- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
ZnO nanorods array as light absorption antenna for high-gain UV photodetectors
摘要： Hydrothermal method provides the advantages of simple, low-temperature growth conditions, low cost and large surface areas for the samples. Also, exciton dissociation can be enhanced by surface plasmon resonance (SPR) due to the plasmonic absorption enhancement of incident light. In this paper, high-gain ultraviolet (UV) photodetectors based on vertically aligned ZnO nanorods (ZnO-NRs) array as light absorption antenna were presented, in which ZnO-NRs array was prepared by hydrothermal method. Our experimental data showed that the device performance of the UV photodetector Au/ZnO(ZnO-NRs:Au-NPs)/Au can be further enhanced after the gaps of ZnO-NRs array were filled with Au nanoparticles (Au-NPs). The photo-to-dark current ratio and the specific detectivity of the UV photodetector Au/ZnO(ZnO-NRs:Au-NPs)/Au reached to 1×105 and 1.84×1013 Jones at 2 V under 100 μW/cm2 365 nm illumination, respectively. The physical mechanism for the enhanced performance of the UV photodetectors is discussed.
关键词： Surface plasmon resonance (SPR),ZnO nanorods (ZnO-NRs) array,Ultraviolet (UV) photodetectors,Hydrothermal method,Schottky contact
更新于2025-09-12 10:27:22
-
Sono-photodeposition of Ag over sono-fabricated mesoporous Bi2Sn2O7-two dimensional carbon nitride: Type-II plasmonic nano-heterojunction with simulated sunlight-driven elimination of drug
摘要： The mesoporous Ag/Bi2Sn2O7-C3N4 plasmonic nanophotocatalyst, which synthesized by the hybridization method of sono-dispersion and heat-treatment following with the sono-photodeposition, was applied as an efficient solar-light-driven photocatalyst for degradation of Tetracycline (TC) antibiotic. Also, the Bi2Sn2O7, g-C3N4, Bi2Sn2O7-C3N4, Ag/Bi2Sn2O7 and Ag/C3N4 nanophotocatalysts were synthesized to compare. The characterizations of samples were conducted using XRD, morphology analyses such as FESEM, TEM and AFM, EDX and dot mapping, BET-BJH, FTIR, DRS and pHpzc. The results of morphology analyses showed that about 75.2% of nanoparticles are at the range of 10-20 nm and the minimum and maximum particle sizes were 6.9 nm and 42.2 nm respectively. Moreover, the cubic Ag particles size was about 25.7 nm. Besides, the results of the UV-vis diffuse reflectance spectroscopy analysis illustrated the promotion of the absorption edge of Ag/Bi2Sn2O7-C3N4 (at about 521nm) following with the decrement of band gap (2.38 eV). The photocatalytic activity of Ag/Bi2Sn2O7-C3N4 was obtained higher than other samples (89.1%) due to Bi2Sn2O7-C3N4 type-II heterojunction, porous structure with high specific surface area (66 m2/g) owing to the usage of ultrasonic energy and surface plasmon resonance created using the Ag particle. Moreover, experiments were carried out to investigate the effect of various parameters such as the photocatalyst dosage, initial concentration and pH of TC solution in removing the contaminate molecule from aqueous solution under the light illumination, which was simulated as sunlight, in the presence of photocatalyst and the possible elimination mechanism was proposed for pollutant removal.
关键词： Sono-Hydrothermal,Solar-Light-Driven,Photo-Deposition,Ag/Bi2Sn2O7-C3N4 Nanophotocatalyst,Tetracycline Degradation
更新于2025-09-12 10:27:22
-
AIP Conference Proceedings [AIP Publishing ADVANCES IN BASIC SCIENCE (ICABS 2019) - Bahal, India (7–9 February 2019)] ADVANCES IN BASIC SCIENCE (ICABS 2019) - Synthesis and optical properties of Zn(II) doped graphene quantum dots: Blue to purple emission
摘要： The Graphene Quantum dots (GQDs), fragments of graphene have attracted considerable attention in recent years due to the size, edge effects, quantum confinement and heteroatom doping. The doping of graphene based materials can effectively tune their intrinsic properties, including electronic and optical properties, surface and local chemical reactivity. Herein, we present a comprehensive study of ZnO doped GQDs prepared by a facile hydrothermal method by using ZnO and Graphne Oxide (GO) as a source materials. All the synthesized materials were characterized by UV-Visible Spectroscopy (UV-Vis), Raman Spectroscopy, Fourier Transform Infrared (FT-IR) and Photoluminescence (PL). The morphological characterizations were confirmed by transmission electron microcopy images (TEM). The hydrothermally synthesized material had a size of 5-20 nm by uniform doping of zinc nanoparticles on graphene sheet. The results of PL of Zn(II)-GQDs showed a blue to purple emission with the variation in excitation wavelength from 280nm to 380nm. These doped GQDs were found to be an efficient approach with multicolor emission for biological applications and optoelectronic devices to make the environmental friendly, cost effective and easily scalable.
