Dr. -Ing. C. V. S Kiran

Dr. -Ing. C. Venkata Sai KiranBetter Materials for a Better Tomorrow

Scientist/Engineer,
Vikram Sarabhai Space Centre (VSSC),
Indian Space Research Organization (ISRO)
Thiruvananthapuram, Kerala, India.


About Me

Dr.-Ing. Venkata Sai Kiran Chakravadhanula

Dr. - Ing. Venkata Sai Kiran Chakravadhanula

Scientist/Engineer,
Vikram Sarabhai Space Centre (VSSC)
,
Indian Space Research Organization.
also Associated as

Guest Scientist,
Helmholtz Institute Ulm (HIU) for Electrochemical Energy Storage,
Karlsruhe Institute of Technology(KIT).
Gast Dozent,
Technical University of Darmstadt.
Resume - Password provided on request
List of Publications, conference proceedings and Patent (Last updated on:)
List of invited contributions (Last Updated on:)

Memberships

Member - Deutsche Physikalische Gesellschaft - DPG
Advisor for the Software - Mendeley
Member - European Microscopy Society (EMS)
Member - Deutschen Gesellschaft für Elektronenmikroskopie e.V. (DGE)
Member - Elsevier Connected Panel
Member - Academy for Science, Technology and Communication (ASTC)
Life Member - Indian Institute of Metal (IIM)
Life Member - Electron Microscopy Society of India (EMSI)
Life Member - LM B601- Materials Research Society of India (MRS-I)
Life Member - Powder Metallurgy Association of India (PMAI)
Life Member - LM 711 - Magnetic Society of India (MSI)

Invited Contributions: Dr.-Ing. V.S.K. Chakravadhanula

Invited Contributions

2017
28
Recent Advances in in situ transmission electron microscopy of electrochemical material systems
Link to slides
XXXVIII Annual Meeting of the Electron Microscope Society of India (EMSI) EMSI-2017,
July 17-19, 2017: Mahabalipuram, Tamilnadu, India.
27
Electrochemistry at the nanoscale: in situ transmission electron microscopy
Link to slides
3rd International Freiberg Conference on Electrochemical Storage Materials EStorM,
"Advanced approaches for elucidating electrochemical energy storage and conversion"
June 12-14, 2017: Freiberg, Germany.
26
Stimuli based nanochemistry inside the electron microscope
Link to slides
Symposium & Workshop on Advanced In-Situ Electron Microscopy, Academic Centre for Materials and Nanotechnology,
May 17-18, 2017: Kraków, Poland.
25
Nanoscale Electrochemistry inside the electron microscope
Link to slides
Elektrochemie – Anwendungen in Forschung und Technik, C3 Prozess- und Analysentechnik,
March 27-28, 2017: Frankfurt, Germany.
24
Magnetic Materials: An in situ TEM approach
Link to slides
International Conference on Magnetic Materials and Applications (ICMAGMA-2017), jointly organized by Defence Metallurgical Research Laboratory (DMRL), Hyderabad and Magnetics Society of India (MSI),
Feb. 01-03, 2017: Hyderabad, India.
2016
23
In situ stimuli based characterization of materials at high spatial resolution
Defence Metallurgical Research Laboratory,
Hyderabad
Dec. 2, 2016: Hyderabad, India
22
From conventional towards in situ stimuli based characterization of materials through TEM
International Advanced Research Centre for Powder Metallurgy & New Materials,
Hyderabad
Dec. 1, 2016: Hyderabad, India
21
From beam sensitivity towards in situ electrochemistry in the TEM
Department of Metallurgical and Materials Engineering, IIT Madras & Indian Institute of Metals, Chennai Chapter
Nov. 28, 2016: Chennai, India.
20
Challenges and Possibilities with in situ TEM studies
Link to slides
"JEOL JEM-F200: The new world for In-Situ Applications" JEOL F2 and Gatan
October 20, 2016
JEOL GmbH
Gute Änger 30,
85356 Freising, Germany
19 From beam sensitivity towards in situ electrochemistry in the TEM

Pre Conference Workshop - EMSI 2016: In situ Electron Microscopy (May-30th - June 1st)
Link to slides: 31st May; 01st June;
“International Conference on Electron Microscopy and XXXVII Annual Meeting of the Electron Microscope Society of India (EMSI)
June 2 - 4, 2016,
IIT (BHU) Varanasi, India.
18
Stimuli based in situ characterization of materials at high spatial resolution
Link to slides
Department of Metallurgy and Materials Engineering, Indian Institute of Technology, Chennai
January 11, 2016,
Chennai, Tamil Nadu, India
17
Electron Microscopic characterization of biological materials
Link to slides
“International Conference on Advances in plant and microbe research - ICAPMR 2016”
January 6-8, 2016,
Guntur, Andhra Pradesh, India.
16
Transmission electron microscopy: Current Status and Future Outlook
Department of Chemistry, Defence Institute of Advanced Technology,
January 5, 2016,
Pune, India.
15
Recent advances in Transmission Electron Microscopy
Department of Mechanical Engineering, GITAM school of technology, Hyderabad campus
January 2, 2016,
Hyderabad, Telangana, India
14
High spatial resolution stimuli based in situ characterization of materials using TEM
Department of Physics, Acharya Nagarjuna University
January 1, 2016,
Guntur, Andhra Pradesh, India.
13
Stimuli based in situ characterization of materials using TEM
Department of Mechanical Engineering, Acharya Nagarjuna University
January 1, 2016,
Guntur, Andhra Pradesh, India.
2015
12
High spatial resolution stimuli based in situ characterization of materials using TEM
Department of Physics, Sri Venkateswara University
December 31, 2015,
Tirupati, Andhra Pradesh, India.
11
In situ TEM Electrochemical Studies of a Fluoride based Solid-State Battery
“International Conference on Electron Microscopy and XXXVI Annual Meeting of the Electron Microscope Society of India (EMSI)
July 8-10, 2015,
Mumbai, India.
2014
10
Characterization of Ayurvedic Bhasmas by Transmission Electron Microscopy
Research and Development unit,
Dabur India Limited
July 11, 2014: New-Delhi, India.
9
Reversible in situ TEM electrochemical studies of Fluoride Ion Battery
“International Conference on Electron Microscopy of the Electron Microscope Society of India (EMSI)
July 9-11, 2014,
New-Delhi, India.
2013
8
Structure and deformation processes of nanocrystalline metals characterized by ACOM-STEM in combination with in situ straining
“International Conference on Electron Microscopy and the XXXIV Annual Meeting of the Electron Microscope Society of India (EMSI)
July 3-5, 2013,
Kolkata, West Bengal, India.
2012
7
Advanced transmission electron microscopy of nano-structured materials
Defence Institute of Advanced Technology,
January 2012,
Pune, India.
2011
6
Recent advances in transmission electron microscopy of nano-structured materials
Delhi University,
Dec 7, 2011,
New-Delhi, India.
5
Transmission electron microscopy of nano-structured materials
National Physical Laboratory (CSIR-NPL),
Dec 8, 2011,
New Delhi, India.
4
Advanced transmission electron microscopy of nano-structured materials
Indian Institute of Chemical Technology(CSIR-IICT),
December 2011,
Hyderabad, Andhra Pradesh, India.
2010
3
Synthesis and characterization of the functional metal-polymer and metal-oxide based nanocomposites.
“International conference on nanomaterials: synthesis, characterization and applications (ICN-2010)”,
April 27-29, 2010,
Kottayam, Kerala, India.
2008
2
Polymer-nanocomposites for functional applications
“International conference on advances in polymer technology (APT-2008)”,
September 25-27, 2008,
Kochi, Kerala, India.
1
Polymer-nanocomposites for functional applications
“Second international conference on polymer blends, composites,  IPN’s, membranes, and gels: macro to nano scales (ICBC – 2008)”
September 22-24, 2008,
Kottayam, Kerala, India.


