Turku researcher creates smart material that stores energy and changes color

By AI, Created 8:16 AM UTC, May 29, 2026, /AGP/ – A University of Turku doctoral researcher has developed thin polymer films that can both switch colors and store electrical energy. The work points to future uses in self-tinting windows, flexible electronics and other low-cost smart surfaces.

Why it matters: - The material combines two functions in one film: electrochromic color change and energy storage. - The approach could support self-tinting smart windows that also store solar energy and reduce cooling demand in buildings. - The films were designed to be low-cost, controllable and adaptable for flexible and stretchy substrates.

What happened: - MSc Sachin Kochrekar developed the materials for his doctoral dissertation at the University of Turku in Finland. - The research produced thin polymer films based on porphyrins, molecules found in chlorophyll and hemoglobin. - The dissertation examined how the material performs with nickel, zinc or no metal in the center of the porphyrin structure. - Kochrekar worked in Professor Carita Kvarnström’s Materials Chemistry research group in the Department of Chemistry at the University of Turku.

The details: - The team built membrane structures in two ways: a hybrid structure with an electrically conductive material and a polymer membrane formed by linking porphyrins with a bridge molecule. - Small structural changes had a major effect on performance. - The nickel-based film changed between three colors. - The zinc-based and metal-free films switched between two states. - All materials reacted in less than two seconds. - The films showed clear visual contrast and kept changing color after the power was turned off. - The membranes were also tested for energy storage in a water-based electrolyte. - The water-based electrolyte is safer and more environmentally friendly than commonly used alternatives. - The study says this is the first research to use porphyrin-based polymer membranes as electrochromic supercapacitors in a water-based electrolyte system. - All three materials showed good energy storage properties.

Between the lines: - The work builds on a decade of research at the University of Turku on organic color-changing, or electrochromic, materials. - The porphyrin design draws on a natural system that already transfers electrons efficiently in photosynthesis. - The combination of visible color change and charge storage could make device status easier to see without separate indicators. - The broad application list suggests the technology is being framed as a platform material, not a single-purpose product.

What’s next: - The materials could be developed for sensor technology, flexible electronics, smart clothing and solar energy systems. - Potential applications also include anti-glare rear-view mirrors, sunroofs, display technologies, spectacle lenses and chemical sensors. - Future smart windows could darken in strong sunlight while storing energy at the same time.

The bottom line: - Kochrekar’s dissertation points to a multifunctional material platform that pairs visible signaling with energy storage in a single, fast-switching film.