最新刊期
卷 41 ， 期 6 ， 2020
- 摘要：PbSe quantum dots have attracted a great number of attentions due to their tunable bandgap in a wide range, high photoluminescence quantum yields and low-cost solution process, thus enabling them the potential as key functional materials in infrared region. However, PbSe quantum dots are sensitive to air, resulting in the decrease or even destroy of their optical properties. Overcoating of PbSe quantum dots by a suitable shell, yielding PbSe-based core/shell quantum dots, have been successfully demonstrated to be an effective strategy to improve the chemical stability and optical properties. In this mini-review paper, we summarized the progress of colloidal synthesis methods of PbSe-based core/shell quantum dots and their optoelectronic applications in photodetectors, solar cells, lasers and photocatalysis. We hope the review can attract the attention from both of the industrial and academic researchers.关键词：PbSe;quantum dots;core/shell;infrared;optoelectronics413|412|2更新时间：2020-09-15
Invited Review
- 摘要：Nitride phosphors are born out of structural ceramics, and have beautifully turned into important down-conversion luminescent materials owing to their diversity in structure and specificity in local coordination. They are contributing significantly to advances in semiconductor lighting and display technologies. This article first briefly overviews the discovery of some classic nitride phosphors, and then highlights the inspiration it brings. That is to say, the traditional mode of thinking must be abandoned when conducting the research and development of new materials, but the R & D must rely on industrial needs and be strengthened by tight cooperation between industry and research units.关键词：luminescent materials;nitride phosphors;solid state lighting435|575|2更新时间：2020-09-15
- 摘要：The properties of organic opto-electronic materials are governed by the whole collective as molecular aggregates. Accordingly, the key factors and the control strategies for the structures of molecular aggregates are reviewed by the investigation of mechanoluminescence and organic room temperature phosphorescence materials. The concept of Molecular Uniting Set Identified Characteristic (MUSIC) was proposed by concerning the similarity in the construction of opto-electronic materials and the symphonic performance as real "music", highlighting the key role of molecular aggregates.关键词：molecular aggregates;mechanoluminescence;organic room temperature phosphorescence;organic opto-electronic materials298|1009|2更新时间：2020-09-15
40th Anniversary Special Column——Young Scientist on The Road
- 摘要：The formation energies and thermodynamic/optical transition energy levels of native defects, defect complexes and lanthanide ions in the Sr2MgSi2O7 (SMSO) are calculated from hybrid density functional theory(DFT) with the standard PBE0 functional in order to study their contributions to the thermoluminescence (TL) and long-lasting luminescence (LLL) of the material SMSO:Eu2+, Dy3+. The PBE0-calculated formation energies reveal that the defects/complex VO, SrMg, MgSr and SrMg-MgSr are relatively easily generated in the SMSO samples prepared under reducing atmospheres. The thermodynamic and optical transition energy levels of the easily generated defects/complex above and the lanthanide ions in the host are derived from the PBE0-calculated band gap (of 7.18 eV) and formation energies. Based on their comparison with the experimental results of trap depths of the SMSO:Eu2+, Dy3+, the neutral and singly negatively charged VO and Dy3+ ions (at Sr sites) are supposed to act as the electron traps. The aim of this study is to deeply understand the mechanisms of the TL and LLL in the long afterglow material SMSO:Eu2+, Dy3+ by using first-principles calculations, which can be adopted as the effective supplement of the experiment.关键词：native defects;lanthanide ions;thermodynamic transition energy levels;long-lasting luminescence;first-principles207|235|0更新时间：2020-09-15
