Diaminoanthracene Derivatives as High-Performance Green Host Electroluminescent Materials

Abstract

Diaminoanthracene derivatives 9,10-bis(1-naphthylphenylamino)anthracene (α-NPA), 9,10-bis(2-naphthylphenylamino)anthracene (β-NPA), 9,10-bis( m -tolylphenylamino)anthracene (TPA), and 9,10-bis(diphenylamino)anthracene (PPA) were conveniently synthesized from the corresponding diarylamine and 9,10-dibromoanthracene in the presence of Pd(OAc) 2, tri- tert -butylphosphine, and sodium tert -butoxide in o -xylene. Electroluminescent devices using α-NPA, β-NPA, and PPA as the hole transporters and host emitters were made. Devices consisting of diaminoanthracene (α-NPA, β-NPA, or PPA)/Alq 3 were shown to emit intensive green light from the diaminoanthracene layer instead of the Alq 3 layer. The device performance can be further improved by employing CuPc as the hole-injection layer, α-NPB or m- MTDATA as the hole-transporting layer, and Alq 3 or TPBI as the electron-transporting layer. Very high brightness, current, and power efficiencies and excellent CIE coordinates can be achieved by a suitable combination of these layers. For example, device K, which consists of m -MTDATA(20 nm)/β-NPA(40 nm)/TPBI(50 nm), emits green light at 530 nm and shows a maximum external quantum efficiency of 3.68%, current efficiency of 14.79 cd/A, power efficiency of 7.76 lm/W, and maximum brightness of 64991 cd/m 2 .