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Boosting the efficiency of carbon-based planar CsPbBr3 perovskite solar cells by a modified multistep spin-coating technique and interface engineering
摘要： All-inorganic CsPbBr3 perovskite solar cells (PSCs) have attracted tremendous attentions in the photovoltaic field these days in view of their outstanding stability, especially thermal stability. However, the bromide-rich perovskite, such as CsPbBr3, always suffer from a low phase-purity and poor morphology synthesized by traditional two-step deposition route. Herein, we demonstrate a facile multistep spin-coating strategy to fabricate high-quality CsPbBr3 films on the low-temperature processed compact TiO2 (c-TiO2) electron transport layer (ETL) of the carbon-based PSCs. As-prepared films exhibit more homogeneous with higher CsPbBr3-phase purity and larger average grain sizes up to 1 μm, compared to those prepared through traditional two-step deposition process. The champion power conversion efficiency (PCE) of the planar CsPbBr3 PSC is boosted from 7.05% to 8.12%, getting an increase by 15.2%, due to the increased crystallinity and light-harvesting ability as well as reduced trap states of the CsPbBr3 film. To further enhance the device performance, a SnO2 thin layer with much higher carrier mobility than TiO2 is introduced to passivate the c-TiO2 ETL. It is found that the SnO2 layer can not only improve the surface morphology of the ETL, but also reduce the current shunting pathways in the c-TiO2. The TiO2/SnO2 bilayered ETL possesses a superior electron extraction capability, beneficial to the charge transport and suppression of the interfacial trap-assisted recombination. The best-performing TiO2/SnO2-based CsPbBr3 PSC delivers an excellent fill factor of 0.817 and a high PCE of 8.79%, which is the highest efficiency for planar CsPbBr3 PSCs reported to date. More importantly, the unencapsulated all-inorganic PSCs show a promising humidity and thermal stability with no decline in efficiency when stored in ambient air at room temperature (25 oC) for over 1000 h and 60 oC for one month, respectively. Our work pave the ways for practical applications of cost-effective, highly efficient and stable all-inorganic PSCs.
关键词： carbon-based,TiO2/SnO2,low cost,CsPbBr3,multistep spin-coating,high efficiency and stability
更新于2025-09-09 09:28:46
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Facile synthesis of PtPd/SnO2 nanocatalysts with good photo-electrocatalytic property
摘要： PtPd/SnO2 nanocatalysts were synthesized by a simple one-step way of plasma technique in an aqueous solution of tin(II) chloride by using Pt and Pd metal wire as the electrode pair. PtPd/SnO2/GNs composite catalysts were prepared by an ultrasonic mixing PtPd/SnO2 with GNs (GNs, graphene nanosheets). The PtPd/SnO2/GNs composite catalysts exhibit a signi?cantly enhanced electrocatalytic performance, cycling stability and CO-poisoning tolerance towards methanol oxidation both under acidic and alkaline condition, which attributed to the synergism of PtPd alloy and SnO2. What’s more, the current density of PtPd/SnO2/GNs composite catalyst was obviously improved under light illumination, with 10,029 mA mgPt?1 which was about 1.3 times higher than that without light illumination under alkaline condition. The novel one-step plasma technique could provide a useful approach for fabricating other highly e?cient electrocatalysts.
关键词： PtPd nano-alloy,Nanocomposites,Methanol electro-oxidation,Solution plasma,SnO2 nanoparticles
更新于2025-09-09 09:28:46
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Hemoglobin Immobilization on Multiporous Nanofibers of SnO <sub/>2</sub> and Chitosan Composite for Hydrogen Peroxide Sensing
摘要： A multiporous nanofiber (MPNFs) of SnO2 and chitosan has been used for the immobilization of a redox protein, hemoglobin (Hb), onto the surface of glassy carbon electrode (GCE). The multiporous nanofiber of SnO2 that has very high surface area is synthesized by using electrospinning technique through controlling the tin precursor concentration. Since the constructed MPNFs of SnO2 exposes very high surface area, it increases the efficiency for biomolecule-loading. The morphology of fabricated electrodes is examined by SEM observation and the absorbance spectra of Hb/(MPNFs) of SnO2 are studied by UV-Vis analysis. Cyclic Voltammetry and amperometry are employed to study and optimize the performance of the resulting fabricated electrode. After fabrication of the electrode with the Hb and MPNFs of SnO2, a direct electron transfer between the protein’s redox centre and the glassy carbon electrode was established. The modified electrode has showed a couple of redox peak located at ?0.29 V and ?0.18 V and found to be sensitive to H2O2. The fabricated electrode also exhibited an excellent electrocatalytic activity towards the reduction of H2O2. The catalysis currents increased linearly to the H2O2 concentration in a wide range of 5.0 × 10?6–1.5 × 10?4 M. Overall experimental results show that MPNFs of SnO2 has a role towards the enhancement of the electroactivity of Hb at the electrode surface. Thus the MPNFs of SnO2 is a very promising candidate for future biosensor applications.
