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Surface Plasmon Resonance Based Highly Selective Fiber Optic Dopamine Sensor Fabricated Using Molecular Imprinted GNP/SnO <sub/>2</sub> Nanocomposite
摘要： Fabrication and characterization of a highly selective fiber optic surface plasmon resonance-based dopamine sensor using molecular imprinted graphene nanoplatelets/tin oxide (SnO2) nanocomposite have been reported. The synthesis of sensing layer has been carried out using a series of optimizations and morphological studies. The effectiveness of the sensing layer over other possible probe designs has been proved by performing control experiments for a dopamine concentration range covering the suggested level of dopamine for human being. The limit of detection (LOD) of the sensor evaluated is 0.031 μM, which is lower than the LOD values of various dopamine sensors fabricated using different methods. The specificity of the sensor for dopamine has been confirmed by performing experiments using various interferands while the stability and reusability of the sensor probe have been checked by performing experiments repeatedly for a long period of time. Apart from high sensitivity, low LOD, and fast response, the sensor can be used for remote sensing and online monitoring of dopamine.
关键词： surface plasmon resonance,SnO2 nanoparticles,optical fiber sensor,GNP/SnO2 nanocomposite,graphene,Dopamine,molecular imprinting
更新于2025-09-23 15:23:52
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Magnetic metamorphosis of structurally enriched sol-gel derived SnO2 nanoparticles
摘要： Pure SnO2 and aliovalent substituted polycrystalline Sn0.98?xLa0.02ZnxO2 (x = 0.02, 0.04 and 0.06) samples have been synthesized via sol-gel technique. Rietveld re?nement of X-ray di?raction (XRD) patterns con?rm the single phase tetragonal rutile-type (P mnm 42/) crystalline structure for all the synthesized samples. Crystallite size from XRD analysis is found to decrease from 14 nm to 11 nm as x increases from 0 to 0.06 in Sn0.98?xLa0.02ZnxO2 matrix. Transmission Electron Microscopy further reveals the decrease in average crystallite size from 7 nm for pure SnO2 to 5 nm with increase in Zn2+ concentration in system. Morphological study through Field Emission Scanning Electron Microscopy reveals the agglomeration of nanoparticles on increasing the Zn concentration. The room temperature photoluminescence (PL) measurements mark the change in peak intensity centered around 300–450 nm upon La and Zn co-doping into SnO2 lattice. Deconvolution of PL peak unveil the presence of defects/vacancies and local disorders in (La, Zn) co-doped SnO2 matrix. Further, the magnetic properties have been studied using Vibrating Sample Magnetometer, which envisage the room temperature ferromagnetism (RTFM) in nonmagnetic La3+ and Zn2+ ion modi?ed SnO2. The observed RTFM in (La, Zn) co-doped SnO2 is mainly due to oxygen vacancies which is also supported by PL results.
关键词： Rietveld re?nement,RTFM,SnO2 nanoparticles,Defect states
更新于2025-09-23 15:23:52
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Structural, photoluminescence and magnetic properties of Cu-doped SnO2 nanoparticles co-doped with Co
摘要： Co doped Sn0.98Cu0.02O2 nanoparticles have been synthesized by co-precipitation method. The prepared nanoparticles were characterized by X-ray diffraction, scanning electron microscope (SEM), transmission electron microscopy, Fourier transform infrared spectroscopy, photoluminescence and magnetic measurements. The observed tetragonal rutile structure confirmed by XRD patterns was not altered by Co-doping and the value of average crystallite size lies within 8–14 nm. The formation of high density defect states and the new phases of Co and Sn were responsible for the reduction of energy gap (Eg) with Co-doping; Eg varied between 3.12 and 3.58 eV. The tuning of band gap and luminescence properties by Co-doping suggested that Co = 4% doped sample is a promising material for selective coatings for solar cells; use as antireflective coating materials, and for fabrication of optoelectronic devices. FTIR spectrum has been used to authenticate the formation of Sn–O bond and the existence of Co in Sn–Cu–O. The promotion of higher local disorders and the oxygen-related defects during growth process of SnO2 nanoparticles at Co = 4% is responsible for the higher UV/violet/blue band photoluminescence emission intensity. The overlapping between bound magnetic polarons (BMP) by Co-doping induced the room temperature ferromagnetism. The existence of high density charge carriers and oxygen vacancies at Co = 4% sample might be responsible for highest magnitude of ferromagnetism. The noticed suppression of RTFM at Co = 6% may be due to the enhanced antiferromagnetic interaction between neighbouring Co–Co ion.
