Researchers from Changchun University of Science and Technology, Xi’an Technological University and Cardiff University have found that a patterned layer on top of the active part of a solar panel can avoid the energy losses due to reflection from the surface.

They have devised an approach to the lithographic process used to “print” microelectronic circuits that allows them to add a pattern of microscopic cones to the surface of the solar cell. The features of the pattern are so small that individual parts are shorter than the wavelength of light. This means that incident sunlight becomes trapped rather than reflected, passing on more of its energy to electricity-generation process that takes place within the panel.

The same pattern makes the surface of the solar cell water repellant because there is no surface to which the droplets can grip – similar to the way the surface of a lotus leaf repels water. When it rains the water runs off efficiently leaving the panel clean and dry.