Impact of the chemical nature and position of spacers on controlling the optical properties of silicon quantum dots

Abstract

Nature and length of the spacer as well as the position of the connection played a key role in controlling the optical properties of Silicon Quantum Dots (SQDs) by controlling both type and rate of interaction between the SQDs and dye capping agent.

Benzoyl isothiocyanate modified surface of silica gel as the extraction material for adsorbing steroid hormones in water

“…The deconvoluted peaks of N 1s for the modified silica gel appeared at 400.1 eV, which can be assigned to isothioamides (–NCS). 36 The XPS results were consistent with the FT-IR and TGA data; hence, benzoyl isothiocyanate was successfully grafted onto the silica gel surface.…”

“…The stretching vibration of Si-O of the original silica gel was at 1058 cm −1 . 36 The Si-O-C of the modi-ed silica gel exhibited stretching vibration at 1058 cm −1 , C]C in the phenyl group exhibited bimodal stretching vibration at 1600-1500 cm −1 , 713 cm −1 , and 663 cm −1 , and C]S exhibited stretching vibration at 1390 cm −1 and 1080 cm −1 . 37 The above points conrmed the successful reaction of the silica gel with benzoyl isothiocyanate.…”

Silicon Quantum Dots: Synthesis, Encapsulation, and Application in Light-Emitting Diodes

“…The hydrothermal decomposition of organosilicates such as N-[3-(trimethoxysilyl)propyl]-ethylenediamine (DAMO), 3-aminopropyl triethoxysilane (APTES), or 3-aminopropyl trimethoxysilane (APTMS), in the presence of reducing agents such as LiAlH 4 , sodium citrate, NaBH 4 , and thiourea affords Si QDs (Dasog et al, 2012;Lopez-Delgado et al, 2017;Liu et al, 2018b;Phan et al, 2018;Yi et al, 2019). By varying the reaction time, temperature, and the nature of reducing agent and of the precursor, nanocrystals with QY 65-85% can be synthesized (Ma et al, 2018;Abdelhameed et al, 2019). It is also possible to synthesize SiQDs by the thermal decomposition either of silicon monoxide (SiO) powder heated to 1,350 • C (Lu et al, 2017) or of other precursors, such as silsequioxanes, followed by etching and hydrosilylation (Yu et al, 2017).…”