Projects: Dr.-Ing. V.S.K. Chakravadhanula

Projects

2015
DFG - Forschergruppe Project FOR 2093: Memristive devices: In situ Transmission Electron Microscopic investigations of memristive devices.


Publications: Dr.-Ing. V.S.K. Chakravadhanula

Publications

2017
2016 2015 2014 2013 2012
2011 2010 2009 2008 2007 2006
Conference Proceedings
Coverpages / Frontpage
Patents



2017
78


77


76
O. Wenzel, M. Schwotzer, E. Mueller, V.S.K. Chakravadhanula, T. Scherer, A. Gerdes, “Investigating the pore structure of the calcium silicate hydrate phase”, Materials Characterization, 133, 133-137, 2017. 10.1016/j.matchar.2017.09.035
75
H. Li , G. Gordeev , S. Wasserroth , V.S.K. Chakravadhanula, C.N. Shyam Kumar, F. Hennrich , A. Jorio , S. Reich, R. Krupke, “Inner and Outer Wall Sorting of Double Walled Carbon Nanotubes”, Nature Nanotechnology, 12, 1176-1182, 2017.
10.1038/nnano.2017.207
74
C.N. Shyam Kumar, V.S.K. Chakravadhanula, A. Riaz, S. Dehm, D. Wang, X. Mu, B. Flavel, R. Krupke, C.Kuebel, ”Understanding Graphitization and Growth of free-standing Nanocrystalline Graphene using in situ Transmission Electron Microscopy”, Nanoscale, 9, 12835-12842, 2017.
10.1039/C7NR03276E
73
H. Bhatia, D.T. Thieu, A.H. Pohl, V.S.K. Chakravadhanula, M.H. Fawey, C. Kübel, and M. Fichtner, "Conductivity Optimization of Tysonite-type La1–xBaxF3–x Solid Electrolytes for Advanced Fluoride Ion Battery”, ACS Appl. Mater. Interfaces, 9, 28, 23707, 2017.
10.1021/acsami.7b04936
72
J. Strobel, M. Hansen, S. Dirkmann, K. Neelisetty, M. Ziegler, G. Haberfehlner, R. Popescu, G. Kothleitner, V.S.K. Chakravadhanula, C. Kübel, H. Kohlstedt, T. Mussenbrock, L. Kienle, “In depth nano spectroscopic analysis on homogeneously switching double barrier memristive devices”, Journal of Applied Physics 121, 245307, 2017.
10.1063/1.4990145
71
M.H. Fawey*, D.T. Thieu*, H. Bhatia, T. Diemant, V.S.K. Chakravadhanula, R.J. Behm, C. Kübel, and M. Fichtner, “CuF2 as Reversible Cathode for Fluoride Ion Batteries”, Advanced Functional Materials, 1701051, 2017.* Equal Contribution first authors.
10.1002/adfm.201701051
70
C.B. Minella, P. Gao, Z. Zhao-Kargera, X. Mu, T. Diemant, M. Pfeifer, V.S.K. Chakravadhanula, R. J. Behm, M. Fichtner, “Interlayer-Expanded VOCl as Electrode for Magnesium-Based Batteries”, ChemElectroChem, vol 4, 738-745, 2017.
10.1002/celc.201700034
69
A.S. Parvathy, A. Molinari, A. Benes, C.Loho, V.S.K. Chakravadhanula, O.Clemens,”Conductivity study of thin PLD grown epitaxial films of BaFeO2.5 and hydrated BaFeO2.5-d(OH)2x”, Journal of Physics D: Applied Physics, vol. 50, no. 11, 2017.
10.1088/1361-6463/aa5718
68 A. Sarkar, R. Djenadic, N. J. Usharani, K. P. Sanghvi, V.S.K. Chakravadhanula, A. S. Gandhi, H. Hahn, and S. S. Bhattacharya, “Nanocrystalline multicomponent entropy stabilised transition metal oxides,” Journal of the European Ceramic Society, vol. 37, issue 2, February 2017, 747-754. 10.1016/j.jeurceramsoc.2016.09.018
67
S. Bestgen, O. Fuhr, B. Breitung, V.S.K. Chakravadhanula, G. Guthausen, F. Hennrich, W. Yu, M.M. Kappes, P.W. Roesky and Dieter Fenske, “Ag115S34(SCH2C6H4tBu)47(dpph)6]: synthesis,crystal structure and NMR investigations of a soluble silver chalcogenide nanocluster”, RSC Chemical Science Edge Article, vol 8, 2235, 2017.
10.1039/C6SC04578B
2016
66
J. Strobel, K. Neelisetty, V.S.K. Chakravadhanula, L. Kienle, “Transmission Electron Microscopy on Memristive Devices: An Overview”, Applied Microscopy, Dec 2016.
10.9729/AM.2016.46.4.206
65 V.S.K. Chakravadhanula, T.S. Teodoro, T. Scherer, S.K. Garlapati, A. Kobler, K.K. Neelisetty, M.H. Fawey and C. Kuebel, “Electrochemistry in Liquid Environments: Challenges in the Presence of Accelerated Electrons” Invited, G.I.T. Imaging & Microscopy, EMC Special, August 2016.
Link
64 R. Djenadic, A. Sarkar, O. Clemens, C. Loho, M. Botros, V. S. K. Chakravadhanula, C. Kübel, S. S. Bhattacharya, A. S. Gandhi, and H. Hahn, “Multicomponent equiatomic rare earth oxides,” Materials Research Letters, vol. 3831, no. August, pp. 1–8, Aug. 2016.
10.1080/21663831.2016.1220433
63
X. Mu, A. Kobler, D. Wang, V. S. K. Chakravadhanula, S. Schlabach, D. V. Szabó, P. Norby, and C. Kübel, “Comprehensive analysis of TEM methods for LiFePO4/FePO4 phase mapping: spectroscopic techniques (EFTEM, STEM-EELS) and STEM diffraction techniques (ACOM-TEM),” Ultramicroscopy, vol. 170, pp. 10–18, Nov. 2016.
10.1016/j.ultramic.2016.07.009
62
M. Hammad Fawey, V.S.K. Chakravadhanula*, M. A. Reddy, C. Rongeat, T. Scherer, H. Hahn, M. Fichtner, and C. Kübel, “In situ TEM studies of micron-sized all-solid-state fluoride ion batteries: Preparation, prospects, and challenges,” Microscopy Research and Technique, vol. 79, no. 7, pp. 615–624, Jul. 2016.
10.1002/jemt.22675
61
M.A. Cambaz, B.P. Vinayan, O. Clemens, A.R. Munnangi, V.S.K. Chakravadhanula, C. Kübel, and M. Fichtner, “Vanadium Oxyfluoride/Few-Layer Graphene Composite as a High-Performance Cathode Material for Lithium Batteries,” Inorganic Chemistry, vol.55, no.8, pp.3789–3796, Apr. 2016.
10.1021/acs.inorgchem.5b02687
60
R. Raccichini, A. Varzi, V. S. K. Chakravadhanula, C. Kübel, and S. Passerini, “Boosting the power performance of multilayer graphene as lithium-ion battery anode via unconventional doping with in-situ formed Fe nanoparticles,” Scientific Reports, vol. 6, no. November 2015, p. 23585, Mar. 2016.
10.1038/srep23585
59
P. Wagener, J. Jakobi, C. Rehbock, V.S.K. Chakravadhanula, C. Thede, U. Wiedwald, M. Bartsch, L. Kienle, and S. Barcikowski, “Solvent-surface interactions control the phase structure in laser-generated iron-gold core-shell nanoparticles,” Scientific Reports, vol. 6, no. November 2015, p. 23352, Mar. 2016.
10.1038/srep23352
58
A. Pohl, A. Schröder, A. Guda, V. Shapovalov, V.S.K. Chakravadhanula, R. Witte, T. Diemant, H. Emerich and M. Fichtner, “Graphene oxide based iron fluoride (HTB-FeF3/rGO) composite as high-energy cathode for Li-ion batteries” Journal of Power sources, vol 313, p 213, 2016.
10.1016/j.jpowsour.2016.02.080
57
