Recent advances on improved optical, thermal, and radiative characteristics of plasmonic nanofluids: Academic insights and perspectives

To enhance the assimilation of light in the solar thermal area, we need to focus beyond the thermo-physical properties of the nanoparticles, i.e., optical properties of the nanoparticles (NPs) augment the optical characteristics of the solar spectrum; therefore, the concept of plasmonic nanofluids has been introduced. The plasmonic nanoparticles (mainly work on scattering and absorption mechanisms) suspended in a base fluid are known to enhance the thermal and photon efficiency of the volumetric solar thermal collectors compared to the conventional ones. Further, this study aims to review the most recently published works on plasmonic nanofluids that exclusively present its preparation methods, thermophysical properties, and applications in solar collectors. Following, an overview of the potential features of plasmonic nanofluids and their preparation methods are presented. Afterward, the stability and thermophysical properties of such nanofluids are discussed. Then, the application in solar energy collectors, automotive cooling, as well as biomedical applications are overviewed. Finally, some future directions for further research in this field of study are suggested. In this work, we reviewed the work done in the plasmonic field in the last decade, and we have tried to summarize the results based on published data and future outlooks. This work can benefit researchers in this field as there is no comprehensive review of plasmonic nanofluids available. This work is believed to help the researchers to modernize the latest trends and understand the potential research gap in the optical properties of nanofluids to enhance the performance of solar collectors further and reduce thermal losses.