Synthesis of Colloidal Silicon Quantum Dot from Rice Husk Ash

Abstract

This article describes the synthesis procedure of colloidal silicon quantum dot (Si QDs) from rice husk ash. The silicon quantum dots were capped with 1-octadecene by thermal hydrosilylation under argon gas to obtain octadecyl-Si QDs (ODE-Si QDs). The size separation of ODE-Si QDs was examined by the column chromatography method, which used silica gel (40–63 μm) as the stationary phase. Finally, we obtained two fractions of silicon quantum dot, exhibiting blue emission (B-Si QDs) with an average size of 2.5 ± 0.73 nm and red emission (R-Si QDs) with an average size of 5.1 ± 0.68 nm under a UV lamp (365 nm). The PL spectra of B-Si QDs and R-Si QDs samples show maximum peak energy at 410 nm (3.02 eV) and 700 nm (1.77 eV), respectively, while the quantum yield of Si QDs decreases from 5.8 to 34.6% when the average size decreases from 2.5 nm to 5.1 nm. The above results of PL emission spectroscopy and UV-vis absorption show quantum confined effect in Si QDs.

Strength, Hydraulic, and Microstructural Characteristics of Expansive Soils Incorporating Marble Dust and Rice Husk Ash

“…On the other hand, rice husk is a widely used agriculture waste in the ricemilling process that transforms to RHA upon burning and contains a high amount of amorphous silica. When the RHA reacts with calcium hydroxide, they generate cementitious gels, which helps to improve the compression strength of soil [21,43,44]. It has been established from previous studies that RHA is a very reactive pozzolanic material, and it can efficaciously stabilize high plastic expansive soils either solely or in combination with lime and/or other additives [45,46].…”

Poly(vinyl alcohol)-Modified Colloidal Silicon Nanoparticles for Flexible Screen Printing Inks and Anticounterfeiting Applications

“…36−40 Nonetheless, a major problem in the field of Si NPs is the long-term controversy regarding the correlation between optical spectrum and the structure. 41 Therefore, exploring the luminescence mechanism of Si NPs is of great significance for the development of silicon-based materials in the optical field. In addition, poly(vinyl alcohol) (PVA) is an environmentally friendly polymer material, which exhibits notable characteristics of biocompatibility, biodegradability, nontoxicity, and inertness.…”

“…Consequently, environmentally friendly, nontoxic semiconductor silicon materials have attracted more attention. , Silicon nanoparticles (Si NPs), in contrast to bulk silicon, exhibit pronounced luminescence attributed to the quantum confinement effect and surface state, attributing significant promise for advancing silicon-based optoelectronics, photovoltaics, and biological imaging. , A typical bottom-up method for the synthesis of colloidal Si NPs has attracted much attention. Silicon nanocrystals were obtained by reduction growth reaction in the solvent with silane and strong reducing agent. − Since its inception by Zhong et al in 2013, an extensive of literature has been dedicated to this domain. − It is widely used in anticounterfeiting, optoelectronics, and biological imaging. − Nonetheless, a major problem in the field of Si NPs is the long-term controversy regarding the correlation between optical spectrum and the structure . Therefore, exploring the luminescence mechanism of Si NPs is of great significance for the development of silicon-based materials in the optical field.…”

Recent Advances in Silicon Quantum Dot-Based Fluorescent Biosensors

“…The SiQDs in this state have an optically physical characteristic similar to that of a direct bandgap semiconductor. For cubic SiQDs at a three-dimensional scale ( x , y , z ), the energy difference between electrons and holes can be approximated as the sum of the band gap energy of silicon ( E g ) and the energy contributions from the conduction and valence bands across the entire space of the confined cubical dimensions, as follows [ 11 , 12 ]: where d i is the length of the cubic SiQDs in the i th dimension, n is the quantum number, and m e is the effective mass of the conduction band electrons and m h the effective mass of the valence band holes. This confinement effect (when d i approaches the Bohr radius) causes the energy gap of silicon to widen, enhancing the radiation recombination of holes and electrons.…”