Synthesis, aggregation-induced emission, and electroluminescence of AIEgen designed on bis-carbazole platform

Abstract

The promising applications of organic light emitting devices (OLEDs) as the next-generation lighting technology has boosted global research on small organic fluorescent molecules. However, majority of the organic fluorophores experiences detrimental aggregation caused quenching (ACQ) during their real-world applications. Since the discovery of the AIE phenomena, efforts to develop novel luminescent materials have skyrocketed, creating newer opportunities for the improvement of the properties of the light-emissive materials for OLEDs. Herein we have reported the synthesis of bis-carbazole-derived luminogen by oxidative coupling of the carbazole in good yield. The bis-carbazole luminogen 6 displayed sky-blue-emission in the aggregated state along with excellent electrochemical property and thermal stability, which are considered essential features for constructing high efficiency OLEDs. The luminogen 6 was employed as an emitter for fabricating non-doped OLED and the device resulted in sky-blue emission with CIE coordinates (0.23, 0.41). The light emitting device had a maximum current efficiency of 3.25 cd/A and a maximum external quantum efficiency (EQE) of 5 %, which eventually rolled-off to about 2 % at a J ∼ 50 mA/cm2. Our findings presented a novel way for constructing blue emissive materials for potential application in OLED devices.

Keywords

• Aggregation Induced Emission (AIE)
• Bis-carbazole
• Electroluminescence
• Organic Light Emitting Diodes (OLEDs)