An evaporative co-assembly method for highly ordered inverse opal films

Colloidal self-assembly holds promise for photonic applications as a solution-based, low-cost alternative to top-down photolithography, if significant control of uniformity and defects can be achieved. Herein we demonstrate a new evaporative co-assembly method for highly-uniform inverse opal thin films that involves the self-assembly of polymer colloids in a solution containing a silicate precursor. Nanoporous inverse opal films can be made crack-free and with highly uniform orientation at the cm scale. The silicate between the colloids appears to increase the strength against cracking. This control of defects makes this method well-suited for the low cost fabrication of such films as sensors and photonic devices.