HDEHP assisted solvothermal synthesis of monodispersed REPO4(RE=La-Lu, Y) nanocrystals and their photoluminescence properties

Coordination polymer submicrospheres were successfully synthesized using a solvothermal method using organophosphate (HDEHP) and Y(NO3)(3) without any additional ligand and surfactant under mild conditions. Upon calcination, the obtained precursor produced stable tetragonal phase (t-)YPO4 submicrospheres. XRD, SEM and HRTEM were used to characterize the precursor and calcined samples. The results showed that t-YPO4 submicrospheres were obtained by the thermal decomposition of the precursor, and there was no other phase transition in the process. FTIR and TG-DTA confirmed that the precursor was a coordination polymer formed by HDEHP and Y3+, and the growth process of the spherical precursor was proposed. Furthermore, various REPO4 (RE = La-Lu, except radioactive Pm) spherical particles and the Eu3+ doped YPO4 phosphor were synthesized under similar conditions. The luminescent properties of the YPO4:Eu phosphor were also studied in detail.