin film by mild thermal annealing treatment in pure N2 environment

Tin oxide semiconductors can achieve both n- and p-type conduction, depending on the oxidation state of Sn. An n-type conduction can easily be fabricated; however, considerable optimization is required for fabrication of a p-type behavior. In this study, n-type SnOx thin films, prepared by reactive magnetron sputtering, were converted to p-type behavior using only post-deposition annealing at 600 °C in a pure nitrogen atmosphere. The annealing-temperature-dependent electrical properties of the SnOx thin films led to a remarkable increase in the yield of p-type behavior at 600 °C. X-ray diffraction analysis revealed that the SnOx film had a SnO2-dominant crystal phase and also suggested that N2 molecules dissociated at 600 °C and filled the oxygen vacancy (VO) site as atomic nitrogen. A detailed analysis of the binding state by x-ray photoelectron spectroscopy confirmed an increase in SnO-derived components, the appearance of peaks derived from N–Sn bonding, a decrease in VO caused by nitrogen doping, and charge transfer. Thus, we found that addition of nitrogen atoms promotes a chemical shift from Sn4+ to Sn2+ and that simultaneously passivates VO and contributes to hole generation.

A Theoretical Investigation of Charge Transfer Dynamics from Sensitized Molecule D35CPDT Dye to SnO_2 and TiO_2 Semiconductor

In this research, the dynamics process of charge transfer from the sensitized D35CPDT dye to tin(iv) oxide( ) or titanium dioxide ( ) semiconductors are carried out by using a quantum model for charge transfer. Different chemical solvents Pyridine, 2-Methoxyethanol. Ethanol, Acetonitrile, and Methanol have been used with both systems as polar media surrounded the systems. The rate for charge transfer from photo-excitation D35CPDTdye and injection into the conduction band of or semiconductors vary from a to for system and from a to for the system, depending on the charge transfer parameters strength coupling, free energy, potential of donor and acceptor in the system. The charge transfer rate in D35CPDT / the system is larger than the rate in D35CPDT/ a system depending on transition energy and driving energy. However, the charge transfer for both systems to be large is associated with large transition energy, decreasing driving energy and potential, and increasing strength coupling with Methanol solvent.

Synthesis and applications of tin oxide nanoparticles: An overview

The n-type semiconductor Tin oxide (SnO2), also known as stannic oxide, has received a lot of attention in the semiconductor filed owing to its different applications such as energy saving coatings, gas sensors, photocatalysis, fabrication of glasses, ceramics and so on. In order to tail the properties of nanomaterials, synthesis route plays an important role by altering its physical, chemical and thermal properties. Also, different morphological, structural and optical features lead to better performance of nanomaterials. The present review article elucidates the materials, synthesis conditions and outcomes of various synthesis routes which are used to fabricate SnO2 nanoparticles. Further, the applications of tin oxide nanoparticles in various fields are elaborated in detail. In the last section, we have discussed the role of synthesis routes and future prospects in SnO2 research field.

Metastable Antimony‐Doped SnO2 Quantum Wires for Ultrasensitive Gas Sensors

AbstractDoping is fundamental to controlling the properties of bulk semiconductors. Although the antimony (SbV)‐doping strategy is widely employed in the design of practical tin oxide (SnO2) semiconductor gas sensors for higher signal‐to‐noise ratio, challenges remain to dope semiconductor nanocrystals since the diffusion of impurity atoms may be far from realized at the synthesis temperatures used. Herein, a metastable Sb‐doping strategy is proposed to overcome the serious receptor‐versus‐transducer mismatch in SnO2 quantum wires (QWs). The solvothermal synthesis of colloidal SbIII‐doped SnO2 QWs has been conducted at 180 °C, whereby the antimony amount is varied to optimize the structural and morphological properties for higher surface activity and electrical conductivity. A unique n‐type doping mechanism arising from the stable presence of SbIII on SnO2 (101) facets via SnII‐O‐SbIII is demonstrated. Further, the use of sensitive (down to 4 ppb, the lowest detection limit ever reported), fast (response and recovery time of 43 s and 96 s toward 10 ppm of H2S) gas sensors for H2S detection at near room temperature (40 °C) is showcased. The metastable Sb‐doping strategy may pave the way to ultrasensitive gas sensor possessing low power consumption and excellent integration compatibility to satisfy the increasing demand for ubiquitous and reliable gas detection.

