In a commanding position – and now cheaper

Transparent conductive films are now an integral part of our everyday lives. Whether in smartphones, tablets, laptops, flat screens or (on a larger scale) in solar cells. Yet they are expensive and complex to manufacture. Now, researchers have succeeded in developing a method of producing such TCO films, as they are known, that is not only cheaper, but also simpler and more environmentally friendly. It is a requirement of the touchscreens for all our everyday gadgets that they are transparent and at the same time electrically conductive. Solar cells are also unable to operate without such a film, which allows sunlight to pass through it, but can also conduct the current generated. Conventional "transparent conductive oxide" (TCO) films consist of a mixture of indium and tin oxide. Indium in very much in demand in the electronics industry, but is rare, and therefore expensive. A cheaper option (at least in terms of the materials used) employs zinc oxide mixed with aluminium, which is usually applied to the substrate in a high vacuum by means of plasma sputtering. However, the manufacturing process is complex, making it similarly expensive. In addition, it is energy-intensive and therefore not ideal from an ecological perspective. Empa researchers at the Laboratory for Thin Films and Photovoltaics have now developed a water-based method of applying a TCO film made of aluminium and zinc salts onto a substrate - without a vacuum. Less energy consumption