P. Gao, M. A. Reddy, X. Mu, T. Diemant, L. Zhang, Z. Zhao-Karger, V. S. K. Chakravadhanula, O. Clemens, R. J. Behm, and M. Fichtner, “VOCl as a Cathode for Rechargeable Chloride Ion Batteries,” Angewandte Chemie International Edition, p. n/a–n/a, Feb. 2016.
10.1002/anie.201509564
10.1002/ange.201509564
56
B. P. Vinayan, Z. Zhao-Karger, T. Diemant, V. S. K. Chakravadhanula, N. I. Schwarzburger, M. A. Cambaz, R. J. Behm, C. Kübel, and M. Fichtner, “Performance study of magnesium–sulfur battery using a graphene based sulfur composite cathode electrode and a non-nucleophilic Mg electrolyte,” Nanoscale, vol. 8, no. 6, pp. 3296–3306, 2016.
10.1039/C5NR04383B
55
M. A. Cambaz, M. Anji Reddy, B. P. Vinayan, R. Witte, A. Pohl, X. Mu, V. S. K. Chakravadhanula, C. Kübel, and M. Fichtner, “Mechanical Milling Assisted Synthesis and Electrochemical Performance of High Capacity LiFeBO3 for Lithium Batteries,” ACS Applied Materials & Interfaces, vol. 8, no. 3, pp. 2166–2172, Jan. 2016.
10.1021/acsami.5b10747
54
M. A. Reddy, B. Breitung, C. Wall, S. Trivedi, V. S. K. Chakravadhanula, M. Helen, and M. Fichtner, “Facile Synthesis of Carbon-Metal Fluoride Nanocomposites for Lithium-Ion Batteries,” Energy Technology, vol. 4, no. 1, pp. 201–211, Jan. 2016.
10.1002/ente.201500358
53
Z. Śniadecki, D. Wang, Y. Ivanisenko, V. S. K. Chakravadhanula, C. Kübel, H. Hahn, and H. Gleiter, “Nanoscale morphology of Ni50Ti45Cu5 nanoglass,” Materials Characterization, vol. 113, pp. 26–33, Mar. 2016.
10.1016/j.matchar.2015.12.025
2015
52
F. Mueller, D. Bresser, V. S. K. Chakravadhanula, and S. Passerini, “Fe-doped SnO2 nanoparticles as new high capacity anode material for secondary lithium-ion batteries,” Journal of Power Sources, vol. 299, pp. 398–402, Aug. 2015.
10.1016/j.jpowsour.2015.08.018
51
G. Beck, S. Barcikowski, V. S. K. Chakravadhanula, M. Comesaña-Hermo, M. Deng, M. Farle, M. Hilgendorff, J. Jakobi, J. Janek, L. Kienle, B. Mogwitz, T. Schubert, and F. Stiemke, “An approach for transparent and electrically conducting coatings: A transparent plastic varnish with nanoparticulate magnetic additives,” Thin Solid Films, vol. 595, pp. 96–107, Oct. 2015.
10.1016/j.tsf.2015.10.059
50
S. K. Garlapati, T. T. Baby, S. Dehm, M. Hammad, V. S. K. Chakravadhanula, R. Kruk, H. Hahn, and S. Dasgupta, “Ink-Jet Printed CMOS Electronics from Oxide Semiconductors,” Small, vol. 11, no. 29, pp. 3591–3596, Aug. 2015.
10.1002/smll.201403288
49
A. Riaz, F. Pyatkov, A. Alam, S. Dehm, A. Felten, V. S. K. Chakravadhanula, B. S. Flavel, C. Kübel, U. Lemmer, and R. Krupke, “Light emission, light detection and strain sensing with nanocrystalline graphene,” Nanotechnology, vol. 26, no. 32, p. 325202, Aug. 2015.
10.1088/0957-4484/26/32/325202
48
N. Laszczynski, J. von Zamory, J. Kalhoff, N. Loeffler, V. S. K. Chakravadhanula, and S. Passerini, “Improved Performance of VOx -Coated Li-Rich NMC Electrodes,” ChemElectroChem, July 2015.
10.1002/celc.201500219
47
B. Mojic-Lanté, R. Djenadic, V. S. K. Chakravadhanula, C. Kübel, V. V. Srdic, and H. Hahn, “Chemical Vapor Synthesis of FeOx -BaTiO3 Nanocomposites,” J. Am. Ceram. Soc., vol. 98, no. 6, pp. 1724–1730, Jun. 2015.
10.1111/jace.13531
46
M. Mohri, M. Nili-Ahmadabadi, and V. S. K. Chakravadhanula, “Crystallization study of amorphous sputtered NiTi bi-layer thin film,” Mater. Charact., vol. 103, pp. 75–80, May 2015.
10.1016/j.matchar.2015.03.017
45
R. Raccichini, A. Varzi, V. S. K. Chakravadhanula, C. Kübel, A. Balducci, and S. Passerini, “Enhanced low-temperature lithium storage performance of multilayer graphene made through an improved ionic liquid-assisted synthesis,” J. Power Sources, vol. 281, pp. 318–325, May 2015.
10.1016/j.jpowsour.2015.01.183
44
M. Mohri, M. Nili-Ahmadabadi, J. Ivanisenko, R. Schwaiger, H. Hahn, and V. S. K. Chakravadhanula, “Microstructure and mechanical behavior of a shape memory Ni–Ti bi-layer thin film,” Thin Solid Films, vol. 583, pp. 245–254, May 2015.
10.1016/j.tsf.2015.03.057
43
K. E. Moore, M. Pfohl, D. D. Tune, F. Hennrich, S. Dehm, V. S. K. Chakravadhanula, C. Kübel, R. Krupke, and B. S. Flavel, “Sorting of Double-Walled Carbon Nanotubes According to Their Outer Wall Electronic Type via a Gel Permeation Method,” ACS Nano, vol. 9, no. 4, pp. 3849–3857, Apr. 2015.
10.1021/nn506869h
42
E. Redel, V. S. K. Chakravadhanula, Y. Lan, C. Natzeck, and S. Heissler, “On the self-assembly of TiOx into 1D NP network nanostructures,” Nanotechnology, vol. 26, no. 5, p. 051001, Feb. 2015.
10.1088/0957-4484/26/5/051001
41
V. Hrkac, A. Kobler, S. Marauska, A. Petraru, U. Schürmann, V. S. K. Chakravadhanula, V. Duppel, H. Kohlstedt, B. Wagner, B. V. Lotsch, C. Kübel, and L. Kienle, “Structural study of growth, orientation and defects characteristics in the functional microelectromechanical system material aluminium nitride,” J. Appl. Phys., vol. 117, no. 1, p. 014301, Jan. 2015.
10.1063/1.4905109
2014
40
K. E. Moore, M. Pfohl, F. Hennrich, V. S. K. Chakravadhanula, C. Kübel, M. M. Kappes, J. G. Shapter, R. Krupke, and B. S. Flavel, “Separation of double-walled carbon nanotubes by size exclusion column chromatography.,” ACS Nano, vol. 8, no. 7, pp. 6756–64, Jul. 2014.
10.1021/nn500756a
39
K. Zhang, A. D. R. Pillai, M. Tangirala, D. Nminibapiel, K. Bollenbach, W. Cao, H. Baumgart, V. S. K. Chakravadhanula, C. Kübel, and V. Kochergin, “Synthesis and characterization of PbTe thin films by atomic layer deposition,” Phys. Status Solidi, vol. 211, no. 6, pp. 1329–1333, Jun. 2014.
10.1002/pssa.201300307
38
S. Makumire, V. S. K. Chakravadhanula, G. Köllisch, E. Redel, and A. Shonhai, “Immunomodulatory activity of zinc peroxide (ZnO2) and titanium dioxide (TiO2) nanoparticles and their effects on DNA and protein integrity.,” Toxicol. Lett., vol. 227, no. 1, pp. 56–64, May 2014.
10.1016/j.toxlet.2014.02.027
37
K. Zhang, A. D. R. Pillai, K. Bollenbach, D. Nminibapiel, W. Cao, H. Baumgart, T. Scherer, V. S. K. Chakravadhanula, C. Kübel, and V. Kochergin, “Atomic Layer Deposition of Nanolaminate Structures of Alternating PbTe and PbSe Thermoelectric Films,” ECS Journal of Solid State Science and Technology, vol. 3, no. 6, pp. P207–P212, 2014

