Fluorene–fluorenone copolymer: Stable and efficient yellow-emitting material for electroluminescent devices

摘要: We have synthesized and characterized a new fluorene copolymer exhibiting bright yellow luminescence. In order to ensure complete π-stacking of the active layer, 9-fluorenone monomeric unit (FOne) has been used as comonomer in conjunction with more classical 9,9-di-n-nonylfluorene unit. As expected fluorene-based materials, when excited at 370 nm, corresponding dilute solution photoluminescence spectra exhibit main peak centered 450 nm blue part visible spectrum. However, solid state, immediate structural reorganization layer occurs, leading red-shifted emission (bright emission) 550 nm. The origin emitted light attributed excimers and/or aggregates based on short FOne segments involves mainly exciton transfer between nonaggregated aggregated ones. It is noteworthy that organic light-emitting devices these materials no spectral evolution upon device operatio...