University of Groningen Controlling vacancies in chalcogenides as energy harvesting materials Li, Guowei IMPORTANT NOTE: You are advised to consult the publisher's version (publisher's PDF) if you wish to cite from it. Please check the document version below. Document Version Publisher's PDF, also known as Version of record Publication date: 2016 Link to publication in University of Groningen/UMCG research database Citation for published version (APA): Li, G. (2016). Controlling vacancies in chalcogenides as energy harvesting materials [Groningen]: University of Groningen Copyright Other than for strictly personal use, it is not permitted to download or to forward/distribute the text or part of it without the consent of the author(s) and/or copyright holder(s), unless the work is under an open content license (like Creative Commons). Take-down policy If you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim. Downloaded from the University of Groningen/UMCG research database (Pure): http://www.rug.nl/research/portal. For technical reasons the number of authors shown on this cover page is limited to 10 maximum. Download date: 19-01-2019
Controlling vacancies in chalcogenides as energy harvesting materials Guowei Li
Controlling vacancies in chalcogenides as energy harvesting materials Guowei Li PhD thesis University of Groningen The work described in this thesis was performed in the group Solid State Materials for Electronics (part of the Zernike Institute for Advanced Materials) of the University of Groningen, the Netherlands. This work was supported financially by the Netherlands Organization for Scientific research (NWO) NWO-CW 712.011.003 Zernike Institute PhD thesis series: 2016-31 ISSN: 1570-1530 ISBN (Printed version): 978-90-367-9263-9 ISBN (Electronic version): 978-90-367-9262-2 Cover idea: Guowei Li & Zhuojun Meng Cover design: Zhuojun Meng Printed by: Ipskamp Printing 2
Controlling vacancies in chalcogenides as energy harvesting materials Proefschrift ter verkrijging van de graad van doctor aan de Rijksuniversiteit Groningen op gezag van de rector magnificus prof. dr. E. Sterken en volgens besluit van het College voor Promoties. De openbare verdediging zal plaatsvinden op maandag 7 november 2016 om 09.00 uur door Guowei Li geboren op 29 september 1986 te Shandong, China 3
Promotores Prof. dr. T.T.M. Palstra Prof. dr. R.A. de Groot Copromotor Dr. G.R. Blake Beoordelingscommissie Prof. dr. B.J. Kooi Prof. dr. B. Dam Prof. dr. B. Lotsch 4
CHAPTER 1 Vacancies in functional materials: Perfect imperfection, from properties to applications 1 1.1 Introduction... 1 1.2 Fundamental understanding... 4 1.2.1 Types of vacancies... 4 1.2.2 Vacancy creation... 5 1.3 Properties tailored by vacancy engineering... 6 1.3.1 Band structure tailoring... 7 1.3.2 Electrical transport... 10 1.3.3 Room temperature magnetism... 12 1.4 Applications in energy conversion and storage... 15 1.4.1 Lithium ion batteries... 16 1.4.2 Solar cells... 18 1.4.3 Hydrogen evolution... 21 1.5 Summary and outlook... 23 References... 25 CHAPTER 2 Sample synthesis and characterization 29 2.1 Synthesis... 30 2.1.1 Hydrothermal method... 30 2.1.2 Solid state synthesis... 31 2.2 Structural and physical properties characterization... 32 2.2.1 Powder X-ray diffraction (XRD)... 32 2.2.2 X-ray Photoelectron Spectroscopy (XPS)... 32 2.2.3 Mössbauer spectroscopy... 34 2.2.4 Magnetic Property Measurement System (MPMS)... 35 2.2.5 Physical Property Measurement System (PPMS)... 35 References... 36 CHAPTER 3 High purity Fe 3 S 4 greigite microcrystals for magnetic and electro-chemical performance 37 3.1 Introduction... 37 3.2 Method... 39 3.2.1 Synthesis... 39 3.2.2 Characterization... 40 3.2.3 Electrochemical measurements... 40 3.3 Results and discussion... 41 3.3.1 Phase and morphology characterization... 41 3.3.2 Mössbauer spectra... 42 3.3.3 Magnetic property... 44 3.3.4 Raman spectra of greigite... 47 3.3.5 Electrical transport properties... 48 3.3.6 Electrochemical properties... 49 3.4 Conclusion... 51 Supplementary information... 52 References... 57 CHAPTER 4 Band gap narrowing of SnS 2 superstructures with improved hydrogen production 61 4.1 Introduction... 61 4.2 Experimental... 63 4.2.1 Preparation of flower-like metal sulfide 3D structures... 63 5
4.2.2 Photocatalytic hydrogen evolution... 63 4.3 Results and discussion... 64 4.3.1 Material characteristics... 64 4.3.2 Photocatalytic activity... 65 4.3.3 X-ray photoelectron spectroscopy measurement... 67 4.4 Formation mechanism... 69 4.5 Conclusions... 71 Supplementary information... 73 References... 82 CHAPTER 5 Thermoelectric performance of marcasite FeSe 2 85 5.1 Introduction... 85 5.2 Method... 88 5.2.1 Synthesis... 88 5.2.2 Characterization... 88 5.3 Results and discussion... 89 5.3.1 Phase and morphology... 89 5.3.2 Magnetic properties... 90 5.3.3 Electrical transport properties... 93 5.3.4 Thermoelectric performance... 96 5.4 Conclusions... 98 Supplementary information... 99 References... 105 CHAPTER 6 Metal-insulator transition induced by spin reorientation in Fe 7 Se 8 grain boundaries 109 6.1 Introduction... 109 6.2 Synthesis and characterization... 112 6.3 Results and discussion... 113 6.3.1 Phase and morphology... 113 6.3.2 Electrical resistivity... 114 6.3.3 Magnetization properties... 118 6.3.4 Mössbauer spectra... 121 6.3.5 MI transition mechanism... 125 6.4 Conclusion... 127 References... 128 SUMMARY SAMENVATTING ACKNOWLEDGMENTS 6