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© Andrei Mitrofanov

The research stay of Andrei Mitrofanov took place between 20^th of March 2023 and 21^st of April 2023 in the Group of Prof. Maria Antonietta Loi, University of Groningen, Netherlands. During the internship Andrei developed memristors with organic-inorganic halide perovskites — potential candidates for memory and neuromorphic computing applications. Together with Lijun Chen, doctoral researchers from the group, they found out that naphthalene-based perovskites, investigated in the laboratory in Dresden, are promising materials for memristors. Carefully selecting the structure, the researchers prepared the device with suitable electrical characteristics. The project will be continued in order to thoroughly characterize developed memristors. This internship allowed Andrei not only to expand his knowledge and expertise about halide perovskites and to learn new characterization techniques, but also to meet brilliant young and experienced scientist and expand his professional network

© Jun Yang

Jun Yang conducted research between July 5^th, 2023, and August 17^th, 2023, as a visiting scholar in the group led by Prof. Jianhua Zhang, Shanghai University, China. During his stay, in collaboration with Dr. Xingwei Ding, the group leader, Jun Yang focused on the development of transition-metal dichalcogenide thin films using atomic layer deposition (ALD), which is a promising technique known for its ability to synthesize large-size, high-quality 2D materials (2DMs) with precise thickness control and excellent uniformity. Their investigations revealed that thin films based on sulfur or selenium are highly suitable for electronic fabrication. By carefully adjusting the deposition parameters during the ALD process, they successfully fabricated thin-film transistors with excellent performance. The ongoing research will involve further characterization, including an examination of surface morphology, crystal structure, and low-temperature Hall effect measurements. This collaborative effort not only expands Jun Yang's knowledge and professional network but also holds the potential to yield new discoveries and applications in the field of 2DMs and innovative synthesis techniques. These contributions align with the advancement of materials science and technology.

© Lukas Sporrer

During his research stay in the group of Prof. Hongjie Dai at Stanford University, USA, Lukas Sporrer worked on the application of 2D metal-organic frameworks (MOFs) and covalent organic frameworks (COFs) in lithium, as well as sodium – chlorine batteries. This emerging battery technology uses porous cathode materials to capture the gaseous active species created during cycling. The usage of conducting MOF and COF materials with multiple active sites is a promising approach to improve the battery performance and overcome instability issues. From the 1^st of April to 30^th of August 2023, Lukas Sporrer optimized the electrode preparation using materials that have been previously synthesized by doctoral researchers of the CRC 1415. Learning from the experts in the group of Prof. Dai, he was able to prepare and characterize prototype Li/Cl₂ and Na/Cl₂ batteries with promising performances. Additional work is ongoing to continue the collaboration after his return to Dresden.

© Qing-Long Liu

M. Sc. Qing-Long Liu visited Prof. Volker Blum’s group at Duke University during Oct 16th, 2023 to Dec 1st, 2023 with the funding support from CRC 1415. M. Sc. Qing-Long Liu collaborated with Prof. Volker Blum’s group on two-component GW method development. The two-component GW method is a promising technique to simulate properties of materials containing heavy elements, with the trade-off consideration between accuracy and efficiency. Here they particularly focus on the high precision XPS related properties, and implement this method into the FHI-aims package. During his visit, among many things, they were working closely to solve bugs in the spin-orbit coupling routines when using some specific STO basis set. M. Sc. Qing-Long Liu found this bug in the benchmarking tests, and obtaining correct spin-orbit coupling results is an important prerequisite step of the following GW calculations. Moreover M. Sc. Qing-Long Liu benefited a lot from the conversations with members in Prof. Volker Blum’s group, he got a deeper understanding of the FHI-aims code structure and some crucial steps in the calculation. This fruitful collaboration keeps going after M. Sc. Qing-Long Liu comes back to TU Dresden.

