Organic n-channel field-effect transistors based on arylenediimide- thiophene derivatives

The synthesis, structural, electrochemical, and thin film electrical and electronic structural properties of a series of arylene diimide-oligothiophene n-type semiconductors are reported. This family of compounds allows analysis of the effects on thin film transistor performance of the following: (i) oligothiophene backbone catenation; (ii) naphthalenediimide vs perylenediimide core interchange; (iii) phenylene group introduction in the oligothiophene backbone. Electrochemical experiments indicate similar redox energetics for all members of this series, while thin film transistor measurements reveal markedly different charge transport performances. The highest electron mobility of 0.35 cm² V^-1 s^-1 is recorded for films of benzo[lmn]thieno[3′,4′:4,5]imidazo[2,1-b][3,8]phenanthroline-1,3, 6(2H)-trione, 2-octyl (NDI-1T). Solution-processed field effect transistors were also fabricated and surprisingly exhibit electrical performances surpassing that of the vapor-deposited films in the case of isoquino[6′,5′, 4′:10,5,6]anthra[2,1,9-def]thieno[3′,4′:4,5]imidazo[2,1-a] isoquinoline-1,3,8(2H)-trione, 2-(1-heptyloctyl)-10,12-di-2-thienyl (PDI-3T).