36
D. Nminibapiel, K. Zhang, M. Tangirala, H. Baumgart, V. S. K. Chakravadhanula, C. Kübel, and V. Kochergin, “Growth of Nanolaminates of Thermoelectric Bi2Te3/Sb2Te3 by Atomic Layer Deposition,” ECS J. Solid State Sci. Technol., vol. 3, no. 4, pp. P95–P100, Feb. 2014.
10.1149/2.014404jss
35
M. Kaus, I. Issac, R. Heinzmann, S. Doyle, S. Mangold, H. Hahn, V. S. K. Chakravadhanula, C. Kübel, H. Ehrenberg, and S. Indris, “Electrochemical Delithiation/Relithiation of LiCoPO4:A Two-Step Reaction Mechanism Investigated by in situ X-ray Diffraction, in situ X-ray Absorption Spectroscopy, and ex-situ 7Li/31P NMR Spectroscopy,” J. Phys. Chem. C, vol. 118, no. 31, pp. 17279–17290, Aug. 2014.
10.1021/jp503306v
34
V. S. K. Chakravadhanula, Y. K. Mishra, V. G. Kotnur, D. K. Avasthi, T. Strunskus, V. Zaporojtchenko, D. Fink, L. Kienle, and F. Faupel, “Microstructural and plasmonic modifications in Ag–TiO2 and Au–TiO2 nanocomposites through ion beam irradiation,” Beilstein J. Nanotechnol., vol. 5, pp. 1419–1431, Sep. 2014.
10.3762/bjnano.5.154
33
U. Ulmer, K. Asano, T. Bergfeldt, V. S. K. Chakravadhanula, R. Dittmeyer, H. Enoki, C. Kübel, Y. Nakamura, A. Pohl, and M. Fichtner, “Effect of oxygen on the microstructure and hydrogen storage properties of V–Ti–Cr–Fe quaternary solid solutions,” Int. J. Hydrogen Energy, vol. 49, no. 0, pp. 1–9, Oct. 2014.
10.1016/j.ijhydene.2014.08.152
32
D. Hudry, J.-C. Griveau, C. Apostolidis, O. Walter, E. Colineau, G. Rasmussen, D. Wang, V. S. K. Chakravadhanula, E. Courtois-Manara, C. Kübel, and D. Meyer, “Thorium/uranium mixed oxide nanocrystals: Synthesis, structural characterization and magnetic properties,” Nano Res., vol. 7, no. 1, pp. 119–131, 2014.
10.1007/s12274-013-0379-6
31
B. Das, A. Pohl, V. S. K. Chakravadhanula, C. Kübel, and M. Fichtner, “LiF / Fe / V2O5 nanocomposite as high capacity cathode for lithium ion batteries,” Journal of Power Sources, vol. 267, pp. 203 – 211, 2014.
10.1016/j.jpowsour.2014.05.063
2013
30
B. Breitung, A. R. Munnangi, V. S. K. Chakravadhanula, M. Engel, C. Kübel, A. K. Powell, H. Hahn, and M. Fichtner, “Influence of particle size and fluorination ratio of CFx precursor compounds on the electrochemical performance of C–FeF2 nanocomposites for reversible lithium storage,” Beilstein J. Nanotechnol., vol. 4, pp. 705–713, Nov. 2013.
10.3762/bjnano.4.80
29
M. Schroeder, S. Glatthaar, H. Geßwein, V. Winkler, M. Bruns, T. Scherer, V. S. K. Chakravadhanula, and J. R. Binder, “Post-doping via spray-drying: A novel sol-gel process for the batch synthesis of doped LiNi0.5Mn1.5O4 spinel material,” J. Mater. Sci., vol. 48, no. 9, pp. 3404 – 3414, Jan. 2013.
10.1007/s10853-012-7127-2
28
M. N. Polyakov, E. Courtois-Manara, D. Wang, V. S. K. Chakravadhanula, C. Kübel, and A. M. Hodge, “Microstructural variations in Cu/Nb and Al/Nb nanometallic multilayers,” Appl. Phys. Lett., vol. 102, no. 24, p. 241911, 2013.
10.1063/1.4811822
27
N. Alissawi, V. Zaporojtchenko, T. Strunskus, I. Kocabas, V. S. K. Chakravadhanula, L. Kienle, D. Garbe-Schönberg, F. Faupel, “Effect of gold alloying on stability of silver nanoparticles and control of silver ion release from vapor-deposited Ag-Au/PTFE nanocomposites,” Gold Bull., vol. 46, no. 1, pp. 3–11, Nov. 2013.
10.1007/s13404-012-0073-6
26
A. Reddy Munnangi, B. Breitung, V. S. K. Chakravadhanula, C. Wall, M. Engel, C. Kübel, A. K. Powell, H. Hahn, and M. Fichtner, “CFx Derived Carbon-FeF2 Nanocomposites for Reversible Lithium Storage,” Adv. Energy Mater., vol. 3, no. 3, pp. 308–313, Mar. 2013.
10.1002/aenm.201200788
25
R. Abdelaziz, D. Disci-Zayed, M. K. Hedayati, J.-H. Pöhls, A. U. Zillohu, B. Erkartal, V. S. K. Chakravadhanula, V. Duppel, L. Kienle, M. Elbahri, “Green chemistry and nanofabrication in a levitated Leidenfrost drop,” Nat. Commun., vol. 4, Oct. 2013.
10.1038/ncomms3400
24
R. Chen, R. Heinzmann, S. Mangold, V. S. K. Chakravadhanula, H. Hahn, and S. Indris, “Structural Evolution of Li2Fe1-yMnySiO4 (y=0, 0.2, 0.5, 1) Cathode Materials for Li-Ion Batteries upon Electrochemical Cycling,” J. Phys. Chem. C, vol. 117, no. 2, pp. 884–893, Jan. 2013.
10.1021/jp310935j
23
I. Issac, R. Heinzmann, M. Kaus, Z. Zhao-Karger, H. Geßwein, T. Bergfeldt, V. S. K. Chakravadhanula, C. Kübel, H. Hahn, and S. Indris, “Synthesis and electrochemical performance of nanocrystalline Al0.4Mg0.2Sn0.4O1.6 and Al0.25Mg0.38Sn0.38O1.5 investigated by in situ XRD, 27Al/119Sn MAS NMR, 119Sn Mössbauer spectroscopy, and galvanostatic cycling,” J. Mater. Chem. A, vol. 1, no. 44, p. 13842, 2013.
10.1039/C3TA12805A
22
C. Reitz, C. Suchomski, V. S. K. Chakravadhanula, I. Djerdj, Z. Jagli?i?, and T. Brezesinski, “Morphology, microstructure, and magnetic properties of ordered large-pore mesoporous cadmium ferrite thin film spin glasses,” Inorg. Chem., vol. 52, no. 7, pp. 3744–3754, Apr. 2013.
10.1021/ic302283q
2012
21
M. Guan, W. Wang, E. J. Henderson, Ö. Dag, C. Kübel, V. S. K. Chakravadhanula, J. Rinck, I. L. Moudrakovski, J. Thomson, J. McDowell, A. K. Powell, H. Zhang, and G. a Ozin, “Assembling photoluminescent silicon nanocrystals into periodic mesoporous organosilica,” J. Am. Chem. Soc., vol. 134, no. 20, pp. 8439–8446, May 2012.
10.1021/ja209532e
20
N. Alissawi, V. Zaporojtchenko, T. Strunskus, T. Hrkac, I. Kocabas, B. Erkartal, V. S. K. Chakravadhanula, L. Kienle, G. Grundmeier, D. Garbe-Schönberg, and F. Faupel, “Tuning of the ion release properties of silver nanoparticles buried under a hydrophobic polymer barrier,” J. Nanoparticle Res., vol. 14, no. 7, Jun. 2012.
10.1007/s11051-012-0928-z
19
S. Ren, R. Prakash, D. Wang, V. S. K. Chakravadhanula, and M. Fichtner, “Fe3O4 anchored onto helical carbon nanofibers as high-performance anode in lithium-ion batteries,” ChemSusChem, vol. 5, pp. 1397–1400, Jun. 2012.
