最新刊期
卷 37 ， 期 12 ， 2016
- 摘要：YAG:1%Ce3+,x%Yb3+(x=5, 10, 15, 20, 25) phosphor was synthesized via the high temperature solid state method. The optical properties of the phosphor were characterized by photoluminescence (PL). Under the excitation of 450 nm, the visible broadband emission from Ce3+:5d→4f with the central wavelength of 550 nm was observed. The NIR emission around 1 030 nm from Yb3+:2F5/2→2F7/2 was also observed under the same excitation. The variation of emission intensity with the concentration of Yb3+ shows that the energy transfer exists between Ce3+ and Yb3+, and the quenching concentration of Yb3+ is 15%. For YAG:1%Ce3+,15%Yb3+ sample, the emission spectra and Raman spectra were measured at low temperature (80-300 K). Based on the analyze of temperature characteristics of quantum cutting luminescence, the results show that the phonons of the host material play an important role in the energy transfer from Ce3+ to Yb3+.关键词：quantum cutting;quenching concentration;temperature characteristics;energy transfer137|169|1更新时间：2020-08-12
- 摘要：Two new anthracene derivatives 9,10-bis(2-biphenyl)anthracene (BBPA) and 9,10-bis[2-(α-naphthyl]phenyl] anthracene (BNPA) were synthesized by Suzuki coupling reaction and characterized by 1H NMR, mass spectrum and elemental analysis. The quantum chemistry calculations show that these compounds have non-coplanar structures and their photophysical properties are controlled by the anthracene unit. Both of these compounds exhibit high-efficiency blue emission in CH2Cl2 solutions. The emission spectrum of BBPA as solid film is obviously broader than that measured from CH2Cl2 solution, while the emission spectrum of BNPA as solid film does not broaden compared to that acquired from CH2Cl2 solution. Two deep-blue non-doped electroluminescent devices were fabricated employing BBPA or BNPA as emitting layer. The device based on BBPA exhibits a maximum external quantum efficiency of 2.48% and CIE coordinate of (0.16, 0.09). The device based on BNPA acquires a maximum external quantum efficiency of 2.68% and CIE coordinate of (0.15, 0.07). In addition, both of these devices show low turn-on voltage and high stability.关键词：electroluminescence;deep-blue materials;anthracene derivatives;non-doped devices117|485|0更新时间：2020-08-12
- 摘要：Upconversion luminescence performance of BaGa2ZnO5 powder codoped with Er3+/Tm3+/Yb3+ was studied. Firstly, the preparation condition of BaGa2ZnO5 powder was researched through different preparation technology. XRD analysis proves that BaGa2ZnO5 must be prepared in sealed environment and with more ZnO due to the phrolysis of ZnO. There are eight emission peaks in the upconverted emission spectrum of BaGa2ZnO5:Er3+/Tm3+/Yb3+ powder excited by 980 nm LD, thereinto, 480 nm and 798 nm peaks correspond to energy level transition of Tm3+ ions, and other emission peaks correspond to energy level transition of Er3+ ions. Moreover, the upconverted emission intensities under different exciting power were measured, and the multiple-photon absorption process of each emission peaks was obtained through fitting curve of exciting power-upconversion intensity. At last, the color coordinate of the sample powder was calculated according to the upconversion emission spectrum and standard data of CIE 1931. The color coordinate is (x=0.415 1, y=0.479 4) and is close to the color coordinate of white light. It proves that the prepared sample powder has the application prospect in the field of white luminescence.关键词：BaGa2ZnO5;upconversion;two-photon absorption;three-photon absorption;co-doped with rare-earth102|87|1更新时间：2020-08-12
- 摘要：SiO2:Tb3+ films were prepared on silicon chips by sol-gel method. The photoluminescence characterizations of the films were studied by fluorescence analysis, and the ways to improve the luminescence were explored and analyzed. Excited by 245 nm, the peaks of transition emissions of 5D4-7FJ (J=6, 5, 4, 3) of Tb3+ can be observed. The concentration quenching effect of the system with high concentration doping of Tb3+ ions, can be significantly improved after the co-doping of Si or Al3+. The luminescence intensity of the sample doped by Si and Al3+ is twice as that of Al3+-doped sample. In addition, the oxygen vacancy defect introduced by annealing under Ar atmosphere can make the system get significantly enhanced emissions, and the best annealing temperature is 1 200℃.关键词：Tb3+ ion;silicon-based material;fluorescence analysis;sol-gel method95|97|1更新时间：2020-08-12
