Blue organic light emitting devices with improved colour purity and efficiency through blending of poly(9,9-dioctyl-2,7-fluorene) with an electron transporting material
作者:Jin H. Ahn、Changsheng Wang、Igor F. Perepichka、Martin R. Bryce、Michael C. Petty
DOI:10.1039/b700047b
日期:——
Organic light emitting devices (OLEDs) containing a single blended layer of poly(9,9-dioctyl-2,7-fluorene) (PFO) or poly[9,9-bis(4-octyloxyphenyl)-2,7-fluorene] (PFOPh) and an electron transporting material 2,7-bis[2-(4-tert-butylphenyl)-1,3,4-oxadiazol-5-yl]-9,9-dihexylfluorene (DFD) have been fabricated. The long-wavelength emission (>480 nm) observed for pure PFO and PFOPh structures was reduced significantly and a pure blue emission, with Commission Internationale de l'Eclairage (CIE) colour coordinates (0.157, 0.037), could be achieved. The blended-layer devices also possessed considerably higher efficiencies than the pure PFO, pure PFOPh or the pure DFD structures. It is suggested that the presence of DFD results in an improved balance of charge carriers and provides a micro-encapsulation environment for the polymer chains, hindering the formation of fluorenone defects and their red-shifted emission.
有机发光器件(OLED)含有聚(9,9-二辛基-2,7-芴)(PFO)或聚[9,9-双(4-辛氧基苯基)-2,7-芴](PFOPh)单混合层和电子传输材料 2,7-双[2-(4-叔丁基苯基)-1,3,4-恶二唑-5-基]-9,9-二己基芴(DFD)。在纯 PFO 和 PFOPh 结构中观察到的长波长发射(>480 nm)显著减少,并可实现纯蓝色发射,符合国际照明委员会(CIE)色坐标(0.157, 0.037)。混合层器件的效率也大大高于纯 PFO、纯 PFOPh 或纯 DFD 结构。这表明,DFD 的存在改善了电荷载流子的平衡,为聚合物链提供了微胶囊环境,阻碍了芴酮缺陷的形成及其红移发射。