Magic Family of Discretely Sized Ultrabright Si Nanoparticles.

摘要

We describe a procedure for dispersion bulk Si into a family discretely sized ultrasmall ultrabright nanoparticles. We demonstrate that electrochemically etched, hydrogen capped Si(n)H(x), clusters with n larger than 20 are obtained within a family of discrete sizes. These sizes are 1.0 (Si29), 1.67 (Si123), 2.15, 2.9, and 3.7 nm diameter. We characterize the particles via direct electron imaging, excitation and emission optical spectroscopy, chromatography, and colloidal crystallization. The band gaps and emission bands are measured. The smallest four are ultrabright blue, green, yellow, and red luminescent particles. The availability of discrete sizes and distinct emission in the red, green and blue range is useful for biomedical tagging, RUB displays, and flash memories.