- 摘要：Tm3+/Yb3+ doped aluminum germanate glasses adapting for K+-Na+ ion-exchanged waveguide were fabricated. Absolute characteristic parameters for upconversion (UC) fluorescence of glass samples were measured by integrating sphere coupled with fiber optic spectrometer under the excitation of 975 nm pump laser. The measurement and calculation results show that the effective diffusion coefficient of K+-Na+ thermal ion-exchange is 0.070 μm2/min when Tm3+/Yb3+ doped aluminum germanate glasses are immersed in KNO3 molten salt at 380℃, indicating that the K+-Na+ ion-exchange process is controllable. Tm3+ in aluminum germanate glasses emits 477 nm blue and 806 nm near-infrared (NIR) fluorescence, and the NIR emission plays a dominant role. The absolute fluorescence parameter is identified as a positive correlation with laser power density. When the power density is 1 482 W/cm2, the emission spectral power, emission photon and quantum yield for blue three-photon UC fluorescence are 269 μW, 6.46×1014/s and 1.43×10-4, and the ones for NIR two-photon UC fluorescence are 4 024 μW, 1.63×1016/s and 3.61×10-3, respectively. The absolute characterization for UC fluorescence of Tm3+ in waveguide-typed aluminum germanate glasses provides a valuable reference in developing photoelectronic devices and laser materials.关键词：waveguide-adaptive aluminum germanate glasses;Tm3+ ions;upconversion fluorescence photon quantitative;quantum yields116|130|0更新时间：2020-08-12
- 摘要：With chitosan as raw material, Ca/Zn-nano carboxymethyl chitosan complexing was prepared through carboxymethylation, nanocrystallization and complexing with Ca2+, Zn2+. The structure was characterized by infrared spectroscopy, X-ray diffraction spectroscopy and scanning electron microscopy. The properties of coagulation and hemostatic were investigated. The results show that the polyphosphate structure is contained in nano carboxymethyl chitosan, as Ca2+ and Zn2+ are contained in Ca/Zn-nano carboxymethyl chitosan. Ca2+ and Zn2+ compound successfully with nano carboxymethyl chitosan. The composite has lower crystallization, higher solubility, more uniform round morphology and significant shorter coagulation and hemostasis time. Compared with Zn-nano carboxymethyl chitosan, Ca-nano carboxymethyl chitosan is possessed better structure and better properties of coagulation and hemostasis.关键词：chitosan;chitosan derivatives;nano carboxymethyl chitosan;nanocrystallization129|327|0更新时间：2020-08-12
- 摘要：This paper launched research on the influence of the phosphor layer thickness of laser lighting, and adopted the self-designed reflex lighting module to test. The original scheme of making fixed thickness phosphor layer was used to determine the thickness accurately. With the increasing of the phosphor layer thickness, the flux increases gradually, and presents downtrend after the phosphor layer thickness is over 600 μm. The blue light content shows downtrend before the phosphor layer thickness is 600 μm, and rises slightly after 600 μm, but the overall is stability. The color temperature and blue light content have the same change trend with a proportional relationship. At the same time, this article also verifies the light distribution density has a great influence on the laser illumination.关键词：laser illumination;phosphor layer thickness;luminous flux;blue light content;color temperature135|155|2更新时间：2020-08-12
- 摘要：The spiropyran functionalized diacetylene derivative was prepared by esterification reaction between 10,12-pentacosadiynoic acid and 3',3'-Dimethyl-6-nitro-spiro[2H-1-benzopyran-2,2'-indoline]-1'-ethanol. Then, it was purified via recrystallization and characterized through 1H NMR, MALDI-TOF-MS, elemental analysis, DSC, TGA, IR. The results show that the melt point of the sample is 55℃. It has good thermal stability and begins to decompose until to 282℃. The absorption spectrum shows only one absorption peak (λmax=564 nm) irradiated by UV light (λ=254 nm). The fluorescence spectra indicate the fluorescence peak position is at about 650 nm when the excitation light wavelength varying from 560 to 580 nm. The photoreaction reversibility of the target compound doped in PMMA film is detected, and the results confirm that it has good fatigue resistance.关键词：diacetylene;spiropyran;optical property146|532|2更新时间：2020-08-12
