RESUMO
Tin dioxide (SnO2) is the most-used semiconductor for gas sensing applications. However, lack of selectivity and humidity influence limit its potential usage. Antimony (Sb) doped SnO2 showed unique electrical and chemical properties, since the introduction of Sb ions leads to the creation of a new shallow band level and of oxygen vacancies acting as donors in SnO2. Although low-doped SnO2:Sb demonstrated an improvement of the sensing performance compared to pure SnO2, there is a lack of investigation on this material. To fill this gap, we focused this work on the study of gas sensing properties of highly doped SnO2:Sb. Morphology, crystal structure and elemental composition were characterized, highlighting that Sb doping hinders SnO2 grain growth and decreases crystallinity slightly, while lattice parameters expand after the introduction of Sb ions into the SnO2 crystal. XRF and EDS confirmed the high purity of the SnO2:Sb powders, and XPS highlighted a higher Sb concentration compared to XRF and EDS results, due to a partial Sb segregation on superficial layers of Sb/SnO2. Then, the samples were exposed to different gases, highlighting a high selectivity to NO2 with a good sensitivity and a limited influence of humidity. Lastly, an interpretation of the sensing mechanism vs. NO2 was proposed.
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Antimony-doped tin oxide nanoparticles (ATO NPs) were loaded on a filter paper where they act as a peroxidase mimic without electrochemical or photochemical assistance. The peroxidase mimicking activity is distinctly improved compared to most known nanomaterials and to natural horseradish peroxidase. The catalytic properties depend on the amount of antimony doped into the ATO NPs. A glucose assay was worked out that is based on (a) the oxidation of glucose by glucose oxidase under formation of H2O2, (b) the oxidation of 3,3,5,5-tetramethybenzidine (TMB) catalyzed by ATO NPs to form blue-green colored oxidized TMB on the surface of the paper. The coloration was analyzed with a smartphone. The method has a 21 µM limit of detection and a linear range that extends from 0.5 to 80 mM. Graphical abstract Antimony-doped tin oxide nanoparticles (ATO NPs) combined with 3,3,5,5-tetramethybenzidine (TMB) and triethylamine were coated on the filter paper. After addition of sample solution, the blue-green colored oxidized TMB was generated and recorded by a digital camera.
Assuntos
Antimônio/química , Materiais Biomiméticos/química , Corantes/química , Glucose/análise , Nanopartículas Metálicas/química , Peroxidases/química , Smartphone/instrumentação , Compostos de Estanho/química , Benzidinas/química , Técnicas Biossensoriais/métodos , Catálise , Colorimetria/métodos , Etilaminas/química , Glucose Oxidase/química , Limite de Detecção , OxirreduçãoRESUMO
Li-rich layered oxides (LLOs) with high specific capacities are favorable cathode materials with high-energy density. Unfortunately, the drawbacks of LLOs such as oxygen release, low conductivity, and depressed kinetics for lithium ion transport during cycling can affect the safety and rate capability. Moreover, they suffer severe capacity and voltage fading, which are major challenges for the commercializing development. To cure these issues, herein, the synthesis of high-performance antimony-doped LLO nanofibers by an electrospinning process is put forward. On the basis of the combination of theoretical analyses and experimental approaches, it can be found that the one-dimensional porous micro-/nanomorphology is in favor of lithium-ion diffusion, and the antimony doping can expand the layered phase lattice and further improve the lithium ion diffusion coefficient. Moreover, the antimony doping can decrease the band gap and contribute extra electrons to O within the Li2MnO3 phase, thereby enhancing electronic conductivity and stabilizing lattice oxygen. Benefitting from the unique architecture, reformative electronic structure, and enhanced kinetics, the antimony-doped LLO nanofibers possess a high reversible capacity (272.8 mA h g-1) and initial coulombic efficiency (87.8%) at 0.1 C. Moreover, the antimony-doped LLO nanofibers show excellent cycling performance, rate capability, and suppressed voltage fading. The capacity retention can reach 86.9% after 200 cycles at 1 C, and even cycling at a high rate of 10 C, a capacity of 172.3 mA h g-1 can still be obtained. The favorable results can assist in developing the LLO material with outstanding electrochemical properties.
RESUMO
ZnO-based oxide films are emerging as high-performance semiconductors for field-effect transistors (FETs) in optoelectronics. Carrier mobility and stability in these FETs are improved by introducing indium (In) and gallium (Ga) cations, respectively. However, the strong trade-off between the mobility and stability, which come from In or Ga incorporation, still limits the widespread use of metal oxide FETs in ultrahigh pixel density and device area-independent flat panel applications. We demonstrated that the incorporation of antimony (Sb) cations in amorphous zinc indium oxide (ZIO) simultaneously enhanced the field-effect mobility (µFET) and electrical stability of the resulting Sb-doped ZIO FETs. The rationale for the unexpected synergic effect was related to the unique electron configuration of Sb5+ ([Kr]4d105s05p0). However, the benefit of Sb doping was not observed in the zinc tin oxide (ZTO) system. All the Sb-doped ZTO FETs suffered from a reduction in µFET and a deterioration of gate bias stress stability with an increase in Sb loading. This can be attributed to the formation of heterogeneous defects due to Sb-induced phase separation and the creation of Sb3+ induced acceptor-like trap states.
RESUMO
Kesterite Cu2 ZnSn(S,Se)4 (CZTSSe) is obtained using a facile precursor-solution method followed by selenization. Power-conversion efficiency of 6.0 % is achieved and further improved to 8.2 % after doping the absorber with 0.5â mol % Sb. XRD and Raman spectroscopy show similar characteristics for the undoped and doped CZTSSe. Increasing the Sb concentration increases the grain size and lowers the series resistance. However, further Sb doping beyond 0.5â mol % degrades device performance due to lower open-circuit voltage (and therefore lower fill factor). The effect of Sb doping and the doping concentration are investigated by power-dependent and temperature-dependent photoluminescence studies, revealing that trap density is significant reduced with 0.5â mol % Sb doping. Additional doping beyond 0.5â mol % creates more defects that quench the photoexcited carriers and decrease the open-circuit voltage.
Assuntos
Antimônio/química , Fontes de Energia Elétrica , Etilenoglicóis/química , Cobre/química , Selênio/química , Energia Solar , Soluções , Sulfetos/química , Estanho/química , Zinco/químicaRESUMO
Thin films of antimony doped tin sulphide (SnS:Sb) with different antimony concentrations have been prepared by the spray pyrolysis technique at the substrate temperature of 350°C. The physical properties of the films were studied as a function of increase in antimony dopant concentration (up to 10at.%). The films were characterized by different techniques to study their structural, optical and electrical properties. The X-ray diffraction analysis revealed that the films were polycrystalline in nature and having orthorhombic crystal structure with a preferred orientation in (111) direction. Due to Sb doping, the crystalline quality and the preferential orientation of SnS films were improved up to 6at.% of doping concentration. However, when doping concentration was increased above 6at.%, the crystalline quality and the preferential orientation of SnS films was deteriorated. Atomic force microscopy images revealed that the surface roughness of the films increased due to Sb doping. Optical measurements showed that the band gap values decreased from 1.60eV to 1.15eV with increase in Sb concentration. The photoluminescence spectra displayed that all the samples have an emission peak centered at 760nm. At 6at.% of Sb doping, the film has the lowest resistivity of 2.598×10(-2)Ωcm while the carrier concentration was high.