Temperature-dependent upconversion luminescence of -NaYF4:Yb3+, Er3+ nanoplates

Temperature dependent characteristics of upconversion luminescence in -NaYF4:Yb3+, Er3+ nanoplates under 980 nm excitation were reported. Intense green and red upconversion emissions corresponding to (2H11/2, 4S3/2) &rarr 4I15/2 and 4F9/2 &rarr 4I15/2 transitions of the Er3+ ions were observed, respectively. The green emission around 520 nm and the red emission around 660 nm continuously increase with increasing of temperature. The emission around 545 nm increases from 84 to 204 K and then decreases from 204 to 483 K. The temperature dependence of intensity characteristics was systematically analyzed by a simple three-level system.