Efficient full-colour organic light-emitting diodes based on donor–acceptor electroluminescent materials with a reduced singlet–triplet splitting energy gap

The Cz-DEPVI device showed high efficiencies of L : 13955 cd m −2 , η ex : 4.90%, η c : 6.0 cd A −1 , η p : 5.4 lm W −1 and CIE coordinates of (0.15, 0.06) at 2.8 V.