最新刊期
卷 39 ， 期 12 ， 2018
- 摘要：Monolayer MoSe2 and WSe2 samples were prepared by mechanical exfoliation in diamond anvil cell(DAC). The high-pressure micro-area fluorescence spectroscopy technique was used to study excitons emission behavior under pressure in argon pressure-transmitting medium(PTM). The neutral and negative exciton evolutionary trends of monolayer WSe2 showed an inflection point at 2.43 GPa, and the neutral exciton emission of monolayer MoSe2 appeared a new split peak at 3.7 GPa. Combined with the first-principles calculation and analysis, we confirmed that the mechanism of these discontinuities is the pressure-induced conduction band bottom K-Λ crossover. This result can be extended to the entire two-dimensional layered material family, and laying foundation for the development of exciton devices.关键词：monolayer WSe2;monolayer MoSe2;diamond anvil cell;excitons147|42|0更新时间：2020-08-12
- 摘要：Base on the ambient pressure CVD method, the large-scale Nb doped few-layered MoS2 films were synthesized by using NbCl5 powders as the Nb dopant source. The morphology and the thickness of these films were confirmed by scanning electron microscope and atomic force microscope. Raman spectroscopy and X-ray photoelectron spectrometer measurements confirm that Nb has been doped into the MoS2 film and the Nb doped MoS2 alloy has been formed. The conductivity of the Nb doped few-layered MoS2 has also been collected.关键词：ambient pressure CVD;MoS2 film;Nb doped131|75|0更新时间：2020-08-12
- 摘要：Blue emissive fluorescent material CzPAF-CP based on A-π-D-π-A structure with high exciton utilizing efficiency was prepared. The photophysical and excited state properties of CzPAF-CP were mainly studied by the UV-vis absorption spectra, photoluminescence spectra and theoretical calculation. CzPAF-CP exhibits remarkable solvatochromic effect with a large bathochromic shift of 116 nm in different polar solvents. Further investigation according to Lippert-Mataga equation and transient photoluminescence decay spectra prove that CzPAF-CP possesses a hybridized local and charge transfer state, which can be confirmed by theoretical calculation. Due to the twisting A-π-D-π-A configuration, fluorescence from CzPAF-CP in water/THF mixture with high water fraction does not quench, displaying aggregation induced emission. The OLED using CzPAF-CP as emissive material emits blue light with emissive peak at 452 nm, full width at half maximum of 54 nm and Commission International de L'Eclairage coordinates of (0.150, 0.117). In addition, the device also achieved high efficiency with maximum external quantum efficiency of 6.3%. The resulting exiton utilizing efficiency was determined to be 71.6%, far beyond the theoretical limit for traditional fluorescent material(25%). Such high exiton utilizing efficiency is ascribed to special exited state of hybridized local and charge transfer state and reverse intersystem crossing from triplet exitons to singlet excitons at higher energy level.关键词：OLED;local excited state;charge transfer excited state;exciton utilizing efficiency150|121|4更新时间：2020-08-12
- 摘要：The influence of magnetic field on the polaron properties in the weak coupling of electron and surface optical phonons in monolayer graphene was investigated by using the improved linear combination operator method and the Pekar variational method. The dependences of the energies of the ground state E0, the first excited state E1 and the transition frequency ω of weak-coupling polaron on magnetic field B and Debye cut-off wavenumber kd were derived. Numerical calculations show that the ground state energy E0 of weak-coupling polaron near the Dirac point is an increasing function of strength of magnetic field B and Debye cut-off wavenumber kd, the curves of the polaron's ground state energy E0 of weak-coupling polaron will split into two equal and opposite band; both the first excited state energy E1 and the transition frequency ω are also an increasing function with strength of magnetic field B and Debye cutoff wavenumbers kd.关键词：graphene;polaron;weak-coupling;ground state energy;first exited state129|73|0更新时间：2020-08-12
