Gas sensing of silica photonic crystals for binary gases

In this paper, different types of binary gases were detected by the silica photonic crystals (PCs). It is found that the regulation of gas sensing is very different when silica PCs exposure to different types of binary gases. Here, silica PCs were prepared by the vertical deposition method. The performance of gas sensing was monitored by the shift of photonic band gap (PBG) of PCs. It is noteworthy that we convert the shift of PBG into the volume fraction of adsorption in order to investigate the adsorption behavior. For small-molecule gases, the maximum of adsorption volume fraction of binary gases is smaller than two of the single gases. While for volatile organic compounds (VOCs), the maximum of adsorption volume fraction of binary gases locates between the two individual gases. The different types of gases follow different adsorption model, which are discussed in this work.