Silicon Nanoparticles: Are They Crystalline from the Core to the Surface?

• DOI: 10.1021/acs.chemmater.8b03074
• Publication Date: 2019-01-14T19:44:23Z
• Authors: Alyxandra N. Thie...; Michelle Ha; Riley W. Hooper; Haoyang Yu; Anton O. Oliynyk; Jonathan G. C. Ve...; Vladimir K. Micha...
• Keywords: 02 engineering and technology; 0210 nano-technology

Silicon nanoparticles (SiNPs) are biologically compatible, metal-free quantum dots that exhibit size and surface tailorable photoluminescence. The nanostructure of these materials influences their optical, chemical, material properties hence plays an important role in future-generation applications sensors, battery electrodes, optical materials, contrast agents, among others. In this work, we employ a complement methods including X-ray photoelectron spectroscopy (XPS), bright-field transmission electron microscopy (TEM), powder diffraction (XRD), Fourier transform infrared spectroscopy, 29Si solid-state nuclear magnetic resonance (NMR) to interrogate the bulk structure hydride-terminated SiNPs (H-SiNPs) ranging from 3 64 nm diameter effectively probe surface. By applying methods, have demonstrated H-SiNPs consist dependent layered made up surface, subsurface, core silicon regimes. species manifested by broad underlying feature corresponding NMR spectra between −80 −120 ppm for small (NPs), whereas sharp at higher frequency (ca. −80.9 ppm, 1 full-width half-maximum) present large NPs is attributed well-ordered crystalline core. A critical junction has been identified 9 H-SiNPs, where XPS show features arising species. This structural insight provides essential understanding potential advancement development SiNP-based photovoltaics, anodes, sensors.