Photonic nanomaterials and meta-structures for energy conversion and saving

In addition to biochemical sensing applications, we have made a great deal of efforts in applying photonic nanomaterials and meta-structures to improve the energy conversion and saving efficiency.
With regard to energy conversion, we have systematically examined the roles of plasmonic nanostructures in enhancing the light harvesting and energy conversion efficiencies of various types of solar cells, including the strong competition between plasmonic absorption enhancement and surface energy quenching in a dye-sensitized solar cell (Nano Energy 26, 297-304, 2016), the realization of plasmon-induced broadband light absorption and scattering enhancement in a perovskite thin-film solar cell (Nano Energy 41, 656-664, 2017), quantitative contribution from plasmon-enhanced electric near-field, antenna-amplified light scattering and surface energy transfer to the overall performance of a plasmonic organic solar cell (Small 14 (30), 1800870, 2018), the observation of plasmon-induced defect passivation at grain boundaries in a perovskite solar cell (Light: Science & Applications 10, 219, 2021), and the recent discovery of plasmonic local heating induced strain relaxation in perovskite solar cells for enhanced power conversion efficiency and operational stability (Advanced Energy Materials 12 (19), 2200186, 2022).
With regard to energy saving, my group and research collaborators from local institution, mainland China and US have recently invented an eco-friendly, low-cost smart coating to keep buildings cooler while consuming zero electricity (Advanced Materials 32 (42), 1906751, 2020). This invention is grounded on a totally new cooling mechanism - smart sub-ambient radiative cooling, which can enhance daytime cooling and minimize nighttime heat loss mechanism. It was selected as “Editor’s Choice” of Science 370 (6522), 1287-1288, 2020, reported in Advanced Science News and public media, and receieved a Gold Medal of The International Exhibition of Inventions of Geneva (2022) We have further shown that introducing fluorescent materials into polymeric coatings can covert the absorbed sunlight to fluorescent emissions and hence increase the effective solar reflectance and cooling performance. Using phosphors with smaller Stokes shifts and TiO₂ nanoparticle fillers of appropriate sizes can significantly enhance the effective solar reflectance matching the emission wavelength of the former with the Mie scattering resonance wavelength of the latter, leading to fluorescence-mediated radiative cooling (Journal of Materials Chemistry A 10 (37), 19635-19640, 2022; selected into the themed issue of Emerging Investigators). This new approach provides an effective strategy for making radiative cooling coatings compatible with commercially available inexpensive engineering materials and potentially for realizing colored coatings.