Innovative industrial-scale manufacturing processes

The Industrial solar cells research group develops innovative, mass-production-compatible manufacturing processes for the next generation of silicon solar cells in the areas of PECVD coating, wet chemistry, and screen-print metallization.

A key focus is the PECVD deposition of doped polycrystalline silicon (POLO) – a process that enables excellent surface passivation and low series resistance while maintaining high industrial compatibility. This work lays the foundation for durable and high-performance solar cells that can be efficiently integrated into existing production lines.

High-efficiency POLO IBC solar cells

As part of ongoing research projects in cooperation with equipment manufacturers and solar cell producers, the POLO IBC cell (Interdigitated Back Contact) is being further developed as a promising cell concept for future PV applications, with a focus on higher efficiencies and cost-effective manufacturing processes.

The POLO IBC cell places all contacts on the rear side, minimizing optical losses on the front and improving the cell's current output. The aim is to achieve maximum efficiency with cost-effective fabrication. To this end, we are developing new manufacturing techniques for the low-cost structuring of poly-Si layers using laser ablation or shadow masks. The goal is to scale POLO IBC technology to an industrial level in terms of scalability, throughput, and long-term reliability.

Industry partnerships

In addition to publicly funded projects, the group is also engaged in bilateral industrial collaborations. Together with partners from the PV industry, new IBC solar cell concepts are being developed for specific production environments – covering the entire process from process development to cell characterization.

Close-up of a solar cell
Glass shadow mask and behind it the silicon wafer with local poly-Si coating through the glass mask.
Graphic to visualize the manufacturing process
Lean process flow for the production of POLO IBC solar cells using PECVD deposition with shadow masks, which utilizes many process steps from current PERC+ production.

Projects

Projects related to this topic.
Photovoltaics
Fabrication and custom manufacturing

Batman

Novel wet-chemical batch processes for future industrial silicon solar cells

duration: May 01, 2024 – Oct 31, 2026
Photovoltaics
Fabrication and custom manufacturing

M12PV

M12 photovoltaic research infrastructure as a contribution to technological leadership in the production of silicon solar cells

duration: Mar 01, 2024 – Feb 29, 2028
Photovoltaics
Silicon solar cells and PV modules

OLIVIA

High-performance, cost-effective IBC solar cells for future PV production in Germany

duration: Mar 01, 2024 – Aug 31, 2026
Photovoltaics
Silicon solar cells and PV modules

IBC4EU

Piloting novel cost-competitive bifacial IBC technology for vertical integrated European GW scale PV production value chain

duration: Nov 01, 2022 – Oct 31, 2025
Photovoltaics
Silicon solar cells and PV modules

POPEI

Production technologies for high-performance cost-effective IBC solar cells

duration: May 01, 2021 – Sep 30, 2023
Photovoltaics

2Power

Installation of a laboratory for Si-perovskite tandem solar cells

duration: Nov 01, 2020 – Jul 31, 2023
Photovoltaics
Silicon solar cells and PV modules

HiPER-Ni

Highly efficient nickel-contacted Ag-free POLO2-IBC solar cells

duration: Dec 01, 2025 – Nov 30, 2028
Photovoltaics
Silicon solar cells and PV modules

IBCinD -Innovative and cost-effective process technologies for high-efficiency POLO2 IBC cells for production in Germany

In the IBCinD project, ISFH is developing an industrial process for high-efficiency POLO2 IBC solar cells. The goal is to achieve 26.0% efficiency using innovative coating and structuring technologies, alongside a completely silver-free, cost-effective metallization and interconnection.

duration: Feb 01, 2026 – Mar 31, 2026

Publications

Publications related to this topic.
2023

Towards high-efficiency POLO IBC solar cells based on a PERC+ processing technology

Dullweber, T. and Mertens, V. and Stöhr, M. and Langlois, J. and Mettner, L. and Baumann, U. and Haase, F. and Brendel, R. and Libal, J. and Vogt, A. and Ambrosius, N. and Pernau, T. and Haverkamp, H.
2021

Firing-Stable PECVD SiOxNy/n-Poly-Si Surface Passivation for Silicon Solar Cells

Stöhr, M. and Aprojanz, J. and Brendel, R. and Dullweber, T.
2021

A Detailed Chemical Model for the Diffusion of Phosphorus Into the Silicon Wafer During POCl3 Diffusion

Jäger, P. and Mertens, V. and Baumann, U. and Dullweber, T.
2020

Industrial PERC+ solar cell efficiency projection towards 24%

Dullweber, T. and Stöhr, M. and Kruse, C. and Haase, F. and Beier, B. and Jäger, P. and Mertens, V. and Peibst, R. and Brendel, R.
2020

Evolutionary PERC+ solar cell efficiency projection towards 24% evaluating shadow-mask-deposited poly-Si fingers below the Ag front contact as next improvement step

Dullweber, T. and Stöhr, M. and Kruse, C. and Haase, F. and Rudolph, M. and Beier, B. and Jäger, P. and Mertens, V. and Peibst, R. and Brendel, R.
2025

Industrial implementation of 24%-efficient POLO IBC solar cells and future upgrade to 26%-efficient POLO 2 IBC

Dullweber, Thorsten and Larionova, Yevgeniya and Jäger, Philip and Mertens, Verena and Schimanke, Sabrina and Ripke, Melanie and Baumann, Ulrike and Osman, Alaa and Römer, Udo and Peibst, Robby and Brendel, Rolf and Cokun, Özlem and Çekerek, Gamze and ÇaliArslan, Meri((̧c and Gregory, Geoffrey and Hoffmann, Erik and Centazzo, Massimo

Contact person

Dr. Thorsten Dullweber

Head of PV department: Infrastructure

+49(0)5151-999 642