Nanoparticles and clusters

Contact: Dr. Radian Popescu

Nanoscaled particles show a wide range of fundamentally and technologically interesting properties, which are mainly determined by their size, chemical composition and structure. High-resolution transmission electron microscopy (HRTEM) using our aberration-corrected Titan3 80-300 microscope allows detailed studies of nanoparticle morphologies and their atomic structure. The images below show Au hollow spheres from the group of Prof. Claus Feldmann (Institute for Inorganic Chemistry, KIT).

Scanning transmission electron microscopy (STEM) can be combined with energy dispersive X-ray spectroscopy (EDXS) for chemical analyses on the 1-nm scale. The example below shows lanthanide (Ln)-doped upconverting core-shell nanocrystals (sample: Dr. Damien Hudry, Institute of Microstructure Technology, KIT) with composition profiles of Er/Yb, Y, and Gd through the center of the nanoparticles along the arrow.

Selected conference poster presentations:

The structure of supercrystals made by self-assembled nanoscaled Ag2S hollow spheres and Ag2S nanodiscs (pdf)

TEM investigations of the sintering behavior of noble metal nanoparticles (pdf)

Coarsening of Pt clusters on amorphous carbon substrates (pdf:

Recent publications

M. Kamp, A. Tymoczko, R. Popescu, U. Schürmann, R. Nadarajah, B. Gökce, C. Rehbock, D. Gerthsen, S. Barcikowski, L. Kienle,
Composition and structure of colloidal magnetic high-temperature-phase, stable Au-Fe nanoparticles,
Nanocale Advances 2, 3912 (2020)

H.F. Gaiser, R. Popescu, D. Gerthsen, C. Feldmann,
Ionic-liquid-based synthesis of GaN nanoparticles,
Chem. Commun. 56, 2312 (2020)

A. Egeberg, O. Wenzel, R. Popescu, D. Gerthsen, C. Feldmann,
Pyridine-based Liquid-phase Synthesis of Crystalline TiN and ZnSiN2 Nanoparticles,
ChemistryOpen 9, 1 (2020)

O. Wenzel, V. Rein, R. Popescu, C. Feldmann, D. Gerthsen,
Structural properties and ELNES of polycrystalline and nanoporous Mg3N2, Microsc.,
Microanal. 26, 102 (2020)

D. Hudry, R. Popescu, D. Busko, M. Diaz-Lopez, M. Abeykoon, H. Störmer, P. Bordet, D. Gerthsen, I. Howard, B.S. Richards,
Disorder in multi-shell upconverting nanocrystals: emergence of a new paradigm to control energy migration,
J. Mater. Chem. C 7, 1164 (2019)

A. Egeberg, T. Block, O. Janka, O. Wenzel, D., R. Pöttgen, C. Feldmann,
Lithiumpyridinyl-driven synthesis of high-purity zero-valent iron nanoparticles and their use in follow-up reactions,
Small 15, 1902321(2019)

D. Hudry, I.A. Howard, R. Popescu, D. Gerthsen, B. Richards,
Structure-property relationships in lanthanide-doped upconverting nanocrystals: recent advances in understanding core-shell structures,
Adv. Mater. 31, 1900623 (2019)

A. Egeberg, T. Seifert, P.W. Roesky, D. Gerthsen, C. Feldmann,
Reactive base metal nanoparticles made via one-pot synthesis in multifunctional pyridine,
ACS Omega 4, 7096 (2019)

V. Rein, O. Wenzel, R. Popescu, D. Gerthsen, C. Feldmann,
Nanoporous Mg3N2: Synthesis, CO2 Sorption and Photoluminescence,
J. Mater. Chem. C 6, 4450 (2018)

A. Egeberg, L. Warmuth, S. Riegsinger, D. Gerthsen, C. Feldmann,
Pyridine-based low-temperature synthesis of high-purity CoN, Ni3N and Cu3N nanoparticles,
Chem. Commun. 54, 9957 (2018)

