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21.
Marcin ?roda Katarzyna Cholewa-KowalskaMarek Ró?ański Marek Nocuń 《Optical Materials》2011,33(3):397-401
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. 相似文献
22.
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。 相似文献
23.
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 Cab, the total carotenoid content Ccx, the equivalent water thickness Cw, and the dry matter content Cm (or leaf mass per area), as in the new PROSPECT-5, plus the σII/σI ratio referring to the relative absorption cross section of PSI and PSII, and the fluorescence quantum efficiency of PSI and PSII, τI and τII, 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. 相似文献
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26.
MBS对PVC的改性作用研究 总被引:4,自引:0,他引:4
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。 相似文献
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28.
Optical characterization of arsenic sulfide semiconducting glass films using the transmittance measurements 总被引:2,自引:0,他引:2
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. 相似文献
29.
Housei Akazawa 《Ceramics International》2021,47(3):3292-3298
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. 相似文献
30.
《Displays》2019
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. 相似文献