具有可调控半导体晶体生长功能的有机薄膜晶体管绝缘层材料的设计、合成与性能研究

The performance of organic thin film transistor (OTFTs) has made a rapid progress, and up to now, its carrier mobility are better than the commercial amorphous silicon(0.1-1.0cm2/Vs), but there are still some defects, such as poor stability, high cost, not easy for solution processing. The main factors related with these problems are the properties of organic semiconductor film, gate insulator film and the interface between the two layers. The property of the insulator surface directly affect the morphology and structure of organic semiconductor layer which grows on the insulator film, and further affects the property of carriers of the organic layer. In the process of the former fund, we found that the structure and property of the insulator layer have great influence on the growth of the organic semiconductor . When the side chains of the insulator molecule contains groups similar with the organic semiconductor (pentacene,6p, etc),the group can control the morphology and size of the organic semiconductor crystal layer as the nucleus in the crystallizing process.Besides, these groups can insert into the semiconduct crystal , and increase the interaction between the insulating layer and the semiconductor layer. In this project, we intended to prepare insulator materials with side chains containing groups similar with the organic semiconductor , through adjusting the content of the class group to regulate semiconductor crystal morphology and crystal area, in order to obtain better comprehensive performance. The method is innovative in insulating layer preparation,and provide a new way to increase the overall properties of OTFTs.

有机薄膜晶体管（OTFTs）的性能取得了长足的发展，器件的综合性能已经超过商用非晶硅的水平(0.1-1.0cm2/Vs)，但仍存在稳定性差、成本高、溶液加工较困难等问题。与此密切相关的是有机半导体薄膜、栅绝缘薄膜及它们之间的界面性质。绝缘层表面性质直接影响其上生长的有机半导体薄膜的形态结构，进而影响载流子的传输性质。我们在完成前一个基金的过程中发现聚合物绝缘层材料的结构与性质对于半导体层晶体的生长有很大的影响，当绝缘层分子的侧基上带有和半导体分子结构相似的基团时，该基团作为成核中心可以调控半导体的结晶形态及晶区的大小。同时，这些分子可以插入半导体结晶内，增加二者之间的作用力。在此基础上，本项目拟合成制备具有和半导体分子结构相似的绝缘层材料，通过调控相似基团的含量来调控半导体结晶形态及晶区，以获得更好的综合性能。这种方法是绝缘层制备方面的创新，为提高OTFTs的综合性能提供了新的途径。

有机薄膜晶体管作为微电子技术领域重要的组成部分，因其应用在柔性显示器、化学、生物传感器、射频识别标签、可穿戴电子设备等新兴电子产品中大放异彩。经过几代人的努力，有机薄膜晶体管的器件迁移率从最初10^-5 cm2/Vs到现在普遍大于1 cm2/Vs，甚至可以媲美单晶硅的水平，有机薄膜晶体管（OTFTs）的性能取得了长足的发展，但仍面临稳定性差、成本高、溶液加工较困难等问题。.有机半导体薄膜、栅绝缘薄膜及它们之间的界面性质是迁移率的主要影响因素。本项目合成制备了具有和半导体分子结构相似的绝缘层材料，通过调控相似基团的含量来调控半导体结晶形态及晶区，以获得更好的综合性能。我们得到了针对六联苯/酞菁氧钒型器件的侧链含有联苯结构的聚氨酯型绝缘栅层，进一步在侧链联苯单元上引入-CN提高介电常数，制备了不同含联苯结构单元的可紫外光固化聚氨酯，阈值电压最低为-0.5V；我们还制备了侧链含有联苯单元上以及CN的聚甲基丙酸酯型绝缘栅层。两种器件的介电常数分别为6.8和8.6，介电损耗近位0.04和0.05。中迁移率值分别为0.52 cm2 V-1 s-1 and 0.1 cm2 V-1 s-1，电流开关比大于10^4；最后，我们设计了侧链上还有环碳酸酯单元的高介电聚甲基丙烯酸酯型绝缘层，通过调节环碳酸酯单体的含量，可以实现介电常数在7~10的可调，泄漏电流密度低（< 7 × 10^-7 A/cm2at 100 MV/m）和介电损耗小（< 0.03，10^2 to 10^5 Hz），以这些聚合物作为绝缘层应用到p型的C10-DNTT的TFT器件中，迁移率最高为9.7 cm2 V-1 s-1，电流开关比> 1 × 10^5.