关键词： Multiporous SnO2 Nanofiber,Hemoglobin,Electrical Contact,H2O2 Sensing,Direct Electrochemistry
更新于2025-09-09 09:28:46
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Solvent Assisted Synthesis of Tin-Zinc Oxide Nanoparticles: Structural Characterization and Antimicrobial Activity
摘要： Tin oxide doped zinc oxide nanoparticles (SnO2/ZnO) were prepared via deposition precipitation method with different molar ratios of tin oxide and effect of variation of concentrations of dopant (SnO2) was observed for physical and chemical properties of these nanoparticle. The structural properties of nanoparticles were characterized by thermogravimetric analysis, fourier transform infrared spectrometry, powder X-ray diffraction, scanning electron microscopy and transmission electron microscopy. Their crystallite and structural properties deduced a clear decrement in crystallite size from 9.95 to 2.54 nm. Doping of tin significantly enhanced the photoluminescence and antibacterial properties of SnO2/ZnO nanoparticles. The photoluminescence studies exhibited a strong emission of green-yellow band at 470 nm. The antibacterial activities of these nanoparticles were investigated against Pasteurellamultocida and Escherichia coli by using disc diffusion method.
关键词： Deposition precipitation,SnO2/ZnO,Antimicrobial activity,Photoluminescence
更新于2025-09-09 09:28:46
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Antibacterial and photocatalytic activity of hydrothermally synthesized SnO2 doped GO and CNT under visible light irradiation
摘要： Bacterial and dye pollution are major problems with wastewater treatment. An increasing number of photocatalysts are being used in industry to kill bacterial and reduce pollution. In the present study, highly stable SnO2-doped nanocomposites have been prepared successively by a hydrothermal method. The synthesized nanocomposite was characterized using a range of techniques, such as X-ray diffraction, field emission scanning electron microscopy with energy dispersive X-ray spectroscopy and electron probe micro analysis, ultraviolet–visible spectroscopy, Fourier transform infrared spectroscopy, and high resolution transmission electron microscopy (HR-TEM). The nanocomposites showed significant dose-dependent bactericidal activity in the disc diffusion assay and cell viability test. The S-GO-SnO2 200 μg/mL produced a cell viability of 184.3 ± 11.71 and 172.3 ± 3.05 × 106 CFU/mL for E. coli and P. graminis, respectively. The S-GO-SnO2 showed significant photocatalytic degradation against MB in 120 min. The photocatalyst S-GO-SnO2 showed 159 and 161 × 106 CFU/mL at 150 min in E. coli and P. graminis, respectively. The cells treated with photocatalytic SnO2-doped nanocomposites showed 50% cell death. HR-TEM revealed 50% cell growth inhibition by bacterial damage. This photocatalytic SnO2-doped nanocomposite is a good candidate for treating industrial wastewater treatment contaminated with dyes and bacteria.
关键词： Antibacterial activity,Photocatalytic activity,Hydrothermal syntheses,Visible light irradiation,SGO-SnO2,SCNT-SnO2
更新于2025-09-04 15:30:14
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Effect of Sputtering Technique and Properties of TiO2 Doped with SnO2 Thin Films
摘要： Doped oxide materials of 90% of TiO2 was doped with 10% of SnO2 that target has been deposited at a substrate temperature of 250°C for 1 hour by using DC Sputtering technique. The as synthesized target was TiO2-SnO2 was used to deposit on the glass substrates. The deposited oxide thin film was characterized for their structural, surface morphological, electrical and optical properties. X-ray diffraction is used for studying the nature and structure, scanning electron, atomic force microscopy and transmission electron microscopy are used to identify the surface morphology of the prepared films. The Van der Pauw technique is employed to measure electrical resistivity and Hall mobility of the film. Wide varieties of methods are available for measuring thin film thicknesses. Stylus profilometry will be helpful to find the thickness of the film, structural studies by X-ray, and micros structural analysis of the film.
关键词： Scanning Electron microscopy (SEM),Stylus profilometry,TiO2-SnO2,X-ray diffraction (XRD),UV-Vis-NIR spectrometer
更新于2025-09-04 15:30:14
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Anisotropic optical properties of highly doped rutile SnO <sub/>2</sub> : Valence band contributions to the Burstein-Moss shift
摘要： The interband absorption of the transparent conducting semiconductor rutile stannic oxide (SnO2) is investigated as a function of increasing free electron concentration. The anisotropic dielectric functions of SnO2:Sb are determined by spectroscopic ellipsometry. The onsets of strong interband absorption found at different positions shift to higher photon energies with increasing free carrier concentration. For the electric field vector parallel to the optic axis, a low energy shoulder increases in prominence with increasing free electron concentration. We analyze the influence of different many-body effects and can model the behavior by taking into account bandgap renormalization and the Burstein-Moss effect. The latter consists of contributions from the conduction and the valence bands which can be distinguished because the nonparabolic conduction band dispersion of SnO2 is known already with high accuracy. The possible origins of the shoulder are discussed. The most likely mechanism is identified to be interband transitions at |k| > 0 from a dipole forbidden valence band.
