C60与rubrene混合薄膜的光学性质

Optical absorption of C60 and rubrene hybrid films with different blending ratios

本文采用高真空热蒸镀法于衬底温度70℃下在玻璃基片上制备C60和rubrene混合薄膜。将两种材料的粉末置于不同的坩埚中共同蒸发,通过控制坩埚的加热温度来控制混合的比例,达到了制备混合薄膜的效果。利用原子力显微镜和台阶仪对薄膜的表面形貌和厚度进行测量,通过紫外-可见分光光度计获得了薄膜的透射谱和反射谱。实验结果表明了混合后的薄膜并不是都出现明显的吸收峰值。当C60:rubrene混合比为1:4、1:2、1:1、2:1、4:1时,利用透射谱和反射谱分别作出吸收光谱,借用Tauc公式求得能隙值,发现当混合比为1:1时,薄膜表面形貌最为均匀,吸收峰值最大,能隙最小。

The hybrid film of C60 and rubrene was deposited on glass substrates under 70℃ using high vacuum thermal evaporation. The two powder materials were evaporated simultaneously in different crucible so as to achieve various hybrid films.The mixture ratio was adjusted by controlling the crucible temperature. The atomic force microscope, step profiler and ultraviolet-visible spectrophotometer were employed to examine the surface morphology, thickness, transmittance and reflectance spectra of the films. The results show that not all hybrid films have the apparent absorbance peak. The absorbance spectrum can be determined through transmittance and reflectance spectra, when the C60：rubrene mixing ratios are 1：4, 1：2, 1：1, 2：1 and 4：1. The energy gap value was obtained using the Tauc formula. It indicates that the most uniform film, the maximum absorbing peak and the minimum energy gap are obtained, when the C60：rubrene ratio is 1：1.