Towards red-NIR emission of platinum(II) complexes

The exploration of near-infrared (NIR) emitting materials has been drawing great research interest due to their applications in many fields of technology and medicine. However, such materials usually exhibit low stability and low luminescence quantum yields, so there is still a great demand for the search new emitters that would overcome these limitations. Platinum(II) complexes have the ability to enter into metal-metal interactions, which leads to the formation of new excited states, such as metal-metal-ligand charge transfer (MMLCT), and are very promising NIR materials. It has been observed that the emission properties of Pt(II) complexes can be bathochromically shifted towards the NIR or red region using different approaches. This review summarizes methods for tuning the emission properties of Pt(II) complexes and shifting the emission towards the red and NIR regions of the electromagnetic spectrum.