Patterning Complex Line Motifs in Thin Films Using Immersion-Controlled Reaction-Diffusion.

Abstract

The discovery of self-organization principles that enable scalable routes toward complex functional materials has proven to be a persistent challenge. Here, reaction-diffusion driven, immersion-controlled patterning (R-DIP) is introduced, a self-organization strategy using immersion-controlled reaction-diffusion for targeted line patterning in thin films. By modulating immersion speeds, the movement of a reaction-diffusion front over gel films is controlled, which induces precipitation of highly uniform lines at the reaction front. A balance between the immersion speed and diffusion provides both hands-on tunability of the line spacing ( <math xmlns="http://www.w3.org/1998/Math/MathML"> <semantics><mrow><mi>d</mi> <mo>=</mo> <mn>10</mn> <mo>-</mo> <mn>300</mn> <mspace></mspace> <mi>μ</mi> <mi>m</mi></mrow> <annotation>$d = 10-300 \; \umu \text{m}$</annotation></semantics> </math> ) as well as error-correction against defects. This immersion-driven patterning strategy is widely applicable, which is demonstrated by producing line patterns of silver/silver oxide nanoparticles, silver chromate, silver dichromate, and lead carbonate. Through combinatorial stacking of different line patterns, hybrid materials with multi-dimensional patterns such as square-, diamond-, rectangle-, and triangle-shaped motifs are fabricated. The functionality potential and scalability is demonstrated by producing both wafer-scale diffraction gratings with user-defined features as well as an opto-mechanical sensor based on Moiré patterning.