Human energy needs are insatiable and they continue to grow as the number of new electronic devices increases. What’s more, we’re almost always on the move and therefore constantly depend on the power source to charge our smartphones, tablets and laptops. In the future, sockets (at least for this purpose) may become obsolete. Then it will be possible to recharge the devices from our own clothes. With the new polymer, which is applied to textile fibers, jackets, t-shirts, etc., can soon begin to function as solar collectors and, therefore, as a mobile energy source, reports Nano Energy magazine.

The problem of flexibility of fluorescent materials

The solar industry already uses materials that can use indirect or diffuse light to generate energy. These materials contain special fluorescent materials and are called “fluorescent solar concentrators”, or LSC for short. The fluorescent materials in the LSC capture scattered ambient light and transmit its energy to the actual solar cell, which then converts light into electrical energy.

At present, however, LSCs are only available as rigid components and are not suitable for use in textile products. The fact is that they are not flexible and permeable to air and water vapor. An interdisciplinary research team led by Luciano Bosel from the Laboratory of Biomimetic Membranes and Textiles of the Swiss Federal Material Science and Technology Laboratory (EMPA) has succeeded in combining several of these fluorescent materials into a polymer that provides the necessary flexibility and air permeability for use in textiles.

Known polymer with complex properties

This new material is based on the properties of linear and superbranched amphiphilic block copolymers, which are already available on the market as contact lenses made of silicon hydrogel. The special properties of the polymer – permeability to air and water vapor, as well as flexibility and stability – are based on special chemical properties.

“The reason we chose this polymer is because we can combine two non-miscible fluorescent materials in nanoscale and allow them to interact with each other. Of course there are other polymers in which these materials can be integrated; but this would lead to aggregation and thus energy production would be impossible,” explains Bozel.

Solar concentrators for clothes

In collaboration with colleagues from two other laboratories, Empa, Thin Films, Photovoltaics and Advanced Fibers, the Boesel team added two different fluorescent materials to the gel fabric, making it a flexible solar concentrator. As with large scale (rigid) collectors, fluorescent materials capture a much wider range of light than is possible with conventional photovoltaic cells. New solar collectors can be applied to textile fibers without the fabric becoming brittle and prone to crackling or the accumulation of water vapor in the form of sweat. Solar collectors, which can be adapted for permanent wear on the human body, offer a huge advantage for the ever increasing demand for energy, especially for portable devices.