关键词： optical properties,photoluminescence,Graphene Quantum dots,hydrothermal method,Zn(II) doping
更新于2025-09-12 10:27:22
-
Ethanol-Precipitation-Assisted Highly Efficient Synthesis of Nitrogen-Doped Carbon Quantum Dots from Chitosan
摘要： Nitrogen-doped carbon quantum dots (NCQDs) were prepared from chitosan through a hydrothermal reaction. When ethanol precipitation was used as the puri?cation method, a high product yield of 85.3% was obtained. A strong blue ?uorescence emission with a high quantum yield (QY) of 6.6% was observed from the NCQD aqueous solution. Physical and chemical characteristics of the NCQDs were carefully investigated by transmission electron microscopy (TEM), X-ray di?raction (XRD), Fourier transform infrared spectra (FTIR), Raman spectra, X-ray photoelectron spectroscopy (XPS), and transient ?uorescence spectra. Experimental results showed that diameters of the NCQDs were in the range of 2?10 nm. The carbon quantum dots possess good water dispersibility and precipitation by ethanol. When used for metal ion detection, the detection limit of the NCQDs for Fe3+ was as low as 1.57 μM. This work proposed a facile method to synthesize NCQDs from chitosan with high yield and demonstrated that carbon quantum dots derived from chitosan were promising for ion detection.
关键词： ethanol precipitation,metal ion detection,chitosan,hydrothermal reaction,Nitrogen-doped carbon quantum dots
更新于2025-09-12 10:27:22
-
Photovoltaic Properties of an rGO/Pt Counter Electrode with AZO Photoanode for Dye-sensitized Solar Cells under Low Light Intensity
摘要： This study used reduced graphene oxide (rGO) applied to a platinum (Pt) counter electrode to improve light conversion efficiency. The study also used an Al-doped Zinc Oxide (AZO) nanosheet / TiO2 photoanode for the dye-sensitized solar cell (DSSC). Photovoltaic characteristics, electrochemical impedance spectroscopy (EIS), field-emission scanning electron microscopy (FE-SEM) and Raman spectroscopy were used to analyze DSSC. The different light intensities and photovoltaic characteristics were analyzed to determine optimal light intensity conditions. The unmodified Pt counter electrode was compared with the rGO/Pt counter electrode, photovoltaic conversion efficiency (η) increased from 3.60% to 4.04% due to the rGO modification as it possesses a higher specific surface area. Its low cost also makes it suitable for mass production. In addition, an AZO nanosheet / TiO2 photoanode was fabricated to form a double-layer structure in which photovoltaic conversion efficiency was 4.47 %. Finally, a DSSC with an AZO / TiO2 photoanode and rGO/Pt counter electrode was fabricated and had an photovoltaic conversion efficiency of 5.05 %. This study also analyzed the photovoltaic parameters of DSSC under different intensities, which shows the optimal photovoltaic conversion efficiency of 5.54% under 30mW / cm2.
关键词： photovoltaic conversion efficiency,low light intensity,Al-doped Zinc Oxide (AZO),hydrothermal synthesis,Dye-sensitized solar cell (DSSC),reduced graphene oxide (rGO)
更新于2025-09-12 10:27:22
-
Three-dimensional ZnO nanorods growth on ZnO nanorods seed layer for high responsivity UV photodetector
摘要： Three-dimensional ZnO nanorods (NRs) were synthesized by hydrothermal method on ZnO seed layer including horizontal ZnO NRs. The ZnO seed layers consist of different values of NRs were synthesized by spin-coating. The different seed layers and ZnO nanorods arrays were characterized using field emission scanning electron microscopy, X-ray diffraction. Horizontally dispersed NRs on the substrate formed an overlapping junction structure into seed layer as ZnO NRs network. NRs grown on the seed layer including horizontal NRs were oriented in different directions to form three-dimensional ZnO NRs in flower shape. The electrical resistance of sensors based NRs array decreased dramatically with increasing NRs added to ZnO seed layer. Results show that ultraviolet photocurrent increased from 1.7 to 23 μA which is suitable for fabrication of practical photodevices.
关键词： UV photodetector,ZnO nanorods,seed layer,photocurrent,hydrothermal method
更新于2025-09-12 10:27:22
-
Effects of precursor concentration on hydrothermally grown ZnO nanorods as electron transporting layer in perovskite solar cells
摘要： Electron transporting later (ETL) with nanorod structure provides a special passage for which free electrons can easily travel through the layer. ETL also helps to prevent the recombination and to enhance the attaching ability of the perovskite layer and thus improving the conversion efficiency of the perovskite solar cell. In this work, the investigation on the hydrothermal process of n-type ZnO nanorods (ZnO NRs) layer is carried out at the temperature below 100 oC and under the atmospheric pressure. Four concentrations of aqueous precursor solution consisting of zinc nitrate hexahydrate and hexamethylenetetramine are used in the experiment (25 mM, 50 mM, 75 mM and 100 mM). Subsequently, the perovskite solar cells, with normal structure of FTO- glass/ZnO dense layer/ZnO NRs/PCBM/Perovskite/P3HT/Ag, are fabricated. The optimum power conversion efficiency of 2.26% was obtained from the device prepared with 100 mM precursor solution. The concentration of solution used in the hydrothermal process affects the size and density of ZnO NRs and, in turn, affects the conversion efficiency of the cells.
