A novel hyperbranched conjugated polymer for electroluminescence application

摘要

A novel hyperbranched conjugated polymer composed of 1,3,5-trivinylicbenzene cores and (2,5-dimethoxyl)-l,4-phenylenevinylene connecting units (HB2) was synthesized via Wittig reaction route. The resulting polymer has good solubility in common organic solvents due to its weak intermolecular interaction and low solvation energy. PL and EL properties of HB2 were inspected. In film, absorption of HB2 was slightly blue shifted from absorption in solution while PL emission was red shifted from that of solution. These marked differences suggested a large change in inter and/or intra-molecular interaction from solution to solid film. Single layer light emitting diodes were fabricated utilizing HB2 as the emitting layer. Dispersing HB2 into a PVK matrix caused significant changes in the device performance. Bright blue emission >800 cd/m~2 can be achieved at a bias of 24 V for the ITO/PVK:HB2 = 5:1/Ca/Al devices and efficiency of the polymer blend devices was an order of magnitude higher than that of the HB2 single layer devices.