Solar Harvesting through Multilayer Spectral Selective Iron Oxide and Porphyrin Transparent Thin Films for Photothermal Energy Generation

Abstract

AbstractA 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 °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.