Framework influence of erbium doped oxyfluoride glasses on their optical properties

Glasses of different matrix (phosphate, borate, silicate and lead-silicate) were studied for their optical properties. The effect of Er dopant on transmittance and luminescence properties was presented. The significant “red shift” and “blue shift” of UV edge absorption were discussed based on the changes in the framework of the borate and phosphate glasses, respectively. It was showed that the integral intensity of the two main optical absorption transitions monotonically increases with the order: phosphate < borate < silicate < lead-silicate. Ellipsometric measurement was applied to obtain the refractive index of the glasses. The correlation between the shift of edge absorption and the change of refractive index was presented. Effect of glassy matrix on luminescence of Er³⁺ was discussed.     

等离子体处理对氧化铟锡(ITO)润湿性及性能参数的影响

在预处理室中对ITO薄膜进行等离子体处理,研究分别在氧气、氮气、氩气及空气四种工作气体下,等离子体处理压强和处理时间对薄膜的润湿性及性能参数的影响。接触角测试仪表征表明,等离子体处理时间越长、处理压强越大,静态H₂O接触角越小,其润湿性越高。分光光度计测试结果表明,经等离子体处理,ITO薄膜透过率较未处理均有所下降。四种工作气体下,等离子体处理压强越大对透过率的影响越小,但随着处理时间的增长影响会增大;相较其他工作气体,氧气等离子体处理整体变化最小。四点探针表征表明,处理后的ITO薄膜方块电阻无明显变化,这是由于等离子体处理只对ITO薄膜表面进行改性,没有改变内部性质。利用霍尔效应测量载流子浓度,没有发现明显变化,与方块电阻不变结论一致。     

FluorMODleaf: A new leaf fluorescence emission model based on the PROSPECT model

A new model of chlorophyll a fluorescence emission by plant leaves, FluorMODleaf, is presented. It is an extension of PROSPECT, a widely used leaf optical properties model that regards the leaf as a pile of N absorbing and diffusing elementary plates. In FluorMODleaf, fluorescence emission of an infinitesimal layer of thickness dx is integrated over the entire elementary plate. The fluorescence source function is based on the excitation spectrum of diluted isolated thylakoids and on the emission spectra of isolated photosystems, PSI and PSII, which are the main pigment-protein complexes involved in the initial stages of photosynthesis. Scattering within the leaf is produced by multiple reflections within and between elementary plates. The input variables of FluorMODleaf are: the number of elementary plates N, also called leaf structure parameter, the total chlorophyll content C_ab, the total carotenoid content C_cx, the equivalent water thickness C_w, and the dry matter content C_m (or leaf mass per area), as in the new PROSPECT-5, plus the σ_II/σ_I ratio referring to the relative absorption cross section of PSI and PSII, and the fluorescence quantum efficiency of PSI and PSII, τ_I and τ_II, that are introduced here as mean fluorescence lifetimes. The model, which considers the reabsorption of emitted light within the leaf, allows good quantitative estimation of both upward and downward apparent spectral fluorescence yield (ASFY) at different excitation wavelengths from 400 nm to 700 nm. It also emphasizes the role of scattering in fluorescence emission by leaves having high chlorophyll content.     

两种测试烟幕透过率方法的对比研究

分别采用多波段红外辐射仪和傅立叶变换红外光谱仪测试了抗红外磷烟幕的透过率，并在对测试结果分析比较的基础上评价了两种测试方法的优劣。     

掺杂Mo6+、Cr6+灵巧膜α-WO3的电致变色效应

本文介绍了单掺杂Ｍｏ＾６＋及双掺杂Ｍｏ＾６＋、Ｃｒ＾６＋的溶胶－凝胶膜α－ＷＯ３的电致变色特性，实验结果与价间电荷跃迁理论所预言的复合膜透射率谱吸收峰移动规律一致，文章还采用晶体结构的离子配位场理论，解释了该复合膜是一种吸收型电致变色材料，其变色机理可归结为膜层中“小极子”跃迁而产生的光吸收。     

