最新刊期
卷 40 ， 期 10 ， 2019
- 摘要：Epidermal growth factor receptor(EGFR)is overexpressed on tumor surface. A surface enhanced Raman scattering(SERS) probe based on epidermal growth factor receptor antibody(anti-EGFR) conjugated Au nanorods(AuNRs probes) was used for EGFR positive cancer cell detection. When AuNRs probes were specific bound to EGFR positive cell, SERS signals from Raman active molecule 4-mercaptobenzoic acid(4-MBA) modified on AuNRs were two to three times more than those cells incubated with 4-MBA labeled AuNRs(AuNRs-MBA). This kind of SERS probe has great potential in the diagnosis of EGFR positive tumor due to its specific targeting, high SERS sensitivity and biocompatibility.关键词：surface-enhanced Raman scattering(SERS);gold nanorods;human epidermal growth factor(EGFR antibody)188|218|1更新时间：2020-08-12
- 摘要：Molybdenum disulfide quantum dots (MoS2 QDs), as a typical representative of transition metal dichalcogenides(TMDs), had attracted much attention due to the unique optical properties and huge potential applications. In this paper, MoS2 QDs were fabricated through a facile solvothermal method from MoS2 powder crystals. Under certain excitation conditions, MoS2 QDs had strong fluorescence properties and were used as fluorescence probes to detect dopamine (DA). The results showed that the average size of the as-prepared MoS2 QDs was about 3 nm, and the fluorescence quantum efficiency was as high as 57.55%. When the concentration of DA changed from 0.02 to 1 000 μmol/L, the fluorescence of the sensing system was quenched with a linear dependence and the limit of detection was 0.32 μmol/L, with extremely high sensitivity. MoS2 QDs sensing system has strong stability and high selectivity for dopamine detection in different pH values and the presence of interferences. MoS2 QDs had potential applications in catalytic reactions, optical imaging, display devices and fluorescence sensing due to the high purity, small size and high fluorescence intensity.关键词：molybdenum disulfide quantum dots;solvothermal method;fluorescence;dopamine detection145|110|0更新时间：2020-08-12
- 摘要：In order to effectively improve the thermal stability of luminescence in violet-emitting CsPbCl3 perovskite nanocrystals(NCs), the effects of various Ni doping concentrations on their structural and luminescent properties were studied. The Ni doped CsPbCl3 (Ni:CsPbCl3) NCs with various Ni doping concentrations were synthesized at 190℃ by varying the feed Ni/Pb molar ratio. It was found that the quantum yield of 405 nm photoluminescence band in Ni:CsPbCl3 NCs was significantly improved up to 54% with increasing the Ni/Pb feed molar ratio while it started to drop after the molar ratio was higher than 4:1. This is because the nucleation and growth processes of the NCs were influenced in the presence of high concentration NiCl2. In addition, it was observed that the average sizes of Ni:CsPbCl3 NCs were reduced with increasing Ni/Pb molar ratio. The temperature-dependent photoluminescence spectra demonstrated that the Ni doping really reduced thermal quenching of photoluminescence in Ni:CsPbCl3 NCs and greatly enhanced their thermal stability. The experimental results indicated that the enhancement mechanism of luminescence in violet-emitting Ni:CsPbCl3 NCs was attributed to reduction of defects in NCs with Ni doping.关键词：perovskite;doping;photoluminescence;quantum yield;thermal stability260|195|1更新时间：2020-08-12
- 摘要：In order to systematically study the effects of Br on the luminescence intensity and decay time of CuBrxI1-x films, CuBrxI1-x (0 ≤ x ≤ 1) films were prepared on Si wafers by vapor deposition. The luminescence properties and decay curves are measured. The results show that the prepared samples have good crystallinity of CuBrxI1-x (0 ≤ x ≤ 1) solid solution. Compared with the deep-level emission located in the long wavelength band, CuBrxI1-x films show strong near-band edge emission stimulated by ultraviolet light and X-ray. The emission intensity increases rapidly with the increase of Br content, which is beneficial to improve the detection efficiency of the scintillation device. However, the decay time of the sample will slow down with the increase of Br content (40-300 ps). This research is of great significance to the selection of suitable composition of CuBrxI1-x scintillation materials in order to balance the requirements between detection efficiency and time response in actual scintillation detection.关键词：CuBrxI1-x scintillation film;luminescent intensity;decay time171|111|0更新时间：2020-08-12
