薄膜、固体样品中吸收，透射和反射率检测方案

analytikjena s> Fields of Application / Industry： Chemistry / Polymer Industry Clinical Chemistry / Medicine/Hygiene / Health Care Cosmetics Electronics Energy Environment /Water /Waste Food / Agriculture Geology / Mining Material Analysis Metallurgy / Galvanization Pharmacy Refineries/ Petrochemistry Semi-Conductor Technology Others 紫外吸收光谱法测定薄膜的吸收、透射和反射率 摘要： 在材料分析领域，样品的吸收率(光衰减内耗的百分率)、透射率(光穿过介质出去的百分率)和反射率(光反射出去的百分率)是很重要光学的参数，进而能分析材料的结构、厚度等物理性能。比如太阳镜、防晒化妆品以及防晒衣的UV 保护指数的测量，粉末样品漫反射的测量，镜片，薄片等透明材料的透过率的测量，膜厚度/涂层厚度的测量等。 本文利用德国耶拿公司 SPECORD 250 PLUS 紫外分光光度计，结合相应的附件，实现对材料特性参数的研究工作，完成对薄膜样品、固体样品以及粉末样品的相关参数的测定。并详细介绍采用积分球附件，进行材料吸光度，透过率，漫反射的测量；固体样品池架，对材料的吸光度和透过率进行测量；而可变角度反射附件可测量整个波长200-1100nm、入射角度可在11-60度范围内灵活调节，对固体及粉末样品的反射率测定。 Determination of absorbance， transmittance and reflection of plasticfoils General 3 different foils with a thickness of 0，1 and 0，23mm have been analyzed. Determinations wereperformed with SPECORD 250 PLUS by using different accessories. For absorbance andtransmittance measurements a solid sample holder was used. The reflectance measurementswere performed by using integrating sphere and reflectance attachment with variable angle.The sample was put into a solids holder for analysis. Absorbance und transmittance measurement Solid sample holder Figure 1 shows the holder for solid samples. This accessory is suitable for solid samples with adiameter from 20mm and a thickness up to 25mm. Fig. 1 Solid sample holder for SPECORD The measurements were carried out with the following parameter settings： Title： Absorbance/transmittancemeasurement Measurement mode： Scan mode Correction： Reference Range： 200-1100nm Display： Transmittance Step width： 1nm Lamp changeover： 320nm Speed： 50nm/s Slit： 2nm Accessories： none The reference measurement was conducted against air. The sample was placed into the solidholder and fixed with the clip. The following curves show the absorbance (fig. 2) and transmittance(fig.3) of the foils. Fig. 2： Absorbance spectra of the foils AJ1_0，1 AJ1_0，23 AJ4_0，1.1 AJ4_0，23 AJ5 0.1 AJ5_0，23 Fig.3： Transmittance spectra ofthe foils Reflectance measurements a) Integrating sphere The Ulbricht sphere (integrating sphere， fig. 4) is outstandingly suited for transmittance andreflectance measurements of solid and liquid scattering samples as well as of powdery samples.Diffuse reflected light of solid samples with rough surfaces can be collected and transmitted todetector by the sphere. Fig.4： Integrating sphere Scheme： Optical path in the sphere The following parameter settings have been chosen for diffuse reflectance measurement of foils： Title： Reflectancemeasurement Measurement mode： Scan mode Correction： Reference Range： 350-1100nm Display： Reflectance/Remission Step width： 1 Lamp changeover： 320nm Speed ： 20nm/s Slit： 4nm Accessories： Integrating sphere Because of the good reflectance properties of the sphere in visible range the spectra were takenfrom wavelength 350nm. The reference measurement was conducted against Spectralon@insert ofthe sphere. For sample measurement the foils were placed into position for solid samples of thesphere and fixed with the clip. Figure 5 shows the reflectance spectra of the foils. Fig.5： Reflectance spectra of the foils taken by integrating sphere b) Reflectance attachment with variable angle With this accessory (fig.6)， you can determine path length and refractive index of solid samples.This is done by measuring the reflectance at different angles of reflection over a definedwavelength range. The sample table can be turned in vertical direction to vary the reflectanceangle in the range 11°-60°.The optical beam path is the same for all adjustable angles. Fig. 6： Reflectance attachment with variable angle Scheme： Optical path of reflectance attachment For the measurement， an angle of 30° was used. The following parameter settings have beenchosen for analysis： Title： Reflectance measurement Measurement mode： Scan mode Correction： Reference Range： 200-1100nm Display： Reflectance Step width： 1nm Lamp changeover： 320nm Speed ： 50nm/s Slit： 4nm Accessories： Reflectance attachment (variable) Use the knurled screw to set the sample table to the desired angular position of 30°. The referencemeasurement was carried out by using the provided reference mirror. It was placed onto thetabletop and clamped with the sample holding clip. Sample measurement was performed analog toreference measurement. Figure 7 shows the reflectance spectra of the foils. Reflexion/Remission Fig. 7： Reflectance spectra of the foils taken with an angle of 30° Evaluation The SPECORD250 PLUS and the accessories stated above are an useful instrument to analyzethe surfaces of such foils. Depending from the accessory which was used the taken spectra showsdifferences in thickness. Only absorbance and transmittance spectra of the foils AJ4 und AJ5which were carried out with solid sample holder shows differences in thickness. The spectra taken by integrating sphere show no differences in several thickness of the foils. The most suitable accessory for this kind of determination is the reflectance attachment withvariable angle at 30° because all spectra can be differentiated from each other clearly. Printout and further use permitted with a reference to the source. C 2010 Analytik Jena AG Publisher：Analytik Jena AGKonrad-Zuse-StraBe 107745 Jena Telephone +49 (0) 36 41/77-70Fax +49 3641 77-9279 Determination of absorbance， transmittance and reflection of plastic foils/Reference： UV PLUS e| AK