abstract
Electrical conductivity and Seebeck coefficient of freestanding paper of graphene oxide (GO) and GO reduced by heat treatment at 180 degrees C (rGO) are tuned by addition of carbon nanotubes (CNT). The electrical conductivity of rGO with 50% of CNT is raised to similar to 2940 S/m from similar to 613 S/m for pure rGO or similar to 34 S/m for GO with 50% of CNT without reduction. Moreover, Seebeck coefficient of rGO increases with addition of CNT from -7.04 mu V/K for pure rGO to -20.82 mu V/K for rGO with 50% of CNT, presenting n-type conductivity. As result, calculated power factor PF is enhanced with increasing CNT concentration and the highest PF similar to 1.28 mu W/(K(2)m) is obtained for rGO with 50% of CNT. (C) 2018 Elsevier B.V. All rights reserved.
keywords
HYBRID FILMS; LARGE-AREA
subject category
Chemistry; Materials Science; Metallurgy & Metallurgical Engineering
authors
Okhay, O; Goncalves, G; Dias, C; Ventura, J; Vieira, EMF; Goncalves, LMV; Tkach, A
our authors
Oleksandr Tkach
Assistant Researcher
Olena Okhay
Post-Doc Fellowshipacknowledgements
O.O. and G.G. also thank Portuguese Foundation for Science and Technology (FCT) for the GrantsNo. SFRH/BPD/77704/2011 and SFRH/BPD/84419/2012, respectively, as well as UID/EMS/00481/2013-FCT and CENTRO-01-0145-FEDER-022083. C.D. is thankful to FCT for grant SFRH/BD/101661/2014. E.M.F.V. is grateful for financial support through the FCT grant SFRH/BPD/95905/2013. A.T. acknowledges funds by FEDER through Programa Operacional Factores de Competitividade - COMPETE and national funds through FCT within CICECO Project No. - FCOMP-01-0124-FEDER-037271 (FCT Ref. PEst-C/CTM/LA0011/2013) and independent researcher grant No. IF/00602/2013. Seebeck coefficient measurements were supported by FCT with the reference project UID/EEA/04436/2013, by FEDER funds through the COMPETE 2020 - Programa Operacional Competitividade e Internacionalizacao (POCI) with the reference project POCI-01-0145-FEDER-006941 and by the project PTDC/CTM - NAN/5414/2014 (POCI-01-0145-FEDER-016723). M Ferro is acknowledged for STEM analysis.