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For the environmental energy-enhanced interfacial solar vapor generator, through elegant structural designs, there will be a net energy gain from the environment during the solar vapor generation, yielding an evaporation rate exceeding the theoretical value, assuming a 100% solar-to-vapor energy transfer efficiency.

1322 wileyonlinelibrary.com applications in fi elds of healthcare monitoring, human-computer interaction, and electronic skin. [ 12 ] The relative resistance Δ R normalized by the initial resistance R 0 depends on Poisson's ratio ( ν ) and resistivity variation (Δ ρ ) normalized by its initial resistivity ρ 0 through the expression ΔR / R 0 = (1 + 2ν) ε + Δ ρ / ρ 0.[ 13 ] The sensitivity revealed by gauge factor (GF, defi ned as ( ΔR / R 0 )/ ε ) depends on both intrinsic property and structural feature. According to this formula, graphene-based strain sensors have shown low sensitivities due to the rigid and stable structure of intrinsic graphene. [ 14 ] With hardly opened band gap, the GF of a suspended graphene is only about 1.9 under moderate uniaxial strains. [ 15 ] Therefore, structural engineering of graphene is needed to boost the sensitivity of graphene-based strain sensors.Adjustment of the connection channels in graphene is an effective way to alter its resistivity for improved sensitivity in strain sensors. Two common methods for the structural construction of graphene include high temperature processing based chemical vapor deposition (CVD) and solution processing based sheets/fl akes assembly. As for CVD, the resistivity of graphene would be affected by its grain boundary, grain size, and the defect density. [16][17][18] Continuous graphene fi lms grown by CVD could sustain 1% strain with a GF of only 6.1, [ 19 ] and the GF increases to 151 for a 5% strain due to the morphological Large-Area Ultrathin Graphene Films by Single-Step Marangoni Self-Assembly for Highly Sensitive Strain Sensing ApplicationXinming Li , Tingting Yang , Yao Yang , Jia Zhu , Li Li , Fakhr E. Alam , Xiao Li , Kunlin Wang , Huanyu Cheng , Cheng-Te Lin , * Ying Fang , * and Hongwei Zhu * Promoted by the demand for wearable devices, graphene has been proved to be a promising material for potential applications in fl exible and highly sensitive strain sensors. However, low sensitivity and complex processing of graphene retard the development toward the practical applications. Here, an environment-friendly and cost-effective method to fabricate large-area ultrathin graphene fi lms is proposed for highly sensitive fl exible strain sensor. The assembled graphene fi lms are derived rapidly at the liquid/air interface by Marangoni effect and the area can be scaled up. These graphene-based strain sensors exhibit extremely high sensitivity with gauge factor of 1037 at 2% strain, which represents the highest value for graphene platelets at this small deformation so far. This simple fabrication for strain sensors with highly sensitive performance of strain sensor makes it a novel approach to applications in electronic skin, wearable sensors, and health monitoring platforms.