Application of a novel fullerene-containing copolymer to electroluminescent devices

Abstract

The optical properties of a soluble fullerene (C-60)-containing copolymer, (PS)(x)C-60(PMMA)(y), were investigated. We employed the (PS)(x)C-60(PMMA)(y) in a polymer electroluminescent device as a hole-injecting layer. The forward-biased ITO/poly[2-methoxy-5-(2'-ethyl-hexyloxy)-1,4-phenylenevinylene]/(PS)(x)C-60(PMMA)(y)/Al device showed strongly quenched electroluminescence. In contrast, when the device was operated in reverse-bias direction, the luminescence and the yield were enhanced. The turn-on voltage of the reverse-biased device was -2.6 V. The quantum efficiency and the emitted light power were improved by approximate to5 and; approximate to20 times, respectively, compared with those of the single-layer device.