Multi-layered nanoscale cellulose/CuInS sandwich type thin films.

A generic procedure for the manufacturing of cellulose-metal sulfide multilayered sandwich type thin films is demonstrated at the example of copper indium sulfide. These multilayers were created by alternate spin coating steps of precursors, followed by their conversion using either acidic vapors, or heat treatment. As precursors, cellulose xanthate, a widely available cellulose derivative employed in viscose fiber manufacturing and commercial copper and indium xanthates were used. After conversion of the single layers into cellulose and copper indium sulfide, the film properties (structure, thickness, photoelectric activity) of the single and multilayer systems consisting of alternate layers of cellulose and copper indium sulfide were studied. For the proof of concept, up to five layers were built up, showing a clear separation of the cellulose and the metal sulfide layers as demonstrated using cross sectional analysis using ion slope beam cutting and SEM imaging. Finally, the conversion of xanthates was performed using UV light and a mask, allowing for the creation of 2D patterns.