Efficient Nondoped Pure Blue Organic Light-Emitting Diodes Based on an Anthracene and 9,9-Diphenyl-9,10-dihydroacridine Derivative.

ABSTRACT

Organic light-emitting diodes (OLEDs) have been greatly developed in recent years owing to their abundant advantages for full-color displays and general-purpose lightings. Blue emitters not only provide one of the primary colors of the RGB (red, green and blue) display system to reduce the power consumption of OLEDs, but are able able to generate light of all colors, including blue, green, red, and white by energy transfer processes in devices. However, it remains a challenge to achieve high-performance blue electroluminescence, especially for nondoped devices. In this paper, we report a blue light emitting molecule, DPAC-AnPCN, which consists of 9,9-diphenyl-9,10-dihydroacridine and p-benzonitrile substituted anthracene moieties. The asymmetrically decoration on anthracene with different groups on its 9 and 10 positions combines the merits of the respective constructing units and endows DPAC-AnPCN with pure blue emission, high solid-state efficiency, good thermal stability and appropriate HOMO and LUMO energy levels. Furthermore, DPAC-AnPCN can be applied in a nondoped device to effectively reduce the fabrication complexity and cost. The nondoped device exhibits pure blue electroluminescence (EL) locating at 464 nm with CIE coordinates of (0.15, 0.15). Moreover, it maintains high efficiency at relatively high luminescence. The maximum external quantum efficiency (EQE) reaches 6.04 % and still remains 5.31 % at the luminance of 1000 cd m-2 showing a very small efficiency roll-off.