Figure 4

UPS spectra at the SEC, valence, and near the EF regions. (a) ITO, ITO/V2O5, ITO/V2O5/TFB, and ITO/V2O5/TFB/QDs. (c) ITO, ITO/V2O5, ITO/V2O5/PTAA (UVO 40), and ITO/V2O5/PTAA (UVO 40)/QDs. Energy level diagram of (b) ITO/V2O5/TFB/QDs and (d) ITO/V2O5/PTAA (UVO 40)/QDs. Performance of the QLEDs with UVO 40 and TFB HTLs. (e) J-V-L and (f) CE-V-EQE curves.