Scalable Production of Integrated Graphene Nanoarchitectures for Ultrafast Solar-Thermal Conversion and Vapor Generation

Abstract

Solar-thermal conversion is a key technology in harvesting solar energy for a diverse range of applications including water vapor generation. However, simultaneously ultrafast and highly efficient solar-thermal conversion and scalable fabrication of materials and devices to achieve such performance in practical applications still remain the key unmet challenges. Here we report a hierarchical nanoarchitecture that integrates vertically oriented graphene nanosheets and highly porous graphene aerogel to achieve ultrafast solar-thermal response (a temperature increase of 169.7 C within 1 s), resulting from superior photonic absorption and excellent thermal insulation. Through engineering surface water pathways and minimizing interfacial thermal resistances, ultrafast solar-thermal response (reaching 100 C within 34 s) and simultaneously high energy efficiency (89.4%) for saturated vapor generation at 10 sun is achieved. Importantly, we demonstrate high-throughput, scalable fabrication of the unique nanoarchitecture. Ultrafast medical sterilization is demonstrated as a potential practical application of this green, nanotechnology-enhanced system for large-scale solar energy harvesting.

Multifunctional Solar Waterways: Plasma‐Enabled Self‐Cleaning Nanoarchitectures for Energy‐Efficient Desalination

“…The excellent light-harvesting ability can be attributed to the unique morphology of N-fGNs, including the vertical orientation which is nearly parallel to the direction of incident light as well as the wall-like structures, open channels, and exposed edges. [39] When incident light reaches the graphene nanoarrays, it is trapped in the graphene nano-/microchannels and is then almost completely absorbed after multiple internal reflections. Importantly, the role of plasma in the synthesis can be summarized as follows: i) growing fGNs to obtain improved light absorption, ii) doping nitrogen species to achieve hydrophilic wettability, and iii) functionalizing the nanoarchitectures to obtain surface waterways (see more details in Section S6 in the Supporting Information).…”

Structure Architecting for Salt‐Rejecting Solar Interfacial Desalination to Achieve High‐Performance Evaporation With In Situ Energy Generation

“…Instead, the results would be more reasonable and consistent with experimental observations if the temperature of the hot water vapor zone that exists closely to the evaporation surface is considered. [ 25,80–82 ] However, the measurement strategies and the precise boundary condition for this is not yet settled.…”

“…More confined water pathways were proposed to minimize the contact with water, thus saving the heat from conduction loss. 2D water supply employs hydrophilic intermediary materials such as cellulose, [ 91 ] cotton and silk fabrics, [ 47,92–94 ] vertically oriented graphene structures, [ 81 ] air‐laid paper, [ 95 ] etc., for water delivery. In this way only a thin confined water layer is in contact with solar absorbers to supply water for evaporation (Figure 4b).…”

“…It was also found that the absorption reached to its maximum (≈99%) with 10 layers of PPy nanosheets, implying that this effect is deliberately tunable. Photothermal structures with orderly and randomly aligned structures, [ 56,58,90,106 ] especially those vertically oriented nanostructures such as the graphene nanosheets highlighted in Figure 5c, [ 81 ] have also been considered as an important group of materials with superior properties for solar thermal conversion. These oriented structures not only enable broadband light absorption, but also, they are further capable of ultrafast solar thermal response.…”

“…Reproduced with permission. [ 81 ] Copyright 2019, Elsevier. d): 1) Fabrication process, 2) Optical photographs and corresponding SEM images of low‐cost hierarchical aluminum‐based solar absorber with plasmonic Al nanoparticles.…”