Atomistic Interrogation of B–N Co-dopant Structures and Their Electronic Effects in Graphene

Abstract

Chemical doping has been demonstrated to be an effective method for producing high-quality, large-area graphene with controlled carrier concentrations and an atomically tailored work function. The emergent optoelectronic properties and surface reactivity of carbon nanostructures are dictated by the microstructure of atomic dopants. Co-doping of graphene with boron and nitrogen offers the possibility to further tune the electronic properties of graphene at the atomic level, potentially creating p- and n-type domains in a single carbon sheet, opening a gap between valence and conduction bands in the 2-D semimetal. Using a suite of high-resolution synchrotron-based X-ray techniques, scanning tunneling microscopy, and density functional theory based computation we visualize and characterize B-N dopant bond structures and their electronic effects at the atomic level in single-layer graphene grown on a copper substrate. We find there is a thermodynamic driving force for B and N atoms to cluster into BNC structures in graphene, rather than randomly distribute into isolated B and N graphitic dopants, although under the present growth conditions, kinetics limit segregation of large B-N domains. We observe that the doping effect of these BNC structures, which open a small band gap in graphene, follows the B:N ratio (B > N, p-type; B < N, n-type; B═N, neutral). We attribute this to the comparable electron-withdrawing and -donating effects, respectively, of individual graphitic B and N dopants, although local electrostatics also play a role in the work function change.

Carbon Nano‐Onions: A Review of Recent Progress in Synthesis and Applications

“…Doping of CNs with donors or acceptors can form electronexcess n-type or electron-deficient p-type materials. [138][139][140][141] The first strategy is based on doping by heteroatoms during the formation of CNs, and the second strategy is connected to the post-synthesis treatment of already-formed CNs using different oxidizing or reducing agents. For this purpose, doping CNOs with N, B, F, O and S was performed.…”

“…For this purpose, doping CNOs with N, B, F, O and S was performed. [138][139][140][141][142][143][144] Boron-doped CNOs (B-CNOs) were obtained using an in situ method during electron irradiation of a graphitic material in a TEM and via chemical vapour deposition of BCl 3 and C 6 H 6 . [145,146] The direct preparation of CNOs via thermal annealing of NDs using a boron source (H 3 BO 3 or amorphous powder of boron) or nitrogen was recently reported.…”

Synthesis of Hierarchically Porous Nitrogen‐Doped Carbon for Sodium‐Ion Batteries

“…reported that P‐doped porous carbon can be synthesized through a microwave‐assisted route . Binary and ternary heteroatoms co‐doped carbon materials have also been synthesized through the thermolysis of carbon precursors . To date, nitrogen doping is the most widely investigated in carbonaceous materials since nitrogen, acting as an electron donor, can increase the electronegativity and accelerate the charge transfer …”

Heteroatom‐doped Carbon Spheres from Hierarchical Hollow Covalent Organic Framework Precursors for Metal‐Free Catalysis

“…The C1sX PS spectra show four binding energy peaks at 284.4, 285.5,2 86.5, and 288.6 eV,c orresponding to the sp2 carbon, CÀB, CÀNa nd CÀO, respectively (Figure S16 a). [22] In combination with the bondingc onfigurations and the content of Na toms on the surfaceo fB N-HCS (FigureS16 e), BN-HCS-800 and BN-HCS-900 are dominated by separated and bonded Ba nd N, [23] respectively.T herefore, the structural properties of the B,N-codoped carbons pheres can be reasonablyt ailored by changing the pyrolysis temperature of H-COF. [20] The weak shoulder peak of B1sa t1 92.1 eV is related to BC 2 Os peciesi nB N-HCS-700 and BN-HCS-800, [21] whereas no obvious peak of BÀOs pecies was observed in BN-HCS-900.…”

“…These clearly indicate that most of Ba toms are bondedt oCatoms in the form of BC 3 speciesi nB N-HCS-800, whileBatoms predominately generate NÀBÀCs pecies in BN-HCS-900 ( Figure 3d)o wing to the ready formation of BÀNb onds at higher temperatures. [22] In combination with the bondingc onfigurations and the content of Na toms on the surfaceo fB N-HCS (FigureS16 e), BN-HCS-800 and BN-HCS-900 are dominated by separated and bonded Ba nd N, [23] respectively.T herefore, the structural properties of the B,N-codoped carbons pheres can be reasonablyt ailored by changing the pyrolysis temperature of H-COF.…”