关键词： Photoluminescence,SnO2 nanoparticles,XRD,Energy gap,Magnetic properties
更新于2025-09-23 15:23:52
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Room-temperature ferromagnetism and morphology evolution of SnO2 flower-like microparticles by Zn-doping
摘要： We report on the growth of undoped and Zn-doped flower-like microparticles, which are constituted of SnO2 acicular nanoparticles (NPs) aggregated by one of their ends. NPs were synthesized by the hydrothermal method. The morphology of the NPs progressively changes from truncated rods to sharp needles by the effect of Zn doping. This morphology evolution is attributed to an increase of the surface free energy of the NPs' facets and to a modification of the growth front direction. Undoped samples exhibit a very low magnetization attributed to single positive charged oxygen vacancies, while Zn-doped samples exhibit ferromagnetic ordering due to Zn atoms in Sn substitutional positions (ZnSn). Thermal treatment under reducing atmosphere leads to the creation of an excess of VO conducting to a reduction of the magnetization, demonstrating that ferromagnetism in Zn-doped SnO2 NPs is attributed to ZnSn defects and to the octahedrally coordinated oxygen atoms.
关键词： Magnetization,Oxygen vacancies,SnO2 nanoparticles,Morphology,Zn-doped
更新于2025-09-23 15:22:29
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Double Metal Oxide Electron Transport Layers for Colloidal Quantum Dot Light-Emitting Diodes
摘要： The performance of colloidal quantum dot light-emitting diodes (QD-LEDs) have been rapidly improved since metal oxide semiconductors were adopted for an electron transport layer (ETL). Among metal oxide semiconductors, zinc oxide (ZnO) has been the most generally employed for the ETL because of its excellent electron transport and injection properties. However, the ZnO ETL often yields charge imbalance in QD-LEDs, which results in undesirable device performance. Here, to address this issue, we introduce double metal oxide ETLs comprising ZnO and tin dioxide (SnO2) bilayer stacks. The employment of SnO2 for the second ETL significantly improves charge balance in the QD-LEDs by preventing spontaneous electron injection from the ZnO ETL and, as a result, we demonstrate 1.6 times higher luminescence efficiency in the QD-LEDs. This result suggests that the proposed double metal oxide ETLs can be a versatile platform for QD-based optoelectronic devices.
关键词： metal oxide,light emitting diode (LED),SnO2 nanoparticles,quantum dot (QD),double electron transport layer (ETL)
更新于2025-09-23 15:19:57
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Core-Shell ZnO@SnO2 Nanoparticles for Efficient Inorganic Perovskite Solar Cells
摘要： The ideal charge transport materials should exhibit a proper energy level, high carrier mobility, sufficient conductivity, and excellent charge extraction ability. Here, a novel electron transport material was designed and synthesized via using a simple and facile solvothermal method, which is composed by the core-shell ZnO@SnO2 nanoparticles. Thanks to the good match between energy level of SnO2 shell and high electron mobility of core ZnO nanoparticles, the PCE of inorganic perovskite solar cells has reached 14.35% (JSC: 16.45 mA cm-2, VOC: 1.11 V, FF: 79%), acting core-shell ZnO@SnO2 nanoparticles as the electron transfer layer. The core-shell ZnO@SnO2 nanoparticles size is 8.1 nm with the SnO2 shell thickness of 3.4 nm, and the electron mobility is seven times more than SnO2 nanoparticles. Meanwhile, the uniform core-shell ZnO@SnO2 nanoparticles is extremely favorable to the growth of inorganic perovskite films. These preliminary results strongly suggest the great potential of this novel electron transfer material in high-efficiency perovskite solar cells.
关键词： inorganic perovskite solar cells,electron transport material,solvothermal method,core-shell ZnO@SnO2 nanoparticles,high electron mobility
更新于2025-09-19 17:13:59
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Electron Transporting Bilayer of SnO <sub/>2</sub> and TiO <sub/>2</sub> Nanocolloid Enables Highly Efficient Planar Perovskite Solar Cells
摘要： Here, we applied the commercially accessible SnO2 and home-made TiO2 NPs as a combined electron transporting bilayer (ETBL) to achieve a highly efficient planar perovskite solar cell (PSC). The formed cascade-aligned energy levels from the proper stacking of SnO2 and TiO2 layers and the excellent defect-passivation ability of TiO2, SnO2/TiO2 ETBLs effectively reduced energy loss and inhibited defects formation both at the ETL/perovskite interface and within the bulk of perovskite layer as revealed by a comprehensive analysis of photoelectric characteristic analysis, including ultraviolet photoelectron spectroscopy, photoluminescence and electrochemical impedance spectroscopy. Consequently, the PSC devices acquired a high PCE of 20.50% with a Voc of 1.10 V, a Jsc of 24.2 mA/cm2 and an FF of 77%, which are superior to the values of the control device based on single SnO2 layer with a PCE of 18.09% (a 13.3% boosting on PCE). Moreover, there was no degradation after 49 days, indicating the great stability after adding TiO2 layer. Our work demonstrates that the cascaded alignment of energy levels between the electrode and perovskite layer by ETBLs could be an effective approach to improve the photovoltaic performance of the PSCs with excellent long-term stability.
关键词： electron transporting bilayer,perovskite solar cells,SnO2 nanoparticles,TiO2 nanoparticles,cascade-aligned energy level
更新于2025-09-11 14:15:04
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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