Hierarchically Promoted Light Harvesting and Management in Photothermal Solar Steam Generation
This review examines hierarchical light harvesting and management in photothermal solar steam generation (SSG)—a highly promising technology for mitigating global water scarcity. The authors emphasize that efficient, multi-scale light capture is the foundational, yet often underappreciated, driver of SSG performance. By systematically analyzing light-matter interactions across three distinct dimensions—from the molecular/sub-nanoscale, through nano/microscale structures, to macroscopic device geometries—this paper establishes the critical structure-property relationships that govern photothermal conversion efficiency, offering a strategic blueprint for the design of next-generation solar desalination systems.
Fig. 1. The fundamental configuration of a typical SSG system illustrating various physicochemical processes involved: light absorption, photothermal conversion, heat localization and transfer, salt dynamics, and steam generation and condensation.
Technology Overview
The core of SSG lies in utilizing photothermal materials to convert solar energy into thermal energy, which evaporates saline or contaminated water into clean steam. To maximize this solar-to-vapor conversion efficiency, light management must be optimized synergistically across multiple structural scales. At the molecular and sub-nanoscale levels, materials are fine-tuned to enable broad-spectrum solar absorption. Advancing to the nano- and microscale, structures are tailored to enhance light trapping through internal reflections, scattering, and optical confinement effects. Finally, at the macroscopic level, device geometries and spatial configurations are strategically engineered to maximize light capture from various incident angles while minimizing optical losses, ensuring the full potential of photothermal conversion is unlocked.
Applications & Benefits
By leveraging sunlight as the sole energy input, hierarchically engineered SSG provides a cost-effective, sustainable, and scalable solution for freshwater production, directly addressing the impending global water crisis. Beyond standard desalination and wastewater treatment, these advanced systems can serve as multifunctional platforms—simultaneously driving water purification alongside green hydrogen generation or thermoelectric co-generation. This adaptable approach requires no complex infrastructure, making it highly viable for decentralized water-energy nexus applications.
Abstract：
Solar steam generation (SSG) presents a promising approach to addressing the global water crisis. Central to SSG is solar photothermal conversion that requires efficient light harvesting and management. Hierarchical structures with multi-scale light management are therefore crucial for SSG. At the molecular and sub-nanoscale levels, materials are fine-tuned for broadband light absorption. Advancing to the nano- and microscale, structures are tailored to enhance light harvesting through internal reflections, scattering, and diverse confinement effects. At the macroscopic level, light capture is optimized through rationally designed device geometries, configurations, and arrangements of solar absorber materials. While the performance of SSG relies on various factors including heat transport, physicochemical interactions at the water/air and material/water interfaces, salt dynamics, etc., efficient light capture and utilization holds a predominant role because sunlight is the sole energy source. This review focuses on the critical, yet often underestimated, role of hierarchical light harvesting/management at different dimensional scales in SSG. By correlating light management with the structure-property relationships, the recent advances in SSG are discussed, shedding light on the current challenges and possible future trends and opportunities in this domain.
Hierarchically Promoted Light Harvesting and Management in Photothermal Solar Steam Generation
Author：Xu Bolin, Ganesan Muthusankar, Devi Ramadhass Keerthika, Ruan Xiaowen, Chen Weicheng, Lin Chun Che, Chang Huan-Tsung, Lizundia Erlantz, An Alicia Kyoungjin, Ravi Sai Kishore
Year：2025
Source publication：Advanced Materials, Volume 37, Issue 5, 2406666
Subfield Highest percentage： 99% Mechanical Engineering #3 / 740