Fabrication and optical properties of core/shell CdS/LaPO4:Eu nanorods

We report the preparation of CdS/LaPO4:Eu nanorods via a three-step chemical route involving solvothermal preparation of CdS nanorods. Then, the Surface functionalisation of CdS nanorods by citric acid is done. Finally. the formation of the LaPO4 shell is achieved. The core/shell nanostructure is confirmed by X-ray diffraction Studies and transmission electron microscopy (TEM) analysis. The crystal Phase of LaPO4 (shell) changes with changing the temperature of heating. It is interesting to note that the lattice strain of CdS (core) increases from 0.27% to 1.09% for pure US nanorods and core US nanorods, respectively. The lattice strain can be modified front tensile to compressive by changing the crystal phase of the LaPO4 (shell). It is found that the photoluminescence properties are sensitive to the crystal phase of the LaPO4; shell, which can be tuned by temperature of heating. From the decay time measurements, it is evident that the energy transfer occurs from core US nanorods to Eu3+ ions in the LaPO4 shell and the calculated energy transfer efficiency front CdS nanorods to Eu3+ ions is 50.9% for the 600 degrees C heated core/shell nanostructure. The experimental quantum efficiency is 47% for CdS/LaPO4:Eu samples and this efficiency increases due to energy transfer from CdS to Eu3+ ions in the LaPO4 shell.