Abstract
A platinum complex, an OLED and an apparatus for providing visible emission or near-infrared (NIR) emission using the same are described. The platinum complex has a structure represented by formula (I):;wherein A1 to A4 each independently represent a 5-membered or 6-membered unsaturated ring, a first chelating ligand including A1 and A4 fragments has a minus one formal charge, and a second chelating ligand including A2 and A3 fragments has a minus one formal charge.