Navigating Solar Thermal Desalination: A Comprehensive Review of Materials Selection Criteria

Abstract Global water scarcity, intensified by climate change and population growth, necessitates sustainable freshwater solutions. Solar thermal desalination offers promise due to its energy efficiency, yet optimizing system performance hinges critically on material selection, particularly for photothermal absorbers and their substrates. While extensive research addresses photothermal nanomaterials, substrate materials vital for structural integrity, thermal management, and interfacial stability remain underexplored. This review comprehensively examines current advances in solar evaporator components, evaluating photothermal materials and substrates against key selection criteria: thermal conductivity, stability under harsh conditions, scalability, and compatibility. We analyze diverse substrate materials (e.g., metals, ceramics, polymers, bio-based, and aerogels) and their synergistic roles in enhancing evaporation efficiency and durability. Critical gaps in large-scale feasibility, long-term stability under variable solar flux, and cost-performance trade-offs are identified. The review also highlights emerging trends such as 3D-printed substrates and bio-inspired designs to overcome salt accumulation and fouling. By addressing these challenges and outlining pathways for scalable implementation, this work aims to advance robust, economically viable solar thermal desalination technologies for global freshwater security.