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3 ,)! (Ŗ #(. , .#)(Ŗ1#. %FQBSUNFOUPG"QQMJFE1IZTJDT " BM #') ŗ U P % % ŗ 3,)!(ŗ " 0#& <#( #(.,.#)(ŗ1#."ŗ (ŗ ,)(ŗ 3,) ! (ŗ#(. (()-.,/./,-ŗ , . #) (ŗ1 5JNP7FIWJM»JOFO #. " ŗ ,) (ŗ(() -. ,/ . /, -ŗ 9HSTFMG*aeegjj+ 9HSTFMG*aeegjj+ *4#/ #64*/&44 *4#/ QEG &$0/0.: *44/- *44/ "35 *44/ QEG %&4*(/ "3$)*5&$563& " B "BMUP6OJWFSTJUZ M U 4DIPPMPG4DJFODF 4$*&/$& P %FQBSUNFOUPG"QQMJFE1IZTJDT 5&$)/0-0(: 6 XXXBBMUPGJ OJ W $304407&3 F S T %0$503"- J %0$503"- U %*44&35"5*0/4 Z %*44&35"5*0/4 Aalto University publication series DOCTORAL DISSERTATIONS 5/2012 Hydrogen interaction with carbon nanostructures Timo Vehviläinen Doctoral dissertation for the degree of Doctor of Science in Technology to be presented with due permission of the School of Science for public examination and debate in Auditorium K at the Aalto University School of Science (Espoo, Finland) on the 19th of January 2012 at 13 o’clock. Aalto University School of Science Department of Applied Physics Electronic Properties of Materials Supervisor Prof. Risto Nieminen Instructor Dr. Maria Ganchenkova Preliminary examiners Prof. Tapani Pakkanen, University of Eastern Finland Prof. Gotthard Seifert, Technische Universität Dresden Opponent Prof. Kim Bolton, University of Borås Aalto University publication series DOCTORAL DISSERTATIONS 5/2012 © Timo Vehviläinen ISBN 978-952-60-4469-9 (printed) ISBN 978-952-60-4470-5 (pdf) ISSN-L 1799-4934 ISSN 1799-4934 (printed) ISSN 1799-4942 (pdf) Unigrafia Oy Helsinki 2012 Finland The dissertation can be read at http://lib.tkk.fi/Diss/ Publication orders (printed book): [email protected] Abstract Aalto University, P.O. Box 11000, FI-00076 Aalto www.aalto.fi Author Timo Vehviläinen Name of the doctoral dissertation Hydrogen interaction with carbon nanostructures Publisher School of Science Unit Department of Applied Physics Series Aalto University publication series DOCTORAL DISSERTATIONS 5/2012 Field of research Computational physics Manuscript submitted 4 October 2011 Manuscript revised 27 December 2011 Date of the defence 19 January 2012 Language English Monograph Article dissertation (summary + original articles) Abstract The synthesis of various new carbon nanomaterials, such as graphene and three dimensional fullerene solids has created much interest in scientific community, since it is assumed that these novel structures have many potential applications in the field of materials science. However, many important questions are still unanswered, varying from synthesis to interaction between adsorbents and carbon substrate. This thesis presents methods and results for simulations of a wide variety of carbon nanostructures of different dimensionalities: from zero dimensional fullerenes to three dimensional porous carbon structures. In order to simulate a wide range of different time scales, multiscale simulations, which combine ab initio density-functional theory calculations, classical molecular dynamics and the kinetic Monte Carlo method are performed.The focus of the thesis is on the structures which could have revolutionary applications in the future and to which the materials science community has built up great expectations. Functionalization of carbon materials via hydrogenation has recently attracted a lot of attention. Two main mainstream topics are: to modify electronic properties and/or to use the structure for hydrogen storage. For both of these, a profound knowledge of hydrogen interaction with the carbon structures is indispensable to be able to control the material properties. In this thesis, special attention has been paid to hydrogen interaction with carbon nanostructures and how hydrogen modifies the properties of these materials. Also, kinetic behaviour of hydrogen on the studied structures are investigated. The results presented in this thesis clarify hydrogen adsorption/desorption energetics on various carbon nanostructures and how hydrogen can be used as a tool to nano-engineer the electronic properties. In addition, several new carbon nanostructures found in our studies are presented. These novel structures have interesting properties and could be suitable for many applications. Keywords carbon, hydrogen, fullerene, nanotube, interaction, density functional theory ISBN (printed) 978-952-60-4469-9 ISBN (pdf) 978-952-60-4470-5 ISSN-L 1799-4934 ISSN (printed) 1799-4934 ISSN (pdf) 1799-4942 Location of publisher Espoo Location of printing Helsinki Year 2012 Pages 184 The dissertation can be read at http://lib.tkk.fi/Diss/ Tiivistelmä Aalto-yliopisto, PL 11000, 00076 Aalto www.aalto.fi Tekijä Timo Vehviläinen Väitöskirjan nimi Hiilen nanorakenteiden ja vedyn välinen vuorovaikutus Julkaisija Perustieteiden korkeakoulu Yksikkö Teknillisen fysiikan laitos Sarja Aalto University publication series DOCTORAL DISSERTATIONS 5/2012 Tutkimusala