Upconversion emission and its color modulation of the YVO4: Er3+, Yb3+, Cr3+ nanoparticles

With the excitation of a 978 nm laser, the upconversion (UC) emissions of the YVO4:Er3+, Yb3+, Cr3+ nanoparticles include three emission bands located at 524, 552 and 658 nm, respectively. The UC emission characterization confirms that the UC emission of the YVO4:Er3+,Yb3+ nanoparticles can be modulated by the doping of the Cr3+ ions, the increase of the incident laser power and the change of the laser pulse-width. With the doping of the Cr3+ ions, the two green emissions decrease because of the energy transfer from the Er3+ states H-2(11/2) and S-4(3/2) to the Cr3+ ions. With the increase of the incident laser power, the two green emissions increase due to the decrease of the transfer rate of the energy transfer path to the state F-4(9/2) of the Er3+ ions. With the increase of the incident laser pulse-width from 0.2 to 6 ms the intensity ratio of the emission at 524 nm to the emission at 658 nm increases from 0.063 to 0.19, which is due to the number accumulation at the state H-2(11/2) due to the small transfer rate from the Er3+ state H-2(11/2) to the Cr3+ ions. The experimental results confirm that the concentration of the Cr3+ ions has less effect on the average life-time of the UC emissions at 524, 552, and 658 nm. (c) 2024 Society of Photo-Optical Instrumentation Engineers (SPIE)