- 摘要：B doped ZnO (BZO) films were prepared on glass substrate by LPCVD method. The effect of hydrogen atmosphere annealing on the optical and electrical properties of BZO thin films was studied. The results show that the phase structure and the transmittance of the BZO films have no change after annealing in the hydrogen atmosphere, but the electrical conductivity of the BZO films is obviously improved. The Hall test results reveal that the carrier concentration is almost the same after hydrogen annealing, but the mobility is dramatically increased. The results in this paper should provide a reference for further improving the optical and electrical properties of BZO thin films.关键词：low pressure chemical vapor deposition;ZnO thin film;optical properties;carrier concentration;hall mobility129|193|1更新时间：2020-08-12
- 摘要：For the very narrow ridge waveguide width, the etching marks and etching methods in the manufacturing of the semiconductor tapered laser chip were studied in this paper. The double photolithography alignment mark using two different precisions for the ridge area and the tapered area was proposed to refine the alignment in the etching of ridge waveguide and tapered waveguide. The photolithography alignment marks were arranged in different place in different photolithography figure, and they interacted each other in order to keep the photolithography alignment marks clear and complete in repeated etching. By using this method, the etched chip delivers 4.026 W CW output at 7 A current with the center wavelength of 963 nm, and the slow and fast direction beam quality is 1.593 mm·mrad and 0.668 mm·mrad, respectively.关键词：tapered diode laser;ridge waveguide;photolithography alignment marks;wafer photoetching121|169|0更新时间：2020-08-12
- 摘要：In order to enhance the uniformity and irradiation intensity of UV-LED area curing, an optical system for array UV-LED curing area-focusing was constructed. Based on the geometrical optics and Fresnel's law, the derivation of lens contour was completed, and the optimum resolution of lens array was calculated. The results show that the light is controlled effectively by lens, the irradiance intensity and irradiance uniformity of area-focusing are improved, while the structure of array is more compact. When the half value of the light source is 27.5° and 15.5°, the uniformity is 95.3% and 98.6%, and the irradiance intensity is 2.5 and 6.4 times larger than Lambertian optical source array. The influence of working distance and the parameters of chip on area-focusing optical source system is also analyzed, and the simulation results are verified by experiments. These results provide theoretical basis for the application of UV-LED and optical design.关键词：optical design;freeform surface;approximate Lambertian source;ultraviolet curing;array117|132|4更新时间：2020-08-12
- 摘要：The transfer matrix calculation model was used to study a unique display device employing low-dimensional phase-change thin film (PCMs). The optical properties of the device based on the germanium antimony tellurium alloy Ge2Sb2Te5 (GST) thin films were studied by simulation. It was showed how such a system, when combined with a transparent electrode such as indium tin oxide (ITO), could be used as displays on reflective and transparent substrates both on rigid and flexible surfaces. To understand the relationship between the thickness of ITO and GST layers and the overall optical properties of the stack, the reflectivity spectrum of the stack was systematically computed while the thickness of each layer was gradually increased. For the reflection type device, the thickness of ITO has great influence on the reflection spectrum of the device, and the color of the device can be changed by changing the thickness of ITO. When the thickness of GST is 12 nm, the color contrast of the device is the best which is achieved by changing the phase of GST between amorphous and crystalline, and the power consumption is low. For the transmission type device, the transparency of the device can be very high by using ultra-thin GST film, but the transparency declines rapidly when the thickness of GST is more than a few nanometers.关键词：transfer matrix;phase-change thin film;display device;color contrast107|114|2更新时间：2020-08-12
