Cost-effective and eco-friendly laser-processed cotton paper for high-performance solar evaporation

Recently, interfacial solar-driven evaporation has received tremendous attention due to its potential for enhancing solar thermal conversation ability via heat localization at the evaporation interface. Diverse materials and configurations have been explored to boost the evaporation using plastic foam as the thermal insulator at the cost of complex assembly and environmental threats. Herein, we demonstrate a biodegradable, cost-effective, and scalable three-dimensional (3D) cotton paper-based solar steam generator prepared by one-step laser-induced forward transfer in the ambient atmosphere. The as-prepared evaporator has excellent solar absorption ability. The defining advantages of this method are that it can easily form a 3D structure and it is free from hazardous raw material involvement and waste generation. With further novel design by using a natural air gap instead of artificial plastic material to insulate the steam generation area and the underlying bulk water, the as-prepared evaporation system can achieve a high evaporation rate of 1711 g m⁻² h⁻¹ with a corresponding efficiency of 83% under one sun illumination. Such solar vaporization functions offer new insights into the future development of high-performance solar steam generators through an environmentally friendly and cost-effective pathway.