Capturing solar energy requires a joint between two electrical conductors. It is at the join that the magic happens and the high energy electrons are swept away to operate a device or charge a battery before their energy is lost. The molecular level details of the joint are critical. Get them wrong and we have a very low efficiency or short lived device. Get them right and we might be able to capture solar energy to make electricity, drive new chemical reactions, even make renewable liquid fuel from water and CO2. Measuring details of the join is very difficult, it is by necessity buried between two materials and has to operate in a complex chemical environment. In this work quantum mechanics is used to predict what happens at a join between two oxides of metallic copper. This join has already been shown to have interesting properties for capturing solar energy. Here the nitty gritty details are worked out and the imperfections in the structure are revealed. Missing atoms and localised quantum states that limit efficiency. Now we know why energy is lost we hope to design and grow new structures that capture solar energy in a cost effective and sustainable manner.
Authors: Aleksandar Živković, Giuseppe Mallia, Helen E. King, Nora H. de Leeuw, Nicholas M. Harrison