软模板纳米压印技术及其对共轭高分子的取向控制研究

Pattern transfer and molecular chain orientation modulation by soft template during the nanoimprint lithography

纳米压印模板通常需要经过电子束光刻、电子束沉积、光刻胶剥离、反应离子刻蚀等一系列复杂工艺获得,这使得纳米压印模板的制作难度大,成本高.寻找一种灵活简单的纳米压印模板制备方法以提升纳米压印模板的制作效率,是广泛应用纳米压印技术的研究重点和难点.本文以写好光栅结构的电子束光刻胶层为母模板,获得聚二甲基硅氧烷软模板,并以此为模板对共轭高分子聚(9,9-二辛基)芴薄膜进行纳米压印,实现光栅结构转移,成功制备出纳米光栅结构的共轭高分子薄膜.偏振吸收谱和透射电镜结果表明,纳米压印实现图案转移的同时,还可以将共轭高分子的主链控制在光栅条纹方向,这将对有机发光器件性能的提升具有重要的意义.研究结果还表明,应用该方法同样可以对聚(9,9-二辛基芴共苯并噻二唑)薄膜进行光栅图案化,同时实现其取向控制.

The templates for the nanoimprinting are fabricated usually through a series of steps, such as E-beam lithography, E-beam deposition, liftoff and reactive ion etching. Any mistake during these steps would lead to the failure of the fabrication, so the template is always expensive and difficult to make. Under this circumstance, it is really important to find an effective way to build the template. In this report, the patterned photoresist layer is used as a mother set of the pattern definition of the soft template polydimethylsiloxane. The grating structure of conjugated polymer poly （9,9-dioctylfluorene） film is successfully obtained by this template in the nanoimprinting process. In addition, we also find the anisotropy of molecular chain distribution. Both the transmission electron microscope diffraction pattern and the polarized absorption spectrum are used to prove that this anisotropy is induced by the molecular chain alignment, which would be really helpful in future applications in organic emission equipment. Moreover, this result is also applicable to the poly （9,9-dioctylfluorenyl-2,7-diyl）-alt-co-（1,4-benzo-2,1’,3-thiadiazole） film system.