Using Stable Radicals To Protect Pentacene Derivatives from Photodegradation

摘要

Organic transistors and organic devices have a variety of applications in molecular electronics and in the up-and-coming area of organic molecular spintronics. The use of inexpensive and facile ink-jet methods is possible for the fabrication of organic semiconductors. Pentacene and its derivatives have attracted increasing interest as promising electronic materials owing to their high hole mobility. Pentacene is the most promising candidate for organic field-effect transistor (OFET) applications. However, its chemical instability in the presence of light and air prevents practical applications. Efforts have been made to improve the stability by the addition of substituents. The most notable example is 6,13-bis(triisopropylsilylethynyl)pentacene,in which the 6- and 13-positions of pentacene are protected by triisopropylsilylethynyl groups. For this pentacene derivative, extremely high hole mobility of 1.8 cm~2V~(-1)s~(-1) was reported for the thin film. However, the addition of substituents to photoactive carbon sites prevents further functional modifications because both the 6- and 13-positions are blocked by the substituents and also the characteristic nature of the pentacene moiety is changed.