- 摘要：The Eu3+-doped lanthanum cerium composite oxides (the molar ratio of La to Ce is 1:1 and 1:2, respectively) were sol-gel synthesized by using cerium nitrate, lanthanum and europium oxide as raw materials, and appropriate amount of citric acid as chelating agent. The crystal structure, luminescent properties and chromaticity coordinate of the samples with different composition were analyzed through X-ray diffraction patterns, scanning electron microscope, Raman spectra and photoluminescence. The results reveal that the composite samples are of cubic fluorite structure with the space group Fm3m, which is almost identical with CeO2 except for larger lattice parameter a. The powder morphology shows round shape and the particle sizes are around 50-60 nm. Excited with 466 nm blue light, the characteristic red transition (5D0→7F2) emission of Eu3+ at 613 nm and 628 nm plays predominant roles. As the doping concentration of Eu3+ is stable at 15%, the luminescence intensity of lanthanum cerium composite is obviously superior to CeO2, and the luminescence is further optimized as the molar ratio of La to Ce is 1:1. Due to the coincidence of 466 nm blue light with the emission of GaN chips, the Eu3+-doped lanthanum cerium composite oxide may potentially be used in solid state lighting fields.关键词：sol-gel method;rare earth;luminescence;lanthanum cerium composite oxide;cerium oxide169|238|1更新时间：2020-09-15
- 摘要：In this work, the Sr6Ca4(PO4)6F2 is selected as host compound. The Eu2+/Mn2+ ions are selected as doped ions. H3BO3 is used as agent. The phosphors are prepared by the solid-state method. The single-phase was proved by the XRD pattern of phosphor. There are two reasons for the decrease of quantum efficiency of Sr6Ca4(PO4)F2:Eu2+, Mn2+. One is the concentration quenching effect of Mn2+, and the other is "bottleneck effect" and "anti-bottleneck effect" in the energy transfer of Eu2+-Mn2+. The quantum efficiency of Sr6Ca4(PO4)F2:Eu2+, Mn2+ can be enhanced by doping auxiliary agent H3BO3 and regulating cations. For the luminescent centers of Eu2+ and Mn2+, their crystal field environments can be analyzed by the data of refinement, and their emission intensities in the two manipulation methods can be also explained.关键词：luminescence;Sr6Ca4(PO4)6F2;energy transfer;cation substitution159|175|2更新时间：2020-09-15
- 摘要：In this work, a solvothermal process was used to synthesize the β-NaYF4:20%Yb3+/2%Er3+ core nanoparticles(NPs) and β-NaYF4:20%Yb3+/2%Er3+@β-NaYF4:x%Yb3+(x=0, 20, 50, 70, 100) core-shell NPs. The size of the core NPs and core-shell NPs is about 30 nm and 40 nm respectively, implying that the thickness of the layer is 5 nm. After coating a β-NaYF4 shell without Yb3+ doping, the upconversion(UC) intensity is increased with a factor of 14 and 25 for green emission and red emission respectively, resulting from the suppression of deexcitation of Yb3+ ions by the core-shell structure. However, the UC intensity is decreased dramatically with the increasing Yb3+ ions concentration in the shell, due to the inefficient energy transfer process between the Yb3+ ions in the shell and the Er3+ ions in the core caused by the large distance between them. As the β-NaYF4 shell completely converts to β-NaYbF4, the UC intensity decreased 98.8% and 99.4% for green and red emission, respectively.关键词：rare earth;upconversion;energy transfer;β-NaYF4243|114|9更新时间：2020-09-15
- 摘要：The up-conversion luminescent material BaMoO4:Yb3+/Tm3+ was prepared by hydrothermal method. The thermal stability and luminescence properties of the materials were studied by changing the synthesis temperature and test temperature. It indicated that, when CYb3+=6% and CTm3+=1.5%, the grain size of the samples increased after recrystallization at 743 K, but the luminescence properties and thermal stabilities of the samples were improved obviously. The samples had high degree of crystallinity and they were tetragonal system. By measuring the up-conversion emission spectra and the decay curves of the samples, it was found that the thermal stability of the samples was excellent. The quantum yield of the sample was 1.5% and the emission color was uniform. Therefore, the sample has high luminescence property, thermal stability and practical value.关键词：up-conversion luminescence;thermal stability;recrystallization180|130|0更新时间：2020-09-15
- 摘要：In order to improve the fluorescence stability of perovskite quantum dots(PQDs) (CsPbX3, X=Cl, Br, I) and realize long-term application in the next generation of flat panel displays and solid-state lighting, the effect of potassium on the fluorescence performance of PQDs was studied. First, CsPbBr3 PQDs were synthesized by hot injection method. Then, potassium oleate (KOA) was reacted with the above-objected PQDs to prepare K-modified PQDs(K-PQDs). Finally, these PQDs were applied to the emitting layer of the quantum light emitting diodes(QLEDs). The experimental results show that when the content of KOA is 20 μL/mL, the fluorescence performance of K-PQDs is better than unmodified PQDs. Compared with devices made with unmodified PQDs, the maximum luminance of devices made with K-PQDs increased from 1 845 to 4 300 cd/m2, and the maximum current efficiency increased from 0.3 to 1.3 cd/A. Therefore, the introduction of potassium can effectively suppress the generation of surface defects of PQDs, reduce the loss of photoluminescence quantum yield(PLQYs), enhance the fluorescence stability of PQDs, and achieve more excellent device performance.关键词：perovskite quantum dots;potassium element;halogen vacancy;stability213|214|1更新时间：2020-09-15
