Effects of Electron-Withdrawing Groups on Nitrogen-Containing Perylene Diimide Analogues and Their Properties

摘要

Electron-accepting π-conjugated compounds have attracted attention as a componentof charge-transfer complexes.Recently,they are actively investigated in the research fieldof organic electronics as n-type organic semiconductors (OSCs) used in field-effecttransistors (FETs),photovoltaic cells and so on.For application to n-channel FETs,OSCsare desired to have a deep lowest unoccupied molecular orbital (LUMO) level,such as≤-4.0 eV versus vacuum level,a large π-conjugated system with well-delocalized LUMOand an assembled structure in the solid state suitable for charge-carrier (electron) transport.Yet,an expansion of π-conjugated system usually leads to shallower LUMO level,whichcould result in unstable or poor n-type FET performances.Very recently,our groupsucceeded in overcoming the problem:3,4,9,10-benzo[de]isoquinolino[1,8-gh]quinolinetetracarboxylic diimide (BQQDI),wheretwo aromatic carbons of perylenetetracarboxylic diimide (PDI),one of the most famousn-type OSCs,were selectively replaced with nitrogen,was synthesized,leading to deepenedLUMO levels by ~0.3 eV (-4.11 eV) and air-stable n-channel FET performances with themobilities up to 3 cm~2 V~(-1) s~(-1).