Sol–gel deposition and luminescent properties of LaMgAl11O19:Ce3+/Tb3+ phosphor films

Rare earth ions (Ce3+, Tb3+)-doped LaMgAl11O19 phosphor films were deposited on quartz glass substrates by Pechini sol–gel and dip coating method. X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT–IR), thermogravimetric and differential thermal analysis (TG–DTA), atomic force microscopy (AFM), field emission scanning electronic microscopy (FESEM), photoluminescence (PL) spectra, and lifetimes were used to characterize the resulting films. The results of XRD indicated that the magnetoplumbite structure LaMgAl11O19 phase can be obtained at 1200 °C on quartz glass substrates. This was further verified by the results of FT–IR and TG–DTA. AFM study showed that uniform films have an average grain size of 150 nm and a root mean square (RMS) roughness of 4 nm. The thickness of the films characterized by FESEM is about 340 nm. LaMgAl11O19:Ce3+ film showed the parity and spin allowed 5d–4f band emission of Ce3+ with a maximum at 350 nm. Ce3+, Tb3+-codoped LaMgAl11O19 films showed the band emission of Ce3+ and characteristic emission of Tb3+, namely, 5D3,4-7FJ (J=6, 5, 4, 3) due to an efficient energy transfer from Ce3+ to Tb3+ in the host.