| Co-precipitation method | NaYbF4:Tb@NaYF4:Tb@NaYF4:Eu, NaYF4:Yb/Er, YPO4:Bi/Eu, CaMoO4:Eu | Low cost, environmentally friendly, convenient synthesis, generally requires subsequent calcination treatment | 40,50,51,52 |
| Hydrothermal/solvothermal method | NaYF4:Yb/Er/Nd, YF3, LaF3, YbF3, NaYF4:Eu, Na(Y1.5Na0.5)F6 | Low synthesis temperature, mild conditions, small oxygen content, insignificant defects, stable system, special reaction equipment is required, and organic additives are usually required to control the form | 41,53,54,55 |
| Thermal decomposition method | YF3:Yb/Tm, LaF3, NaYF4:Yb/Er/Tm, | The synthesized UCNPs have good dispersion, high crystallinity, regular morphology, uniform crystal phase, expensive precursors, high reaction temperature, and easy synthesis of core-shell structure products | 42,43,59,60 |
| Sol-gel method | BaTiO3:Er, TiO2:Er | Good product uniformity, controllable particle size, lower hardness, higher purity, difficult to control morphology, high temperature calcination is required | 44 |
| Microemulsion method | ErF3, YbF3 | Simple device, uniform and controllable particle size, easy operation, low yield and poor dispersion | 45 |
