Fabrication and PBG modification of gradient colloidal photonic crystal

Colloidal photonic crystals with controllable layers were fabricated by improved convective self-assembly method, and isotropic O₂ plasma etching was used to construct gradient structure. The gradient(along the surface normal) could be controlled by plasma treatment, leading to a wider tuning range of the stop band compared with colloidal photonic crystals without gradient. The photonic band gap(PBG) of the gradient colloidal photonic crystal was modified through controllable deposition of gold and amorphous silicon. Furthermore, a fluorescent molecule(Rhodamine B) was penetrated into the interstice of gradient colloidal crystals, and it exhibited an 8.6-fold enhancement of fluorescence emission. According to the tunable optical property of gradient colloidal photonic crystals(GCPCs), they could be used in fields such as photonics, catalysis and life science.