Non-noble metal based broadband photothermal absorbers for cost effective interfacial solar thermal conversion

In recent years, noble metal-based solar absorbers have been extensively studied as their pronounced plasmonic resonances and high solar-to-thermal conversion efficiency. However, the high cost of noble metals is the unavoidable roadblock restricting the way towards scalability. In this work, we report a nickel-based photo-thermal absorbers, which is capable of realizing an average solar absorption of similar to 97% in the range of 400-2500 nm originating from relatively weaker collective plasmonic resonances but more pronounced single electron excitation. Importantly, it is easily fabricated via the straightforward physical deposition and cost-effective with a raw material price of similar to 0.3% gold and similar to 20% of silver. We used it for interfacial solar vapor generation and realized an evaporation rate of similar to 0.9 kg m(-2) h(-1) under one sun, almost comparable to the counterparts made from noble metals. The excellent performance combined with the cost effective and scalable fabrication process makes it be a promising candidate for mass off-grid solar desalination.