Efficient deep blue electrophosphorescent devices based on platinum(II) bis(n-methyl-imidazolyl)benzene chloride

► A series of blue-emitting Pt(N^C^N)Cl complexes are synthesized. ► External Quantum Efficiency of 15.7% and CIE coordinates of (0.16, 0.13) are achieved. ► Demonstrate deep blue phosphorescent OLEDs using carbazole-based host materials. ► Low efficiency roll-off at high current achieved by efficient charge balance.