Fig. 1. Synthetic routes of compound DTRz，DCNTRz and DBTRz.

Fig. 2. HOMO and LUMO distribution of compounds

Fig. 3. TGA&DSC curves of DTRz，DBTRz and DCNTRz.

Fig. 4. Cyclic voltammetry curves of DTRz，DBTRz，and DCNTRz in DMF solution.

Fig. 5. UV-Vis absorption，fluorescence（in toluene solution）and phosphorescence（at 77 K in thin film）spectra of（a）DTRz，（b）DBTRz，（c）DCNTRz；（d）PL spectra of DTRz，DBTRz，DCNTRz in toluene solution.

Fig. 6. PL emission spectra of each host and mixed hosts.（a）NBPBC∶DTRz；（b）NBPBC∶DBTRz；（c）NBPBC∶DCNTRz；（d）Mixed hosts’ PL of DTRz，DBTRz，DCNTRz and UV-Vis of Pt（BPP）.

Fig. 7. Current density-voltage of the electron-only devices for the compounds DTRz，DBTRz and DCNTRz.

Fig. 8. Chemical structure of materials used in the device

Fig. 9. Energy diagram used in the green PhOLEDs devices

Fig. 10. Luminance-voltage-current density curves of device I，II，III.

Fig. 11. Current efficiency-luminance-power efficiency curves of the devices I，II，III.

Fig. 12. Electroluminescence curves of devices I，II and III at 4 V and photoluminescence spectra of Pt（BPP）in dichloromethane.

Fig. 13. Life time（LT95）curves of device I，II，III.