10.1002/cssc.201200139
18
H. T. Beyene, V. S. K. Chakravadhanula, C. Hanisch, T. Strunskus, V. Zaporojtchenko, M. Elbahri, and F. Faupel, “Vapor Phase Deposition, Structure, and Plasmonic Properties of Polymer-Based Composites Containing Ag-Cu Bimetallic Nanoparticles,” Plasmonics, vol. 7, pp. 107 – 114, Sep. 2012.
10.1007/s11468-011-9282-8
17
Y. K. Mishra, V. S. K. Chakravadhanula, V. Hrkac, S. Jebril, D. C. Agarwal, S. Mohapatra, D. K. Avasthi, L. Kienle, and R. Adelung, “Crystal growth behaviour in Au-ZnO nanocomposite under different annealing environments and photoswitchability,” J. Appl. Phys., vol.112, no.6, p.064308, 2012.
10.1063/1.4752469
16
V. S. K. Chakravadhanula, C. Kübel, T. Hrkac, V. Zaporojtchenko, T. Strunskus, F. Faupel, and L. Kienle, “Surface segregation in TiO2-based nanocomposite thin films.,” Nanotechnology, vol. 23, no. 49, p. 495701, Dec. 2012.
10.1088/0957-4484/23/49/495701
2011
15
J. Jakobi, A. Menéndez-Manjón, V. S. K. Chakravadhanula, L. Kienle, P. Wagener, and S. Barcikowski, “Stoichiometry of alloy nanoparticles from laser ablation of PtIr in acetone and their electrophoretic deposition on PtIr electrodes.,” Nanotechnology, vol. 22, no. 14, p. 145601, Feb. 2011.
10.1088/0957-4484/22/14/145601
14
V. S. K. Chakravadhanula, T. Hrkac, V. Zaporojtchenko, R. Podschun, V. G. Kotnur, A. Kulkarni, T. Strunskus, L. Kienle, and F. Faupel, “Nanostructural and functional properties of Ag-TiO2 coatings prepared by co-sputtering deposition technique,” J. Nanosci. Nanotechnol., vol. 11, no. 6, pp. 4893–4899, 2011.
10.1166/jnn.2011.3881
13
M. K. Hedayati, M. Javaherirahim, B. Mozooni, R. Abdelaziz, A. Tavassolizadeh, V. S. K. Chakravadhanula, V. Zaporojtchenko, T. Strunskus, F. Faupel, and M. Elbahri, “Design of a perfect black absorber at visible frequencies using plasmonic metamaterials.,” Adv. Mater., vol. 23, no. 45, pp. 5410–4, Dec. 2011.
10.1002/adma.201102646
12
M. Elbahri, M. K. Hedayati, V. S. K. Chakravadhanula, M. Jamali, T. Strunskus, V. Zaporojtchenko, F. Faupel, “An omnidirectional transparent conducting-metal-based plasmonic nanocomposite.,” Adv. Mater., vol. 23, no. 17, pp.1993–7, May 2011.
10.1002/adma.201003811
11
A. Kulkarni, V. S. K. Chakravadhanula, V. Duppel, D. Meyners, V. Zaporojtchenko, T. Strunskus, L. Kienle, E. Quandt, and F. Faupel, “Morphological and magnetic properties of TiO2/Fe50Co50 composite films,” J. Mater. Sci., vol. 46, no. 13, pp. 4638–4645, Feb. 2011.
10.1007/s10853-011-5366-2
2010
10
H. T. Beyene, V. S. K. Chakravadhanula, C. Hanisch, M. Elbahri, T. Strunskus, V. Zaporojtchenko, L. Kienle, and F. Faupel, “Preparation and plasmonic properties of polymer-based composites containing Ag–Au alloy nanoparticles produced by vapor phase co-deposition,” J. Mater. Sci., vol. 45, no. 21, pp. 5865–5871, Jun. 2010.
10.1007/s10853-010-4663-5
9
E. Quiroga-González, L. Kienle, C. Näther, V. S. K. Chakravadhanula, H. Lühmann, and W. Bensch, “Zero- and one-dimensional thioindates synthesized under solvothermal conditions yielding ?-In2S3, ?-In2S3 or MgIn2S4 as thermal decomposition products,” J. Solid State Chem., vol. 183, no. 12, pp. 2805–2812, Dec. 2010.
10.1016/j.jssc.2010.09.024
8
Y. K. Mishra, S. Mohapatra, V. S. K. Chakravadhanula, N. P. Lalla, V. Zaporojtchenko, D. K. Avasthi, and F. Faupel, “Synthesis and Characterization of Ag-Polymer Nanocomposites,” J. Nanosci. Nanotechnol., vol. 10, no. 4, pp. 2833–2837, Apr. 2010.
10.1166/jnn.2010.1449
2008
7
V. S. K. Chakravadhanula, M. Elbahri, U. Schürmann, H. Greve, H. T. Beyene, V. Zaporojtchenko, and F. Faupel, “Equal intensity double plasmon resonance of bimetallic quasi-nanocomposites based on sandwich geometry,” Nanotechnology, vol. 19, no. 22, p. 225302, Jun. 2008.
10.1088/0957-4484/19/22/225302
6
H. T. Beyene, A. Kulkarni, S. Jebril, V. S. K. Chakravadhanula, C. Hanisch, T. Strunskus, V. Zaporojtchenko, and F. Faupel, “Plasmonic properties of vapour-deposited polymer composites containing Ag nanoparticles and their changes upon annealing,” J. Phys. D. Appl. Phys., vol. 41, no. 12, p. 125409, Jun. 2008.
10.1088/0022-3727/41/12/125409
5
K. Hoppe, W. Fahrner, D. Fink, S. Dhamodoran, A. Petrov, A. Chandra, A. Saad, F. Faupel, V. S. K. Chakravadhanula, and V. Zaporojtchenko, “An ion track based approach to nano- and micro-electronics,” Nucl. Instruments Methods Phys. Res. Sect. B Beam Interact. with Mater. Atoms, vol. 266, no. 8, pp. 1642–1646, Apr. 2008.
10.1016/j.nimb.2007.12.069
4
F. Faupel, V. Zaporojtchenko, T. Strunskus, H. Greve, U. Schürmann, H. T. Beyene, C. Hanisch, V. S. K. Chakravadhanula, N. Ni, A. Gerber, E. Quandt, and R. Podschun, “Functional Polymer Nanocomposites,” Polym. Polym. Compos., vol. 16, no. 8, pp. 471–483, 2008.
1032176
3
Y. K. Mishra, V. S. K. Chakravadhanula, U. Schürmann, H. K. Sehgal, D. Kabiraj, S. Ghosh, V. Zaporojtchenko, D. K. Avasthi, and F. Faupel, “Controlled reduction of size of Ag nanoparticles embedded in teflon matrix by MeV ion irradiation,” Nucl. Instruments Methods Phys. Res. Sect. B Beam Interact. with Mater. Atoms, vol. 266, no. 8, pp. 1804–1809, 2008.
10.1016/j.nimb.2008.01.040
2007
2
F. Faupel, V. Zaporojtchenko, H. Greve, U. Schürmann, V. S. K. Chakravadhanula, C. Hanisch, A. Kulkarni, A. Gerber, E. Quandt, and R. Podschun, “Deposition of Nanocomposites by Plasmas,” Contrib. to Plasma Phys., vol. 47, no. 7, pp. 537–544, Nov. 2007.
10.1002/ctpp.200710069
2006
1
A. Biswas, O. C. Aktas, F. Hidden, H. Eilers, and V. S. K. Chakravadhanula, “Large broadband visible to infrared plasmonic absorption from Ag nanoparticles with a fractal structure embedded in a Teflon AF® matrix,” Appl. Phys. Lett., vol. 88, no. 1, p. 013103, 2006.
10.1063/1.2161401
Conference Proceedings: Dr.-Ing. V.S.K. Chakravadhanula

