The FPL of the thin films were determined using an integrating sphere (λexc = 305 or 340 nm) under a N2 atmosphere at 298 K. Values quoted inside the parentheses are in air. Average lifetime 𝜏 !"# = Σ𝐴 $ 𝜏 $ % /Σ𝐴 $ 𝜏 $ , where 𝐴 $ is the pre-exponential for lifetime 𝜏 $ . Prompt and delayed emissions were measured by TCSPC and MCS, respectively (λexc = 379 nm). The performance of the OLEDs is summarized in