No abstract

We demonstrate the combined effects of a microcavity structure and light-recycling filters (LRFs) on the forward electrical efficiency of phosphor-converted white organic light-emitting diodes (pc-WOLEDs). The introduction of a single pair of low- and high-index layers (SiO(2)/TiO(2)) improves the blue emission from blue OLED and the insertion of blue-passing and yellow-reflecting LRFs enhances the forward yellow emission from the YAG:Ce(3+) phosphors layers. The enhancement of the luminous efficacy of the forward white emission is 1.92 times that of a conventional pc-WOLED with color coordinates of (0.34, 0.34) and a correlated color temperature of about 4800 K.

A solution processable polymer was synthesized, by incorporating pyrene groups into the backbone of the polyaniline chain, and used as an emissive layer in an organic light emitting diode. The polyaniline base was reacted with acid chloride of pyrene butyric acid to form pyrene-functionalized polyaniline chains. The source of pyrene moiety was acid chloride of pyrene butyric acid. The formation of polymer from acid chloride of pyrene butyric acid and polyaniline was confirmed by the FTIR and 1 H-NMR spectroscopy. Differential scanning calorimetry revealed high glass transition temperature of 210 o C. Due to the presence of pyrene moieties in the backbone, the polyaniline synthesized in the present study is solution processable with light emitting property. The photoluminescence spectrum of the polymer revealed that emission lies in the blue region, with a peak at 475 nm. The light emitting device of this polymer exhibits the turn-on voltage of 15 V.