Rapid aqueous-phase synthesis of highly stable K0.3Bi0.7F2.4 upconversion nanocrystalline particles at low temperature

Lanthanide-doped K_0.3Bi_0.7F_2.4 nanocrystalline particles are synthesized through an ultrafast (only 1 min) and aqueous-phase chemical method at low temperature (room temperature ∼ 90 °C), which can be used as pigments for anti-counterfeiting.