New project: advancing copper-based solar cells with ultra-barrier spatial ALD films

Kalpana Systems and TU Delft have launched a new collaboration to accelerate the transition to copper-based metallization in solar cells, supported by the Dutch RVO EKOO: Electricity subsidy programme. The CAPSUL project focuses on the encapsulation of flexible and lightweight solar cells where scarce, costly silver is replaced with copper. Project results are expected in 2030. 

Why copper metallization matters for the future of solar energy  

With demand for solar energy growing globally, the industry faces a critical challenge: reducing dependence on scarce and costly silver. Traditional solar cells rely heavily on silver for metallization, but the availability and costs of this material pose a barrier to further scaling.  

The shift towards copper-based metallization is both economically and strategically essential. However, copper requires effective encapsulation to prevent degradation from moisture and oxygen exposure. 

The CAPSUL solution: spatial ALD barrier films for lightweight solar panels 

The CAPSUL Project aims to solve this challenge by developing ultra-barrier aluminium oxide coatings on PET films, produced through our patented roll-to-roll spatial Atomic Layer Deposition (sALD) technology. These coatings will serve as a protective layer for the copper metallization used in lightweight, circular solar panels.  

These flexible films provide high-performance encapsulation for copper metallization. Besides protection against moisture, UV radiation, and fire hazards, it also enables new applications in building-integrated and portable solar energy solutions. 

Dive into the different applications of spatial ALD for solar PV 

Key benefits 

• Improved durability: Aluminium oxide barrier coatings significantly enhance resistance to moisture, UV exposure, and thermal degradation. 

• Lightweight and flexible modules: The encapsulation architecture supports emerging applications, including building-integrated PV, portable solar, and curved surfaces. 

• Reduced reliance on silver: Copper is abundant, cost-effective, and widely available. 

• Lower production costs: Replacing silver metallization and optimising encapsulation reduces material costs. 

• Lower environmental footprint: Replacing silver and optimising encapsulation supports circular material loops and reduces CO₂ impact. 

Roadmap  

The project will pave the way for mass production of these lightweight, flexible solar cells by 2030, strengthening Europe’s renewable energy independence and innovation leadership. 

More information on the CAPSUL project 

Are you curious about the process or how the project can benefit your business? Please contact Kees Boshuijer, Project Lead for Kalpana Systems, through our contact form.