Fig. 3: Template-assisted droplet network fabrication and output.

a,b, Preparation of a large-scale patterned power source network. First, seven droplets were deposited in a mould, by using a programmable microinjector, and formed a hexagonal ‘flower-like’ structure (a). Droplet networks can be drawn into a truncated pipette tip by capillary action and arranged in three dimensions. Hexagonal assemblies of droplets were layered to form larger droplet networks (b). n refers to the number of units. c, Bright-field images of a mould with multiple droplet hexagons. The volume of each droplet was about 4 nl. Scale bar, 600 μm. d, Zoom-in of a single hexagonal layer. Scale bar, 200 μm. e, Stacks of 7 and 28 power units. Scale bar, 600 μm. f, After four-step sequential deposition into a spiral mould, droplets self-assembled into a chain of power units (Methods). g,h, Twenty power units were connected (g; scale bar, 1.2 mm) to generate an output voltage sufficient to light up a red light-emitting diode (h).