Recent Advances in Solar Steam Generators: Photothermal Materials, Structural Architectures, and Energy Conversion Applications

Abstract

Solar steam generation has emerged as a highly efficient and sustainable technology for water purification, desalination, and decentralized energy applications, particularly in off-grid and resource-constrained regions. Unlike conventional solar thermal systems that rely on bulk water heating, solar steam generators utilize localized interfacial heating to achieve high solar-to-vapour conversion efficiencies under low solar concentration. This review presented an analysis of recent advances in solar steam generation technologies, focusing on photothermal materials, structural design strategies, performance characteristics, and system integration pathways. Carbon-based materials, plasmonic nanoparticles, semiconductor oxides, and biomass-derived absorbers were examined in terms of optical absorption, thermal management, cost, and scalability. The methodology employed was systematic analytical literature review, drawing on peer-reviewed articles, conference proceedings, and review papers indexed in Scopus, Web of Science and Google Scholar, published between 2010 and 2025. Key findings revealed that carbon-based and biomass-derived photothermal materials can achieve solar-to-vapour conversion efficiencies of 80–93% under one-sun illumination, while interfacial floating and three-dimensional structural designs offer superior salt rejection and heat localization compared to conventional bulk-heating configurations. Integration of solar steam generators with thermoelectric generators and organic Rankine cycle systems was shown to be feasible for off-grid electrification, though long-term durability and techno-economic viability under field conditions remain critical outstanding challenges.