NATURE MATERIALS | ADVANCE ONLINE PUBLICATION | www.nature.com/naturematerials 1

news & views Skin is a large, flexible and robust organ that covers and protects the body from external damage. At the same time it has an important sensory role, it is the attachment site for touch, pain and thermoreceptors. This multifunctional biological model is inspiring the development of electronic equivalents — referred to as ‘electronic skin ’ — consisting of large-area networks of sensors that detect pressure, temperature and other environmental stimuli, and are usually realized on pliable or stretchable substrates. These devices have been proposed as advanced biomimetic prostheses and diagnostic tools, as well as a means to provide robots with sensory perceptions, an ambitious technological goal that brings to mind the ‘machine-human ’ in the science-fiction movie Metropolis or the sentient android Data in Star Trek. Engineers and materials scientists are working on the functional complexity of these sensors — adding data processing and actuation capabilities — and on their mechanical properties, aiming to realize devices that conformably adapt to the skin and ensure a reduced risk of tissue reaction or alteration of the normal biological functions. Writing in Nature Materials, two independent groups now report the fabrication of electronic skins that complement sensing tasks with added functionalities: Ali Javey and co-workers report a flexible touch sensor with integrated output capabilities1 and John Rogers and colleagues describe an array of thermal sensors and heaters that enable full thermal characterization of human skin with an accuracy that is unavailable with other methods at present2. Javey and collaborators1 developed a sophisticated electronic skin that is able to detect pressure stimuli, the intensity of which are simultaneously displayed on an integrated array of organic light-emitting diodes (OLEDs). Each pixel of this electronic skin consists of a pressure sensor and a thin-film transistor that controls the current driving a coloured OLED. It is noteworthy that this complex architecture, comprising materials rather unconventional for the electronics industry, such as carbon nanotubes, organic semiconductors and carbon nanoparticles, can be attained on large areas and with high yield using conventional microfabrication processes