- 摘要：The charge density, energy band structure, density of states and project density of states of H-terminated borophene nanoribbons with different widths are studied using the first principle calculations based on density functional theory. The results show that the conductive properties of boron nanoribbons with different widths are completely different. The borophene nanoribbons with width-5 are degenerate semiconductors and the band gap value is 0.674 eV. The energy band structure of borophene nanoribbons with width-7 has metal properties. The project density of states indicates that the near Fermi level of width-5 is mainly contributed by B-2s, 2p electronic states. The low-valence band is induced by H-1s electronic states with localization for eliminating unstability of edge. The contributions of B-2p and H-1s electronic states are dominant with width-7. The hybridization effect of B-2p and H-1s electron states near the Fermi energy level affects the whole material property.关键词：borophene nanoribbons;energy band;first principle calculations;project density of states171|102|1更新时间：2020-08-12
- 摘要：The spectra and dynamic properties of Eu 4f76pns(n=7, 8) autoionizing states are studied systematically with the resonance-ionization spectroscopy(RIS) and the velocity-map imaging(VMI) techniques. The RIS technique is utilized to obtain the spectra of Eu 4f76pns(n=7, 8) autoionizing states with the three-step excitation:the wavelengths of the first two-step lasers are fixed, while that of the last-step laser is scanned around the region of the 4f76pns(n=7, 8) autoionizing states. The VMI technique is used to detect the dynamic process of autoionization, from which the branching ratio(BR) of ions and the angular distribution(AD) of ejected electrons from Eu 4f76p7s autoionizing states are achieved. The heavy configuration interaction is observed in the spectra of Eu 4f76pns(n=7,8) autoionizing states, measured with RIS spectroscopy technique. The present study reveals the profound variations of AD and BR with energy in the region of the 4f76p7s autoionization resonance, highlighting the complicated nature of the autoionization process for the lowest member of Eu 4f76pns autoionization series. Population inversion is observed by analysis of the BR, while the validity of the well-known isolated core excitation(ICE) technique used for obtaining autoionization spectrum is discussed.关键词：Eu atom;autoionizing states;spectrum;angular distribution;branching ratio179|59|0更新时间：2020-08-12
- 摘要：Due to the advantages of light-weight, roll-to-roll processing, bendability, unbreakable, portability and wearability, flexible solar cells can provide people with electricity in various fields and have a very wide range of application prospects. In recent years, inspired by the excellent power conversion efficiency of organic-inorganic hybrid perovskite solar cell (PSC) based on a rigid substrate, flexible PSC has also received widespread attention. At present, the record of conversion efficiency of flexible PSC has reached 18.1%. This review article presents the recent research progress of flexible PSC and summarizes recent development of the key materials including flexible substrates, transparent electrodes and interfacial transport layers applied in flexible PSCs. The advantages and disadvantages of these materials in flexible PSC are discussed. Finally, the future development of flexible PSC is prospected.关键词：perovskite solar cell;flexible;transparent electrode;interfacial transport layer;flexible substrates140|98|0更新时间：2020-08-12
- 摘要：Hot pixels of imagers induced by space radiation may result in performance degradation of space photoelectric detection and space imaging system. In this paper, generation and annealing mechanisms of hot pixels on CMOS image sensors(CIS) are studied by proton irradiation experiments. First, in order to investigate the properties of hot pixels induced by protons, several CIS samples were irradiated with two different energy levels (3 MeV and 10 MeV) of proton beam. In irradiation processes, characterizations of samples were carried out at different fluence points. Second, annealing experiments were carried out on the CIS samples after the irradiation. The annealing behaviors of hot pixels induced by protons of 3 MeV and 10 MeV were investigated. For the same fluence of proton irradiation, the number of hot pixels induced by 3 MeV proton beam is about 2.3 times as the situation of 10 MeV proton beam. However, comparing with the average gray value of hot pixels induced by proton beam, 10 MeV is larger than 3 MeV. And the number of hot pixels produced by both energy levels increased linearly with the increasing of proton fluence. In the room temperature annealing process, the number of hot pixels decreased significantly, and the hot pixels induced by 10 MeV protons were more stable than those induced by 3 MeV protons. It was found that the interaction between each proton and each pixel is independent with each other. Under different energy levels, proton incidence produced different defects which led to different hot pixels.关键词：CMOS image sensor;hot-pixels;proton irradiation;displacement damage;dark signal134|125|1更新时间：2020-08-12
