VTT offers new solution for smart farming with biodegradable solar cell module

The global push for digitalisation in agriculture is driving increased use of measurement electronics on farms. However, challenges related to power supply and electronic waste remain. In response, VTT has developed a biodegradable solar cell module through an international green electronics research initiative.

The solar cell module created by VTT is compact and lightweight enough to be attached directly to a plant stem or a large leaf. Roughly the size of a credit card, the cell is highly flexible and extremely thin. After the growing season, both the cell and its rechargeable power supply naturally decompose.

According to Maria Smolander, Research Team Leader at VTT, biodegradability is a critical factor when applying solar cells to agriculture. She noted that leaving a cell in the field poses no harm, even in close contact with soil, since it contains no harmful substances that could leach into the environment or worsen microplastic pollution. Smolander also observed that although sensors are not yet widely used in agriculture, this biodegradable innovation opens up greater potential for their integration into farming practices.

Compostable device created by international consortium

The solar cell module is part of a three-year collaborative project aimed at developing degradable cultivation sensors. Participating research institutions include Tampere University, University of Glasgow, Lukasiewicz Institute of Microelectronics and Photonics (Łukasiewicz-IMIF), Centre Suisse d’Electronique et de Microtechnique S.A. (CSEM), and McGill University, with funding from CHIST-ERA and various national research councils, including the Research Council of Finland.

Liisa Hakola, Senior Scientist at VTT, stated that while agriculture served as a practical testbed for the project, the broader goal is to examine how electronics can be produced in a more environmentally responsible way.

Within the project, VTT was responsible for developing the solar cell, while Tampere University created a supercapacitor that stores energy. The research also yielded compostable sensors and data modules capable of transmitting collected environmental data wirelessly.

Marja Välimäki, Senior Scientist at VTT, explained that the goal is not high energy output but rather support for low-consumption sensors that track environmental conditions. She said that the solar cell was not designed to match the performance or longevity of traditional cells.

Development of a biodegradable cell set new requirements

VTT’s experience in state-of-the-art solar cell production provided a strong foundation, but designing a biodegradable version required new approaches. The components had to be engineered not to degrade prematurely or trigger decomposition in adjacent materials.

Hakola noted that biodegradable materials tend to be more vulnerable to environmental stressors like heat and humidity. She added that sensors needed to be as light as possible in order to be attached directly to plants.

Depending on environmental conditions, the solar cell degrades within weeks or months. Its service life can be adjusted using protective coatings.

The cell developed by VTT uses a bio-based thin film substrate and incorporates some inorganic materials. Even with protective layering, the entire cell remains only a few tenths of a millimetre thick, with the solar portion measuring less than 35 µm.

Regulation requires more precise data collection

The use of measurement technologies on farms is expanding in response to the need for more precise data to improve crop yields, manage plant diseases, and reduce emissions. Increasingly, regulations also demand detailed environmental measurements.

Välimäki pointed out that, for instance, EU regulations require routine analysis of nutrient loads in soil samples. She explained that the new biodegradable solar cell provides a flexible, sustainable means of powering sensors, allowing for real-time environmental monitoring and data collection.

In parallel, VTT is also engaged in a broader EU-funded IoT research project that focuses on merging sensor technologies with clean, circular economy practices and environmentally friendly electronics.