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We demonstrate silicon-based phosphor materials which exhibit bright photoluminescence from near-infra-red to green. The colloidal composites which are composed of silicon quantum dots (SiQDs) attached on micro-size silicon particles are synthesized by electrochemical etching of silicon wafers and then dispersed in ethanol. Subsequently, isotropic etching by HF/HNO3 mixture controls the size so as the emission wavelength of SiQDs, and forms an oxide passivating shell. The phosphors can further react with alkoxysilanes to form a stable suspension in non-polar solvents for solution-processing. The resulting red-light-emitting SiQD-based phosphors in chloroform exhibit photoluminescence external quantum efficiency of 15.9%. Their thin films can be efficiently excited by InGaN light-emitting diodes and are stable in room condition.

we present a new optical microfluidic mixing approach via surface tension driven force sustained by the localized surface plasmon (LSP) energy. The phonon energy associated with the non-radiative damping of LSP on an Au nanostructure creates thermal gradients capable of actuating a convective fluid flow. Experimental evidence and modeling results both show that LSP from the Au nanostructure is crucial to establish a temperature gradient with sufficient magnitude to induce the convective flow when using a low-power laser source.

Opto-Plasmonic Tweezers are proposed as a new optical manipulator and rotator for biological cells. The approach utilizes polarized light to excite localized surface plasmon resonance (LSPR) on an array of Au nanostructure. Large dielectrophoretic trapping force is expected to be induced by the highly non-uniform scattering field from the resonant oscillating dipoles. Fine orientation control of the cells can be realized by tuning the polarization state of the input light.