- 摘要：In order to investigate bimolecular excited state emission of 4, 4, 4-tris(N-carbazolyl) triphenylamine(TCTA), a single-layer device(ITO/MoO3/TCTA/LiF/Al) and a bilayer heterojunction device(ITO/NPB/TCTA/TPBi/Bphen/LiF/Al) were fabricated, respectively. Optical and electrical characteristics of devices and steady-state spectra of films were measured. The following conclusions are drawn. (1)Electroluminescent (EL) spectra of single layer devices demonstrate two emission peaks:425 nm and 600 nm. The peak at 425 nm is originated from the emission of TCTA monomer according to photoluminescent (PL) spectrum of TCTA film, and the peak centered at 600 nm is attributed to the emission from electromer. White color with 1931 CIE values of (0.381, 0.343) was obtained for the single layer devices because of the superposition of blue emission peaked at 425 nm and orange emission centered at 600 nm. (2)TCTA/TPBi bilayer device exhibited EL spectra peaked at 440 nm, which is belonged to the emission of TCTA+TPBi- electroplex according to the PL and UV-Vis absorption spectra of TCTA, TPBi and TCTA/TPBi films. Meanwhile, better properties were shown in the bilayer device than those of single devices. The maximum brightness was 930 cd/m2 and CIE coordinates were (0.18±0.01, 0.14±0.01) for applied voltages varying from 6 V to 11 V.关键词：TCTA;electromer;electroplex;bimolecular excited state183|348|0更新时间：2020-09-15
Synthesis and Properties of Materials
- 摘要：The fabrication process and test results of the GaN based pin avalanche detector are described in detail. The avalanche in obtained device occurs at a reverse bias of 71 V, and the multiplication factor reaches 5×104. It is found that the p-layer carrier concentration is an important parameter affecting the device performance. Combined with the analysis of electric field intensity distribution, a method to estimate the carrier concentration in p-layer is proposed, and further calculation indicates that the maximum electric field value at avalanche breakdown is 2.6 MV/cm, which is similar to the previously reported values for GaN avalanche detectors. At last, Hall test and Secondary ion mass spectroscopy(SIMS) results are consistent with those estimated by the model calculation.关键词：GaN;avalanche detector;Poisson equation172|134|0更新时间：2020-09-15
- 摘要：AlGaN-based deep ultraviolet light-emitting diodes (DUV-LEDs) employing irregular H-shaped quantum barriers in the active region by modulating Al composition have been investigated. It has been found that the H-shaped quantum barriers by insertion of double spike barriers with higher Al composition can effectively improve both the internal quantum efficiency (IQE) and light output power (LOP) compared to commonly adopted single-Al-composition barrier for AlGaN multiple quantum wells (MQWs). It is verified that electrons in the active region are effectively blocked by the raised barriers, while holes can gain more kinetic energy to cross the barrier height and then be injected into the active region. Thus the carrier recombination rate in the DUV-LEDs adopting the H-shaped quantum barriers can prevail much over the conventional one.关键词：AlGaN;deep ultraviolet light-emitting diodes;quantum barrier196|185|0更新时间：2020-09-15
- 摘要：A new numerical model for a 2 μm thulium-doped self-similar pulsed laser was established using nonlinear Schr dinger equation (NLSE). In this model, NLSE was used to describe the generation and propagation of the pulse in the laser. The evolution of the pulse in the laser cavity was simulated using MATLAB software. The parameters such as the net dispersion, the gain coefficient and the saturable absorber were optimized. The typical 2 μm self-similar pulse generation area and characteristics were obtained through simulation. In the optimal operating range, a high-power parabolic pulse with strict positive chirp with the energy of 7.87 nJ and the pulse width of 30.58 ps was obtained. At the same time, the effects of parameters such as the net dispersion, the gain coefficient and absorber on the self-similar pulse were analyzed. We simulated the grating for dispersion compensation. The output pulse width reached 547 fs and the pulse peak power reached 20.85 kW. This paper gives guidance for obtaining high-power self-similar pulses.关键词：2 μm self-similar pulse;nonlinear Schrödinger equation;numerical simulation;fiber optics137|249|4更新时间：2020-09-15