- 摘要：A series of SnS2 thin films were deposited on glass substrates by RF magnetron sputtering a SnS2 target. The effects of the preparation conditions on the properties of the films were studied. The crystal and phase structure of the thin films were investigated by X-ray diffraction and laser Raman spectroscopy. The chemical composition, optical properties of the SnS2 thin films were characterized by energy disperse X-ray spectroscopy, ultraviolet-visible-near infrared spectrophotometry (UV-Vis-NIR). The atomic ratio, optical constants and bandgap of SnS2 thin film were calculated and analyzed. The results show that the optimal condition for SnS2 thin films is the sputtering power of 60 W and argon pressure of 0.5 Pa. The film is aligned along (001) preferred orientation, the transmittance and refractive index are high in the visible region, the extinction coefficient is small, and the direct bandgap is 2.81 eV. The n-SnS2/p-Si heterojuction devices were fabricated. The devices exhibit good rectifying behaviors and weak photovoltaic properties. The photocurrent under the reverse bias voltage is increased with the increasing of illumination intensity. The photoconducting mechanism of the devices is controlled by the presence of exponential distribution of trap centers in the forbidden band of SnS2.关键词：SnS2 thin films;RF magnetron sputtering;optical properties;heterojunction device136|145|3更新时间：2020-08-12
- 摘要：The properties of deep center in InP1-xBix grown by gas source molecular beam epitaxy(GSMBE) were firstly investigated using deep level transient spectroscopy (DLTS). For the sample of InP, E1 peak is observed under majority-carriers filling pulse conditions. It locates at Ec-0.38 eV with capture cross section of 1.87×10-15 cm2. For the sample of InP0.9751Bi0.0249, H1 peak is observed under minority-carriers filling pulse conditions. It locates at Ev +0.31 eV with capture cross section of 2.87×10-17 cm2. The deep level E1 is considered to originate from the intrinsic antisite of PIn. The deep level H1 is attributed to the formation of Bi pairs or complex Bi related clusters. It is very meaningful to make clear the causes of the two defects in the InP(Bi) materials for device application.关键词：InPBi;deep center;deep level transient spectroscopy (DLTS);gas source molecular beam epitaxy(GSMBE)125|88|0更新时间：2020-08-12
- 摘要：In order to improve the emission efficiency of light-emitting diodes, reduce the quantum-confined Stark effect induced by stain, and increase the wave function overlap of electron and holes, InGaN/GaN based LEDs with array nanorods structure were fabricated by utilization of nanoimprint lithography (NIL) and nano-fabrication processes. It demonstrates the uniform and bight emission, lower leakage current (~10-7), optimized turn on voltage (~3 V). The uniform electroluminescence (EL) of InGaN/GaN MQW NR arrays has been successfully achieved as well, with a slight blue shift compared to that of the planar devices due to the lower quantum-confined Stark effect. It is confirmed that the defects and dislocations density is lower, strain accumulated in the film is released, quantum-confined Stark effect is reduced(relaxed degree~70%), and the wave function overlap of electron and holes is increased and light extraction efficiency is improved.关键词：InGaN/GaN;light-emitting diodes;nanorods;nanoimprint lithography110|217|2更新时间：2020-08-12
- 摘要：The sensor elements based on GaN high electron mobility transistor (HEMT) have considerable advantages on sensitivity, response speed, detection surface, and harsh environment adaptability because of the features of HEMT, such as high 2DEG density at the hetero-interface, wide band gap, high breakdown voltage, stable chemical properties, and high electron mobility. In this paper, the structures, mechanism, progress of work, advantages and disadvantages about the two mature types of sensors developed from GaN-based HEMT basic structure are discussed and summarized firstly. Then, the latest progress on three kinds of nevel GaN-based HEMT sensors is reviewed in detail focusing on the device material and the optimization of gate structure and material. Among them, GaN-based HEMT photodetector is highlighted in the aspects of the material system, key process, detector structure, principle and new mechanisms. Finally, the future direction for the development of GaN-based HEMT sensor elements is explored.关键词：AlGaN/GaN heterojunction;2DEG;GaN-based HEMT sensor;gate structure;photodetector114|326|4更新时间：2020-08-12