Y.-C. Chen, R. Popescu, D. Gerthsen,Y.-K. Hsu, Y.-G. Lin, C. Feldmann,
Biomimicry of peapod-design endows Au@Nb@HxK1-xNbO3 with near-infrared active plasmonic hot electron injection for water splitting,
Nature Communications 9, 323 (2018)

D. Hudry, D. Busko, R. Popescu, D. Gerthsen, A.M.M. Abeykoon, C. Kübel, T. Bergfeldt, B.S. Richards,
Direct evidence of significant cation intermixing in upconverting core@shell nanocrystals: toward a new crystallochemical model,
Chem. Mater. 27, 9238 (2017)

C. Schöttle, S. Rudel, R. Popescu, Dagmar Gerthsen, Florian Kraus, C. Feldmann,
Nanosized Gadolinium and Uranium: two representatives of high-reactivity Lanthanide and Actinide metal nanoparticles,
ACS Omega 2, 9144 (2017)

J. Jung-König, M. Sanhaji, R. Popescu, C. Seidl, U. Schepers, D. Gerthsen, I. Hilger, Claus Feldmann,
Microemulsion-made gadolinium carbonate hollow nanospheres showing magnetothermal heating and drug release,
Nanoscale 9, 8362 (2017)

A. Egeberg, C. Dietrich, C. Kind, R. Popescu, D. Gerthsen, S. Behrens, C. Feldmann,
Bimetallic NiIr4 and NiOs4 alloy nanoparticles and their catalytic performance in hydrogenation reactions,
Cat.Chem.Cat. 9, 3524 (2017)

M. Wanner, D. Gerthsen, S.-S. Jester, B. Sarkar, B. Schwederski,
Treatment of citrate-capped Au colloids with NaCl: a TEM, EAS und EPR study of the accompanying changes,
Colloid and Polym. Sci. 283, 783 (2005)

R. Werner, M. Wanner, G. Schneider, D. Gerthsen,
Island formation and dynamics of gold clusters on amorphous carbon films,
Phys. Rev. B 72, 045426 (2005)

M. Dubiel, X. Yang, R. Schneider, H. Hofmeister, K.-D. Schicke,
Structure and properties of nanoparticle-glass composites
Phys. Chem. Glasses 46, 2, 148-152 (2005)

M. Dubiel, X. Yang, R. Schneider, H. Hofmeister, K.-D. Schicke,
Structure of silver nanoparticles in silicate glasses and of nanoparticle-glass interfaces,
Phys. Chem. Glasses 46, 4, 389-393 (2005)

M. Wanner, R. Werner, D. Gerthsen,
Dynamics of gold clusters on amorphous carbon films induced by annealing in a transmission electron microscope,
Surface Science 600, 632 (2006)

C. Zimmermann, C. Feldmann, M. Wanner, D. Gerthsen,
Nanoscale gold hollow spheres via microemulsion approach,
Small 3, 1347 (2007)

Radian Popescu, Erich Müller, Matthias Wanner, Dagmar Gerthsen, Marco Schowalter,
Andreas Rosenauer, Artur Bottcher, Daniel Loffler, Patrick Weis,
Increase of the mean inner Coulomb potential in Au clusters induced by surface tension and its implication for electron scattering,
Phys. Rev. B 76, 235411 (2007)

M. Dubiel, R. Schneider, H. Hofmeister, K.-D. Schicke, J.C. Pivin,
Formation of argentic clusters and small Ag nanoparticles in soda-lime silicate glass,
Eur. Phys. J. D 43, 291-294 (2007

E. Prestat, R. Popescu, H. Blank, R. Schneider, D. Gerthsen,
Coarsening of Pt nanoparticles on amorphous carbon film,
Surf. Sci. 609, 195 (2013)

