Patterning Submicrometer Thick Inorganic Nanoparticle Films by Solution Process and Application for Light Trapping in Solar Cells

We present a low-cost fabrication process to deposit patterned inorganic nanoparticle films with submicrometer thickness and in turn to build higher dimensional structures through sequential multilayer deposition. Oxide nanoparticle films including semiconductors, dielectrics, and conductors have been patterned by moulding or imprinting from their solvent-suspension/paste using polydimethylsiloxane stamps. The easily controlled film thickness and good duplication fidelity with high resolution allows one to fabricate various layered structures, such as double layer and multilayer structures with minimized residual materials between them to finally define quasi-3D structures. Our experiment shows that colloidal suspension of materials can readily be patterned by stamping techniques with similar quality as compared to well-developed thermal or UV imprinting using solvent-free molecule-based materials. The usability of the fabricated structure is further demonstrated by integration of a 2-D grating on dye sensitized solar cell for improved power conversion efficiency.