Voltage independent white emission from all solution processed polymer light-emitting diode with dual emitting layers spaced by an alcohol soluble conjugated polymer as interlayer

摘要

Spatial control of recombination zone in multilayer white polymer light emitting diode (WPLED) is highly desirable for stable white-light emission. In this work, the utilization of 18-crown-6 (Cn6)-grafted polyfluorene (PFCn6) as an interlayer in between two emitting layers is demonstrated to control the recombination zones for the multilayer WPLED with β-phase and rubrene doped poly(9,9-di-n-octylfluorene) (PFO) as blue- and yellow-emitting layers, respectively. The device gives the maximum brightness of 15,695 cd/m~2 and maximum efficiency 5.43 cd/A, accompanying with voltage-independent electroluminescence spectrum having invariant Commission Internationale de L'Eclairage (CIE) coordinates of (0.32, 0.36). The performance with the luminance efficiency 5.43 cd/A and voltage independent white emission is the highest record among the reported multilayer WPLED.