M. Sc. Volodymyr Shamraienko's research fellowship took place between 15 September 2023 and 15 December 2023 in the group of Prof. Nicholas A. Kotov, University of Michigan, USA. The central task of the research stay abroad was to adapt the current self-assembly process to produce mirror asymmetric superstructures with controlled polarisation rotation. Inspired by recent breakthroughs in the creation of two-dimensional (2D) nanoparticle networks at the nanometre and centimetre scale, they worked with Dr. Engin Er to develop a controlled 2D assembly method for modified gold hedgehog particles. The modification and optimisation of the resulting 2D structure led to the creation of a graph-theoretical (GT) description of the 2D assembly to determine correlations between structural parameters and material properties. This research will be continued in order to develop and characterise different assembly techniques. This short-term research stay has enhanced and broadened Mr. Shamraienko's knowledge and helped him to acquire the competences required to develop new professional knowledge and skills to fulfil the tasks throughout his scientific career.

During his research stay in the group of Prof. Sung Ho Jhang at Konkuk University, South Korea, who specializes in the transport and electronics study of 2D materials, M. Sc. Dongho Shin worked on SnSe₂ thin film transistor grown by atomic layer deposition (ALD). Recently, the researchers could successfully deposit the SnSe₂ using SnCl₄ and (trimethyltin)selenium precursors which have never been reported. SnSe₂ stands out as a promising candidate owing to its intrinsic n-type semiconductor behavior and high carrier mobility. However, realizing efficient field-effect transistors (FETs) using SnSe₂ remains a challenge, particularly in achieving a distinct switch-off state.^[1-3] During hisresearch stay, Dongho Shin investigated the FET characteristics of SnSe₂ thin films and explored the incorporation of Sb₂Te₃ to induce switching behavior. FETs were fabricated using conventional photolithography and sputtering techniques. The SnSe₂ FETs were characterized using vacuum probe station and Keithley 4200 semiconductor characterization equipment. The SnSe₂ thin films exhibited superior electrical properties attributed to their high carrier concentration. However, the FETs did not demonstrate significant switching behavior, and the gate dependence was not pronounced.^[4] In conclusion, the researchers have successfully fabricated SnSe₂ thin films and explored their potential for FET applications. Ongoing research will focus on further elucidating the material properties and optimizing device performance.

^{[1] T. Pei, L. Bao, G. Wang, R. Ma, H. Yang, J. Li, C. Gu, S. Pantelides, S. Du, H. J. Gao, Appl. Phys. Lett. 2016, 108, DOI 10.1063/1.4941394.
[2] H. Xu, J. Xing, Y. Huang, C. Ge, J. Lu, X. Han, J. Du, H. Hao, J. Dong, H. Liu, Nanoscale Res. Lett. 2019, 14, DOI 10.1186/s11671-019-2850-0.
[3] J. Liu, M. Zhong, X. Liu, G. Sun, P. Chen, Z. Zhang, J. Li, H. Ma, B. Zhao, R. Wu, W. Dang, X. Yang, C. Dai, X. Tang, C. Fan, Z. Chen, L. Miao, X. Liu, Y. Liu, B. Li, X. Duan, Nanotechnology 2018, 29, DOI 10.1088/1361-6528/aadf5a.
[4] T. Kim, Y. Kim, E. K. Kim, Sensors Actuators, A Phys. 2020, 312, 112165.}

© Albrecht Wäntig

From April to June 2024, M. Sc. Albrecht Wäntig was hosted as a CRC 1415 research fellow at Ulsan National Institute of Science & Technology (UNIST), Republic of Korea. In the group of Prof. Jong Beom Baek, M. Sc. Albrecht Wäntig focused on applying organic 2D materials (2DMs) as metal free next-generation electrocatalysts. He namely explored in the CRC 1415 previously synthesized 2D polyarylene vinylenes (PAVs) as catalysts for the oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) which play main roles in metal-air batteries or fuel cells. The usage of 2DPAVs with their stable framework structure and strong conjugation is promising to significantly increase the catalyst’s performance. Learning the electrochemistry and characterization techniques from the experts in the group of Prof. Baek, M. Sc. Albrecht Wäntig could prove that specifically strong donor-acceptor based 2DPAVs with high density of active sites have the potential to eventually replace precious metals in ORR/OER electrocatalysts. Additional work to conclude his scientific findings is done in the frame of the CRC 1415 after his return to Dresden.

• First Place: M. