The use of nanofluids improves the overall performance of solar thermal collectors and has been studied explicitly in the last decade. More recently, to overcome the limitations of surface based solar collectors, novel nanofluid seeded direct absorption solar collectors (DASCs) have been proposed for effective solar energy conversion. Plasmonic nanofluids, the colloids of plasmonic nanoparticles such as Au, Ag, Cu, Al etc. in base fluids, have emerged as promising thermal media for novel DASCs. Due to the inherent localized surface plasmon resonance effect (LSPR), these novel media show high thermal gain and photo thermal conversion potentials compared to other types of nanofluids. Therefore, this review focuses on recent progress and challenges in the use of plasmonic nanofluids in DASC-based solar thermal applications. The state-of-the-art includes reporting the recent experimental and numerical results in low, medium and high-temperature DASCs as well as hybrid photovoltaic/thermal (PV/T) technology, which utilises nanofluids as beam splitter. We have also tried to provide a review of optical characteristics of plasmonic nanoparticles along with the latest developments in the synthesis of complex nanoparticle morphologies and blends for broadband absorption of solar spectrum. Finally, authors have tried to highlight the challenges, grey areas and possible future research directions for the potential applications of plasmonic nanoparticles in futuristic solar harvesting applications.

纳米流体的使用提高了太阳能集热器的整体性能，并在过去十年中得到了明确的研究。最近，为了克服基于表面的太阳能收集器的局限性，已经提出了用于有效太阳能转换的新型纳米流体种子直接吸收太阳能收集器（DASC）。等离子纳米流体是基液中等离子纳米粒子（如金、银、铜、铝等）的胶体，已成为新型 DASC 的有前途的热介质。由于固有的局部表面等离子体共振效应 (LSPR)，与其他类型的纳米流体相比，这些新型介质显示出高热增益和光热转换潜力。因此，本综述重点关注在基于 DASC 的太阳能热应用中使用等离子体纳米流体的最新进展和挑战。最先进的技术包括报告最近在低温、中温和高温 DASC 以及混合光伏/热 (PV/T) 技术中的实验和数值结果，该技术利用纳米流体作为分束器。我们还试图提供对等离子体纳米粒子光学特性的综述，以及合成复杂纳米粒子形态和用于太阳光谱宽带吸收的混合物的最新进展。最后，作者试图强调等离子体纳米粒子在未来太阳能收集应用中的潜在应用所面临的挑战、灰色地带和可能的未来研究方向。它利用纳米流体作为分束器。我们还试图提供对等离子体纳米粒子光学特性的综述，以及合成复杂纳米粒子形态和用于太阳光谱宽带吸收的混合物的最新进展。最后，作者试图强调等离子体纳米粒子在未来太阳能收集应用中的潜在应用所面临的挑战、灰色地带和可能的未来研究方向。它利用纳米流体作为分束器。我们还试图提供对等离子体纳米粒子光学特性的综述，以及合成复杂纳米粒子形态和用于太阳光谱宽带吸收的混合物的最新进展。最后，作者试图强调等离子体纳米粒子在未来太阳能收集应用中的潜在应用所面临的挑战、灰色地带和可能的未来研究方向。