Tunable multicolor and white emission NaLuF4:Yb, Nd, Ln (Ln = Er, Tm, Er/Tm) microstructures

A facile and surfactant-free molten salt method has been proposed to prepare a well-defined one-dimensional NaLuF4:Yb3+,Nd3+,Er3+,Tm3+ nanorods for the first time. It is found that by properly tuning the sensitizer (Nd3+) concentration in the host matrix upon 980 nm laser diode (LD) excitation, white up-conversion (UC) emission was achieved. Also, by doping Yb3+/Er3+/Tm3+/Nd3+ in NaLuF4 the relative intensities of different emissions can be precisely adjusted in a broad range. Consequently, by appropriately controlling the emission intensity balance of blue, green and red basic colors in multicolor UC emissions, a strong white light can be realized in NaLuF4:Yb3+, Er3+,Tm3+,Nd3+ structures. UC mechanisms were analyzed in detail based on the emission spectra. The as-synthesized abundant luminescence colors in a wide region contribute themselves great potential applications. Furthermore, by manipulating the sensitizer concentration the paper provides an effective and facile method to gain a desired color.