- 摘要：By using one-dimensional ZnO nanowires and two-dimensional graphene composite structure to integrate onto p-GaN surface, the current expansion and the efficiency improvement of LED light extraction were both achieved. Comparing the devices with or without ZnO nanowires, it was found that ZnO nanowires could increase the light extraction efficiency of GaN LED by 30%. The key parameters, such as opening voltage, working voltage and reverse leakage current of the two type of devices were analyzed, and the results verified that the structure used in GaN LED didn't deteriorate the electrical properties of LED. The complex structure adopted in this paper for GaN LED can not only achieve a good Ohmic contact without the using of ITO, but also enhance the extraction of light.关键词：ZnO;GaN LED;graphene;transparent conductive layer108|151|2更新时间：2020-08-12
- 摘要：The interaction between calf thymus DNA and anti-cancer drug dacarbazine was investigated using isothermal titration calorimetry(ITC), spectroscopy, viscosity and other methods. The hyperchromic effect and blue shift in the absorption spectra as well as viscosity decline are observed clearly after the interaction between dacarbazine and DNA. Furthermore, the binding constant and number of binding sites are also recorded by ITC, presenting that the interactions of the dacarbazine with DNA can be categorized for two modes:a non-classical intercalation type and surface binding effect. In former, ΔH1<0, ΔS1>0, K1=5.63×104, the binding site is 0.10. In latter, only surficial interaction during the combination of the drug molecule with DNA occurs, not embedding into the hydrophobic part of the DNA molecule, due to ΔH2>0, ΔS2>0, K2=1.00×103, and the binding site of 9.99. Meanwhile, UV method is also employed to find the binding constant of Ka=6.70×104, which is consistence with ITC observation.关键词：DNA;dacarbazine;spectroscopy;interaction mechanism;isothermal titration calorimetry98|158|2更新时间：2020-08-12
- 摘要：The principle and method of surfaced bi-directional reflective distribution function (BRDF) and irradiation were introduced. The measuring platform of surfaced BRDF on 532 nm/1 064 nm and irradiation was built to study the temperature dependence of the reflectance and irradiation of metallic target grided by emery(320 mesh). The results show that the ground metallic target approximates lambert radiator, and the reflectivity is lower than 0.25. The surfaced reflective distribution, reflectivity and irradiation are almost consistence below 320℃.关键词：bi-directional reflective distribution function;irradiation;metallic target;temperature change109|553|2更新时间：2020-08-12
- 摘要：Aiming at the problem of poor spectral reconstruction accuracy from trichromatic camera responses, a method was presented for spectral reflectance reconstruction based on the interim connection space (ICS) for spectral data and trichromatic digital camera. Firstly, the training samples with known spectral reflectance and polynomial fitting method were utilized to establish a transform matrix from the trichromatic camera responses to the ICS response values. Then, the target samples or pixels were mapped to the ICS by means of the transform matrix. Finally, spectral reflectance reconstruction of each sample or pixel was implemented via an appropriate spectral reconstruction algorithm using ICS response values and the reconstruction accuracy is evaluated in terms of chromaticity difference and spectral root mean square error. In addition, the inverse distance weighted least square method was applied to calculate the transform matrix to improve the conversion accuracy from the camera response to the ICS response value. The experimental results show that the proposed method is feasible and has reliable precision. Compared to the spectral reflectance reconstruction from trichromatic camera responses, the chromaticity reconstruction accuracy and spectral reconstruction accuracy of the proposed method are significantly improved. The mean chromaticity difference and mean spectral root mean square error are 1.145 2 and 0.010 3, respectively. It can meet the needs of digital archives, high fidelity color reproduction, etc.关键词：interim connection space for spectral data;spectral reflectance reconstruction;inverse distance weighted least square method127|112|3更新时间：2020-08-12
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