The FPL of the 2 wt% doped film in mCP decreased to 65% under air. The FPL of DDiKTa-F is slightly higher compared to both DiKTa (FPL = 46%) and DDiKTa (FPL = 68%) in 2 wt% doped films in mCP. At the same doping concentration, the FPL in phosphine oxide-based hosts DPEPO and PPT are similar at 74 and 78%, but the lPL are red-shifted at 510 and 511 nm, respectively, due to their higher polarity (Figure ).