Coverpages

2016


2013

2011
2016
API§
4
B. P. Vinayan, Z. Zhao-Karger, T. Diemant, V. S. K. Chakravadhanula, N. I. Schwarzburger, M. A. Cambaz, R. J. Behm, C. Kübel, and M. Fichtner, “Performance study of magnesium–sulfur battery using a graphene based sulfur composite cathode electrode and a non-nucleophilic Mg electrolyte,” Nanoscale, vol. 8, no. 6, pp. 3296–3306, 2016. 10.1039/C5NR04383B0.86
3
M. A. Reddy, B. Breitung, C. Wall, S. Trivedi, V.S.K. Chakravadhanula, M. Helen, and M. Fichtner, “Inside Cover: Facile Synthesis of Carbon-Metal Fluoride Nanocomposites for Lithium-Ion Batteries,” Energy Technology, vol. 4, no. 1, pp. 2–2, Jan. 2016.
10.1002/ente.201500523
0.90
2013
2
M. A. Reddy, B. Breitung, V. S. K. Chakravadhanula, C. Wall, M. Engel, C. Kübel, A. K. Powell, H. Hahn, and M. Fichtner, “Inside Front Cover: CFx Derived Carbon-FeF2 Nanocomposites for Reversible Lithium Storage,” Adv. Energy Mater., vol. 3, no. 3, pp. 308–313, Mar. 2013.
10.1002/aenm.201370012
1.07
2011

1
M. K. Hedayati, M. Javaherirahim, B. Mozooni, R. Abdelaziz, T. Ali, V. S. K. Chakravadhanula, V. Zaporojtchenko, T. Strunskus, F. Faupel M. Elbahri, “Frontispiece: Perfect Plasmonic Absorber: Design of a Perfect Black Absorber at Visible Frequencies Using Plasmonic Metamaterials,” Adv. Mater., vol. 23, no. 45, p. 5409, 2011.
10.1002/adma.201190180
0.94
Conference Proceedings: Dr.-Ing. V.S.K. Chakravadhanula

