DropEner aims to the development of rain panels, i.e. drop energy harvesters compatible with functioning under outdoor conditions, based on triboelectric nanogenerator (TENG) concepts and employing scalable and high yield production technologies. The project will demonstrate the application of an innovative concept recently patented by the NanotechOnSurfaces & Plasma Lab (CSIC-US)1 on the harvesting of the kinetic energy coming from liquid drops in the sudden and instantaneous contact with a triboelectric surface embedded in a capacitor-like architecture. Because of the parallelism with the architecture of a CCD image sensor pixel, we have entitled this invention as “Tixel”. Hence, this is the first TENG undoubtedly relaying on nano and microstructured architectures with the potential to generate high-density power by the implementation of Tixel arrays. Moreover, in a further step forward in the state-of-the-art in the exploitation of solid-liquid contact energy harvesters, DropEner pursues the development of durable and transparent Tixels. Such a challenge opens new scenarios for the exploitation of drop energy harvesters, among others, making them fully compatible with solar cells, including Silicon and Third Generation technologies (as Dye-Sensitized Solar Cells (DSCs) and Perovskite Solar Cells (PVs)).