title: Rapid electrostatics-assisted layer-by-layer assembly of near-infrared-active colloidal photonic crystals.
abstract: Here we report a rapid and scalable bottom-up technique for layer-by-layer (LBL) assembling near-infrared-active colloidal photonic crystals consisting of large (⩾1μm) silica microspheres. By combining a new electrostatics-assisted colloidal transferring approach with spontaneous colloidal crystallization at an air/water interface, we have demonstrated that the crystal transfer speed of traditional Langmuir-Blodgett-based colloidal assembly technologies can be enhanced by nearly 2 orders of magnitude. Importantly, the crystalline quality of the resultant photonic crystals is not compromised by this rapid colloidal assembly approach. They exhibit thickness-dependent near-infrared stop bands and well-defined Fabry-Perot fringes in the specular transmission and reflection spectra, which match well with the theoretical calculations using a scalar-wave approximation model and Fabry-Perot analysis. This simple yet scalable bottom-up technology can significantly improve the throughput in assembling large-area, multilayer colloidal crystals, which are of great technological importance in a variety of optical and non-optical applications ranging from all-optical integrated circuits to tissue engineering.
authors: Department of Chemical Engineering, University of Florida, Gainesville, FL 32611, United States.
authors: Khalid
authors: K
authors: Askar
authors: Department of Chemical Engineering, University of Florida, Gainesville, FL 32611, United States.
authors: Sin-Yen
authors: SY
authors: Leo
authors: Department of Chemical Engineering, University of Florida, Gainesville, FL 32611, United States.
authors: Can
authors: C
authors: Xu
authors: Department of Chemical Engineering, University of Florida, Gainesville, FL 32611, United States.
authors: Danielle
authors: D
authors: Liu
authors: Department of Chemical Engineering, University of Florida, Gainesville, FL 32611, United States. Electronic address: pjiang@che.ufl.edu.
authors: Peng
authors: P
authors: Jiang
keywords: Colloidal crystals; Electrostatics; Langmuir-Blodgett; Layer-by-layer; Photonic crystals; Self-assembly