Color-tuning Pt(ii) complexes for natural-light electrophosphorescence

Two cyclometallated Pt(ii) complexes with Pt-Cpy bonded tetradentate ligands, Pt(pzpy-czOpy) and Pt(pzpy-czcl), have been fully investigated, showing that a simple strategy that reduced torsion could properly direct towards broad spectrum emission. Details in the photo- and electro-luminescence reveal entirely different types of localized emissions for the two complexes as well as their color tunability in devices. Luminescence of the complex responds to the mode of photo- or electro-excitation, resulting in different radiative relaxation process and also their emission spectra. Efficient and durable broad-spectrum OLEDs of cyan, greenish yellow, yellow and white colors were fabricated with simple structures, giving state-of-the-art performance in tuning the emission for natural color electroluminescence.