最新刊期
卷 40 ， 期 5 ， 2019
- 摘要：Er3+ doped and Er3+-Yb3+ co-doped Ca12Al14O32F2 were synthesized by solid-state reaction method at 1 250℃ and the upconversion luminescence (UCL) properties of the phosphor were studied under 980 nm excitation. The phosphor exhibits green (549 nm) and red (655 nm) emission, which corresponding to 4S3/2, 2H11/24I15/2 and 4F9/24I15/2 transitions of Er3+ respectively. The UCL intensity of the single doped sample increased firstly and then decreased with the increasing Er3+ concentration and the optimum concentration is 0.8%. The UCL intensity of Ca12Al14O32F2:Er3+, Yb3+ prepared in reducing atmosphere is enhanced by 2 times, which might be due to the encaged ions. The dependence of the UCL intensity on excitation powder proves that the observed emissions are obtained via two absorption processes. The transition mechanism of phosphor excitation under 980 nm is discussed in detail.关键词：Er3+;Ca12Al14O32F2;high temperature solid state reaction;upconversion luminescence153|90|4更新时间：2020-08-12
- 摘要：BaGd2(MoO4)4:Tb3+ and BaGd2(MoO4)4:Tb3+,Eu3+ phosphors were synthesized by high temperature solid state method and their structure and luminescent properties were analyzed by means of X-ray diffraction, excitation and emission spectra, and luminescent decay curves. Under excitation of 290 nm, BaGd2(MoO4)4:Tb3+ phosphors give rise to a intense green emission at 550 nm, indicating the samples can be used as green-emitting phosphors. The optimum concentration of Tb3+ ions is 50%, and the dipole-dipole interaction is the main reason for the concentration quenching. As the Eu3+ ions were co-doped in BaGd2(MoO4)4:Tb3+ phosphors, the characteristic emissions of both Tb3+ and Eu3+ ions can be observed. With the increasing concentration of Eu3+ ions, the emission intensities of Tb3+ ions decreased, while those for Eu3+ ions were enhanced. The energy transfer efficiencies between Tb3+ and Eu3+ ions were calculated on the basis of lifetimes of Tb3+ ions in BaGd2(MoO4)4:Tb3+,Eu3+, and the energy transfer mechanism was confirmed to be dipole-dipole interaction according to the relations between lifetimes and activator concentrations.关键词：molybdate;phosphors;energy transfer;tunable color143|106|3更新时间：2020-08-12
- 摘要：In this paper, Sr3MgSi2O8:Eu3+ red phosphor was synthesized by sol-gel method. The phase, morphology and luminescence properties of the powders obtained by calcination at different temperatures (950, 1 050, 1 150, 1 250℃) were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), fluorescence spectrum (PL) and X-ray photoelectron (XPS). According to the results of XRD, the prepared sample is orthorhombic Sr3MgSi2O8. The results of scanning electron microscopy and specific surface area show that the phosphor obtained by heat treatment at 1 150℃ has the largest specific surface area, which can reach 90.213 1 m2/g. In addition, the diameter is uniform; the infrared spectrum shows that the sample contains Si-O-Si, Mg-O and Sr-O chemical bonds; all samples show strong emission peaks at 614 nm and 702 nm, corresponding to the5D0→7F2 and 5D0→7F4 transitions of Eu3+ when the excitation wavelength is 394 nm, which belongs to red light emission. As the heat treatment temperature increases, the intensity of the emission peak corresponding to the sample first increases and then decreases, that is, the temperature quenching effect occurs. The Sr3MgSi2O8:Eu3+ red phosphor synthesized by heat treatment at 1 150℃ has the best luminescence performance. The optimum heat treatment temperature is 1 150℃.关键词：sol-gel method;phosphor;Sr3MgSi2O8:Eu3+;luminescence performance151|125|2更新时间：2020-08-12
- 摘要：α-GaOOH nanorod arrays on FTO substrates are synthesized by a simple hydrothermal method for the first time, which can be used as a precursor and converted via hydrothermal reaction into ZnGa2O4 nanocubes due to a dissolution-recrystallization process. The characterization results of samples indicate that as-prepared ZnGa2O4 on FTO belongs to cubic system and has the cubic morpohology with the size of about 500 nm. A series of photocatalytic experiments have been performed under simulated sunlight irradiation and the results indicate that ZnGa2O4 nanocubes show both enhanced adsorption and photocatalytic abilities for methylene blue compared with rhodamine B and congo red, and only show weak photocatalytic activity for methyl orange. As electron scavenger and oxygen provider, H2O2 can facilitate the formation of free radicals with high chemical reactivity and make as-prepared samples possess continuous and enhanced photocatalytic activity of dyes.关键词：α-GaOOH nanorod;ZnGa2O4 nanocubes;hydrothermal method;photocatalysis118|247|1更新时间：2020-08-12