- 摘要：The non-invasive and real-time pH detection is of significant importance in biomedicine fields. In this paper, a fluorescent pH nanosensor based on flourescein isothiocyanate(FITC) is prepared by a facile coprecipiation method. The fluorescence intensity of FITC changes obviously with the increase of pH. When the pH changes from 3 to 9, the fluorescence intensity of FITC increases up to about 38 times. The pH detection can be realized by measuring fluorescence intensity changes of FITC. The value of pKa is calculated to be 6.07. The fluorescent pH nanosensor has small particle size, high sensitivity, good reversibility and excellent biocompatibility, which is promising in intracellular pH detection.关键词：flourescein isothiocyanate;pH detection;nanoparticle;fluorescence sensing121|219|3更新时间：2020-09-15
Device Fabrication and Physics
- 摘要：Since persistent luminescent materials are free from real time excitation, which can effectively eliminate the interference of excitation light source and auto-fluorescence from complex sample, near infrared persistent luminescent materials attract wide attentions in the field of biological imaging. However, there are relatively few reports on its application in fluorescence sensing, especially in metal cations detection. The near-infrared persistent luminescent nanophosphor ZnGa2O4:Cr3+, Sn4+ (ZGSC) was synthesized by hydrothermal method, and worked as fluorescent probe after coating with silicon ZnGa2O4:Cr3+, Sn4+@SiO2 (ZGSC@SiO2), which is well dispersed in an aqueous solution. Based on the phenomenon that the fluorescence of ZGSC@SiO2 can be quenched by Fe3+, a fluorescence sensing method with good selectivity and interference free was established for detecting Fe3+. The background interference can be effectively eliminated by using time-resolved spectrum, and high signal-to-noise ratio detection can be realized. The detection linear range is 50-800 μmol/L, and the detection limit is 25.12 μmol/L. Three kinds of iron supplement oral liquid were selected as the real samples, and the content of total iron and Fe3+ were detected. The results show that the total iron contents in the three samples are matched well with the contents claimed in the labels. The average recoveries of total iron content in the three samples were 99.00%-99.79%, and the average recoveries of Fe3+ content were 99.90%-102.69%. The RSDs of the total iron content are 2.416%-3.808% and the RSDs of the Fe3+ content are 3.263%-4.296%, respectively. The Fe2+ content can be obtained by subtracting Fe3+ content from the total iron content in the sample. Therefore, the fluorescence sensing system can simultaneously detect Fe3+ and Fe2+, and can be used for quality control of the effective valence state Fe2+ in iron supplement oral liquid.关键词：near-infrared persistent luminescence;ZnGa2O4:Cr3+, Sn4+;Fe3+;time-resolved spectra technique241|121|3更新时间：2020-09-15
- 摘要：Based on the property that the electrochemiluminescence (ECL) signal could be significantly enhanced after adenosine triphosphate (ATP) aptamers interacted with ATP molecules, an ECL aptasensor was developed to detect ATP. A nano-Au electrode was obtained by electrodeposition method. The probe DNA with 3'-terminal labeled by ruthenium complex was self-assembled to the surface of the nano-Au electrode with the sulfhydryl group modified on the 5'-terminal, and then hybridized with the ATP aptamer which 5'-terminal was labeled by ferrocene molecule, to form rigid linear double-stranded DNA. Thus, the constructed sensor produced weak ECL signal. After incubation in an ATP solution, the aptamer molecules could dissociate from the probe DNA and fall off from the electrode surface due to the strong specific binding of ATP molecules and ATP aptamer, and the probe DNA on the electrode surface could form hairpin like stem ring structure, resulting in a stronger ECL signal. The linear range of ECL intensity and the logarithm of the ATP concentration was 10.0~1.0×105 pmol/L with a detection limit of 5.0 pmol/L, and the correlation coefficient was 0.995 9. The sensitivity and detection range of the sensor are higher than those reported so far, which shows the potential application of ATP detection.关键词：electrochemiluminescence;aptamer;biosensor;adenosine triphosphate267|322|1更新时间：2020-09-15
Luminescence Applications and Interdisciplinary Fields
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