G. Mayer, M. Fonin, U. Rüdiger, R. Schneider, D. Gerthsen, N. Janßen, R. Bratschitsch
Structural and optical properties of high-quality ZnO nanocrystals embedded in SiO2 fabricated by rf-sputtering
Nanotechnology 20, 075601 (2009)

R. Popescu, R. Schneider, D. Gerthsen, A. Böttcher, D. Löffler, P.Weiss, M. Kappes
Coarsening of mass-selected Au clusters on amorphous carbon at room temperature
Surf. Sci. 603, 3119 (2009)

P. Leidinger, R. Popescu, D. Gerthsen, C. Feldmann
Nanoscale La(OH)3 hollow spheres and fine-tuning of its outer diameter and cavity size
Small 6, 1886 (2010)

G. Kiliani, R. Schneider, D. Litvinov, D. Gerthsen, M. Fonin, U. Rüdiger, A. Leitenstorfer, R. Bratschitsch
Ultraviolet photoluminescence of ZnO quantum dots sputtered at room-temperature
Optics Express 19, 1641 (2011)

Li Shang, R.M. Dörlich, S. Brandholt, R. Schneider, V. Trouillet, M. Bruns, D. Gerthsen, G.U. Nienhaus
Facile preparation of water-soluble fluorescent gold nanoclusters for cellular imaging applications
Nanoscale 3, 2009 (2011)

P. Leidinger, R. Popescu, D. Gerthsen, H. Lünsdorf, C. Feldmann
Nanoscale copper sulfide hollow spheres with “phase-engineered” composition: covellite (CuS), digenite (Cu1.8S), chalcocite (Cu2S)
Nanoscale 3, 2544 (2011)

C. Zurmühl, R. Popescu, D. Gerthsen, C. Feldmann
Microemulsion-based synthesis of nanoscale TiO2 hollow spheres
Solid State Sciences 13, 1505 (2011)

Li Shang, A. Naghmeh, F. Stockmar, W. Send, V. Trouillet, M. Bruns, D. Gerthsen, G. U. Nienhaus
One-pot synthesis of near-infrared emitting, dihydrolipoic acid capped gold clusters for cellular fluorescence imaging
Small 7, 2614 (2011)

P. Leidinger, N. Dingenouts, R. Popescu, D. Gerthsen, C. Feldmann
ZnO Nanocontainers: Structural study and controlled release
J. Mater. Chem. 22, 14551 (2012)

Li Shang, Linxiao Yang, F. Stockmar, R. Popescu, V. Trouillet, M. Bruns, D. Gerthsen, G.U. Nienhaus
Microwave-assisted rapid synthesis of fluorescent gold nanoclusters for imaging Hg2+ in living cells
Nanoscale 4, 4155 (2012)

C. Kind, R. Popescu, R. Schneider, E. Müller, D. Gerthsen,  C. Feldmann
Phase-engineering of advanced bimetallic In–Cu/Ag/Au nanostructures via tailored Microemulsion-based Reaction
RSC Adv. 25, 9273 (2012)

F. Gyger, P. Bockstaller, D. Gerthsen, Claus Feldmann
Ammonia-in-oil-microemulsions and their application
Angew. Chem. Internat. Ed. 52, 12443 (2013)

P. Leidinger, R. Popescu, D. Gerthsen, C. Feldmann
Nanoscale Ag2S hollow spheres and Ag2S nanodiscs assembled to 3D nanocrystal superlattices
Chem. Mater. 25, 4173 (2013)

H. Dong, R. Popescu, D. Gerthsen, C. Feldmann
Shape-stabilized Bi2Te3-capped Tellurium nanorods
Z. Anorg. Allg. Chem. 639, 2406 (2013)

H. Dong, T. Schnabel, R. Popescu, D. Gerthsen, E. Ahlswede, C. Feldmann,
Se@CuSe Core@Shell nanoparticles: colloidally stable Se-precursor for thin-film manufacturing of CIS solar cells
J. Colloid Interface Sci. 415, 103 (2014)