Synthesis and photoluminescence of Y,Eu co-doped ZnO red phosphor

A red emitting ZnO·Y2O3:Eu phosphor has been prepared using pyrolysis technique at temperatures ≤1000 °C. When NH4Cl was used as an ingredient, its luminescence efficiency was quite high indicating that Cl− ions act as charge compensators since the introduction of Y3+ and Eu3+ cations in ZnO lattice demands the introduction of equal amount of excess anions. However, Na+ or Li+ quenches the luminescence efficiency of ZnO·Y2O3:Eu. Due to ZnO host absorption, the excitation peaks of ZnO·Y2O3:Eu phosphor near 260 nm and 394 nm are suppressed while the one at 468 nm is intense. This red emitting phosphor may find applications when monochromatic excitation such as lasers are involved. XRD data of (Zn0.93Y0.07)Oz:Eu3+,Cl− shows the presence of the ZnO phase as well as the Y2O3 phase. It shows that Y2O3 forms a sublattice within ZnO host. This is supported by the PL data of (Zn0.93Y0.07)Oz:Eu3+,Cl− which showed no significant change in the PL efficiency with increase in ZnO molar concentration.

A typical PL excitation (a for λemis = 496 nm and c for λemis = 611 nm) and emission (b for λexci = 381 nm and d for λexci = 468 nm) spectra of ZnO:Zn (Phosphor Technology Ltd., UK) (a and b, respectively) and ZnO·Y2O3:Eu (c and d, respectively).Figure optionsDownload as PowerPoint slide