Dithieno[3,2-a:3′,2′-j][5,6,11,12]chrysene diimides and their molecular energy level regulation

Abstract

Dithieno[3,2-a:3′,2′-j][5,6,11,12]chrysene diimides (DTCDIs), a new class of organic dyes, with a twisted molecular backbone were designed and synthesized. The optical and electrochemical properties, charge transport behaviors and the single crystal structure were investigated. The cyanation of the DTCDI backbone was carried out to fine-tune the molecular energy levels. The addition of two cyano groups to the DTCDI backbone reduced the HOMO and LUMO energy levels by 0.35 and 0.30 eV, respectively. The energy levels could be further reduced with the addition of two more cyano groups leading to 0.32 and 0.22 eV reductions in HOMO and LUMO energy levels and stabilization of the energy levels. A tetracyano-substituted DTCDI derivative showed an electron mobility of 0.25 cm² V⁻¹ s⁻¹ and a current on/off ratio of 10⁶ in its organic thin film transistors.