Research project APOLON

Investor-oriented development of POLO technology for local PV production

Currently, Germany covers its demand for solar modules almost entirely from imports. However, several strategic, geopolitical and ecological aspects lead us to expect a willingness to invest in the resumption of domestic PV production in the coming years. The task of the APOLON project is to show potential investors a competitive technology concept for the implementation of PV production in Germany and the European Union. The basis for this is POLO (poly-Si on Oxide) technology, whose strengths include very high efficiencies and the avoidance of rare materials.

Research project APOLON



February 2023 to January 2026

Funded by

Federal Ministry for Economic Affairs and Climate Action

Project participants

  • Institute for Solar Energy Research in Hameln (ISFH)
  • Institute of Networked Energy Systems
  • LPKF SolarQuipment GmbH
  • centrotherm international AG

With the aim of demonstrating a positively assessable technology concept for the implementation of PV production in the EU, the APOLON research project (funded by the Federal Ministry for Economic Affairs and Climate Action) is addressing several critical developments at once. For example, in the current market situation, in addition to supply bottlenecks, the danger of political pressure from PV supplier countries and the threat of additional costs for companies when using products from non-compliant production as a result of the Supply Chain Act cannot be ruled out.

Schematic view of a POLO back junction solar cell. A novel feature is the use of a passivating contact made of polysilicon on silicon oxide (POLO) on the back of the cell.

Byungsul Min

The POLO technology is suitable for implementing this project not only because of its close technological proximity to the leading, highly tested and cost-efficient PERC+ technology, but also because it is expected to be its successor technology according to analyses by the Institute for Solar Energy Research (ISFH), which is involved in the project. Against this background, a technology concept for the implementation of PV production in the EU that can be positively evaluated from the perspective of future European investors should be available by the end of the project term.

Specifically, this involves, among other things, demonstrating a module efficiency of 23 % with POLO technology, which is significantly more efficient than today's mainstream PERC technology. Once an investment decision has been made, it should be possible to implement this in pilot production within one year on systems that have been tested for mass production. In addition, new plants and processes are to be developed in advance of an upgrade technology for reduced costs and environmental impact in the medium term (compared to the basic technology that can be implemented in the short term).

In the APOLON research project, the Institute of Networked Energy Systems is mainly concerned with the ecological and economic evaluation of these new production processes, which have hardly been studied so far. For this purpose, the POLO technologies and their production processes are evaluated using Life Cycle Assessment (LCA) and Life Cycle Cost Analysis (LCCA) from an economic and ecological point of view. These results will be compared to the currently dominant PERC+ technology in order to be able to determine and quantify, for example, production costs, electricity production costs and environmental impacts depending on the manufacturing processes.

In addition, the analyses carried out can contribute to the identification of opportunities for improvement and optimisation of the POLO technology. On the one hand, this will provide a clearer perspective of the economic and ecological impacts of this technology, and on the other hand, it will pave the way for the local production of POLO-based photovoltaic modules as well as for future investments.