Efficient and Good Color Quality Single-Emitting-Layer Fluorescent White Organic Light-Emitting Diode Employing a Novel 8-Hydroxyquinoline Derivative as Yellow Emissive Component

Abstract

Efficient, good color quality, two-component single-emitting layer fluorescent white organic light emitting diode (WOLED) has been developed using a novel 2-substitutd-8-hydroxyquinoline derivative, (E)-2-(2-(9-p-toly1-9H-carbazo1-3-y1)viny1) quinolin-Zinc(MCzHqZn), as yellow dopant. The WOLED with the optimizing MCzHqZn-doped concentration of 2 wt% exhibits maximum current efficiency of 2.3 cd/A with the Commission Internationale del'Eclairage (CIE) coordinates of (0.320, 0.347). From the brightness at 1000 to 5000 cd/m 2 , the current efficiency roll-off of the device is 9.0%. White light emission is achieved by combining blue and yellow emissions emitted from NPB and MCzHqZn, respectively. The MCzHqZn emission is mainly attributable to the direct carrier trapping (DCT) at the dopant sites. Moreover, the WOLED exhibits excellent color stability, high color rendering index (CRI) and appropriate correlated color temperature (CCT) in a wide range of voltage. The CIE coordinate region is (0.310-0.324, 0.333-0.335) at various current density (20-858 mA/cm 2 ), corresponding CRI of (78-81). The CIE coordinates correspond to CCT is 5914 K at 8532 cd/m 2 .