High throughput manufacture of colloidal crystal monolayers with optimisable crystallinity

Abstract The unique optical and structural properties of colloidal crystal monolayers offer great potential for integration into batteries, solar panels, and sensors. However, commercial adoption is limited by manufacturing challenges. Conventional methods such as Langmuir-Blodgett deposition, spin coating, and drop casting are batch processes and are intrinsically slow. In this context we demonstrate that roll-to-roll slot die coating is a scalable, reproducible, and high throughput alternative for continuous manufacture of colloidal crystals. By using multi-scale characterisation tools to quantify long range order, we show that roll-to-roll slot die coating can produce hexagonal close packed crystalline colloid domains with long range order that can be varied via control of the substrate velocity. This tuneability offers a route to adjust material properties for specific functional applications that is compatible with self-optimising and closed loop control approaches. Slot die coating consequently has the potential to radically improve 2D colloidal crystal fabrication speed and repeatability and consequently unlock new opportunities for advanced device manufacture.