Fig. 1. Principle and characterization of exciplex produced by NPB and TPBi. (a) Principle of excimer generation at NPB/TPBi interface; (b) normalized PL spectra of NPB and TPBi monolayers and NPB∶TPBi(1∶1) hybrid film

Fig. 2. Characterization of films and devices. (a) Comparison of absorption spectrum of Ir(DMP-IQ)₂(acac) film and PL spectrum of NPB∶TPBi (1∶1) hybrid film; (b) normalized EL spectrum of device A; (c) CIE coordinates of device A

Fig. 3. Structure of device B and molecular structure of corresponding materials. (a) Structure of device B; (b) chemical structures of organic materials used in device B

Fig. 4. Performance comparison of device A and device B. (a) Characteristic curves of luminance and voltage; (b) characteristic curves of current density and current efficiency; (c) characteristic curves of current density and EQE; (d) normalized EL spectra

Fig. 5. Performance comparison of device A and device B. (a) Energy level diagram of device C; (b) EL spectrum and CIE image of device C

Fig. 6. Characterization of EL luminescence performance of devices D1--D4. (a) Normalized EL spectra of devices D1--D4; (b) light-emitting color of devices D1--D4; (c) normalized EL spectra of devices with spacer layer thickness of 5, 10, 15 nm

Fig. 7. Schematic of relative energy levels of luminescent materials

Fig. 8. Performance curves of devices E1--E5. (a) Luminance and voltage; (b) current efficiency and current density; (c) EQE and current density; (d) normalized EL spectra

Fig. 9. Theoretical model of mCP in ternary system with different doping ratio. (a) Lower proportion model Ⅰ; (b) moderate scale model II; (c) high proportion of model Ⅲ

Fig. 10. Performance curves of device S1--S5. (a) Luminance and voltage; (b) current efficiency and current density; (c) EQE and current density; (d) normalized EL spectra