Efficient full-spectrum white polymer light-emitting diodes by plasma polymerization

Abstract

Efficientfull-spectrum white polymer lightemitting diodes (WPLEDs) were fabricated using singlelayer luminescent polymer produced by onestep plasma polymerization from naphthalene (PEN) (and car bazole (PENCB)) derivatives. W P LEDs based on the plasma polymers had demonstrated effici en t pu r e wh ite ligh t electroluminescence th at cover s the full visible spectral range w i t h excellent color stability. A new monomer injection method e nables excellent structural retention and excellent device repr oducibility. Monomers of good luminescent quality and char ge transport behavior can be selected to synthesize the light-e mitting polymer without considering their individual chemical b ehaviors. It provides an opportunity of onestep reaction with molecularly smooth, pinhole free and high quality films. Fullspectrum electroluminescence (EL) emission was originated f rom molecular excitons, intermolecular excimers and electro mers. It was produced pure stable white light emission at CIE coordinates of (0.33,0.34). Excellent luminance efficiency of 9.8 cd/A and a power efficiency of 2.1 lm/W were obtained. The efficiency reported here was based on films and devices not yet optimized. This new method merits further study as it manifests great potentials for simplifying the WPLEDs proce ss to enable a new type of high efficient, low-cost, and largearea-compatible processes.