- 摘要：In order to effectively reduce the density of GaAs surface states and obtain a stable high-performance passivation film, hydrazine solution is used to passivate the surface of GaAs (100).The concentration of hydrazine solution, the Na2S concentration, and the passivation time were optimized by photoluminescence. The PL intensity of the hydrazine concentration passivated GaAs samples is 1.22 times higher than non-passivated. The surface composition and morphology of GaAs before and after passivation of hydrazine solution were analyzed by X-ray photon spectroscopy and atomic force microscopy. Experimental results indicate that the surface oxides can be removed by the hydrazine solution effectively, and a uniform, flat GaN passivation layer can be formed on the surface. Through the surface stability measurement, it is found that the PL intensity of passivated GaAs surface does not have obvious degradation after several days in the open air, indicating that the surface of the GaAs after passivation is stable.关键词：hydrazine;GaAs;passivation;photoluminescence;GaN175|247|0更新时间：2020-08-12
- 摘要：A GaAs/AlAs quantum well, with a 15 nm-thick GaAs well surrounded by a 5 nm-thick AlAs barrier, is δ-doped with Be acceptors of various doping levels at the well center. The ionized acceptor diffused profiles within the quantum well are solved by the diffusion equation. The additional potential, due to both the ionized acceptor diffused profile and hole distribution in valence-band subbands, is incorporated into the quantum well potential. The self-consistent solution and converged hole energy eigenvalue for the Schrödinger's and Poisson's equations are looked for by an iterative method. It is found through calculations that the energy of the heavy-hole ground state hh has changed by about 1 meV, while it is red-shifted towards the valence-band top with increasing Be acceptor doping concentrations. The calculated results are in a good agreement with experimental results.关键词：doping levels;δ-doped;GaAs/AlAs quantum wells;acceptor diffused profiles317|51|0更新时间：2020-08-12
- 摘要：To obtain β-Ga2O3 films with high quality, we optimized conventional GaN high temperature oxidation. The β-Ga2O3 thin films were prepared from GaN thin films by one-step and two-step high temperature oxidation, respectively. The prepared samples were characterized by X-ray diffraction (XRD), filed emission scanning electron microscopy (FESEM) and Raman spectroscopy. The results showed that the GaN films could not be completely oxidized at 950℃, and the sample obtained directly at 1 150℃ had no obvious crystal orientation. In contrast, the GaN films were completely oxidized by two-step oxidation method, and the obtained β-Ga2O3 films had obvious crystal orientation along the direction of <201>. The surfaces of the samples obtained by two-step oxidation showed nanowire structures. The optimized oxidation time was oxidation at 950℃ for 3 h followed by oxidation at 1 150℃ for 1 h, the obtained sample had most obvious nanowire structures, and the diameters of the nanowires were about 30-40 nm. Raman spectroscopy confirmed that the sample obtained under this condition had high crystalline quality. By analyzing the structure and morphology properties of different samples, we found that different oxidation modes at different temperatures were the main causes of these results.关键词：gallium oxide;wide bandgap simiconductors;high temperature oxidation155|56|2更新时间：2020-08-12
Synthesis and Properties of Materials
- 摘要：The white laser light source synthesized by red, green and blue(RGB) direct semiconductor laser has the advantages of high conversion efficiency, good color rendering index and high output power. It is one of the new generation ideal lighting source and display source. Based on the RGB three-color diode laser devices, through the space beam combining and wavelength beam combining, the RBG lights are coupling into a single optical fiber, optical fiber output beam power more than 100 W. The power ratio of different colors is carried out according to the colorimetry principle. The white light with a power of 63 W and a color temperature of 5 710 K,which is less than 12.2% compared with the standard white light D65 was obtained. On this basis, by adjusting the output power of the red laser, a white light output with a power of 58.4 W and a color temperature of 6 480 K was gotten. Compared with standard white light D65, the deviation of color temperature was less than 3.08%. The light source based on this structure can achieve different display effects by adjusting the laser power ratio.关键词：RGB;diode laser;beam combining;white laser;laser display486|1358|2更新时间：2020-08-12
- 摘要：UV photodetectors based on SnO2 material usually have high optical responsivity. However, due to the continuous photoconductivity, its response time is usually very long, which limits its application in the field of photodetection. Here we investigated the effect of surface modification on the performance of SnO2-based photodetector. The high crystal quality SnO2 microwires were prepared by chemical vapor deposition and photodetector based on single SnO2 microwires were also fabricated. At the same time, organic perovskite MAPbBr3 with high quality was also prepared using solution method and the devices based on SnO2 decorated with MAPbBr3 were fabricated in the following. Both devices exhibited significant response in the UV region with a peak at 250 nm. Compared to the device made by a single SnO2 microwire, the responsivity of the device decorated by CH3NH3PbBr3 showed as much as ten times higher and the response time reduced from tens or even hundreds of seconds to 0.9 s. The experiment results indicate that the method we used is very promising for the preparation of high performance SnO2 photodetectors.关键词：photodetector;SnO2;perovskite;CH3NH3PbBr3205|123|1更新时间：2020-08-12
