Diaminoanthracene derivatives as high-performance green host electroluminescent materials

Diaminoanthracene derivatives 9,10-bis(1-naphthylphenylamino)anthracene (alpha-NPA), 9,10-bis(2-naphthylphenylamino)anthracene (alphabeta-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 alpha-NPA, beta-NPA, and PPA as the hole transporters and host emitters were made. Devices consisting of diaminoanthracene (alpha-NPA, beta-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, alpha-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)/beta-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 1m/W, and maximum brightness of 64991 cd/m(2).