关键词： concentrations,hydrothermal process,normal structure,perovskite solar cells,ZnO nanorods
更新于2025-09-12 10:27:22
-
ε-Poly-L-lysine-protected Ti3C2 MXene quantum dots with high quantum yield for fluorometric determination of cytochrome c and trypsin
摘要： Titanium carbide quantum dots functionalized with ε-poly-L-lysine (PLL) were synthesized by sonication cutting and hydrothermal synthesis. The deprotonated Ti3C2 MXene quantum dots (Ti3C2 MQDs) exhibit excitation wavelength-dependent blue photoluminescence with typical excitation/emission peaks at 330/415 nm and a quantum yield of 22% due to strong quantum confinement. The fluorescence of ε-poly-L-lysine protected Ti3C2 MQDs (PLL-protected Ti3C2 MQDs) is reduced via an inner filter effect after the addition of cytochrome c (cyt-c). Response to cyt-c is linear in the 0.2 to 40 μM concentration range and the detection limit is 20.5 nM. In the presence of trypsin, cyt-c is hydrolyzed to small peptides, and the Fe3+ ion in cyt-c probably is reduced to Fe2+ with the aid of the digestive enzyme. This results in the restoration of the blue fluorescence of the modified MQDs. Fluorescence increases linearly in the 0.5 to 80 μg mL?1 trypsin concentration range with the detection limit of 0.1 μg mL?1. The method was successfully applied to the determination of cyt-c and trypsin in spiked serum samples.
关键词： Hydrothermal method,Inner filter effect,Fluorescence,Trypsin,Cytochrome c,Ti3C2 MXene quantum dots
更新于2025-09-12 10:27:22
-
Facile preparation of high fluorescent carbon quantum dots from orange waste peels for nonlinear optical applications
摘要： A facile and eco‐friendly hydrothermal method was used to prepare carbon quantum dots (CQDs) using orange waste peels. The synthesized CQDs were well dispersed and the average diameter was 2.9 ± 0.5 nm. Functional group identification of the CQDs was confirmed by Fourier transform infrared spectrum analysis. Fluorescence properties of the synthesized CQDs exhibited blue emission. The fluorescence quantum yield of the CQDs was around 11.37% at an excitation wavelength of 330 nm. The higher order nonlinear optical properties were examined using a Z‐scan technique and a continuous wave laser that was operated at a wavelength of 532 nm. Results demonstrated that the synthesis of CQDs can be considered as promising for optical switching devices, bio‐scanning, and bio‐imaging for optoelectronic applications.
关键词： Z‐scan analysis,fluorescence quantum yield,CQDs,HR‐TEM,hydrothermal method
更新于2025-09-11 14:15:04
-
Highly ordered combined structure of anodic TiO2 nanotubes and TiO2 nanoparticles prepared by a novel route for dye-sensitized solar cells
摘要： Combined structure of anodic TiO2 nanotubes and TiO2 nanoparticles (TiNTs-TiNPs) has been synthesized by a facile combination of hydrothermal and chemical vapor deposition methods. Ordered TiO2 nanotubes with smooth walls were fabricated by two step anodization method in ethylene glycol containing NH4F at 50V. This nanotubular array after annealing at 450 oC was subjected to the hydrothermally produced gaseous environment in an autoclave with diluted TiCl4 solution at its bottom. Vapors of TiCl4 were allowed to react chemically with water vapors for predefined time durations at 180 oC that resulted in the deposition of TiO2 nanoparticles on tubes’ surface and side walls. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) confirmed that for one hour reaction duration, nanoparticles were evenly coated on the walls of nanotubes, whereas, longer durations tend to deteriorate the tubular structure. Consequently, the ordered TiNTs-TiNPs array produced after one hour coating has shown better performance for dye-sensitized solar cell DSSC) in back illumination mode with 130 % increase in efficiency as compared to the device based on bare TiO2 nanotubes. The same photoanode has higher reflective properties with higher scattering ability. The solar cell based on this photoanode exhibits higher external quantum efficiency and effective charge transport properties. This study shows that porous ordered 1D structures based on TiO2 are of crucial importance for the high performance of DSSCs.
关键词： TiO2 nanotubes,anodization,ordering,TiO2 nanoparticles,hydrothermal
更新于2025-09-11 14:15:04