Observation of a magic discrete family of ultrabright Si nanoparticles

Abstract

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 (Si 29 ), 1.67 (Si 123 ), 2.15, 2.9, and 3.7 nm in diameter. We characterize the particles via direct electron imaging, excitation and emission optical spectroscopy, 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 ͑RGB͒ range is useful for biomedical tagging, RGB displays, and flash memories.

Room-Temperature Reactivity Of Silicon Nanocrystals With Solvents: The Case Of Ketone And Hydrogen Production From Secondary Alcohols: Catalysis?

“…5 The silicon wafers were cleaved into 2.5 x 4.5 cm strips, and immersed in 50:1 solution of deionized water and hydrofluoric acid (49%, Fluka) for 3-4 minutes for native oxide removal. The silicon was then laterally anodized while being dipped into a 3:2:1 solution of hydrogen peroxide, H 2 O 2 , (30% by volume), methanol (≥ 98% purity), and HF (49%, Fluka).…”

“…The nanoparticles were dispersed into an organic solvent by sonicating the strips for 15 minutes. Unlike Belomoin et al, 5 no post-processing steps were used to break down larger structures and recover larger crystals. We were very careful to perform all experiments in controlled atmosphere.…”

“…For example real breakthrough for this particle size-effect has been made by Haruta in the case of gold for which dramatic increase of catalytic properties has been detected for small Au nanoparticles (NPs). 25 We have been using an inexpensive method, through colloidal etching, 5 to fabricate silicon nanoparticles whose size is around 2.5 nm (Figure 1 and description in supporting information). It was therefore interesting to explore the possible catalytic properties of these nanoparticles.…”

Synthesis of Diagnostic Silicon Nanoparticles for Targeted Delivery of Thiourea to Epidermal Growth Factor Receptor-Expressing Cancer Cells

“…[14][15][16][17] The size tunable emission [18][19][20] , high brightness 21 , and high photostability compared to organic dyes 22 , have made SiNPs attractive materials as fluorescent cellular markers. In addition, silicon is abundant and economical 23 but more importantly silicon has low inherent toxicity.…”

Optical Properties of Nanostructured Silicon

“…Belomoin et al [10] demonstrated that electrochemically etched, hydrogen-capped Si n H x clusters with n larger than 20 are obtained as a family of discrete sizes. These sizes are 1.0 (Si 29 ), 1.67 (Si 123 ), 2.15, 2.9, and 3.7 nm in diameter.…”