Soft lithography contacts to organics

Organic materials play an increasingly important role in (opto)electronics, particularly in low-cost or flexible devices. A major challenge is the contact between the electrodes and the organic material. Processes developed for inorganic semiconductors are inapplicable because of the sensitivity of organic materials to heat, radiation, and chemicals. Deposition of metal(s) through shadow masks onto organic materials is commonly used, despite problems with ill-controlled interfaces and material damage. In addition, conventional approaches restrict device size to >1 µm. Clearly, a better technique is needed. In this article, two soft lithography methods for making contacts to organic materials are reviewed: nanotransfer printing (nTP) and soft-contact lamination (ScL). These new approaches produce devices that outperform those made by conventional methods. The link between better device performance and better interfacial control is explained, and nanoscale devices are described.