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As a spontaneous solar-thermal energy conversion technology with high photothermal efficiency, solar-driven interfacial evaporation has attracted enormous attention. However, considering the inadequate light illumination most of the time in a day and the expensive light-concentrating facilities, achieving high energy conversion efficiency under low solar flux is in great demand. In this work, we develop a broadband solar absorber based on graphene hybrid aerogels with MoS 2 nanoflower decoration and nitrogen doping (MNGA). Synthesized via a two-step hydrothermal method, the porous MNGA shows self-floating ability, good thermal insulation, and a strong solar absorption of ≈93% in the visible to near infrared range. The nanoflower-like MoS 2 decoration and nitrogen doping modulate the surface hydrophilicity jointly. Compared to nitrogen-doped GA , MNGA shows a reduced surface hydrophilicity, while still ensuring good wettability for water transport. Under low solar flux (0.3−1.0 sun), MNGA presents a high energy conversion efficiency (89.7−96.9%) and excellent cycling performance. It is endowed with good salt resistivity and recycling stability, maintaining an average efficiency of 96.6% under 1 sun illumination and stable performance during 10-cycle evaporation tests. These hybrid aerogels with outstanding photothermal performance, self-floating ability, salt resistivity, and durability offer a potential approach to realize water purification and desalination in daily life.

In various applications, infrared (IR) detectors with quick responses and high sensitivity at room temperature are essential. This work synthesizes carbon nanotube aerogel films (CAFs) with an ultra-low density of 1.33 mg cm–3. Transient electrothermal (TET) technology is used to characterize the thermal and electrical transport of CAFs in the temperature range of 320 to 10 K. CAF has record-low thermal conductivity (2.5 mW m–1 K–1 at 320 K) and thermal diffusivity (2.24 × 10–6 m2 s–1 at 320 K) in vacuum. The TCR of CAF is −0.11%/K at 295 K, which is 57% higher than that of the MWCNT films. In addition, the comprehensive bolometric performance of carbon nanotube aerogels is tested and analyzed, including the photothermal response, resistivity responsivity, and response time to lasers of a broad spectrum from ultraviolet to near-infrared. The relative responsivity of CAF to lasers of different wavelengths is found to be consistent. The response time of CAF with 200 μm suspended length is measured to be as short as 2.95–3.03 ms (framing rate of 330–339 per second). In addition, the resistive response of the CAF sample to a blackbody radiator and the radiation of the human hand also shows good sensitivity and repeatability. These results demonstrate the promising application of CAF as a sensitive and fast-response uncooled bolometer.

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