Digitalization, Industry 4.0 and particularly the »Internet of Things« (IoT) count as significant growth markets. It is expected that in 2020, two-digit billions of »Things«, i. e. sensors as well as general devices and components of consumer electronics, will be connected with each other via the Internet. These all have to be supplied with energy at the lowest possible cost. This can be done by »energy harvesting«, among other approaches. Small amounts of energy from movement or heat are gathered, or primarily photovoltaic energy conversion of ambient lighting is applied.