碳六十有機場效電晶體的形貌控制與元件表現分析

Abstract

作為有機薄膜電晶體使用，碳六十具有低自組能以及高度有序的固態結構等有利於產生高載子遷移率的優點，故其運用於N-type有機場效電晶體的可能性被廣泛研究。然而，除結晶性外，結晶取向與晶體的薄膜型態亦對電晶體表現影響重大。本論文開發一碳六十晶體成長與薄膜形貌控制方法，利用硬化後的聚二甲基矽烷輔助碳六十結晶，並產生具有取向性的碳六十晶體陣列，同時透過篩選溶劑，來改變碳六十的結晶習性，在二硫化碳與鄰二氯苯中成功製備大面積，具備取向性的片狀碳六十晶體。此晶體在有機電晶體元件中提供1.38 cm2 V-1 s-1的高電子遷移率。電子繞射實驗說明了結晶習性的變化導因於碳六十結晶結構的改變，具有面心最密堆積的碳六十晶體將較於六方晶系的晶體容易生成片狀晶體。大多數研究所培養的碳六十晶體雖取向性佳，但為針狀晶體，故有晶體橫向面積不足，不易鋪滿電極與製作大面積有機場效電晶體的問題，本研究提供了較完整的碳六十晶體成長機制探討，也提供了一個大面積製作碳六十有機場效電晶體的方法。

C60 has been used in organic field effect transistor(OFET) due to its extremely low reorganization energy, highly order solid-state structure and strong intermolecular interactions, which facilitate efficient charge transfer and high mobility. Crystal orientation of C60 significantly affects the performances of C60-based OFETs. Previous studies indicated that high electron mobility can be achieved in well-oriented C60 crystalline domains. However, the lateral dimension of the C60 domain was limited by needle-like crystal habit of C60. Large-area production of C60 OFET is thus difficult. In this study, a novel PDMS assisted crystal growth method was developed. The method allowed the use of solvents, which changes the needle-like crystal habits into disc-like habits. Electron mobility as high as 1.38 cm2 V-1 s-1 was delivered by the well-oriented and lateral-sized C60 crystalline domains, prepared by PDMS-assisted crystal growth method.