Enhancement of sensitivity of silica photonic crystals to carbon dioxide by APTES modification

The photonic band gap (PBG) of photonic crystals (PCs) has been proven to move in different gas atmospheres. According to this characteristic, silica PCs were used for the detection of different gases with low concentrations from 1 ppb to 100 ppm in our previous work. (3-aminopropyl)-triethoxysilane (APTES) was used as a modifier for the surface modification of SiO2 colloidal spheres, and the amino groups were grafted onto the surface of the colloidal spheres by chemical grafting. In this work, the influence of modifier dosage on gas sensitivity and optical properties was discussed. The results suggest that the PCs modified with APTES has improved the gas-sensitivity of CO2. It was worth noting that the PCs before and after modification have different adsorption behaviors under single gas and mixed gas atmospheres.