- 摘要：The phenomenon of LED sample detection and its failure mechanism were reported. This phenomenon included the short-circuit failure, LED light source, the flux decreased and blackening the surface of the chip hole anomaly. We used many methods, including metallographic, mechanical micro and static test, combining with many instruments, including optical microscope, scanning electron microscope and X-ray analysis characterization. The analysis reveals that LED abnormalities and failures are caused by the following reasons. First, the coating of silver ion and impurity sulfur ions lead to blackening of the light source. Second, the antistatic voltage of the chip is low. Some samples were subjected to electrostatic breakdown. And in addition, a large number of voids exist in the Ni-Sn eutectic layer beneath the view of the chip. It causes the uneven stress of the chip through the complex structure, the thermal conductivity decreases, and the chip surface cracks and breaks while the sample is working. This results in short-circuit fault of PN junction. Third, residual impurity ions in the encapsulation adhesive corrode the negative electrode of the chip. It causes the electrode to fall off. It leads to leakage, light weak and dead lights.关键词：light-emitting-diode (LED);invalid analysis;electrode;chip;encapsulation165|100|1更新时间：2020-08-12
- 摘要：In the wet-oxidation process, we used a new home-made infrared light source microscope and a CCD observer to look down at the imaging system to monitor changes in the color of oxidized spots on the wafer being oxidized. According to this ratio which was calculated by comparing the size of the oxidized point obtained by the CCD camera with the actual oxidation point size, the size of the actual oxidized wafer was obtained by the color change size of the oxidized point. By observing the color change size of the oxidized point, the oxidation process was adjusted to ensure the accuracy of controlling the oxidation aperture of vertical cavity surface emitting lasers(VCSELs) to within ±1 μm. Based on the oxidation experiments, the effect of high Al content on the shape of oxidation pores, the change of oxidation rate with temperature and the change of oxidation depth with time were obtained. When the furnace temperature was 420℃, the temperature of the water bath was 90℃ and the flow rate of the oxidizing gas was 200 mL/min, the oxidation rate was 0.31 μm/min and modulation rate of the 850 nm VCSELs was 4×25 Gbit/s. Room temperature conditions, the sub-unit operating voltage 2.2 V, the threshold current 0.8 mA, the ramp efficiency of 0.8 W/A, when the current was 6 mA, the power was 4.6 mW.关键词：vertical cavity surface emitting lasers (VCSELs);AlxGa1-xAs;wet oxidation;oxidation rules141|111|3更新时间：2020-08-12
- 摘要：The emission efficiency of InGaN/GaN multiple quantum well(MQW) light emitting diode(LED) reduces if it is grown on single crystalline silicon substrates because of the enhanced strain between interfaces. A possible strategy to solve this problem is introducing periodic Si δ-doped GaN instead of Si uniformly doped GaN as the n-GaN layer. In this work, steady-state(SS) photoluminescence spectra(PL) and time-resolved(TR) PL spectra for LED sample with either Si uniformly doped GaN or periodic Si δ-doped GaN working as n-type GaN layer were tested for comparison. Relative emission efficiencies and recombination rates for each sample were extracted, then systematically analyzed. The results turned out that:the main PL peak redshifted from 531 nm to 579 nm after introducing periodic Si δ-doped n-GaN layer; the average activation energy related to nonradiative recombination increased from (18±3) meV to (38±10) meV, as well