Formation of rare-earth upconverting nanoparticles using laser vaporization controlled condensation

Rare earth doped upconverting nanoparticles have been synthesized via laser vaporization controlled condensation (LVCC) and their photoluminescence properties were characterized using 980 nm laser diode excitation. This procedure is highly tunable, specifically by increasing the Yb3+ to Er3+ concentration the observed green emission decreases and the observed red emission increases. We have also shown that nearly equal peaks of blue, green and red emissions producing a virtually white upconverter could be synthesized by appropriately mixing Tm3+, Ho3+, and Er3+. We have also investigated the upconversion efficiency in a variety of lattices including Y2O3, Gd2O3 and La2O3. TEM confirmed that the as-formed particles were ~ 10 nm in size and XRD indicated that the overall crystal structure was predominately cubic.