Highly Luminous Sky-Blue Organic Light-Emitting Diodes Based on the Bis[(1,2)(5,6)]indoloanthracene Emissive Layer

Abstract

An in-depth analysis of the electro-optical and light emissive properties was carried out with a new fused heteroacene, the bis [(1,2)(5,6)] indoloanthracene. The compound was synthesized in a straightforward bidirectional manner from 1,4-dibromo-2,5-diodobenzene utilizing a reaction cascade of isomerisation and cyclisation sequences. Bis-[(1,2)(5,6)] indoloanthracene exhibits bright luminescence with high quantum yield in solution as well as in the solid state. By using this novel semiconductor as active layer, an efficient OLED has been fabricated for which its emission pattern resembles at least two emitters in a single emissive region originated from the same molecule. One has its origin from the single molecule and is similar to the luminescence spectra in solution, whereas the other functions through the formation of aggregates being similar with the emission pattern found with crystals of bis-[(1,2)(5,6)]indoloanthracene. As a result bright sky-blue OLEDs with very high luminance exceeding 10000 cd/m 2 were obtained. Such color pattern and performance has not previously been observed with low molecular weight, electron-rich fused polycyclic aromatic compounds and indicate a promising new class of materials for development.

Novel Zinc Complex with an Ethylenediamine Schiff Base for High-Luminance Blue Fluorescent OLED Applications

“…That is why both complexes are stable in S1 state, but do not exist in the ground electronic state. The idea about two excimers at 433 and 468 nm is also proved by the biexponential behaviour of photoluminescence decay 62,63 measured at these emission maxima with the predominant contribution of long-lifetime component 15.9 ns (83%) and 22.5 ns (81%), respectively ( Figure S3). (Table 2 in Ref.…”

Nine-ring angular fused biscarbazoloanthracene displaying a solid state based excimer emission suitable for OLED application

“…. 27 Notably, the experimentally determined E HOMO energy of 3 is remarkably low for such a highly extended π--conjugated molecular scaffold containing nine rings and it emphasizes a better oxidation stability of 3.…”

“…The packing in the thin film of 3 is clearly less dense than in the analogous thin layers of bisindoloanthracene. 27 Although the aromatic ribbon here is more extended, the bulkier and longer alkyl groups may provide more significant repulsion between the aromatic planes. Morphology.…”

“…In shorter bisindoloanthracene, this effect is not so pronounced. 27 All the p--(S1), α--(S2) and β--(S5) have in--plane polarization usual for the ππ*--states. The differences in the observed intensities are caused only by the symmetry and shape of the corresponding MOs wavefunctions.…”

Non‐Doped Sky‐Blue OLEDs Based on Simple Structured AIE Emitters with High Efficiencies at Low Driven Voltages

“…All the devices exhibited reasonably low driven voltage. The device performance of 3TPEI is better than several materials (including TPE‐containing materials) reported for non‐doped sky blue OLED devices . The data of electroluminescence performance of the devices is summarized in Table .…”