- 摘要：Ba3SiO5:Eu phosphor was synthesized by solid-state reaction method at a mild reducing atmosphere. BaCO3, SiO2,Eu2O3 were the raw materials. The results show that the optimized fabrication condition for Ba3SiO5 is that Ba/Si atomic ratio should equal to 3, annealed temperature should be 1 200℃. Under 254, 365, 410 nm excitation, Ba3SiO5:Eu phosphor would give out broadband emission(centered at 566 nm, related to Eu ion 4fn-15d→4fn), and the absolute PL quantum yields are 70%, 50%, 10% respectively. The photoluminescent lifetime is 102 ns. The excitation monitored by 566 nm has a broadband emission in the range of 250-450 nm centered at 360 nm, with a small peak at 410 nm. The optimal Eu dopant content is 5%. From the curve of luminescent intensity vs. dopant content, the energy transfer way of activator in Ba3SiO5 can be deduced as electric quadrupole-quadrupole interaction.关键词：barium silicate;cesium ions;high temperature solid-state method;photoluminescent spectra;energy transfer140|182|1更新时间：2020-08-12
Synthesis and Properties of Materials
- 摘要：Carbon nanodots(carbon dots) are a new type of nano-luminescent materials, which have such characteristics as excellent luminescence performance, good biocompatibility, low toxicity, good water solubility and easy surface functionalization, and have shown potential application value in the fields of optoelectronic devices, biological imaging and photothermal therapy. However, there are a variety of precursor materials for the synthesis of carbon nanodots, and the synthesis methods are different, leading to the complex and diverse luminescence mechanisms. This article mainly aims at preparing of nitrogen doped carbon nanodots by using citric acid as a carbon source or ammonia and urea as nitrogen source and solvent and microwave thermal methods, exploring the luminous mechanism of the carbon and inhibition of carbon accumulation induced fluorescence quenching method, and further research points of carbon in solid state lighting, visible in the field of optical communication, biological imaging and treatment of field application prospect.关键词：nitrogen doped carbon nanodots;luminescence mechanism;solid lighting;biological imaging;heat treatment300|3852|8更新时间：2020-08-12
Invited Paper
- 摘要：Aiming at the problem that the ultra-thin light guide micro-die is difficult to process, combined with the isothermal hot stamping method, a new "equivalent substitution" imprinting process is proposed, which is to reduce the microstructure replication height by controlling the molding process parameters. The equivalent structure smaller than the microstructure of the mold is formed on the substrate, which breaks through the idea of completely replicating the microstructure of the mold during the hot stamping process, reduces the difficulty of processing the microstructure mold, and thus innovates the high quality super forming process of a thin light guide plate. The specific experiment was designed with polymethyl methacrylate (PMMA) as the substrate, and the 0.25 mm thick light guide plate was processed to verify the feasibility of this method. The experimental results show that this new "equivalent substitution" imprint process can not only reduce the manufacturing difficulty and processing cost of the mold, but also greatly improve the performance of the ultra-thin light guide plate. Compared with the thermostatic upper and lower mold differential thermal imprint process, the uniformity was increased by 23% and the overall molding time was shortened to 20 s.关键词：isothermal hot embossing;equivalent replacement hot stamping;ultra-thin light guide plate;process parameters;replication height;uniformity153|292|0更新时间：2020-08-12
- 摘要：Near-infrared luminescence origin of Bi-doped amorphous silica thin film is discussed by the XPS characterizations and selective PL measurements. The nature of the near-infrared emission in amorphous silica thin film is considered as both the transition of Bi+ ions from 3P1 to 3P0 and the transition of Bi0 from 2D3/2 to 4S3/2. Further, the confined crystallization growth strategy is designed for fabricating uniform-size Au quantum dots embedded in Bi-doped silica thin film. Through controls of the doping amounts of Au ions, the NIR emission of Bi ions in silica thin film can be wavelength-tunable and enhanced by nearly 300% on the optimum Au ions doping amount. The thickness of thin film is 90 nm and the formation of Au quantum dots with different average sizes and number densities have been confirmed by the high-resolution TEM images. Temperature-dependent PL emission spectra suggest parts of Au ions may play a role of eliminating hydroxyl groups, which gives rises to greatly enhanced PL intensity in the near-infrared region. We anticipate that both greatly enhanced and wavelength-tunable NIR luminescence and discussion of luminescence origin would shed light on future research of Bi ions-doped luminescent materials.关键词：amorphous silica;sol-gel method;thin films;photoluminescence119|232|0更新时间：2020-08-12
