1 UMR CNRS 6226, "Institut des Sciences Chimiques de Rennes", Université de Rennes 1-Campus de Beaulieu, 35042 Rennes cedex, France. cyril.poriel@univ-rennes1.fr.
A new high triplet organic semi-conductor based on a donor-spiro-acceptor design has been synthesised and used as a host material in high performance (EQE = 11.4%) sky blue phosphorescent organic light emitting diodes.