Giant enhancement in vertical conductivity of stacked CVD graphene sheets by self-assembled molecular layers

Abstract

Layer-by-layer-stacked chemical vapour deposition (CVD) graphene films find applications as transparent and conductive electrodes in solar cells, organic light-emitting diodes and touch panels. Common to lamellar-type systems with anisotropic electron delocalization, the planeto-plane (vertical) conductivity in such systems is several orders lower than its in-plane conductivity. The poor electronic coupling between the planes is due to the presence of transfer process organic residues and trapped air pocket in wrinkles. Here we show the plane-to-plane tunnelling conductivity of stacked CVD graphene layers can be improved significantly by inserting 1-pyrenebutyric acid N-hydroxysuccinimide ester between the graphene layers. The six orders of magnitude increase in plane-to-plane conductivity is due to hole doping, orbital hybridization, planarization and the exclusion of polymer residues. Our results highlight the importance of interfacial modification for enhancing the performance of LBL-stacked CVD graphene films, which should be applicable to other types of stacked two-dimensional films.

Real-time reliable determination of binding kinetics of DNA hybridization using a multi-channel graphene biosensor

“…The shift in the positive direction by PBASE was explained by its p-doping effect through the charge transfer between the pyrene group and graphene44, which was also confirmed here by ultraviolet photoelectron spectroscopy, as the work function is increased by ∼0.3 eV (Supplementary Fig. 6).…”

“…Here, the high specificity of the sensor for DNA detection can mainly be attributed to the probe-DNA-specific recognition of its complementary partner. In addition, the use of PBASE linkers further reduces nonspecific electrostatic stacking binding of unrelated DNA on the graphene surface4446.…”

Rapid Detection of COVID-19 Causative Virus (SARS-CoV-2) in Human Nasopharyngeal Swab Specimens Using Field-Effect Transistor-Based Biosensor

“…After PBASE was applied to the graphene surface, the statistical data of the 2D peak position were shifted to a higher frequency (∼3.27 cm −1 ), indicating p-doping by the π−π interaction between PBASE and graphene ( Figure 2C). 23,24 The mapping images also show that the average I 2D /I G ratio of PBASE-treated graphene (I 2D /I G = ∼1.87) is significantly lower than that of pristine graphene (I 2D /I G = ∼3.61) due to existence of some disorder on the graphene ( Figure 2D,E). The XPS survey data show the principal C 1s, O 1s, and N 1s core levels ( Figure 2F).…”

Graphitic Mesoporous Carbon Loaded with Iron–Nickel Hydroxide for Superior Oxygen Evolution Reactivity

“…[40] To further demonstrate the elemental composition of Fe-Ni hydroxide/GMC, C1s, Fe 2p, and Ni 2p X-ray photoelectron spectroscopy (XPS) spectraw ere investigated, and the results are shown in Figure4a-c. [41] The Fe 2p 3/2 peak in Figure 4b was greater than Fe 2p 1/2 because of spin-orbit coupling, and the ratio of Fe 2p 3/2 to Fe 2p 1/2 was approximately 2:1. [41] The Fe 2p 3/2 peak in Figure 4b was greater than Fe 2p 1/2 because of spin-orbit coupling, and the ratio of Fe 2p 3/2 to Fe 2p 1/2 was approximately 2:1.…”

“…The C1ss pectra revealed that the bindings tates of carbon were ÀSiÀC( 283.5 eV), ÀCÀCÀ (sp 2 , 282.6 eV), ÀC=CÀ (285.5 eV), ÀCÀO( 286.2 eV), ÀC=O( 287.2 eV) and O=CÀOÀ (289.0 eV). [41] The Fe 2p 3/2 peak in Figure 4b was greater than Fe 2p 1/2 because of spin-orbit coupling, and the ratio of Fe 2p 3/2 to Fe 2p 1/2 was approximately 2:1. The separation between the envelope (711.7 eV) and the satellite (719.2 eV) of Fe 2p 3/2 was7 .5 eV,w hichi sc onsistent with the Fe 3 + oxidation state and is different from the value for Fe 2 + ( % 5eV), [42,43] confirming that Fe existed as the Fe 3 + valence state in the Fe-Ni hydroxide/GMC.…”