Synthesis and Properties of Luminescent Silicon Nanocrystal/Silica Aerogel Hybrid Materials

Abstract

Exploiting the chemical compatibility of transparent high surface area silica aerogels and environmentally benign luminescent silicon nanocrystals (SiNCs) opens the door to a new class of silicon-based hybrid materials. Hydrophilic SiNCs of various sizes and surface groups that photoluminesce throughout the visible and NIR spectral regions were synthesized and incorporated into a tetramethyl orthosilicate containing solution to produce luminescent aerogels of varied transparency. Photoluminescence (PL) spectroscopy performed on solutions and aerogel monoliths containing SiNCs reveal that the optical properties of SiNCs are dependent on their size and surface chemistry. Furthermore, the incorporation of SiNCs into aerogels does not influence their PL response. The nitrogen adsorption–desorption measurements indicate that the physical properties of aerogels may be tailored by changing the SiNC size and surface chemistry. Adding to the appeal of the present work, PL quenching of SiNC-loaded aerogel upon exposure to nitrobenzene confirms that SiNCs remain chemically accessible.