Applications of hot-exciton anthracene and imidazole derivatives in integrated organic blue-emitting diodes and ultraviolet photodetectors

Abstract

We prepared four emitters using 1,2-diphenyl-1H-phenanthro [9,10-d]imidazole (PPI) as the chromophore unit, anthracene as the bridge and 1-naphthyl, 2-naphthyl, benzene and phenylcarbazole as peripheral groups, namely PPIAn1N, PPIAn2N, PPIAnp and PPIAnCz, and used them in integrated organic light-emitting diodes (OLEDs) and ultraviolet organic photodetectors(UVOPDs). All these four molecules exhibit hybridized local and charge transfer (HLCT) excited states with maximum emission peaks at ∼433, 448, 446 and 450 nm in the film state, respectively. The non-doped OLED based on PPIAn2N exhibits excellent performances with a deep-blue emission at ∼452 nm, CIE coordinates (Commission International de L’Eclairage) of (0.15, 0.11) and a maximum external quantum efficiency (EQE) of 7.3%. The integrated OLED–UVOPD based on PPIAn2N achieves a detectivity of 2.53 × 10¹² Jones, a switching ratio of 4.57 × 10⁴, a turn-on voltage of 3 V and a maximum power efficiency of 6.3 lm W⁻¹. Our work highlights the application of integrated multifunctional devices in the deep-blue emission zone.