Yuhang Jing

Doping-Induced Tunable Wettability and Adhesion of Graphene.

We report that substrate doping-induced charge carrier density modulation leads to the tunable wettability and adhesion of graphene. Graphenes water contact angle changes by as much as 13° as a result of a 300 meV change in doping level. Upon either n- or p-type doping with subsurface polyelectrolytes, graphene exhibits increased hydrophilicity. Adhesion force measurements using a hydrophobic self-assembled monolayer-coated atomic force microscopy probe reveal enhanced attraction toward undoped graphene, consistent with wettability modulation. This doping-induced wettability modulation is also achieved via a lateral metal-graphene heterojunction or subsurface metal doping. Combined first-principles and atomistic calculations show that doping modulates the binding energy between water and graphene and thus increases its hydrophilicity. Our study suggests that the doping-induced modulation of the charge carrier density in graphene influences its wettability and adhesion [corrected]. This opens up unique and new opportunities for the tunable wettability and adhesion of graphene for advanced coating materials and transducers.

Thermal conductivity of hybrid graphene/silicon heterostructures

The success of fabricating single layer graphene and silicon nanofilm (could be as thin as single layer so far) has triggered enormous interest in exploring their unique physics and novel applications. An intuitive idea is to investigate what happens if we construct a heterostructure composed of these two sheets. In this paper, we perform nonequilibrium molecular dynamics simulations to systematically investigate the in-plane thermal transport in graphene/silicon/graphene (Gr/Si/Gr) heterostructures. The effects of Si film thickness, interfacial interaction strength, and length on the thermal conductivity of the Gr/Si/Gr heterostructures are explicitly considered. Our simulations identify a unified scaling law for thickness dependence of thermal conductivity of the Gr/Si/Gr heterostructures, despite different interfacial interaction forms are used (weak van der Waals interaction and strong covalent bonding). By quantifying relative contribution from phonon polarizations and defining heat flux onto single ...

Correction to Doping-Induced Tunable Wettability and Adhesion of Graphene.

I Note Added in Proof, we cited a relevant paper published on June 1, 2016 (Nano Lett., 2016, 16 (7), pp 4447−4453. DOI: 10.1021/acs.nanolett.6b01594) by Hong et al. In order to fully acknowledge this recent work that reports conclusions that are similar to our independently performed work, we would like to (1) remove our claim in reference to “for the first time” from the paragraphs referenced below, and (2) add the sentences below discussing the work of Hong et al. to our paper. In the abstract and conclusion paragraphs, “for the first time” is removed to read as below, respectively: Our study suggests that the doping-induced modulation of the charge carrier density in graphene influences its wettability and adhesion. In conclusion, we used experimental, analytical, and simulation studies to demonstrate that the WCA of graphene can be modulated by doping. In the first paragraph before the last sentence, we would like to add the sentences below: We have also become aware of the work by Hong et al. during the proof stage of our paper. Our work independently demonstrates and further supports similar findings reported in Hong et al., showing doping-induced wettability modulation of graphene.