White light-emitting organic electroluminescent devices using the poly(N-vinylcarbazole) emitter layer doped with three fluorescent dyes

Abstract

White light-emitting electroluminescent devices were fabricated using poly(N-vinylcarbazole) (PVK) as a hole-transporting emitter layer and a double layer of 1,2,4-triazole derivative (TAZ) and tris(8-quinolinolato)aluminum(III) complex (Alq) as an electron transport layer. The PVK layer was doped with fluorescent dyes such as blue-emitting 1,1,4,4-tetraphenyl-1,3-butadiene, green-emitting coumarin 6, and orange-emitting DCM 1. A cell structure of glass substrate/indium-tin-oxide/doped PVK/TAZ/Alq/Mg:Ag was employed. White emission covering a wide range of the visible region and a high luminance of 3400 cd/m2 were obtained at a drive voltage of 14 V.

Spectroscopic studies of different poly3hexylthiophene chain environments in a polyfluorene matrix

“…[6,7] These properties could be very important for example when trying to achieve white emission, one of the most important developments in the field of polymer emitting devices, where complex mixtures are used in order to gain broad white emission and balanced electron and hole transport within a single "emission" layer. [8,9,10,11] Polyfluorenes have been extensively studied for display applications, owing to their pure blue and efficient electroluminescence coupled with a high charge carrier mobility and good processability. [12] Several studies have been reported, including mixing of polyfluorenes with different emissive materials and applying them in single or multiple layers.…”

Simulating charge transport in organic semiconductors and devices: a review

“…Organic light-emitting diodes (OLEDs) are already widely used in display applications due to their capability to produce light across the visible spectrum [424] and tunability of the OSCs optical and electrical properties through molecular design [425]. However, their compatibility with flexible substrates and cheap fabrication methods points to future applications in solid-state lighting and flexible displays [7,426,427].…”

More light from organic light-emitting diodes

“…e first report on white OLEDs dates back to 1994, when a Japanese group combined red, green and blue (RGB) laser dyes in a common matrix and achieved light emission over a broad spectral range [4]. Despite its simplicity in preparation, achieving white light emission with good and stable colour quality in this way is not that straightforward, because charge recombination and energy transfer processes between the different dyes need to be well controlled.…”