Facile synthesis of picenes incorporating imide moieties at both edges of the molecule and their application to n-channel field-effect transistors

Picene derivatives incorporating imide moieties along the long-axis direction of the picene core (C-n-PicDIs) were conveniently synthesized through a four-step synthesis. Photochemical cyclization of dinaphthylethenes was used as the key step for constructing the picene skeleton. Field-effect transistor (FET) devices ofC(n)-PicDIs were fabricated by using ZrO(2)as a gate substrate and their FET characteristics were investigated. The FET devices showed normally-offn-channel operation; the averaged electron mobility (mu) was evaluated to be 2(1) x 10(-4), 1.0(6) x 10(-1)and 1.4(3) x 10(-2)cm(2)V(-1)s(-1)forC(4)-PicDI,C-8-PicDIandC(12)-PicDI, respectively. The maximum mu value as high as 2.0 x 10(-1)cm(2)V(-1)s(-1)was observed forC(8)-PicDI. The electronic spectra ofC(n)-PicDIs in solution showed the same profiles irrespective of the alkyl chain lengths. In contrast, in thin films, the UV absorption and photoelectron yield spectroscopy (PYS) indicated that the lowest unoccupied molecular orbital (LUMO) level ofC(n)-PicDIs gradually lowered upon the elongation of the alkyl chains, suggesting that the alkyl chains modify intermolecular interactions between theC(n)-PicDImolecules in thin films. The present results provide a new strategy for constructing a high performancen-channel organic semiconductor material by utilizing the electronic features of phenacenes.