Solar Harvesting Through Multilayer Spectral Selective Iron Oxide And Porphyrin Transparent Thin Films For Photothermal Energy Generation

A fundamental challenge in energy sustainability is efficient utilization of solar energy towards energy-neutral systems. The current solar cell technologies have been most widely employed to achieve this goal, but are limited to a single-layer 2D surface. To harvest solar light more efficiently, a multilayer system capable of harvesting solar light in a cuboid through transparent photothermal thin films of iron oxide and a porphyrin compound is developed. Analogous to a multilayer capacitor, an array of transparent, spectral selective, photothermal thin films allows white light to penetrate them, not only collecting photon energy in a 3D space, but generating sufficient heat on each layer with significantly increased total surface area. In this fashion, thermal energy is generated via a multilayer photothermal system that functions as an efficient solar collector, energy converter and generator with high energy density. A solar-activated thermal energy generator that can produce heat without any power supply and reach a maximum temperature of 76.1 degrees C is constructed. With a constant incoming white light (0.4 W cm(-2)), the thermal energy generated can be amplified 12-fold via multilayers. The multilayer system extends another dimension in solar harvesting and paves a new path to energy generation for the energy-neutral system.