Photolithographically-Patterned Electroactive Films and Electrochemically Modulated Diffraction Gratings

This manuscript presents an overview of work directed toward the creation of arbitrary micron-scale patterns of electroactive polymer films by the application of photolithography. A brief overview of work by other groups in the field is followed by a detailed description of work from our own labs which resulted in the development of methods to pattern a variety of different electroactive materials, including Ru− and Os−polypyridine complexes, viologen-based polymers, and a low-potential polythiophene. The discussion provides detail on the photolithographic methodology. In addition, the spatially-patterned films are characterized by using optical and scanning electron microscopy. The voltammetric and spectroelectrochemical properties of several of the lithographically-patterned films are also presented. Finally, photolithography is applied to fabricate electrochromic optical diffraction gratings. The diffraction efficiency of these electroactive gratings can be modulated by an electrochemical stimulus. The properties and mechanism for operation of the electrochromic gratings are described.