TY - JOUR AU - Tan, Meiling AU - Hao, Shuwei AU - Meng, Xiangbin AU - Liu, Jing AU - Shang, Yunfei AU - Yang, Chunhui AU - Chen, Guanying PY - 2015 TI - pH Mediated Control Synthesis of Lanthanide-Doped YPO4 Upconversion Nano/Microcrystals JF - American Journal of Engineering and Applied Sciences VL - 8 IS - 3 DO - 10.3844/ajeassp.2015.310.317 UR - https://thescipub.com/abstract/ajeassp.2015.310.317 AB - A pH-mediated rational control over the phase transformation, morphology and size of lanthanide doped YPO4 nano/microcrystals has been accomplished using a hydrothermal route. The morphology of the resulting particles evolves from the spheres, to the nanoflakes and finally to the nanorods when increasing the pH value of the reaction solution from 1 to 9, while the induction of crystal phase transformation from a tetragonal structure to a hexagonal structure takes place at pH = 5. When excited at 980 nm, the hexagonal phase YPO4•0.8H2O: 18%Yb3+, 2%Er3+ nanoflakes prepared at pH = 7 exhibit the strongest UC emission intensity among investigated samples of varying size, phase and morphologies. This work provides a paradigm on the controlled synthesis of lanthanide doped upconverting orthophosphates, which hold great promise for various photonic and biophotonic applications.