Abstract:

Fused furans and their derivatives have been used to develop organic optoelectronic functional materials due to their high rigidity， good coplanarity， and extended π-conjugated structure. However， compared with fused thiophenes and their derivatives， the structural diversity of fused furans and their derivatives remains limited， which restricts their further development. To address this issue， we fused imide groups with naphtha［2，3-b∶6，7-b'］difuran（NDF） units to synthesize a series of DFPI-Cn molecules， and systematically investigated their physicochemical properties as well as their performance in organic field-effect transistor devices. All the molecules exhibit good thermal stability， and their crystallization and melting temperatures gradually decrease with increasing alkyl side chain length. The molecular skeleton is slightly twisted， and the electron cloud distributions of the highest occupied molecular orbital and the lowest unoccupied molecular orbital are uniformly delocalized over the entire conjugated framework. The N-alkyl chains of the imide groups have no obvious effect on the absorption and emission spectra of the molecules in solution， but significantly modulate their absorption spectra in solid films. All three molecules show red emission. Single-crystal structure analysis reveals that DFPI-C5C5 molecules adopt a one-dimensional packing mode： two adjacent molecules form a dimer in a head-to-tail manner， and the dimers further stack with a certain rotation angle. The DFPI-C5C5 nanowire crystals prepared by physical vapor transport exhibit single-crystal characteristics and a flat surface morphology. Organic field-effect transistor devices based on these nanowire crystals show p-type charge transport properties with a hole mobility of up to 3.7×10⁻³ cm²·V⁻¹·s⁻¹. This work provides a new approach for the development of novel fused furan-based organic semiconductor materials.

Key words: Fused furan, Conjugated molecule, Imide