Kesterite based monograin photovoltaics: The ideal solution for sustainable power supply

Whereas the growth of PV installations is well under way in highly developed countries mainly by installing highly efficient monocrystalline silicon modules in larger and larger PV installations, the progress of electrification especially in cities as well as in poor countries providing access to electricity grids stays far behind the targets agreed on when accepting the UN Sustainable Development Goals (SDGs). Still more than 40% of the world population (3 billion people) have no possibility to use clean fuels and technologies for clean cooking. Low cost decentralized and flexible PV may provide a fast solution allowing also to harvest solar energy from building facades and on rooftops in densely populated regions as well as on tents or provisional shelters if needed. Here the monograin technology offers a versatile solution allowing for very low-cost local printing of very high quality single crystalline earth abundant solar powders as well as complete recycling of valuable materials in a circular economy. We here report the latest progress of this technology based on Kesterite materials. The outline of a completely vacuum-free printing process for the solar cell powder as well as for all contact materials will be shown, currently being set up as a prototype in our lab. As has been demonstrated already for most of the process steps, also commercially available printing lines as used in screen printing e.g., for traffic signs can directly be used. The design for a circular (cradle-to-cradle) economy makes it the currently only PV technology fully sustainable with very low material losses and energy input. The main commercial advantage is the possibility to produce already in relatively small scale (MWp/a) for very low costs, so that this technology is especially suitable also for developing countries interested in decentralized power production in remote areas.