The lab published two in-depth overview articles in the field of mesostructure formation:

Nanocrystal Assemblies: Current Advances and Open Problems
This review appeared in ACS Nano and is coauthored by 42 authors. The paper grew from discussions on these topics among the participants of the workshop “Nanoparticle Assemblies: A New Form of Matter with Classical Structure and Quantum Function”, held at the Kavli Institute for Theoretical Physics (KITP), Santa Barbara/CA, USA, from March 27 to May 19, 2023. This study is a broader-view study linking different scales, fundamentals, and methods, emphasizing open problems to inspire and push forward research in the field.

Mesomorphology of Clathrate Hydrates from Molecular Ordering
This perspective appeared in the Journal of Chemical Physics. The paper discusses the coupling of molecular ordering with the mesoscales, including (i) the emergence of porous patterns as a combined factor from the walk over the free energy landscape and 3D competitive nucleation and growth and (ii) the role of molecular attachment rates in crystallization–diffusion models that allow predicting the timescale of pore sealing. It discusses the use of discrete models (molecular dynamics) to build continuum models (phase field models, crystallization laws, and transport phenomena) to predict multiscale manifestations at a feasible computational cost.

Jyoti joined the group as a PhD student. She will be conducting research on the computational design of nanomaterials. Welcome!

Harsha Namdeo joined the group as a PhD student. She will be conducting research on understanding interactions and self-assembly behavior of nanoparticles. Welcome!

The German Research Foundation just announced that CRC 1411 will receive funding until 2028.

The long-term vision of CRC1411 is to develop particle systems with controlled size, shape and composition. The innovative approach in CRC1411 is is that these materials are first developed and optimized for specific product properties in computer models. In the second step, the computer then predicts optimal synthesis conditions that lead to particles with these desired properties. This approach reverses typical manufacturing processes and promises fast and resource-efficient access to functional particle-based materials with optimal characteristics.

Carlos Lange Bassani received an EAM Starting Grant. This grant is an encouragement for young researchers to venture into inovative and risky projects, and is a stepping stone towards ERC grant applications. Congratulations!

Simulation vs. microscopy images of nanocrystal habits. Simulations use rejection-free kinetic Monte Carlo to grow realistic-sized nanocrystals atom-by-atom. References of microscope images: [1] Xia et al., J. Am. Chem. Soc. 2012, 134, 1793; [2] Ahn et al., J. Mat. Chem. C 2013, 1, 6861; [3] Chen et al., Nature Comm. 2020, 11, 3041; [4] Sun et al., ACS Nano 2021, 15, 15953, [5] Xia and Xia, Nano Lett. 2012, 12, 6038; [6] Langille et al., Science 2012, 337, 954.

Nanocrystal (NC) superlattices are a novel way to design functional materials. Nanomaterial chemists thrived in forming NCs with controlled size and shape and assembling them into superstructures. Functionality of these materials relies on precise control of NC habits and superstructure formation, as well as on the electronic coupling between NCs –that is, it is an inherently multiscale process–, but multiscale models did not keep pace with recent advances in the field.

The proposed project upscales from atomic to realistic-sized NCs with 10s-of-millions of atoms via rejection-free kinetic Monte Carlo based on the semi-Gibbs ensemble. Of interest is the role of strain accumulation affected by defects, lattice mismatch, and geometric frustration, thus kinetically entrapping NCs into lower symmetry habits –that is, NC shapes that do not comply with the symmetry of the underlying crystalline structure. Coupling with reactor scales (the environment) to understand mass transfer-limited crystallization is also pivotal to predicting the yield of denser NC populations. A multiscale understanding from atom-to-NC-to-environment will optimize NC synthesis conditions and design strategies for new NC habits.

The tetrahedral geometry is ubiquitous in natural and synthetic systems. Regular tetrahedra do not tile space, which makes understanding their self-assembly behavior a formidable challenge. In 2009, simulations of hard tetrahedra —that is particles with the shape of a regular tetrahedron, interacting only by excluded volume interactions— discovered a dodecagonal quasicrystal stabilized by entropy alone. But while this quasicrystal forms robustly and reproducibly in simulation, it competes with periodic approximants and cannot be the thermodynamic ground state in the limit of infinite pressure. In this limit, the densest packing will eventually prevail, which is a simple (in comparison) dimer crystal.

Finally, after 14 years, our simulation predictions are confirmed. Yi Wang from the group of Xingchen Ye at Indiana University (USA) experimentally realized multiple phases of tetrahedron colloids where vertex sharpness, surface ligands, and the self-assembly environment play key roles in the formation of the quasicrystal and the dimer crystal. Our colleagues at the Institute of Micro- and Nanostructure Research at FAU resolved the complex three-dimensional structure of the quasicrystal by a combination of electron microscopy, tomography, and synchrotron X-ray scattering. The joint findings demonstrate the predictive power of computer simulations as well as the importance of accurate control over nanocrystal attributes and the assembly method to realize increasingly complex nanopolyhedron supracrystals.

Read about the research here:

Yi Wang, Jun Chen, Ruipeng Li, Alexander Götz, Dominik Drobek, Thomas Przybilla, Sabine Hübner, Philipp Pelz, Lin Yang, Benjamin Apeleo Zubiri, Erdmann Spiecker, Michael Engel, Xingchen Ye
Controlled Self-Assembly of Gold Nanotetrahedra into Quasicrystals and Complex Periodic Supracrystals
Journal of the American Chemical Society 145, 17902 (2023)