- 摘要：In order to improve the photoelectric conversion efficiency of polymer solar cells, PbSe quantum dots were doped in the active layer and the effect of the material on the cells was studied. Firstly, PbSe quantum dots were prepared by thermochemical method. The size and crystallinity of PbSe quantum dots were controlled by changing the amount of oleic acid and reaction time. Quantum dots were characterized by transmission electron microscopy (TEM) and X-ray diffraction (XRD), and the optimum reaction conditions were determined. Then PbSe quantum dots with different mass fractions were doped into polymer solar cells with structure of ITO/ZnO/PTB7:PC71BM/MoO3/Ag. Through J-V performance test and ultraviolet absorption spectrum test, the influence mechanism of PbSe quantum dots on solar cells was analyzed. The experimental results show that when the molar ratio of PbO to OA is 1:2 and the reaction time is 3 min, the quantum dots with uniform size distribution between 3 and 7 nm and good crystallinity can be obtained. The short circuit current density and photoelectric conversion efficiency can be increased by 8.37% and 37.41% by doping 3% into polymer solar cells and the performance of polymer solar cells has been improved effectively.关键词：polymer solar cells;PbSe quantum dots;active layer;doping184|187|5更新时间：2020-08-12
- 摘要：Inkjet-printed quantum dot light-emitting diodes(QLEDs) have received widely attention, owing to their potential for use in large-area full-color pixelated display with high material utilization. However, the performance of the inkjet-printed QLEDs is always inferior to the spin coated devices with the same structure. In this study, the performance of the inkjet-printed green QLEDs based on PVK layer and the effects of quantum dot ink formula on transport layer interfaces were investigated. It is revealed that layer erosion is a key issue for performance of inkjet-printed QLEDs. An external quantum efficiency of 6.3% was achieved in inkjet-printed green QLEDs with high-quality film and interface by employing the orthogonal solvent via optimizing inkjet printing technology.关键词：inkjet printing;quantum dot light-emitting diodes;electroluminescence;layer erosion258|199|5更新时间：2020-08-12
- 摘要：An highly efficient tandem organic light-emitting device (OLED) was realized by employing multilayer structure of CsN3/Al/HAT-CN as charge generation unit (CGU). The charge generation and transporting processes within CGU were discovered by analyzing electroluminescence properties of the fabricated dual-color tandem device with yellow and green emissions. The maximum efficiencies of Alq3-based tandem device are as high as 6.4 cd/A and 2.3 lm/W, respectively, and at the given driving current density of 20 mA/cm2, the current efficiency and luminance of tandem device are 5.3 cd/A and 1 064.9 cd/m2, as are about 2-fold those of corresponding single-unit device. The results demonstrate CsN3/Al/HAT-CN is able to function as CGU effectively. Finally, by studying the EL and emission pattern characteristics of the tandem device, we illustrated that the improvement on current efficiency and luminance results from simultaneous emission in two emitting layers under driving current density instead of the optical microcavity.关键词：charge generation unit;tandem structure;electron injection barrier;Lambertian distribution158|264|1更新时间：2020-08-12
- 摘要：Metal sub-wavelength periodic array structures have attracted great interest due to their potential applications in the construction of meta-material, and the investigation of the metal sub-wavelength periodic array structures is essential for the development of optoelectronic devices, such as optical filters, ultrafast optical switches and optical limiters etc., operating in the microwave and THz spectral region. In this thesis, we investigated numerically and experimentally the transmission properties of the metal sub-wavelength periodic array structures in the THz spectral region based on the finite-difference time-domain method and the terahertz time domain spectroscopy technique. The U-shaped open resonators with huge aspect ratio were designed. We employed the electron beam exposure and ion beam lithography technology to construct the samples and measured its transmission spectrum. At the same time, we explored the dependence of the transmission on the structure parameters and tried to find out the physical mechanism for the abnormal transmission. After a series of studies, it was found that the localization of THz wave and electric field enhancement could be achieved by the U-shaped open resonator. The incident THz wave could be localized in a region whose dimension is only one-thousand of the central wavelength of the THz wave. We believe that the U-shaped open resonators with huge aspect ratio could be applied in the fabrication of sensors and other optical devices in the future.关键词：THz wave U-shaped open resonator;terahertz time domain spectroscopy technique;electric field enhancement158|293|0更新时间：2020-08-12