Conference Proceedings

2016
2015 2014
2013
2012
2011
2010
2009
2008
2007
2006

2016
12
O. Wenzel, M. Schwotzer, A. Gerdes, T. Scherer, and V. S. K. Chakravadhanula, “Nanoscale characterization of CSH gel pores with scanning transmission electron microscopy transmission electron microscopy,” in Innovation in Construction Materials, 2016, no. April, pp. 1–2.
10.1002/ente.201500358
2015
2014
11
V. S. K. Chakravadhanula, M. Hammad, C. Kübel, T. Scherer, C. Rongeat, A. Reddy Munnangi, M. Fichtner, and H. Hahn, “Reversible in situ TEM Electrochemical studies of Fluoride Ion Battery,” Microsc. Microanal., vol. 20, no. S3, pp. 1620–1621, Aug. 2014.
10.1017/S1431927614009830
2013
10
V. S. K. Chakravadhanula, C. Kübel, A. R. Munnangi, B. Breitung, A. K. Powell, M. Fichtner, and H. Hahn, “TEM Investigations on FeF2 based Nanocomposite Battery Materials,” Microsc. Microanal., vol. 19, no. S2, pp. 1524–1525, Oct. 2013.
10.1017/S1431927613009616
9
A. D. R. Pillai, K. Zhang, K. Bollenbach, D. Dminibapiel, W. Cao, H. Baumgart, V. S. K. Chakravadhanula, C. Kübel, and V. Kochergin, “ALD Growth of PbTe and PbSe Superlattices for Thermoelectric Applications,” ECS Trans., vol. 58, no. 10, pp. 131–139, Oct. 2013.
10.1149/05810.0131ecst
8
D. Nminibapiel, K. Zhang, M. Tangirala, H. Baumgart, V. S. K. Chakravadhanula, C. Kübel, and V. Kochergin, “Microstructure Analysis of ALD Bi2Te3/Sb2Te3 Thermoelectric Nanolaminates,” ECS Trans., vol. 58, no. 10, pp. 59–66, Oct. 2013.
10.1149/05810.0059ecst
2012
2011
7
V. S. K. Chakravadhanula, K. Kelm, L. Kienle, V. Duppel, A. Lotnyk, D. Sturm, M. Heilmaier, G. J. Schmitz, A. Drevermann, F. Stein, and M. Palm, “TEM studies of the ternary Ti36Al62Nb2 alloy,” Mater. Res. Soc. Symp. Proc., vol. 1295, pp. mrsf10–1295–n03–09, Feb. 2011.
10.1557/opl.2011.181
2010
6
V. S. K. Chakravadhanula, A. Kulkarni, A. Lotnyk, V. Zaporojtchenko, F. Faupel, and L. Kienle, “Real Structure of FeCo-TiO2 Nanocomposites,” in Zeitschrift für anorganische und allgemeine Chemie, 2010, vol. 636, no. 11, pp. 2090–2090.
10.1002/zaac.201009083
5
V. Hrkac, Y. K. Mishra, V. S. K. Chakravadhanula, S. Jebril, D. K. Avasthi, R. Adelung, and L. Kienle, “Au-ZnO Nanocomposites for Functional Devices,” in Zeitschrift für anorganische und allgemeine Chemie, 2010, vol. 636, no. 11, pp. 2081–2081.
10.1002/zaac.201009064
2009
4
V. S. K. Chakravadhanula, Y. K. Mishra, V. G. Kotnur, T. Hrkac, L. Kienle, D. K. Avasthi, D. Fink, V. Zaporojtchenko, and F. Faupel, “Formation of TiO-single crystals in Ag-TiO2 based nanocomposites by swift heavy ion irradiation,” in CLEO/Europe - EQEC 2009 - European Conference on Lasers and Electro-Optics and the European Quantum Electronics Conference, 2009, vol. 225302, no. 2008, pp. 1–1.
10.1109/CLEOE-EQEC.2009.5192300
3
V. S. K. Chakravadhanula, A. Kulkarni, A. Lotnyk, V. Duppel, and V. Zaporojtchenko, “Morphological properties of TiO2/Fe50Co50 composite films,” in Microscopy Conference 2009 in Graz (Multinational Conference on Microscopy and Dreiländertagung), 2009, vol. 3, pp. 149–150.
10.3217/978-3-85125-062-6-447
2
V. S. K. Chakravadhanula, A. Lotnyk, Y. K. Mishra, T. Hrkac, V. Zaporojtchenko, D. K. Avasthi, D. Fink, L. Kienle, and F. Faupel, “Formation of TiO - Single Crystals in Ag-TiO2 based Nanocomposites by Swift Heavy Ion Irradiation,” in Microscopy Conference 2009 in Graz (Multinational Conference on Microscopy and Dreiländertagung), 2009, vol. 3, pp. 111–112.
10.3217/978-3-85125-062-6-428
2008
2007
1
F. Faupel, V. Zaporojtchenko, H. Greve, U. Schürmann, H. T. Beyene, C. Hanisch, V. S. K. Chakravadhanula, A. Biswas, A. Gerber, E. Quandt, and R. Podschun, “Polymer nanocomposites for functional applications,” Proceedings of the 2nd International Conference of Electroactive Polymers: - Materials and Devices, 2007, vol. II, pp. 78–88.
Link
Conference Proceedings: Dr.-Ing. V.S.K. Chakravadhanula

Patents

2010





2010
1
M. Elbahri, V. S. K. Chakravadhanula, F. Faupel, T. Strunskus, V. Zaporojtchenko, and M. K. Hedayati, “Metall-Komposit-Beschichtung mit hoher optischer Transmissivität im visuellen Spektrum,” DE 10 2010 050 110 B3 2012.01.192010.
DE 10 2010 050 110 B3
WO2012055397
Research: Dr.-Ing. V.S.K. Chakravadhanula

Research Areas

In situ Transmission Electron Microscopy

    In situ Electron Microscopy is the emerging field of Electron Microscopy involving Electron Microscopy under dynamic conditions with various stimuli. Based on these stimuli used, a variety of techniques/method are divided and are termed as in situ TEM techniques. Research and Developmental activities in these fields are gaining increasing importance, as the demands from the synthesis and fabrication groups increase, requiring the dynamics of materials modifications during their processes, understanding the basics of the process, therby leading towards an efficient material, its process and its properties.

    As an example, the video below depicts in situ TEM in liquids towards understanding the growth of Ag within a AgNO3 solution using an Posseidon single tilt sample holder from Protochips Inc. More information: Link

AgNO3 Solution - Electron Beam
Video: Depicting the growth of Ag in a dilute AgNO3 solution inside a Posseidon Liquid TEM Sample Holder from Protochips Inc.
Video is 4 X speed.



Transmission Electron Microscopy of Battery Materials (Electrodes and Electrolytes)

    Research in the field of energy storage systems has gained huge importance in all sectors of  life. Batteries contribute towards the major systems of Energy strorage systems. Improving the cycling capabilities, energy storage capacities, safety and security are the primary aspects which need a deeper understanding of the individual components of the battery i.e., Electrodes and Electrolytes. Presently there is exploding research towards development of new battery chemistries, new nanostructures of the individual components towards meeting the energy storage demands of the world. Therby leading to huge demand for high spatial resolution characterization of such components not only in the as-prepared state but also during various stages of cycling or even after cycling. In all the aforementioned cases, TEM offers a good choice, towards acheiving high spatial resolution. But the expectations of the researchers towards TEM has also been increasing with the advances of in situ electron microscopy, towards understanding the morphological, structural and compositional changes during the process of charging and discharging. For this purpose, the effective dose of the individual components of the battery are pivotal, ignoring which leads to the analysis of electron beam modified components as components of the battery. Thus modifying the complete electrochemistry of the battery. Analysis of individual components of the battery, their beam stability and the critical electron dose under varying imaging techniques become the key parameter. Hence understanding the radiation damage (either Radiolysis, Knock-on-damage or sputtering and heating) leading to either crystallization, amorphization or removal of material remains pivotal.

    Understanding this thereby leads towards "Better Materials for a Bettery Battery thereby Better Energy Storage System for a Better Tomorrow".

In situ TEM studies of Battery Materials

    Research in the field of in situ energy storage systems has gained huge importance in the present decade where batteries, besides being pivotal, also needs improving in their cycling capabilities, energy storage capacities, safety and security which need a deeper understanding of the interfaces of the battery i.e., Anode-Electrolyte and Cathode-Electrolyte. Many research groups around the world try to understand this towards the development of new battery chemistries, new nanostructures of the individual components towards meeting the energy storage demands of the world.
    TEM, being a high spatial resolution characterization tool enables the understanding of the variations or modifications at the nano-scale. Together with in situ sample holders with continous imaging during any experiment, high spatial resolution involves higher electron doses, increasing the effective dose applied on the system that might lead to radiation damage. Towards understanding the morphological, structural and compositional changes during the process of charging and discharging during an in situ TEM electrochemical cycling experiements, electron microscopists might be misled towards studying the electron beam modified materials and their electrochemical cycling.
    Effectively the calculation of the critical dose of the individual components of the battery in separate experiments are pivotal. Ignoring this might leads to the analysis of electron beam modified components as components of the battery, thereby studying the electrochemistry of the electron beam modified battery. More information: Link

In situ TEM studies of Memristive Materials

    Memristors are nanoscale resistive switching devices. Memristors have been of huge interest for memory, logic and neuromorphic applications in the recent times. Generally, their switching effects in dielectric-based devices are assumed to be caused by conducting filament formation across the electrodes. But the nature of the filaments, their growth mechanisms and dynamics are in huge debate, which demand in situ high spatial resolution characterization techniques. In situ transmission electron microscopy with its imaging, structural and compositional analysis at the nanoscale is an optimum technique to understand the growth mechanisms and dynamics. Through systematic ex situ and in situ TEM studies on nanoscale devices under various programming conditions, the underlying mechanisms can be identified. The results obtained through  deserves particular attention for continued device optimization.
Indexing, mapping and evaluating the Indian Electron Microscopes and Facilities

Based on the understanding of various EM facilities around the world and the experience gained in establishing collaboration, I myself initiated a project on the evaluation of EM characterization facilities in India in a view to enhance the future perspective and dream of establishing state-of-the-art characterization facility for India. This report will be published and would aid towards this dream. In the google map above you find all the FEI TEM's-Blue Color, JEOL TEM's-Green Color and Hitachi TEM's-Brown Color. The EMSI zonal headquarters are also available, but one has to open the flap out and select EM Soceities and unselect the TEM.
Traditional Indian Materials: Correlating known properties with the morphology, structure and chemical composition
Indian rich traditions have a variety of cultural heritage. Traditionally there have been a healthy era of non-processed (traditionally-processed) materials, used in day to day activities. Many of these materials have been used even today in villages, because of the knowledge given by the ancestors. Unfortunately less scientific evidenceexists . An effort is here made to correlate the known functionality or the properties with a scientific understanding by studying the morphology, structure and chemical compositon of the corresponding materials.
Transmission Electron Microscopy of Ayurvedic medicines prepared by herbal routes.