- 摘要：By using the material of AlAs with high thermal conductivity in the n-type distributed Bragg reflector (DBR) and increasing the thickness ratio of the AlAs layer, the thermal conductivity of N-side DBR was greatly increased and the high temperature performance of the device was improved. VCSELs devices were produced, and the results of DC test under different temperature conditions showed that the maximum thermal rollover optical output power was 9 mW at 25℃, and the maximum optical output power of 5 mW was achieved at a thermal rollover current of 11 mA at 85℃, showing high DC performance of high temperature operation. The far field divergence angle was less than 17°. Eye diagrams were clear under different temperature conditions varying from 0℃ to 70℃, indicating that the devices met the requirements of high temperature 25 Gbit/s operation.关键词：distributed Bragg reflector;vertical cavity surface emitting lasers;quantum well;metal-organic chemical vapor deposition156|179|6更新时间：2020-08-12
- 摘要：The commonly-used xenon solar simulator has the disadvantage of high cost, short life circle and high power consumption. In order to improve the accuracy of the solar cell test, a multi-wavelength LED solar simulator was designed. The spectral matching, non-uniformity and instability of the irradiance satisfy the class A standard specified in IEC60904-9-2007. Moreover, a corresponding solar cell test syst-em was developed, having the function of light source control, data processing, temperature calibration and parameter calculation. The experiment results showed that the electrical characteristics of monocrystalline sili-con solar cell could be accurately obtained, and the results were stable, comfirming the reliability of the light source and the scientificalness of the test method.关键词：solar simulator;LED;test;temperature calibration138|266|1更新时间：2020-08-12
- 摘要：Organic heterojunction connector(OHC) layers were widely used in tandem organic light emitting diodes(OLEDs) for their good light transmittance and technological compatibility with OLEDs. In a tandem OLED, the OHC layers, serving as the charge generation layer, played an important role in tandem OLEDs to function efficiently. In order to obtain the OHC layers with best performance, the devices with the structure of glass/ITO/tris(8-hydroxyquinoline) aluminum (Alq3)(60 nm)/C60(x nm)/CuPc(y nm)/N,N'-bis(naphthalen-1-yl)-N,N'-bis(phenyl)-be-nzidine (NPB)(40 nm)/Al(100 nm) were fabricated. The current density-voltage characteristic of the fabricated devices revealed that the OHC layer with the structure of C60/CuPc can generate charge carriers effectively, and show the largest charge carrier generation ability with the structure of C60(30 nm)/CuPc(10 nm). The forming physical mechanism of optimized OHC layer was reasonably explained. The results obtained in this paper can present an in-depth understanding of the working mechanism of tandem OLED and help ones fabricate high efficiency OLED.关键词：organic heterojunction connector layer;organic light emitting diodes;structure optimization;charge generation ability132|190|0更新时间：2020-08-12
Device Fabrication and Physics
- 摘要：In this paper, the properties of emission spectra of two double-level atoms coupled with two single-mode cavity system with off-resonant dissipation were studied. We investigated the effects of the detuning between the atom and the cavity field, the cavity decay rate and the atom dephasing on emission spectra of the system. The results show that the cavity field spectrum of the system presents three peak structure and the atomic emission spectrum presents double peak structure. In the case of detuning, both the cavity field spectrum and the atomic emission spectrum are asymmetric. When the atom and cavity field are off-resonant compared with the resonance condition, the peak position has obvious drift and the middle peak has obvious increase. Increasing the detuning between cavity field and atom will cause the edge peak to drift to low frequency and change its spectral intensity. Increasing the detuning between atoms and cavity field can make the spectrum drift to low frequency and change the spectral intensity of all peaks. As the decay rate of cavity field increases, the intensity of edge peak will decrease under the condition of resonance. In the case of detuning, the strength of all peaks will reduce. As the atom dephasing increases, the intensity of all peaks of the spectrum will reduce in the case of resonance or off-resonant.关键词：quantum master equation;non-resonant coupling;dephasing;emission spectrum114|178|0更新时间：2020-08-12