as the decreasing of nonradiative recombination rate became slower with increasing temperature, and the nonradiative recombination rate at room temperature became smaller; at the same time, the average radiative recombination rate decreased with increasing temperature in major temperature range, which indicated that exciton localization dominated the radiative recombination processes. The average depth of localized state for excitons increased and the average radiative recombination rate at low temperature decreased. To sum up, because of the releasing of strain in MQW, the defect density that related to nonradiative recombination can be reduced, and the device performance can be improved if using periodic Si δ-doped n-GaN layer to replace Si uniformly doped GaN working as n-type GaN layer in InGaN/GaN MQW LED on silicon substrate.关键词：InGaN/GaN multiple quantum well;luminescence;time-resolved photoluminescence;silicon substrate171|39|1更新时间：2020-08-12
- 摘要：In order to obtain a 355 nm pulsed laser with a triple frequency efficiency up to 60%, the combination of Gaussian mirror and plano-concave reflection mirror is used as laser resonance cavity. The Gaussian mirror is a convexo-concave mirror, the radius(r) of curvature is 2 m. The radius of curvature of the plano-concave reflection mirror is 9 m. Through the electro-optically Q-switched, 1 064 nm laser output is obtaimed. Then the 1 064 nm local oscillator is amplified by traveling wave, 1 064 nm fundamental frequency light of single pulse energy 1.01 J is obtained, the repetition frequency is 10 Hz and the pulse width is 7.3 ns. The class Ⅰ phase-matched LBO crystal is used for SHG and the class Ⅱ phase-matched LBO crystal is used for SFG to obtain 355 nm ultraviolet laser output. Through the analysis of the output characteristics and nonlinear crystal parameters of the second harmonic and third harmonic, and experiments, finally the 355 nm UV laser output is achieved that the single-pulse energy is 608 mJ, the pulse width is 5.7 ns and the line width is 2 nm. Through optimizing the conversion efficiency of double frequency, the conversion efficiency of 355 nm UV light got by the processing SFG from 1 064 nm fundamental light reaches 60%.关键词：solid laser;high efficiency and high energy;LBO crystal;355 nm UV laser169|95|1更新时间：2020-08-12
- 摘要：In order to reduce the optical absorption of ITO thin films to UV waveband and to prepare low voltage as well as high power ultraviolet LEDs, the preparation process of 365 nm UV LED based on metal-doped ITO(Metal-ITO) transparent conductive layer was studied. The ITO thin films of different thickness and doped with different metals on ITO layer were grown by using 1 cm thickness quartz substrate, and the resistance and transmittance of the films were studied under different annealing conditions. The change of bandgap of Metal-ITO thin films was analyzed. Then, the Metal-ITO thin films were grown on 365 nm epitaxial wafers and completed the electrode growth, 14 mil×28 mil formal LEDs were prepared. Finally, the photoelectric properties of LED with Electroluminescence(EL) equipment were tested and compared. The experimental results show that the bandgap of Al-ITO thin film can be increased by 0.15 eV compared with that of ITO thin film. After annealing at 600℃, the square resistance is reduced by 6.2 Ω/□ and the transmittance is 90.8%. At 120 mA injection current, the decrease of voltage of 365 nm LED is 0.3 V and the increase of light output power is 14.7%. So, the Metal-ITO film can influence the bandgap of the film and along with the change of photoelectric performance of UV LED.关键词：ITO;metal-dope;film energy gap;UV LED161|88|0更新时间：2020-08-12
- 摘要：TiO2 nanotubes arrays were fabricated on ITO substrate via a liquid phase deposition method, with the assistance of ZnO nanorods arrays template, and the morphologies and structures of the samples were characterized by using SEM and XRD. Furthermore, the photoelectrochemical photodetector was fabricated with ITO as counter electrode and the photocurrent and spectral responses were measured. In addition to the high sensitivity and self-powered characteristic, the photodetector also revealed a splendid wavelength selectivity in the spectral range between 300 and 400 nm at zero bias voltage. Meanwhile, it is interesting to note that self-powered TiO2 nanotubes UV-photodetector has the excellent stability and repeatability, and the rise time and decay time are 0.33 s and 0.38 s, respectively.关键词：TiO2 nanotubes;liquid phase depositon;UV photodetector142|63|0更新时间：2020-08-12