Device Fabrication and Physics
- 摘要：In order to replace human eyes to detect the color information on the surface of objects, this paper designs a handheld LED light source spectrophotometer. First, by calculating the tristimulus values of different measurement wavelength distributions and resolutions under the irradiation of standard light source, and comparing their accuracy, the wavelength distribution of 400-700 nm and the resolution of 10 nm were selected as the main parameters of the light source. Then, the lighting source was researched. The uniform color space coordinates of halogen tungsten lamp, pulse xenon lamp and LED light source were compared, and the LED light source was selected as the lighting source of the instrument. Finally, lighting design and overall structure design were carried out. The experimental results showed that the maximum illumination intensity at the target center of the color detector is 9.91×10-3 lm/mm2, and the average illumination is 7.06×10-3 lm/mm2. It basically met the design requirements of high precision, light miniaturization, sufficient and even illumination of the handheld spectrocolorimeter.关键词：spectrophotometer;LED;annular illumination;illuminance138|112|1更新时间：2020-08-12
- 摘要：The contact position, contact area, contact stress and flexibility of single lens support structure in an optical system are important influencing factors of the system's imaging quality. Topology optimization of the single-lens contact support structure is carried out using the aberration index PV value as the optimization objective to reduce geometric aberration aberration in the single mirror caused by gravitational force. We first establish the contact topology optimization model, then use a linear elastic structure in unilateral contact with a rigid support as-modeled by Signorini's contact conditions as an example to verify the model. The aberration index PV value of the lens is described as a function of lens deformation; thus, the value serves as a functional objective of the topology optimization model. We use the SIMP method to describe the topology optimization design variables, and the augmented Lagrange multiplier method to solve the contact condition. The optimal solution of the topology optimization model can be solved via MMA optimization algorithm. The optimal topological configuration of supporting structures that satisfy geometric aberration requirements is defined by the optimal solution of the design variables. We found that the PV value of the lens can be reduced by 14% and the lens surface RMS value by 13.8% after applying the proposed method. We also tested the lens PV value and RMS value on an experimental platform supported by the optimal contact support structure. The surface of the plane mirror surface PV values decreased by 60.4% and 42.9%, and the RMS values by 74.3% and 38.9%. To this effect, the optimal contact support structure effectively improves the precision of the single lens support and demonstrates significant potential for practical application.关键词：topology optimization;optomechanics;mirrors analysis;optical machanical structure197|587|0更新时间：2020-08-12
- 摘要：The white eyes superlattice concentric ring luminescent pattern is observed in the dielectric barrier discharge for the first time. Its spatiotemporal structure is investigated by using photomultiplier tubes and an intensified charge-coupled device camera. The results show that the pattern is composed by odd-numbered rings and even-numbered white-eye rings. The dots of odd rings are denoted as filaments O(Odd number, O), the center dots of white eyes in the even rings are denoted as filaments E(Even number, E), and the white halo is denoted as H(Halo, H). All filaments O discharges at the first pulse of the rising edge of the voltage and partially O discharges at the falling edge of the voltage, H discharges at the current envelope of the rising edge of voltage, E discharges at the falling edge of the voltage. The time correlation measurement of O and E shows that the discharge sequences of O and E are random at the falling of voltage edge. A high-speed video camera was used to take pictures and the result shows that each volume discharges in this pattern induce surface discharges. The H in the odd number rings causes the discharge of partial filament O at the falling edge of the voltage. The rearrangement of the wall charges by the surface discharges results in the randomness of the O and E discharge sequences.关键词：luminescent pattern;dielectric barrier discharge;surface discharge;wall charge187|185|0更新时间：2020-08-12
Luminescence Applications and Interdisciplinary Fields
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