Where IL and IR refer to the intensities of left-and right-handed light, respectively. Pure left-or right-handed light is obtained when gPL reaches +2 or -2. For a chiral emissive material to be relevant for practical applications such as OLEDs, the |gPL| should be as high as possible, the photoluminescence quantum yield (FPL) should be high, and emission should be narrowband.