Highly effective upconversion broad-band luminescence and enhancement in Dy2O3/Au and Sm2O3/Au composites

Upconversion (UC) nanomaterials with the ability to convert incident infrared photons to visible or ultraviolet emissions have attracted remarkable interest and hold great promising applications ranging from bioimaging to display devices. However, their low UCL efficiency does not satisfy the requirement of various practical applications. In this work, we successfully prepared Dy2O3/Au and Sm2O3/Au nanocomposites by a simple co-precipitation method. X-Ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and photoluminescence (PL) spectroscopy were used to characterize the samples. The UC broadband enhancements illuminating with various power density of 980 nm are systemically investigated. The maximum UCL enhancement is 35-fold and 48-fold for Dy2O3/Au and Sm2O3/Au nanocomposites under 980 nm excitation. The UC population processes and enhancement mechanism are carefully studied. The luminescence enhancement in the composites is mainly attributed to the enhanced thermal effect.