We next proceeded to fabricate vacuum-deposited bottom-emitting OLED devices using Here, HATCN was used as a layer for hole injection (HIL), TAPC and TCTA play the role in hole transporting layers (HTL), mCP acts as an electron blocking layer (EBL), TmPyPB acts as both an electron transport layer (ETL) and a hole blocking layer (HBL) due to its deep HOMO (-6.7 eV), and LiF acts as an electron injection layer (EIL) by modifying the work a At 298 K, values quoted are in degassed toluene solutions prepared by three freezepump-thaw cycles: for λPL the λexc = 340 nm; for lifetime λexc = 379 nm. b Obtained from the onset of the prompt fluorescence (time window: 1 ns -100 ns) and phosphorescence spectra (time window: 1 ms -8.5 ms) measured in 2-MeTHF glass at 77 K, λexc = 343 nm. c Quinine sulfate in H2SO4 (aq) was used as the reference (ΦPL = 54.6%, λexc=360 nm) for the solution-state measurements. Values quoted are in degassed solutions, which were prepared by three freeze-pump-thaw cycles.