关键词： interband absorption,spectroscopic ellipsometry,Burstein-Moss shift,SnO2,bandgap renormalization
更新于2025-09-04 15:30:14
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Electrical characteristics and carrier injection mechanisms of atomic layer deposition synthesized n-SnO<sub>2</sub>/p-Si heterojunction
摘要： The SnO2/Si heterojunction was prepared through depositing SnO2 thin film onto p-Si substrate by means of atomic layer deposition using TDMASn (tetrakis(dimethylamino)tin) and deionized water as precursors. We found that there were three types conduction process in the SnO2/Si heterojunction. When the temperature was lower than 340 K, the carrier conduction at low bias mainly was direct tunneling. Whereas, the carrier transport at high bias turned into Fowler-Nordheim (F-N) tunneling. At temperature above 340 K, the carrier injection mechanism showed coexistence of thermionic emission and direct tunneling when the applied voltage was low, while in the high applied voltage region the thermionic emission and F-N tunneling existed simultaneously. The saturated reverse current obtained from the current-voltage characteristic at different temperature indicated that there was no barrier saddle point in the SnO2/Si heterojunction. The rectification ratio at ±4.5 V varied from 176 to 327, which was better than traditional ZnO-based heterojunction. The calculated conduction band offset and valence band offset between SnO2 and Si were 0.68 eV and 2.12 eV, respectively. The smaller conduction band offset compared with the valence band offset led to the control of the electron transport easier than that of the hole transport. We believe the results in this study should be helpful in understanding the interfacial carrier injection mechanism of silicon-based oxide structure at various temperatures and bias voltages.
关键词： Fowler-Nordheim tunneling,direct tunneling,SnO2/Si heterojunction,thermionic emission
更新于2025-09-04 15:30:14
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The Modification Mechanism of Lanthanum Doping in Ti/Sb- SnO2 Electrode and its Electrocatalytic Behavior of Degradation of p-nitrophenol
摘要： Element doping is one of the effective means to improve the electrochemical performance of electrode. In order to improve the electrocatalytic performance of Ti/Sb-SnO2 electrode, lanthanum was selected as a promoter to dop in the electrode coating. The micrograph and the structure of the electrode were characterized by SEM and XRD. Element composition of catalyst layer was determined by EDS. The electrochemical performance of Ti/Sb-SnO2-La electrode was detected by electrochemical workstation. Doped and undoped electrodes were used to treat simulated p-nitrophenol (p-NP) wastewater. The electrochemical degradation efficiency of the two electrodes for treating p-NP was compared. The results showed that 92.8% p-NP was removed when using Ti/Sb-SnO2-La as anode, which is much higher than that when using Ti/Sb-SnO2 as anode. The effect of electrolytic parameters (electrolytic voltage, applied voltage, electrode distance, electrolyte concentration and pH value) on p-NP degradation were also studied. On the basis of electric catalytic oxidation mechanism, the degradation mechanism of p-NP was deduced. According to the experimental results, the electrocatalytic performance of the La doped electrode was superior for the treatment of p-NP wastewater.
关键词： p-NP wastewater,electrocatalytic,rare earths,Ti/Sb-SnO2-La electrode
更新于2025-09-04 15:30:14
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Applicability of the thin-film approximation in terahertz photoconductivity measurements
摘要： Thin mesoporous photoconductive layers are critically important for efficient water-spitting solar cells. A detailed understanding of photoconductivity in these materials can be achieved via terahertz transient absorption measurements. Such measurements are commonly interpreted using the thin-film approximation. We compare this approximation with a numerical solution of the transfer function without approximations using experimental results for thin-film mesoporous tin oxide (SnO2) samples which range in thickness from 3.3 to 12.6 mm. These samples were sensitized with either a ruthenium polypyridyl complex or a porphyrin dye. The two sensitizers have markedly different absorption coefficients, resulting in penetration depths of 15 mm and 1 mm, respectively. The thin-film approximation results are in good agreement with the numerical work-up for the short penetration length dye. For the longer penetration length samples, the thin-film formula fails even for thicknesses of only 3 mm (cid:2) k/100. The imaginary part of the conductivity calculated using the thin-film formula was significantly larger in magnitude than the value without approximations. This discrepancy between the commonly used thin-film approximation and the numerical solution demonstrates the need for a careful analysis of the thin-film formula.
关键词： thin-film approximation,terahertz photoconductivity,mesoporous SnO2,ruthenium polypyridyl complex,porphyrin dye
更新于2025-09-04 15:30:14