Abstract
Studying the properties and stability of silicon nanoparticles (Si-np) in aqueous environments may lead to novel applications in biological systems. In this work, we use absorption and photoluminescence (PL) spectroscopy to characterize ultrasmall Si-np prepared through anodic etching and ultrasonic fractionation of a crystalline Si wafer. Their behavior is studied over time in 2-propanol and during treatments with water, NaOH, HCl, and H 2O 2. The observed population is divided into two types of material: bright species consisting of well-etched Si-np, -1 nm in diameter, and dark species derived from partially etched or aggregated Si structures. The dark material is seen by its scattering in the 2-propanol and water solutions and is largely removed via precipitation with the NaOH or HCl treatment. The bright material includes three distinct species with their respective emissions in the UV-B, UV-A, and hard-blue regions of the spectrum. The hard-blue PL is shown to have a simple pH dependence with a pK a -3, providing an important insight into its chemical origin and signaling for possible application of Si-np as environmental probes. Our results offer some potential for tailoring the PL properties of ultrasmall Si-np through control of their surface chemistry.
Original language | English (US) |
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Pages (from-to) | 19786-19797 |
Number of pages | 12 |
Journal | Journal of Physical Chemistry B |
Volume | 109 |
Issue number | 42 |
DOIs | |
State | Published - Oct 27 2005 |
ASJC Scopus subject areas
- Physical and Theoretical Chemistry
- Surfaces, Coatings and Films
- Materials Chemistry