- 摘要：Thin-film photovoltaics play an important role in the quest for clean renewable energy. Recently, methylammonium lead halide perovskites were identified as promising absorbers for solar cells. To improve the absorption of perovskite solar cells(PSCs) and modify the distribution of the generation rate of charge carriers, the one dimensional periodic sinusoidal nano-grating structure is introduced into PSCs. We characterize the coupled modes between surface plasmon polaritons(SPPs) and Fabry-Pérot(F-P) resonance, and analyze how they are affected by the period and height of the grating and the thickness of the active layer. The coupled modes enhance the light field in the weak absorbance spectrum region. Meanwhile, the width of coupled spectrum shows strong grating height dependence and will get a broad spectrum enhancement when the grating height is larger than 50 nm. The enhanced localized electric field near the interface of Ag/ETL expands into the active layer with an exponential decay length of~100 nm, results an absorption enhancement near the ETL/active layer interface. We calculate the absorption of the active layer by using a finite-difference time-domain(FDTD) method and the absorbance (the optimized grating structure with the grating period, the grating height and the thickness of active layer is 250 nm, 50 nm and 300 nm, respectively) is improved by 12% in wavelength range of 650-800 nm in transverse magnetic (TM) light incidence condition. We also demonstrate an increased generation rate of charge carriers near the ETL/active layer interface due to the enhanced field. The normalized generation rate increases by 41%(110%) in the position of 250 nm(200 nm) away from the HTL/active layer interface in PSCs. A balanced generation rate in the whole active layer will improve the diffusion of electrons and the collection of carriers, result in the increasement of the power conversion efficiency.关键词：perovskite solar cells;surface plasmon polaritons;sinusoidal gratings;rsonance coupling156|93|1更新时间：2020-08-12
- 摘要：Different materials(CuPc, ZnPc, C60) were used as the cathode buffer layers in typical OLED(ITO/TPD/Alq3/Al) prepared by evaporation, respectively. The influences of those materials on electroluminescence characteristics were investigated and relative mechanisms were discussed. Energy level structure, surface morphology, refractive index, nano-interface and some other mechanisms were used to discuss the injection and transportation of carriers. It is found that the buffer layers can evidently improve the device's performances:not only decrease the drive voltage(to 4.2 V), but also increase the current density and efficiency(to 13.49 lm/W), as well as enhance the stability(the intensity remained above 90% after 180 s). Device with CuPc layer achieves the best performance. Besides, CuPc and ZnPc cathode buffer layers show strong absorbing properties on OLED's spectrum between 550 nm and 650 nm, while C60 layer did not exhibit this effect. This is because the absorption coefficient of each material corresponds to different wavelengths. The results explain that CuPc and ZnPc cathode buffer layers could commendably improve OLED's characteristics, while fullerene(C60) is a good choice if there is a strict request on spectrum.关键词：organic light emitting diode;cathode buffer layers;mental-phthalocyanine;fullerene148|64|1更新时间：2020-08-12
- 摘要：In a Tris-HCl buffer solution at pH 7.4, ultraviolet spectroscopy, fluorescence spectrometry combined with ethidium bromide(EB) fluorescence probes, resonance scattering spectroscopy, and DNA melting point(Tm) experiments and molecular simulation techniques were used to investigate the binding site and binding mechanism between the artemisinin(QHS) and calf thymus DNA (ctDNA). Spectral results showed that QHS and DNA had a color-reducing effect, and the addition of QHS caused the static fluorescence quenching of EB-DNA system. When QHS interacted with DNA, its resonance scattering peak at 467 nm sharply increased, and the Tm value of DNA increased by 5℃. This showed that QHS was competitively inserted into the base pair of DNA. The calculated binding constants of QHS and DNA were 1.43×103 L/mol(298 K) and 0.99×103 L/mol(304 K). The molecular simulation results showed that the structure of the QHS pyran ring was intercalated between the GA base pairs in the DNA minor groove region. Hydrogen bonds and van der Waals forces were the main noncovalent interactions between them. This conclusion was consistent with the results obtained by spectroscopy and thermodynamics.关键词：artemisinin;calf thymus DNA;multi-spectroscopic techniques;molecular modeling125|96|4更新时间：2020-08-12
