Kalyon PV evaluated POLO IBC development within the IBC4EU project using its fully integrated industrial manufacturing infrastructure
The company demonstrated compatibility between POLO IBC processing and existing PERC production lines with minimal additional equipment
Thinner 130 µm wafers, industrial-scale cell processing, and outdoor module validation highlighted the scale-up potential of back-contact technology
The PV industry’s transition path beyond TOPCon is becoming increasingly important as manufacturers seek higher-efficiency architectures without having to rebuild their production infrastructure. One leading candidate is back-contact (BC) technology, where the focus is now shifting from laboratory-scale efficiency demonstrations toward industrial feasibility. This includes compatibility with existing production lines, yield management, throughput, and process integration.
At the TaiyangNews High in Efficiency, Low In Silver: Back Contact Technology From Europe webinar, held in April 2026, Özlem Coşkun, R&D Executive – PV Technologies and Applications at Kalyon PV, discussed the industrial perspective on BC technology within the IBC4EU project. Rather than focusing only on efficiency records, the presentation addressed what these developments mean in a real manufacturing environment. It also explored how BC technologies can be integrated into current production ecosystems.
Kalyon PV operates as a fully integrated solar manufacturer in Ankara, Türkiye, producing ingots, wafers, cells, and modules under the same roof. According to Coşkun, this structure allows new technologies to be evaluated directly under industrial production conditions rather than only at laboratory scale. The company’s roadmap has evolved from G1 PERC production in 2020 to M10 PERC, and then to TOPCon module manufacturing in 2023. Most recently, Kalyon PV established a new G12R TOPCon+ production line.
The company sees BC technology as a logical continuation of this evolution. Coşkun described advanced BC architectures as ‘one step away from TOPCon’ due to their efficiency potential and reduced shading losses. Within the IBC4EU project, the consortium is working on 2 advanced BC concepts: p-type POLO IBC and n-type PolyZebra structures.
A major focus of the work involved evaluating compatibility with existing production infrastructure. Kalyon PV produced gallium-doped Czochralski ingots and wafers optimized for POLO IBC applications. She said the company worked across a wide resistivity range of 0.7-4.8 Ω·cm and identified an optimized range of around 1-2 Ω·cm for POLO IBC. Minority carrier lifetime values reached up to around 3 ms, indicating strong starting material quality for high-efficiency IBC cells.
Wafer studies focused on reducing material consumption without compromising quality. The company reduced wafer thickness from 175 µm to 130 µm while maintaining controlled total thickness variation (TTV) and low breakage rates. Optimized slicing parameters reduced kerf losses, while tungsten diamond wire demonstrated cutting quality comparable to conventional solutions. These developments improve material utilization and lower the production cost per wafer.
On the cell side, Kalyon PV evaluated POLO IBC integration on p-type industrial wafers using modified PERC process flows. The work included cross-experimental studies on texturing, cleaning, and passivation, as well as the optimization of AlOx/SiNx and poly-Si passivating contacts. Industrial-size M10 cell designs were also developed in collaboration with ISFH. The studies demonstrated that scalable POLO IBC production can be achieved using industrially compatible process flows.
The comparison between PERC and POLO IBC process sequences showed that several conventional PERC steps are no longer required. These include phosphorus diffusion, co-diffusion, selective emitter formation, and front-side silicon nitride passivation. At the same time, BC structures introduce additional complexity in rear-side passivation and metallization. This shifts the focus of the process toward alignment precision, passivation quality, and automation control.
Module-level validation was also carried out under outdoor operating conditions in Ankara. The testing platform included 3 IBC module types, along with a reference PERC module. Performance monitoring under real operating conditions allowed the consortium to evaluate industrial applicability at module level and assess how process improvements translate into field performance.
Several industrial challenges remain. Coşkun highlighted yield sensitivity, particularly when working with thinner wafers, as well as throughput impacts from additional process steps. Automation and process control requirements also become more demanding in BC manufacturing due to the metallization architecture and alignment sensitivity. Despite these challenges, the overall outlook was positive, with strong compatibility observed between POLO IBC and existing PERC infrastructure.
Coşkun also touched on the broader industrial transition path. He said that the move from PERC to TOPCon is comparatively straightforward, requiring mainly additional process steps. The shift to BC technologies, however, is more complex due to the specialized metallization design and tighter automation requirements. However, she described the pathway as feasible for industrial-scale manufacturers and emphasized that BC technology is no longer only a high-efficiency concept but a realistic industrial production pathway.
Alongside industrial manufacturing, Kalyon PV continues to expand its R&D activities in advanced PV technologies. The company’s R&D center includes more than 100 personnel, indoor and outdoor testing infrastructure, and participation in multiple international projects covering BC, tandem, perovskite, agrivoltaics, recycling, and Industry 4.0 applications. According to the company, this infrastructure supports development from material level through module and system validation.
Access Kalyon PV’s full presentation here.