Bark, Hyunwoo Lee, Jeongmin Lim, Hosun Koo, Hye Young Lee, Wonmok Lee, Hyunjung 2024-01-20T03:01:04Z 2024-01-20T03:01:04Z 2021-09-05 2016-11-23 1944-8244 https://pubs.kist.re.kr/handle/201004/123417 We report a simple method for preparing highly efficient thermoelectric materials through the fabrication of nitrogen doped reduced graphene oxide (GO) with a porous structure. The samples were produced by thermal annealing of GO/nitrogen-rich polystyrene (N-PS) particle composite films using a colloidal templating method. N-PS particles served as a nitrogen dopant source for the nitrogen-doped thermally reduced graphene oxide (TrGO) as well as sacrificial particles for the porous structure. The S values of the porous TrGO films were negative, indicating that the samples were transformed into n-type materials. Their porous structures simultaneously resulted in materials with high sigma values and low in-plane kappa values by providing numerous air cavities for phonon scattering and destruction of the anisotropic structure, maintaining an interconnected structure for an electron transport path. Thus, the porous TrGO films exhibited enhanced power factors and low kappa values. The highest ZT value of 1.39 X 10(-4) was attained for a porous TrGO film annealed at 1100 degrees C, which was 1200 times higher than that of a nonporous TrGO film. This study emphasizes that an isotropic orientation of two-dimensional materials has a significant effect on the suppression of in-plane kappa, leading to their enhanced thermoelectric performance. English American Chemical Society CARBON NANOTUBES THERMOELECTRIC PERFORMANCE 3-DIMENSIONAL GRAPHENE OXIDE-FILMS THIN-FILM CONDUCTIVITY OPTIMIZATION LAYER ELECTRODES FIGURE Simultaneous Nitrogen Doping and Pore Generation in Thermo-Insulating Graphene Films via Colloidal Templating Article 10.1021/acsami.6b09836 1 ACS Applied Materials & Interfaces, v.8, no.46, pp.31617 - 31624 ACS Applied Materials & Interfaces 8 46 31617 31624 scie scopus 000388913900016 2-s2.0-84999271487 Nanoscience & Nanotechnology Materials Science, Multidisciplinary Science & Technology - Other Topics Materials Science Article CARBON NANOTUBES THERMOELECTRIC PERFORMANCE 3-DIMENSIONAL GRAPHENE OXIDE-FILMS THIN-FILM CONDUCTIVITY OPTIMIZATION LAYER ELECTRODES FIGURE ZT reduced graphene oxide nitrogen doping colloidal templating porous structure