- 摘要：Transmission characteristics of two-dimensional photonic crystals Mach-Zehnder interferometer are analyzed, then the two-dimensional photonic crystal waveguides, circular cavity and Mach-Zehnder interferometer are combined with a reasonable way. In the end, a XOR gate based on two-dimensional photonic crystals Mach-Zehnder interferometer is proposed. Plane wave expansion (PWE) is used to analyze the band structure of two-dimensional photonic crystal, and finite difference time domain(FDTD) is used to verify the steady-state distribution of optical signals in the device. The research shows that the structure can achieve XOR logical functions, with high logical contrast 7.88 dB, fast response cycle 0.388 ps and high transmission rate 7.87 Tbit/s. And the structure size is only 13 μm×14 μm so that it is easily to integrate. The XOR logic structure based on two-dimensional photonic crystals Mach-Zehnder interferometer, makes the design of photonic crystal logic gate more diverse, and it also provides the foundation for half adder and full adder design of two-dimensional photonic crystals, which has important research significance.关键词：silicon-based optical;XOR logic gate;plane wave expansion method;finite-difference time-domain method126|65|2更新时间：2020-08-12
- 摘要：Non-destructive identification of pesticide residues in spinach was studied using hyperspectral imaging. The hyperspectral images between 900 nm and 1 700 nm were obtained with the help of hyperspectral imager. The original spectra were corrected by multivariate scatter correction (MSC). The principal component analysis (PCA) was used to analyze the spectral data of different spinach samples, the results showed that PCA could effectively discriminate different kinds of pesticide residues spinach samples on the visualization level. In addition, chi-squared test feature selection algorithm was separately combined with four learning algorithms (e.g. support vector machine, naive Bayes, decision tree and linear discriminant analysis) to get the best bands and optimal discriminant model(linear discriminant model) with the help of 10-fold cross-validation technique. The selected eight characteristic wavelengths are 1 439.3, 1 442.5, 1 445.8, 1 449, 1 452.3, 1 455.5, 1 458.7, 1 462 nm and the prediction accuracy by optimal discriminant model is 0.993 and 10 times of cross validation standard deviation is 0.009. The results show that hyperspectral imaging technology can accurately identify the types of pesticide residues on spinach leaves.关键词：hyperspectral imaging technology;spinach leaves;pesticide residue types157|85|6更新时间：2020-08-12
- 摘要：The original spectrum of compound fertilizer was obtained by VIS-NIR spectroscopy analyzer. After pre-treatment with multiplicative scatter correction(MSC) and first derivative, a partial least squares(PLS) model of total nitrogen(TN) content in compound fertilizer was established, which achieved rapid, accurate and non-destructive measurement. By selecting different wavelength models, the best fundamental band for predictive determination coefficient(R2), prediction standard deviation(SRMSEP) and relative analysis error(KRPD) were obtained. On the basis of the basic band, the optimal wavelength algorithm was used to obtain the predictive deterministic coefficient and the predictive standard deviation of the model after adding the wavelength. Through analysis, this article finally determined to add 42 preferred wavelengths. The experimental results show that the prediction deterministic coefficient of the model after adding the preferred wavelength is increased from 0.760 4 without the preferred wavelength model to 0.991 1, the SRMSEP is reduced to 1/5, and the KRPD is increased by 5 times.关键词：compound fertilizer;TN;VIS-NIR spectroscopy;PLS;optimizing waveleghth139|95|4更新时间：2020-08-12
