Benzo[k]fluoranthene-based linear acenes for efficient deep blue organic light-emitting devices

Abstract

This paper presents studies for the application of new fluorescent benzo[k]fluoranthene-based linear acenes as dopants in deep blue organic light-emitting diodes (OLEDs). Benzo[k]fluoranthene derivatives are easily prepared, and the substituents of the derivatives can be easily replaced by different functional groups. These benzo[k]fluoranthene-based linear acenes have a high photoluminescence intensity of around 430 and 460 nm in the solid state. The fluorescent emission spectra can be modulated by tuning the substituents and the conjugated length of the emissive core. The deep blue electroluminescence spectra remain unchanged, while the devices are biased at the high current density regime and in a stress test after the long-term operation. The Commission Internationale de l'Eclairage (CIE) chromaticity coordinates (x, y) of the deep blue OLEDs approach (0.15, 0.09), which is close to the National Television System Committee standard blue position (0.14, 0.08). The deep blue OLED has a maximum brightness, light turn-on voltage, luminous efficiency and external quantum efficiency of over 6000 cd m⁻², below 3.5 V, ∼1.61 cd A⁻¹, and 1.8%, respectively.