In situ differential reflectance spectroscopy of thin crystalline films of PTCDA on different substrates
In situ differential reflectance spectroscopy of thin crystalline films of PTCDA on different substrates
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不同基底上PTCDA薄膜的原位差示反射光谱
DOI：
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发表时间：
2005
期刊：
影响因子：
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通讯作者：
T. Fritz
中科院分区：
文献类型：
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作者：
H. Proehl;R. Nitsche;T. Dienel;K. Leo;T. Fritz
我们报道了在多晶和单晶表面生长的原型有机半导体PTCDA（3,4,9,10-苝四羧酸二酐）薄膜的激子性质。提出了一种利用差分反射光谱（DRS）测量超薄有机分子晶体光学特性的灵敏装置。该工具允许在现场进行测量，即在实际薄膜生长过程中，并且在宽光谱范围内，甚至在具有高对称性的单晶表面或金属表面上进行测量，而反射各向异性光谱（RAS）或荧光激发光谱等广泛使用的技术则无法进行测量。如果采用透明衬底，DRS得到的光谱与薄膜的吸收光谱基本相似，简化了分析。在单晶白云母（0001）和Au（111）衬底上单层到多层PTCDA薄膜的情况下，可以监测从单体到二聚体再到晶体样吸收光谱的固态吸收的形成。
We report an investigation of the excitonic properties of thin crystalline films of the archetypal organic semiconductor PTCDA (3,4,9,10-perylenetetracarboxylic dianhydride) grown on poly- and single crystalline surfaces. A sensitive setup capable of measuring the optical properties of ultrathin organic molecular crystals via differential reflectance spectroscopy (DRS) is presented. This tool allows to carry out measurements in situ, i.e., during the actual film growth, and over a wide spectral range, even on single crystalline surfaces with high symmetry or metallic surfaces, where widely used techniques like reflection anisotropy spectroscopy (RAS) or fluorescence excitation spectroscopy fail. The spectra obtained by DRS resemble mainly the absorption of the films if transparent substrates are used, which simplifies the analysis. In the case of mono- to multilayer films of PTCDA on single crystalline muscovite mica(0001) and Au(111) substrates, the formation of the solid state absorption from monomer to dimer and further to crystal-like absorption spectra can be monitored.