Powering Nanocrystal‐Based Heat Engines With Light‐Emitting Metasurfaces That Influence Their Temperature

Resonant photonic structures, such as metasurfaces, photonic crystal cavities, optical antennas, and Fabry‐Pérot resonators, provide considerable levies to modify the absorption and emission properties of semiconductors. Here, using the example of colloidal PbS nanocrystals (NCs) coupled to Au metasurfaces, we show that such structures also offer opportunities for controlling the temperature upon continuous wave illumination. We first introduce a general method to measure the carrier temperature in a complex photonic environment and then use it to discuss several representative examples of thermal management by metasurfaces. We then show how this knowledge can be applied to convert light into electricity in unconventional ways by powering an NC‐based heat engine with a light‐emitting metasurface that induces a negative gradient of temperature, opening up avenues for self‐powered photodetectors, solar cells, and any applications where large temperature gradients and/or fast variations are needed.