MBS对PVC的改性作用研究

研究了ＭＢＳ对ＰＶＣ的改性作用。实验表明，随着ＭＢＳ用量的增加，对体系的物理机械性能，透光率、浊度和应力泛白都有不同程度的影响。用ＳＥＭ观察材料从脆性转变为韧性断裂表面形貌的变化，Ｂｒａｂｅｎｄｅｒ流变仪试验表明，ＭＢＳ是ＰＶＣ的优良改性剂。     

乙二醇产品质量波动分析及处理

介绍了乙二醇产品质量的变化情况,分析了影响产品质量的原因,采取了有效的处理措施,取得了很好的效果。     

Optical characterization of arsenic sulfide semiconducting glass films using the transmittance measurements

The interference transmission spectra T(λ) at normal incidence for different thicknesses of amorphous arsenic sulfide semiconducting films deposited by thermal evaporation method were obtained in the spectral region from 400 nm up to 2500 nm. The direct analysis proposed by Swanepoel, which is based on the use of the extremes of the interference fringes in order to derive the real and imaginary parts of the complex index of refraction, and also the film thickness. The dispersion of n is discussed in terms of the Wemple–DiDomenico's single-oscillator model. In addition, the optical band gap has been determined from the absorption coefficient values using Tauc's procedure, i.e. from the relationship , where K is a constant. The optical band gap is interpreted in terms of the bond-strengths of the chemical bonds present in the glass compositions under study. The results were achieved for stoichiometric composition As₄₀S₆₀ and non-stoichiometric composition As₃₅S₆₅.     

Characterization of Bi2O3 thin films for doping photoluminescent Er3+ ions

Undoped and Er³⁺-doped Bi₂O₃ thin films were sputter-deposited on Si(100) substrates. Sufficiently oxidized Bi₂O₃ films with refractive indices between 2.17?2.23 were obtained at a wavelength of 633 nm; these values are comparable to those of bulk Bi₂O₃ crystals. While the film composition was stable for deposition temperatures between room temperature (RT) and 450 °C, the refractive index steeply decreased above 450 °C and reached 1.4 at 600 °C. The lowering of the optical transmittance spectra indicated aggregation of metallic Bi and darkening of the film. All films exhibited X-ray diffraction patterns of α-Bi₂O₃. The direct and indirect bandgap energies derived from the Tauc plots were 3.4–3.7 eV and 1.9–2.5 eV, respectively, depending on the O₂ flow rate and deposition temperature. Upon excitation of Er³⁺-doped Bi₂O₃ films at 532 nm, Er³⁺ emissions peaking at 1537 and 1541 nm appeared, and the photoluminescence spectra included fine structures reflecting crystal-field splitting. Resonant excitation of Er³⁺ 4f levels and indirect excitation via the defect levels of Bi₂O₃ followed by energy transfer to Er³⁺ contributed to the emission. The films deposited at RT with Er concentrations of 2 at.% had the emission intensity of Er³⁺, but concentration quenching strongly suppressed the Er³⁺ emission because the doped Er³⁺ ions stayed inside the Bi₂O₃ crystals. At deposition temperatures above 400 °C, the concentration quenching was mitigated possibly because out-diffusion of Er³⁺ ions reduced the effective number of Er³⁺ ions in the Bi₂O₃ crystalline domains.     

An integrated method based on energy concentration for evaluating normally distributed spectra in the visible region

This work proposes a method to scientifically quantify the quality of normally distributed visible spectra from the viewpoint of energy concentration: high transmittance, narrow spectral width, and small deviation from the target wavelength in the target region. In the proposed method, the spectral width of the spectrum is compared with that of a reference spectrum before its deviation from the target wavelength is examined. After extracting the maximum transmittance, a performance index of the spectrum is obtained in a percentile value. The effectiveness of the proposed method was analytically proven by surface plasmon resonance-generated spectra with five design features and five variations in each feature. The results indicated that the proposed method not only substantially reflected the predictions made by intuitive visual inspections, but also avoided misleading and ambiguous results evaluated by existing full-width-at-half-maximum (FWHM) method, figure-of-merit (FOM) method, and coordinates on the chromaticity diagram. In addition to the numerical analysis, the experimentally obtained spectra of phosphors in white light emitting diodes were also evaluated. The results proved that the proposed method can successfully highlight the scaled performance difference among the spectra, which is not supported by existing FWHM and FOM methods by simultaneously considering the aforementioned three characteristics of a spectrum.