Dynamic reflection of colloidal assembly for photonic sensing and detection

Colloidal photonic crystal sensors have attracted more and more interests in the chemical analysis, environmental monitoring, and biomedical investigations. However, there are still many challenges for the practical application, which requires either the innovations in photonic crystal materials or improvement of analytic methods. Here, we are going to introduce a new technique, that is dynamic reflection spectra (DRS), which is applied to improve the performance and extend the scope of application for PC sensors. Using time-resolved dynamic reflection spectra of SiO2/PEGMA/EG photonic crystal gel, one can judge the type of solvent molecules loaded to the gel according to the geometric characteristics of the DRS pattern. With the help of time-resolved dynamic reflection spectra of SiO2 PC, one can determine the liquid viscosity according to the infiltration time (color change time) for the PC sensor. In the PC based thin layer chromatography, one use spatial-resolved dynamic reflection spectra to precisely determine the location of sample spots, especially for chemicals with lower concentrations, which significantly improves the accuracy for the determination of retention factor (Rf) values. It is believed that the dynamic reflection spectra will play an important role in the photonic sensing, as it fully taps the potential of sensing material and provides abundant information to realize the accurate sensing.