Son, Su-Young Jo, Hae-Na Park, Min Jung, Gun Young Lee, Dong Su Lee, Sungho Joh, Han-Ik 2024-01-19T20:04:48Z 2024-01-19T20:04:48Z 2021-09-02 2019-04-10 1944-8244 https://pubs.kist.re.kr/handle/201004/120107 The thermal conductivity (kappa) of two-dimensional conducting and transparent carbon nanosheets (CNSs) prepared by a catalyst- and transfer-free process is calculated for the first time by the optothermal Raman technique. A systematic structural analysis of CNSs reveals that the thickness of polymer films affects the interaction between molecules and a Si wafer significantly, thus helping to determine the ratio of sp(2) and sp(3) bonding configurations of carbon (C) atoms in the CNS. Notably, the holding time of carbonization can realize a hierarchical structure with graphitic carbon dots emerging from the CNS through the rearrangement of carbon atoms, leading to the excellent kappa value of 540 W/(m.K) at 310 K. It is demonstrated that an appropriate increase in carbonization time can be an effective approach for improving the ratio of sp(2)- to sp(3)-bonded C atoms in the CNS. The thermal conductivity of the CNS with the highest ratio of sp(2)- to sp(3)-bonded C atoms exhibits superior behavior and is comparable to that of reduced graphene oxide and supported graphene, respectively. Finally, when the CNS with the highest kappa value of 540 W/(m.K) was applied to a heater as the heat-dissipating material, the heater showed the temperature decrease by 14 degrees C compared to the case without the CNS. The catalyst- and transfer-free approach for the synthesis of CNSs is highly desirable for use as heat sink materials or substrates with heat dissipation functions for extensively integrated electronic devices. English American Chemical Society TEMPERATURE-DEPENDENT RAMAN GRAPHENE TRANSPORT MATRIX Unusual Thermal Conductivity of Carbon Nanosheets with Self-Emerged Graphitic Carbon Dots Article 10.1021/acsami.9b01959 1 ACS Applied Materials & Interfaces, v.11, no.14, pp.13616 - 13623 ACS Applied Materials & Interfaces 11 14 13616 13623 scie scopus 000464769400064 2-s2.0-85064128088 Nanoscience & Nanotechnology Materials Science, Multidisciplinary Science & Technology - Other Topics Materials Science Article TEMPERATURE-DEPENDENT RAMAN GRAPHENE TRANSPORT MATRIX thermal conductivities hierarchical structures carbon nanosheets graphitic carbon dots heat sink materials