Conductive Inks

ay from printed circuit boards (PCBs) that used copper containing thick- lm pastes on rigid substrates, which were patterned using a two-step masking and etching process. This process resulted in a surfeit of waste and was expensive due to laborintensive processing of the nal device. By contrast, conductive inks are now available that use existing printing technologies such as screen, gravure, exographic, offset, and inkjet to print conductive traces directly onto rigid and exible substrates relatively cheaply. Much of the impetus for advancements in conductive inks has come from the eld of organic electronics, where the promise of fully printed electronic devices and displays requires printable conductors for contacts and signal bus lines. Printed electronics is experiencing explosive growth, as it provides the microelectronics industry a low-cost fabrication route compared to etched circuits for consumer electronics and similar applications. At the same time, it represents a highvalue opportunity for the printing industry during a period of decline in print media created by the advent of electronic media. In fact, it allows the printing industry to continue to play a role in these emerging technologies, such as electronic book readers, by printing functional components onto exible substrates.

The process of printing conductive ink is used to produce active and passive components such as transistors, resistors, capacitors, diodes, and even complete circuits such as RFID tags, keypads, sensors, and electrodes, as well as backplanes of organic light-emitting diodes (OLEDs) and other electroluminescent displays. End-use applications for printed electronics include medical devices, photovoltaics, smart packaging, exible displays, RFID labels, energy storage, and active clothing. In general, printed electronic circuits have lower performance characteristics and lifetimes than etched circuits, but they also have a signi cantly lower cost. However, they still remain