Highly ordered and gap controllable two-dimensional non-close-packed colloidal crystals and plasmonic-photonic crystals with enhanced optical transmission

We present a facile one-step co-self-assembly method for the fabrication of two-dimensional (2D) non-close-packed (ncp) colloidal crystals (CCs) using polystyrene (PS) colloidal spheres and tetraethylorthosilicate (TEOS) sol. The resultant 2D ncp CCs demonstrated long-range ordering at the centimeter-scale without cracks due to the addition of TEOS sol. The inter-particle gap of the ncp CCs can be easily controlled by varying the amount of TEOS sol added during the assembly process. The crack-free 2D CCs were employed to form hybrid plasmonic-photonic crystals by depositing a thin film of gold. Experimental and simulated transmission spectra of the hybrid plasmonic-photonic crystals were found to be in good agreement. This simple and low-cost method provides a platform for the fabrication of high-quality 2D ncp CCs and may facilitate the development of various applications of ncp CCs.