Figure 4.

Printed electronic tattoos of conductive traces. a) Aerosol jet printing of a conductive trace on a curved biological substrate (apple). b) Sheet resistance of printed traces on inorganic (solid line, glass) and biological (dashed line, leaf) substrates at 20°C (green) and 40°C (blue) at 1, 2, and 3 printing passes. Insert of a leaf with the Duke D printed in nanowire ink. c) Printed conductive circuit on an apple lighting up an LED. d) Conductive traces were printed on a finger and used to deliver power to an LED, which maintains illumination when the finger is bent (e) – see supplemental video for demonstration. f) Scotch tape adhesion test comparing the adhesion between a printed film of silver nanoparticles and silver nanowires, where the nanowires are significantly better adhered to the glass substrate.