Electrochemical grafting of poly(3‐hexylthiophene) on porous silicon for gas sensing

Abstract

The paper reports on the preparation of a porous silicon (PSi)/poly(3-hexylthiophene) hybrid structure and its application in gas sensing. The poly(3-hexylthiophene) was covalently grafted on the PSi surface in a stepwise process. Electropolymerizable thiophene groups were covalently linked to an azide-terminated PSi surface using 'click chemistry' approach. Poly(3-hexylthiophene) films were grown on the thiophene-terminated PSi interface using electropolymerization in acetonitrile in the presence of 3-hexylthiophene monomer.Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM) and electrochemical measurements were performed to follow the chemical composition and structural changes after each step.The sensitivity, response time and capacitance response of the device to gas environment have been investigated. The results show that current-voltage characteristics are modified by the presence of the gas, and the sensor displays a rapid and reversible response at room temperature.

Microwave irradiated click reactions on silicon surfaces via derivertization of covalently grafted poly(PEGMA) brushes

“…Reported here is the surface click chemistry with branched azides or acetylenes on poly(poly(ethylene glycol)monomethacrylate) brushes grafted with robust SiAC links on planar silicon surfaces (Si-g-P(PEGMAAOH)). The Si-g-P(PEG-MAAOH) brushes not only provide a biofouling-repellence background for biomedical applications [31,32], but also increase the density of surface azide or acetylene greatly [33], compared to molecular monolayers [34][35][36]. Their surface click chemistry was investigated with several model organic compounds.…”

Mesoporous Silicon/Polypyrrole Based Structures for Paranitrophenol Sensing

“…After the surface oxidation, the infrared spectra con rm the signi cant oxidation of the PSi surface as it is indicated by the decrease of υSi-Hx and δSiHx bands [17]. An important vibration band of the Si-O bond containing the symmetric and antisymmetric mode stretching vibration of the Si-O-Si bond at 1107cm -1 and 1163 cm -1 , respectively [18], and the SiO2 stretching vibration at 1147 cm -1 . We note again the appearance of a broad absorption between 3480 and 2900 cm −1 due to terminal hydroxyl groups (Si OH) and likely to adsorbed water molecules.…”

Porous silicon gas sensors

“…The detection of toxins, volatile organic compounds, polycyclic aromatic hydrocarbons, and explosives on the level of at least a few ppb was demonstrated using stacked PSi photonic crystals, multilayer structures, and distributed Bragg refl ector structured PSi (Ruminski et al ., 2008;Park et al ., 2010;Kelly et al ., 2011;Kim et al ., 2011). PSi layers with embedded metal oxides, as well as PSi-polymer hybrid structures, have recently been proposed for gas-sensing applications (Belhousse et al ., 2010;Bolotov et al ., 2011;Moshnikov et al ., 2012).…”