Defect Healing in Graphene via Rapid Thermal Annealing with Polymeric “Nanobandage”

Abstract

Overcoming throughput challenges in current graphene defect healing processes, such as conventional thermal annealing, is crucial for realizing post‐silicon device fabrication. Herein, a new time‐ and energy‐efficient method for defect healing in graphene is reported, utilizing polymer‐assisted rapid thermal annealing (RTA). In this method, a nitrogen‐rich, polymeric “nanobandage” is coated directly onto graphene and processed via RTA at 800 °C for 15 s. During this process, the polymer matrix is cleanly degraded, while nitrogen released from the nanobandage can diffuse into graphene, forming nitrogen‐doped healed graphene. To study the influence of pre‐existing defects on graphene healing, lattice defects are purposefully introduced via electron beam irradiation and investigated by Raman microscopy. X‐ray photoelectron spectroscopy reveals successful healing of graphene, observing a maximum doping level of 3 atomic nitrogen % in nanobandage‐treated samples from a baseline of 0–1 atomic % in non‐nanobandage treated samples. Electrical transport measurements further indicate that the nanobandage treatment recovers the conductivity of scanning electron microscope‐treated defective graphene at ≈85%. The reported polymer‐assisted RTA defect healing method shows promise for healing other 2D materials with other dopants by simply changing the chemistry of the polymeric nanobandage.

Surface defect healing in annealing from nanoporous carbons to nanoporous graphenes

“…We also revealed that the thermal treatment 10–16 of NPC s at high temperatures under an inert atmosphere affords the corresponding NPG s by fusing the H-terminated edges, 2,17 and this is the origin of the electrochemical stability of NPG s. This annealing following the CH 4 -CVD synthesis will also improve the integrity of the graphene architecture by reducing the defect concentration, which is helpful to develop stable electrochemical devices using NPG s such as long-lived air–metal batteries etc. 18 The quantitative evaluation of the defect type and concentration before/after annealing will be a starting point for the development of state-of-the-art continuous porous carbon materials based on NPG chemistry, 1,2 but recent investigations on the structural changes upon annealing by changing the size of templates 16,19 gave us a qualitative picture.…”

“…1,3 The use of relatively inert CH 4 9 as the gaseous carbon source is crucial for kinetically achieving the formation of mono-layered carbon. 1 We also revealed that the thermal treatment [10][11][12][13][14][15][16] of NPCs at high temperatures under an inert atmosphere affords the corresponding NPGs by fusing the H-terminated edges, 2,17 and this is the origin of the electrochemical stability of NPGs. This annealing following the CH 4 -CVD synthesis will also improve the integrity of the graphene architecture by reducing the defect concentration, which is helpful to develop stable electrochemical devices using NPGs such as long-lived airmetal batteries etc.…”

Surface Defect Healing in Annealing from Nanoporous Carbons to Nanoporous Graphenes

“…1,3 The use of relatively inert CH4 9 as the gaseous carbon source is crucial for kinetically achieving the formation of mono-layered carbon. 1 We also revealed that the thermal treatment [10][11][12][13][14][15][16] of NPCs at high temperatures under an inert atmosphere affords the corresponding NPGs by fusing the H-terminated edges, 2,17 and this is the origin of the electrochemical stability of NPGs. This annealing following the CH4-CVD synthesis will also improve the integrity of the graphene architecture by reducing the defect concentration, which is helpful to develop stable electrochemical devices using NPGs such as long-lived air-metal batteries etc.…”

Recent advances and emerging opportunities in rapid thermal annealing (RTA) of polymers

“…11 Further advancements have been made to incorporate an adhesive moiety, 9 spatial control of dopants via block copolymer (BCP) self-assembly, 8,12 dendrimers, 16,17 brushes, [18][19][20] and micelles. 8 Recently, Senger et al extended the polymeric spin-on doping approach to healing defective graphene by doping nitrogen, 21 suggesting that this approach has an enormous opportunity for other classes of materials, not only for traditional semiconductors.…”

“…However, there might be unexplored chemical structures, which are not used in SAMs for monolayer doping. For instance, a recent work by Senger et al demonstrated commercially available, branched polyethylenimine as a polymeric nitrogen dopant, 21 suggesting an immense opportunity to design new polymeric dopants that are not accessible by small molecular synthesis.…”