Efficient Pyrazolo[5,4-f]quinoxaline Functionalized Os(II) based Emitter with Electroluminescence Peak Maximum at 811 nm

Upon fusing the pyrazinyl pyrazole entity in giving pyrazolo[3,4- f ]quinoxaline chelate, the corresponding Os(II) based NIR emitter exhibited "invisible" and efficient electroluminescence with peak max. at 811 nm and a maximum external quantum efficiency of 0.97% and suppressed efficiency roll-off till a current density of 300 mA cm -2 .