- 摘要：The interactions between fluorophore tyrosine residues(P-Tyr) and tryptophan residues (P-Tyr) of pepsin(PEP) and nifedipine(NDP) at 298, 310 and 318 K were studied by synchronous fluorescence spectroscopy. The results showed that the drug quenches the fluorescence of P-Tyr and P-Trp by means of dynamic quenching. The number of binding sites was 1, and the main force was hydrophobicity. The fluorescence quenching ratio of NDP to PEP amino acid residues at 310 K was P-Trp 53.43%>P-Tyr 46.57%, meaning the binding site was closer to P-Trp. The binding rates of NDP to protein were P-Tyr:69.43%-87.15% and P-Trp:73.64%-90.60%, established a binding model, respectively. The Hill coefficient nH was about 1, meaning this combination has no synergistic effect with subsequent ligand. The binding distance r was less than 7 nm in both cases. Thus, non-radiative energy transfer exists between NDP and P-Tyr as well as between NDP and P-Trp.关键词：synchronous fluorometry;nifedipine;pepsin;amino acid residues;interaction mechanism137|77|0更新时间：2020-08-12
- 摘要：A recyclable mercury(Ⅱ) optical sensor based on pyrene-functionalized core-shell magnetic silica nanosphereswas developed and demonstrated by sol-gel grafting reaction. The obtained multifunctional microspheres displayed excellent fluorescence sensitivity and selectivity towards Hg2+ over other competing metal ions. A good linearity Stern-Volmer working plot (R2=0.998 3) between the fluorescence intensity of multifunctional microspheres and the concentration of Hg2+ was constructed with a satisfactory detection limit of 2.3×10-8 mol·L-1. Their fluorescence response in the presence of Hg2+ is found to be almost reversible when treated by EDTA solution. Moreover, these pyrene-functionalized magnetic silica nanospheres can efficiently remove Hg2+ in aqueous solution and easily separated by appling an external magnetic field. These results indicate that functionalized core-shell magnetic silica microspheres are potentially promising materials for simultaneously detecting and removing environmental pollutants.关键词：optical sensor;magnetic silica nanospheres;recyclable;mercury removal109|79|0更新时间：2020-08-12
- 摘要：To analyze the trap level at low temperature and obtain more information about the defect structure of materials, a low-temperature thermoluminescence(TL) spectrum measurement system based STM32 micro-controller was developed. Low-temperature sample chamber was designed and the samples were cooled by liquid nitrogen. The heating current was controlled by STM32 so that TL glow curves or three-dimensional(3D) TL spectra were obtained at a constant heating rate. The system has a high-precision temperature range of 85-400 K and the heating rate ranges from 0.1-10 K/s. The drive circuit of X-ray and ultraviolet light controlled by STM32 are designed for sample excitation. A CCD and a PMT are installed in the system to obtain two-dimensional(2D) TL glow curves and 3D TL spectrum respectively. In this paper, the system is used to test the TL and radioluminescence(RL) of (Lu,Y)2SiO5:Ce3+ (LYSO:Ce3+) scintillator and SrSO4:Dy3+. The luminescence around 108, 200, 380 K is observed in LYSO:Ce3+. The emission band is between 390 and 450 nm, which is a clear broad-band spectra. The emission peak due to the self-trapped excitons(STE) from host at low-temperature quenches above 166 K. The emission peaks of Ce3+ broaden into a single peak at 309 K, the emission peaks of SrSO4:Dy3+ are at 178, 385 K and the wavelength are 480, 575, 660, 750 nm due to the energy transitions of Dy3+, they are narrow-band spectra. The system can provide some merits, such as friendly interface, credible experimental data, higher intelligentization and simple operations.关键词：low-temperature thermoluminescence (TL);LYSO;radioluminescence (RL);self-trapped excitons (STE);defect structure146|75|0更新时间：2020-08-12
- Address：No.3888 Dong Nanhu Road, Changchun, Jilin, China Postal code：130033
- Tel：0431-86176862 Email：fgxbt@126.com
- Technical support is provided by Beijing Founder electronics co., LTD 吉ICP备11002662号-17
京公网安备11010802024621 - It is recommended to read the content of this site in Chrome&IE9+. Please switch to extreme mode in browser 360.
- Cookies We use cookies to help provide and enhance our service and tailor content. By continuing, you agree to the use of cookies.
0