    Ayurvedic medicines are nano-/micro- materials made by all-green technologies and are the Traditional Indian Medicine. Actual prepration strategies and recepies are mentioned in the vedas. This alternate medicine has proved to be very helpful in treating diseases. But characterization of such materials involves high resolution techniques in addition to bulk characterization techniques. Morphology, Structure and Compositional analysis is pivotal towards the establishment of standards for the Ayurvedic medicines or "Bhasmas".

TEM studies of the ternary Ti36Al62Nb2 alloy

    Al-rich Ti-Al alloys attracted some attention during the past years due to the possibility of their application as light-weight, high-performance materials at elevated temperatures. The effect of the addition of Nb to Al-rich Ti-Al alloys has been studied for Ti36Al62Nb2 by a combined approach of transmission electron microscopy (TEM) techniques for unraveling the structure and composition at the nanoscale. Structural analyses on as-cast ternary alloys revealed the presence of h-TiAl2-, Ti3Al5- and ?-TiAl-type phases. After heat treatment, phase transformations like the replacement of the metastable h-TiAl2-type by the stable r-TiAl2-type were identified. Additionally, changes of the microstructural features like the formation of interfaces with different orientation relationships are apparent. The orientation and interfacial relationships involved are compared to those of binary Ti-Al alloys rich in Al. More information: Link

Electron Tomography of Nanocomposite Materials

    Unlike the case of polymers, in the case of Ag nanoparticles on TiO2, segregation of the clusters on the surface also provides a fast pathway for Ostwald ripening without any restrictions by elastic distortions at least for those clusters which are in direct contact with the surface.

    3D electron tomography was employed on the TiO2 based nanocomposite thin ?lms to explain the two step model for the particle size distribution. First step involved the formation of small nanoparticles during vacuum phase deposition or on the growing surface. Second step after the deposition process involved the formation of larger particles through particle coarsening by Ostwald ripening and surface segregation. More information: Link

Ag-TiO2 Tilt Series Ag-TiO2 Visualization
Video: showing the acquired tilt-series with a single-tilt Tomography sample holder
Video: showing the visualization of the reconstructed volume where TiO2 is transparant and Ag has been given golden color.

In situ TEM heating of oxide-based Nanocomposites

   A study involving the in situ heating of the TiO2 based nanocomposites in the TEM con?rms the absence of the formation of TiO unlike the SHI irradiation. Changes of the microstructure of the nanocomposite ?lm upon annealing allowed demonstrating the absence of the formation of TiO but rather only the crystallization of the TiO2.

Au_TiO2_heating
Fig: In–situ heating of the 11 % MVF Au–TiO2 nanocomposites at (a) room temperature (b) 100 °C(c) 200 °C, (d) 300 °C, (e) 400 °C and (f) 500 °C (total time 3 hrs).
Particle Size Distribution Au-TiO2 nanocomposites
Fig: Particle size distribution of the Au–TiO2 nanocomposite in the above figure at (a) room temperature (b) 100 °C (c) 200 °C, (d) 300 °C, (e) 400 °C and (f) 500 C (total time 3 hrs).



Swift Heavy Ion Irradiation of Noble-metal based Nanocomposite Materials

   Tuning the optical properties of nanocomposites can be achieved by using swift heavy ion irradiation (SHI) of the nanocomposites. The SHI beamlines from both the Hahn–Meitner–Institute in Berlin, Germany and the Inter University Accelerator Center in New–Delhi, India, were employed in this work. The TiO phase formation on SHI irradiation with increasing ?uence was understood by the interaction of two different counteracting mechanisms, where at lower ?uences, the tendency towards the formation of TiO existed with the larger unaffected areas and at higher ?uences, the destruction of the evolved TiO phase into fragments was evident. This served as an evidence for the counter play between "hit" and "no–hit", "single–hit" and "multiple–hit" processes. More information: Link

TiO + SAED + Simulated
Fig: Brightfield TEM image of the TiO crystal formed at the fluence of 3 X 1012 ions/cm2 with the associated experimental (center) and simulated (right) SAED patterns showing clearly the single crystalline nature in the zone axis of [2 1 1]. SAED pattern simulations were done using the the software JEMS.

SHI irradiation of Ag nanoparticles embedded in PTFE matrix shows a marginal dissolution of Ag nanoparticles along with a slight agglomeration of nanoparticles. At higher ?uences, carbon rich areas were observed, which were as a result of the carbonization along the ion tracks.

PTFE + SHI
Fig: SHI irradiation induced changes in the PTFE matrix of the nanocomposite along the ion tracks.



    Enhancement of the silver ion release after SHI irradiation at a fluence was observed to the fact that the ion trajectories after irradiation provide better silver ion release.

SHI Ion release
Fig: Enhanced release of silver ions after SHI irradiation at a fluence of 1×1013 ions/cm2 when compared to the pristine sample.


Transmission Electron Microscopy of Nanocomposites

Synthesis and Characterization of Nanocomposite Materials through vapor-phase deposition methods

   Nanocomposite thin film coatings with a wide range of metal volume fractions were prepared by co–sputtering of TiO2/Teflon and Ag/Au/Cu from two different magnetron sources simultaneously in a home made deposition chamber under high vacuum conditions. Two different types of host materials a polymeric (PTFE) and a ceramic (TiO2) were studied in this work. Morphology, optical and antibacterial properties of these nanocomposites were examined. The formation of metallic nanoparticles upon vapor phase co–deposition of a metal and a dielectric matrix component can be understood in terms of the high cohesive energy of the metal and the low metal-matrix interaction energy which lead to high metal atom mobility on the growing composite surface and metal aggregation whenever metal atoms encounter each other or a metal cluster.  

    In addition, efforts towards tuning of the double plasmon resonances by tailoring the dielectric separation were carried out. Bimetallic nanocomposites based on sandwich geometry in polymer system, the changes in the particle plasmon spectra of sandwiched Au nanoclusters as a result of the presence of Ag nanoclusters in their vicinity and vice versa was studied. Also, the optimum dielectric barrier thickness for the observation of equal intensity double plasmon resonance was reported. Functionality of the nanocomposites in terms of the antibacterial properties was studied. Cultures of B.megaterium, S.aureus, S.epidermidis and E.coli were used to study the effect on the Ag–TiO2 nanocomposites. Additionally, silver ion release studies were carried out at dfferent MVFs by using X-ray photoelectron and UV-Vis/NIR spectroscopies. More Information: Link


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