Laskennallinen fysiikka Käsikirjoituksen pvm 04.10.2011 Korjatun käsikirjoituksen pvm 27.12.2011 Väitöspäivä 19.01.2012 Kieli Englanti Monografia Yhdistelmäväitöskirja (yhteenveto-osa + erillisartikkelit) Tiivistelmä Uusien hiilen nanomateriaalien kuten grafeenin ja 3-dimensioisten fullereenipolymeerien syntetisointi on herättänyt tiedepiireissä paljon kiinnostusta, koska oletetaan, että näillä materiaaleilla on monia käytännön sovelluksia. Monet tärkeät kysymykset liittyen näiden materiaalien syntetisointiin sekä nanorakenteiden vuorovaikutuksiin niihin adsorboituneiden hiukkasten kanssa ovat kuitenkin vielä vastaamatta. Tämä väitöskirja esittelee menetelmät ja tulokset useiden erilaisten hiilen nanorakenteiden simulaatioista: 0-dimensioisista fullereeneistä 3-dimensioisiin huokoisiin hiilirakenteisiin. Työssä on käytetty monen mittakaavan simulaatioita jotta on pystytty mallintamaan ilmiöitä mahdollisimman laajalla aikaskaalalla. Nämä simulaatiot yhdistävät tiheysfunktionaaliteoriaan perustuvia laskuja, klassista molekyylidynamiikkaa ja Monte Carlo menetelmiin perustuvia simulaatiomalleja. Väitöstyön painopiste on rakenteissa joilla voi tulevaisuudessa olla käänteentekeviä sovelluksia ja joihin tiedepiirit kohdistavat suuria odotuksia. Hiilimateriaalien ominaisuuksien muokkaaminen hydraamalla on viime aikoina saanut paljon huomiota. Hydrauksella on pyritty joko muokkaamaan elektronisia ominaisuuksia tai käyttämään hiilimateriaalia vedyn varastointiin. Molemmissa tapauksissa syvällinen ymmärrys vedyn ja hiilirakenteen välisestä vuorovaikutuksesta on välttämätöntä. Tässä väitöskirjassa on tarkasteltu erityisesti vedyn vuorovaikutusta hiilen nanomateriaalien kanssa ja tutkittu kuinka vety muokkaa näiden materiaalien ominaisuuksia. Vedyn kinetiikka hiilen nanorakenteissa on myös yksi väitöksen tutkimuskohteista. Tämän väitöskirjan tulokset selventävät vedyn adsoptio/desorptio kinetiikkaa hiilen nanorakenteissa ja kuinka vetyä voidaan käyttää näiden materiaalien elektronisten ominaisuuksien muokkaamiseen. Lisäksi, väitöskirja esittelee useita uusia nanorakenteita joilla on mielenkiintoisia ominaisuuksia ja joita voidaan mahdollisesti käyttää monissa sovelluksissa. Avainsanat hiili, vety, fullereeni, nanoputki, vuorovaikutus, tiheysfunktionaaliteoria ISBN (painettu) 978-952-60-4469-9 ISBN (pdf) 978-952-60-4470-5 ISSN-L 1799-4934 ISSN (painettu) 1799-4934 ISSN (pdf) 1799-4942 Julkaisupaikka Espoo Painopaikka Helsinki Vuosi 2012 Sivumäärä 184 Luettavissa verkossa osoitteessa http://lib.tkk.fi/Diss/ Preface This thesis has been prepared in the Computational Nanoscience group (COMP), in the Department of Applied Physics, Aalto University School of Science during the years 2006-2011. I wish to thank Prof. Risto Nieminen for the opportunity of working in COMP, advice, and ideas during this work. I am grateful to my instructor Dr. Maria Ganchenkova who has given me excellent guidance during the research work. I also like to thank the members of the Electronic Properties of Materials group for inspiring research atmosphere. I especially wish to thank M.Sc Laura Oikkonen and Dr. Vladimir Borodin for contributing to this work. This research has been supported by Academy of Finland through the Centre of Excellence Program (2006-2011) and in the framework of the project SA 120004. I acknowledge the generous computing resources provided by IT Center for Science Ltd (CSC). Family and friends, thank you! Espoo, December 2011 Timo Vehvil¨ainen Contents Preface i List of Figures iv List of Abbreviations vii List of Publications ix 1 Introduction 1 1.1 Carbon of different dimensionalities ............... 1 1.1.1 0Dcarbon:Fullerenes.................. 2 1.1.2 1Dcarbon:Nanotubes.................. 4 1.1.3 2Dcarbon:Graphene................... 8 1.1.4 3D carbon: Carbon solids and exotic carbon structures 11 1.2 Hydrogenated carbon: properties and applications ....... 17 1.3 Goals and objectives of the work ................ 20 2 Computational methods and techniques 21 2.1 Computational methods in condensed matter physics ..... 21 2.2Densityfunctionaltheory..................... 24 2.2.1 Basic principles ...................... 24 2.2.2 Accuracyoftheresults..................27 2.3 Computational methods for the moving nuclei ......... 27 2.3.1 Calculationofphonons.................. 27 2.3.2 Finding minimum energy paths for reactions ...... 29 2.3.3 Dynamicalsimulations.................. 32 2.3.4 Simulation of kinetic processes .............. 34 2.4Simulationpackages........................ 35 2.4.1 Vienna Ab-initio simulationpackage.......... 35 2.4.2 Abinit........................... 36 2.4.3 CPMD........................... 37 2.4.4 CASINO.......................... 37 2.4.5 PARCAS......................... 37 2.5 Definitions ............................
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