Tailoring the molecular design of twisted dihydrobenzodioxin phenanthroimidazole derivatives for non-doped blue organic light-emitting devices?

RSC Advances Pub Date: 2018-08-14 DOI: 10.1039/C8RA05004J

Abstract

Three fused polycyclic aryl fragments, namely, naphthyl, methoxynaphthyl, and pyrenyl have been used to construct blue-emissive phenanthroimidazole-functionalized target molecules, i.e., 1-(2,3-dihydrobenzo[b][1,4]dioxin-6-yl)-2-(naphthalen-1-yl)-1H-phenanthro[9,10-d]imidazole (1), 1-(2,3-dihydrobenzo[b][1,4]dioxin-6-yl)-2-(1-methoxynaphthalen-4-yl)-1H-phenanthro[9,10-d]imidazole (2), and 1-(2,3-dihydrobenzo[b][1,4]dioxin-6-yl)-2-(pyren-10-yl)-1H-phenanthro[9,10-d]imidazole (3). The up-conversion of triplets to singlets via a triplet–triplet annihilation (TTA) process is dominant in these compounds due to 2ET1 > ES1. The pyrenyl dihydrobenzodioxin phenanthroimidazole (3)-based nondoped OLED exhibits blue emission (450 nm) with CIE (0.15, 0.14), a luminance of 53?890 cd m?2, power efficiency of 5.86 lm W?1, external quantum efficiency of 5.30%, and current efficiency of 6.90 cd A?1. The efficient device performance of pyrenyl dihydrobenzodioxin phenanthroimidazole is due to the TTA contribution to the electroluminescent process.

Graphical abstract: Tailoring the molecular design of twisted dihydrobenzodioxin phenanthroimidazole derivatives for non-doped blue organic light-emitting devices
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