- 摘要：The scattering and absorption caused by sand-dust channel will lead to serious attenuation of the laser signals. By considering the characteristics of the sand-dust particle radius distribution and the effects of sand-dust moisture content, the impact of sand-dust on the attenuation characteristics of laser signal is investigated and the expression of signal-to-noise ratio at the receiving end is proposed. Moreover, the bit error rate and channel capacity under sand-dust weather are deduced for the OOK modulation. Furthermore, the effects of atmospheric visibility, transmission distance, sand-dust moisture content and laser wavelength on the bit error rate and channel capacity are simulated. The results show that the channel capacity and system BER performance decrease with the increase of sand-dust moisture content, transmission distance and the decrease of atmospheric visibility. When the atmospheric visibility is 4 km, the system bit error rate achieves 10-2 orders of magnitude with a wavelength of 1 550 nm and a transmission distance of 1 km and the normalized channel capacity is up to 8.48 bps/Hz.关键词：sand-dust channel;complex permittivity;laser attenuation;transmission performance143|193|3更新时间：2020-08-12
- 摘要：In this study, a direct analysis method of acetaminophen(ACOP) was established by ethanediamine-β-cyclodextrins(EN-β-CDs)-functionalized Mn-ZnS quantum dots (Mn/ZnS-QDs) using an electron transfer quenching mechanism. Actetaminophen is a good electron acceptor, which can enter the cavity of β-CDs, and then the fluorescence quenching form resonance electron transfer between actetaminophen and QDs surface. As indicated in experimental results, the fluorescence intensity reached the maximum under the response time was 35 min and the response temperature was 40℃. It was negative linear correlation between the fluorescence intensity and the concentraions of actetaminophen ranges from 1 to 100 ng/L, the detection limit obtained 0.64 ng/L, the relative standard deviation(RSD) was 1.69%(n=11). The method has been successfully applied to the detemination of actetaminophen in blood with the recovery 91.06%-103.82%.关键词：ethanediamine-β-cyclodextrins;Mn-ZnS quantum dots;fluorescence quenching;acetaminophen136|186|2更新时间：2020-08-12
- 摘要：Because the optical properties(absorption coefficient and scattering coefficient) do not have a strict linear relationship with the components proportion, the K-M based color matching model cannot guarantee the prediction precision of components proportion. In view of the problem mentioned above, this paper proposes an ink components proportion prediction model. First, an ink mixing model is established by replacing the absorption coefficient and scattering coefficient in the K-M theory with the reciprocal of spectral reflectance which has a strong linear correlation with the component proportion in certain characteristic wavelengths and introducing a additional nonlinear term. On this basis an ink components proportion prediction model is established. Taking two groups of samples mixed with binary primary inks as an example, the proposed model and method were verified. The experimental results showed that this method could predict components proportion that were close to the real results. The prediction average deviations of the two groups were 1.57% and 3.6% respectively. The proposed model and method can provide a new possibility for the ink components proportion prediction of target sample.关键词：reciprocal of spectral reflectance;component proportion prediction;ink mixing color model;computer color matching158|198|0更新时间：2020-08-12
- 摘要：Since the previous studies on ultrashort pulses and two-level atom systems are mainly based on slow-variable envelope approximations and rotational wave approximations, the nonlinear properties of the derivative terms in these studies cannot be well described. In this paper, FDTD algorithm and prediction-correction method are combined to establish a predictive-corrected FDTD algorithm for the study of the interaction between ultrashort pulses and two-level atom system. It can clearly characterize the time derivative of the electric field at the upper and lower levels of the system. At the same time, a pulse excitation source that can completely invert two-level particles is well established. Our method can be used as a numerical tool for target recognition.关键词：ultrashort pulse;two-level atom system;FDTD algorithm;prediction-correction method;area theorem133|231|0更新时间：2020-08-12
Luminescence Applications and Interdisciplinary Fields
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