Surfaces are fascinating places, where molecules adsorb or desorb, reactions are catalyzed, and redox reactions take place. Accurately positioning molecules on surface is crucial for the development of molecular electronics and advanced devices utilizing nanomaterials and functional monolayers.

In this work, we combined a digital micromirror device (DMD) with a light source and an inverted microscope, to project arbitrary light patterns on a surface. The light catalyzed a click reaction between thiols on the surface, and alkyne on molecules in solution, causing the molecules to covalently bind to the surface. In this fashion, we are able to photopattern arbitrary images of fluorescent dyes and other molecules, such as biotin. We control the surface density of the dye by tuning the dose of light received at each pixel. An important advance in this work is the use of an alternative material for coating the surface with thiols – instead of the common mercaptotrimethoxysilane, we used mercaptosilatrane, which provided higher pattern quality with far fewer defects (Mitmoen and Kedem, ACS Appl. Mater. Interfaces, 2022, 14, 32696−32705).