Plasmonic enhancement in upconversion emission of La2O3:Er3+/Yb3+ phosphor via introducing silver metal nanoparticles

In the present work, authors have synthesized silver (Ag) nanoparticle (NP) embedded La2O3:Er3+/Yb3+ powder phosphor. The synthesis method has resulted in silver oxide-lanthanum oxide composite material. Through subsequent heat treatment of sample in pellet form, the silver metal nanoparticles were formed. The presence of plasmonic Ag NPs in the matrix is confirmed by various techniques. Large enhancement in downconversion as well as upconversion emission intensity of Er3+ ions at various concentrations of Ag NPs is obtained. Large enhancement in the upconversion emission intensity is correlated to the reduction in decay time of S-4(3/2) level in the presence of Ag NPs, and possible reasons for intensity enhancement are discussed. The application of phosphor in fingermark detection is demonstrated.