Artificial photosynthesis: photoanodes based on polyquinoid dyes onto mesoporous tin oxide surface

Dye-sensitized photoelectrochemical cells represent an appealing solution for artificial photosynthesis, aimed at the conversion of solar light into fuels or commodity chemicals. Extensive efforts have been directed towards the development of photoelectrodes combining semiconductor materials and organic dyes; the use of molecular components allows to tune the absorption and redox properties of the material. Recently, we have reported the use of a class of pentacyclic quinoid organic dyes (KuQuinone) chemisorbed onto semiconducting tin oxide as photoanodes for water oxidation. In this work, we investigate the effect of the SnO2 semiconductor thickness and morphology and of the dye-anchoring group on the photoelectrochemical performance of the electrodes. The optimized materials are mesoporous SnO2 layers with 2.5 μm film thickness combined with a KuQuinone dye with a 3-carboxylpropyl-anchoring chain: these electrodes achieve light-harvesting efficiency of 93% at the maximum absorption wavelength of 533 nm, and photocurrent density J up to 350 μA/cm2 in the photoelectrochemical oxidation of ascorbate, although with a limited incident photon-to-current efficiency of 0.075%. Calculations based on the density functional theory (DFT) support the role of the reduced species of the KuQuinone dye via a proton-coupled electron transfer as the competent species involved in the electron transfer to the tin oxide semiconductor. Finally, a preliminary investigation of the photoelectrodes towards benzyl alcohol oxidation is presented, achieving photocurrent density up to 90 μA/cm2 in acetonitrile in the presence of N-hydroxysuccinimide and pyridine as redox mediator and base, respectively. These results support the possibility of using molecular-based materials in synthetic photoelectrochemistry.Graphic abstract

In Situ Local Oxidation of SnO Induced by Laser Irradiation: A Stability Study.

In this work, semiconductor tin oxide (II) (SnO) nanoparticles and plates were synthesized at room conditions via a hydrolysis procedure. X-ray diffraction (XRD) and transmission electron microscopy (TEM) confirmed the high crystallinity of the as-synthesized romarchite SnO nanoparticles with dimensions ranging from 5 to 16 nm. The stability of the initial SnO and the controlled oxidation to SnO2 was studied based on either thermal treatments or controlled laser irradiation using a UV and a red laser in a confocal microscope. Thermal treatments induced the oxidation from SnO to SnO2 without formation of intermediate SnOx, as confirmed by thermodiffraction measurements, while by using UV or red laser irradiation the transition from SnO to SnO2 was controlled, assisted by formation of intermediate Sn3O4, as confirmed by Raman spectroscopy. Photoluminescence and Raman spectroscopy as a function of the laser excitation source, the laser power density, and the irradiation duration were analyzed in order to gain insights in the formation of SnO2 from SnO. Finally, a tailored spatial SnO/SnO2 micropatterning was achieved by controlled laser irradiation with potential applicability in optoelectronics and sensing devices.

Size Effects of Vacancy Formation and Oxygen Adsorption on Gas- Sensitive Tin Oxide Semiconductor: A First Principle Study

Background: Oxygen behaviors play essential roles in the receptor function in the gassensing mechanism of SnO2 semiconductors, the size effect of which is a fundamental phenomenon for the development of gas sensors. Objective: This article discusses the size effect on the oxygen behaviors in the gas-sensitive SnO2 semiconductor. Methods: : The first principle calculation was used to investigate size effect on formation of oxygen vacancies and adsorption of oxygen species in the SnO2 semiconductor. The electrical characteristics of conductivity, band gap and electron transfer in SnO2 crystallites were analyzed by density of states and the Mulliken population. Results: The defect of surface bridge oxygen has the lowest formation energy, and it is most likely to form in the SnO2 semiconductor. The adsorption energies for O- and O2 - are from 1.717 to 3.791 eV and 2.371 to 4.683 eV, respectively. The Mulliken population distribution illustrates that O 2p orbit captures the electrons from the orbits of Sn 5s and 5p as well as O 2s. Conclusion: The formation energies of oxygen defects in complete and defective SnO2 super cells are of positive correlation with crystallite size. The carrier concentration and conductivity are improved by the incremental crystallite size. The adsorption energies of O- and O2 - species on defective SnO2 super cells increase with crystallite size. With the assistance of connecting Sn atoms, the adsorbates of O- and O2 - are able to capture electrons from the inner region of crystallites, resulting in an expansion of depletion layer.

Rare-Earths (Pr, Pm, Sm, Dy, and Tm)-Doped SnO2: Ab Initio, Mean Field, and Monte Carlo Calculation

In this paper, we consider the electronic and magnetic proprieties of five rare-earths (RE = Pr, Pm, Sm, Dy, and Tm)-doped Tin (IV) oxide semiconductor Sn1 − xRExO2 (x = 0.10) in the rutile structure. The presence of the 4f orbitals in our structures pushes us to choose the local density approximation with Self-interaction-corrected (LDA-SIC) to improve the obtained results. We also discuss the critical temperature retrieved from the study the total magnetizations and the susceptibilities using Monte Carlo simulations for each rare-earth element used.

Charge Trapping Augmented Switchable Sub-band-gap Photoresponse of Zinc–Tin Oxide Thin-Film Transistor

In this study, a charge trapping thin-film transistor (TFT) is demonstrated based on a zinc–tin oxide (ZTO) semiconductor channel layer and a stack of AlOx/AZO nanoparticles/SiO2 as the gate dielec...

Developments of MEMS Gas Sensors Based on Tin Oxide semiconductors: Application to Battery-Powered Household Gas Alarms

Developments of MEMS Gas Sensors Based on Tin Oxide semiconductors: Application to Battery-Powered Household Gas Alarms