Double light-emitting layer implementing three-color emission: Using DCJTB lightly doping in Alq3 as red-green emitting layer and APEAn1N as blue-green emitting layer

Abstract

High performance with color stability and simplified device structure with uncomplicated fabrication processes are research focuses in white organic light-emitting diodes (WOLEDs). But it is not easy to simultaneously combine these characteristics into WOLEDs. Herein, efficient and color-stable WOLEDs with double light-emitting layer are constructed. The double light-emitting layer structure is composed of a red-green (RG) emitting light which originate from incomplete energy transfer from the host of tris-(8-hydroxyquinolinato)aluminum (Alq3) to guest of 4-(Dicyanomethylene)-2-tert-butyl-6-(1,1,7,7-tetramethyljulolidin-4-yl-vinyl)−4H-pyran (DCJTB), and a blue-green emitting light from (E)-9-(4-(2-(anthracen-9-yl)vinyl)phenyl)-10-(naphthalen-1-yl)anthracene (APEAn1N). In these WOLEDs, the different doping concentrations of DCJTB in Alq3 were optimized. Finally, a WOLEDs with relatively simple preparation was obtained with a maximum brightness of 9296cdm−2, maximum current efficiency (CE) of 10.17cdA−1, maximum power efficiency (PE) of 5.80lmW−1, maximum external quantum efficiency (EQE) of 4.09%, Commission Internationale de L'Eclairage (CIE) coordinate of (0.41, 0.46) and color rendering index (CRI) of 75 (85), respectively. And the chromaticity coordinate is stable at (0.41, 0.46) with increasing operation voltage. These results reveal that the fluorescent WOLEDs possess simplified fabrication, low cost, relatively high efficiency, acceptable CRI and stable color, simultaneously.