Buildings should wear dresses woven from sunshine

Can we weave our way out of the climate crisis? This is a natural question, as the research project SUNTEX received 2.13 million euro in funding. The project is a collaboration that unites the fashion world with industry and some of the world’s leading researchers in organic solar cells, all working to integrate solar cells into buildings.

In short, they want to wrap buildings in textiles. But how should we understand that? Are we going to see high-rises in Icelandic wool sweaters with turtlenecks?

“It’s not that far off! In essence, we’re wrapping buildings in energy-producing textiles. Think of it like a silk dress for a building instead of an Icelandic sweater—only with the added function of generating electricity.”

So says Dutch designer Pauline van Dongen, one of the key figures behind the SUNTEX project. Since 2010, she has run Pauline van Dongen Studio, which has collaborated with companies like Philips to develop innovative designs, including illuminated sportswear.

In 2018, Forbes named her one of Europe’s most influential women in technology. In 2022, she co-founded the Solar Biennale, an initiative exploring the role of solar energy in design and society.

Photo: Anna Wetzel

With SUNTEX, she continues to explore the connection between solar-cell technology and textile design. She sees great potential in the project, partly because organic solar cells, unlike traditional silicon panels, do not contain harmful chemicals, are highly flexible, and can be printed in any shape.

“We can generate energy via the textile and, for instance, power the building’s lighting. By integrating solar panels directly into the weaving process, we can design a material almost complete when it comes off the loom—only the electrical connections remain.”

But why weave solar cells? What makes this technology unique compared to existing solar-cell technologies?

“There are companies that laminate thin-film solar cells onto existing textiles. We see several challenges with that method: First, it significantly limits recyclability and repair options. We’re working with a modular system where we can separate the textile, organic photovoltaic cells (OPV), and circuitry. It allows us to repair and upgrade the material with more efficient OPV panels when they become available.”

Solar-cell textiles are not new, but previous attempts have struggled with efficiency, durability, and cost. Paradoxically, organic solar cells are not fond of the sun’s UV rays or the oxygen around them. That’s why Professor Morten Madsen from the University of Southern Denmark, who is leading the project’s scientific development, faces several technical challenges.

“One of our biggest challenges is ensuring the solar cells remain stable and efficient over time. We’re developing new ways to encapsulate the cells so they last longer and remain cost-effective,” Morten Madsen explains, adding:

“Specifically, we will investigate new solar-cell materials and configurations to achieve high-performance solar cells and modules with a sufficient lifespan.”


Photo: Anna Wetzel

Morten Madsen, who heads the CAPE (Centre for Advanced Photovoltaics and Thin-film Energy Devices) at SDU, looks ahead to working toward applications requiring mechanical flexibility and stability.

“That circles back to the material properties and how we encapsulate and ‘package’ the cells, which affects their stability under UV light and various weather conditions. Here, we’re working with new organic layers in the solar cell to increase stability. Hopefully, that will open up the possibility of sufficient longevity under those conditions. That is the goal of the project.”

The project recently kicked off and runs for 36 months. In addition to Pauline van Dongen Innovations BV (PVDI) and the University of Southern Denmark, Tentech BV, RWTH – Rheinisch-Westfälische Technische Hochschule Aachen, Kettler Berufskleidung & Technische Textilien GmbH, and Grafisk Maskinfabrik A/S are also involved.

Fact Box
Since SUNTEX is developing building materials, tensile strength is a top priority. The project, therefore, uses recycled high-strength polyester threads. A single thread typically consists of hundreds of fibres, and one can carry up to 9 kg. Five centimetres of the textile can withstand 300 kg. The advantage of polyester threads is that they are much easier to recycle than other high-strength yarns.

SUNTEX uses organic photovoltaic technology because the project partners believe it will become a leading technology. While still relatively young and constantly evolving, it offers significant benefits: it contains no harmful chemicals, can be printed in any shape, and is flexible. This system also gives the textile a high degree of flexibility, and it is possible to recycle the material into new threads again.

Organic photovoltaic cells have the lowest CO₂ footprint compared to other solar cell solutions. Their energy payback time—the time it takes to generate the energy required to produce them—is less than a year.