Directly imprinted laser feedback structures in electroactive conjugated polymers using soft lithography

Abstract

A fundamental aim in organic electronics is an implementation of a polymeric laser diode. For this purpose, an essential step towards this goal is the understanding and fabrication of feedback structures for conjugated polymer lasers. In this work we will present the realization and characterization of a directly imprinted distributed feedback structure into a highly luminescent conjugated polymer, poly(2-methoxy-5(2-ethyl-hexyloxy)-1,4-phenylevevinylene, which was utilized as a model polymer for conjugated laser materials. The presented method permits to directly imprint a distributed feedback grating into the conjugated polymer. Such distributed feedback structures may be fabricated either in the substrate or in the active polymer layer itself. Therefore we chose two accomplished techniques from soft lithography, which has proven itself as a useful tool to pattern a wide variety of materials. By the combination of these two techniques, namely micrmolding in capillaries and liquid embossing, we created a novel technique. We called this new technique liquid imprinting. Under photo-excitation of a frequency doubled Nd:YAG laser, our corrugated distributed feedback structures showed lasing. Because of the inexpensiveness and repeatability, this approach is a very promising candidate for the mass production of conjugated polymer laser devices.