Cover Picture: Development of Lab‐to‐Fab Production Equipment Across Several Length Scales for Printed Energy Technologies, Including Solar Cells (Energy Technol. 4/2015)

Scaling across orders of magnitude: The cover image illustrates how the size of equipment increases upon scaling up polymer solar cell manufacturing using coating and printing techniques from the small laboratory scale to pilot scale, as reviewed in article on from the Technical University of Denmark. The illustration applies generally to all printed energy technologies and shows how you have to transcend from hand-sized to human-sized, increasing the capital investment, running cost, operating cost. and risk. The chain of equipment illustrated, if used progressively by growing scale one step at a time, is an efficient means to manage risk and also to carry out the process development needed during scaling. The step from the spin coater or laboratory coater (not shown) to the microscale roll-to-roll coater or the mini roll coater is already very large in terms of processed area by a factor of several hundred; moving further up in scale quickly implies that one has to bridge the gap in scales by many orders of magnitude in terms of processed area per time. Once the scale is reached one is in a position where enormous output at low cost is granted and this applies to printed light emitters, printed energy storage, or printed energy harvesting; it is all in the approach. In this Special Issue on printed energy technologies, each of these topics and more are addressed among the contributions from the many of the leading groups in the field.