Science & Technology: Printed electronics – Inks and the technical challenges

07
Oct
2011

Introduction

The inkjet printing of conductive materials has attracted much scientific and commercial interest in recent decades, with users finding the technical benefits of inkjet printing particularly persuasive in addition to its wide range of potential applications.

 

Printed electronics are in fact predicted to enjoy a significant market growth (up to 48.2 billion USD by 2017),1 a growth that will be spread over potential applications such as displays, photovoltaic, RFIDs, sensors, memories and printed circuit boards.1,2 In technical terms, inkjet printing – like alternative printing techniques – competes with conventional semiconductor technology (photolithography, vacuum deposition etc.) but it offers distinct advantages, especially in the manufacture of customised products or with flexible or sensitive substrates (contactless material application).1 The much lower initial machine costs, less maintenance and the sparing use of material and ink in drop-on-demand printing processes also greatly enhance the profitability of the manufacturing processes.3 Even so, inkjet printing has so far failed to become established in the electronics industry despite the increasing commercial availability of electrically conductive ink systems.

 

The aim of the present article therefore is to throw some critical light on the technical challenges facing the field of inkjet-printed electronics, and to a initiate a fundamental debate about electrically conductive inks, beginning with a description of the chemistry of some selected conductive inks and their sintering processes, and then considering technical problems involved in their practical use.

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