We report on the electroluminescent properties of complexes of Ru, Os and Ir featuring various ligands. The performance of devices with indium tin oxide (ITO) and gold contacts appears to be dominated by ionic space charge effects. Their electroluminescence efficiency was limited by the photoluminescence efficiency of the films and not by charge injection from the contacts. Record luminous efficiencies of 10Lm/W and brightness exceeding 300 cd/mˆ2 at just 3V are demonstrated in a single layer device with air stable electrodes.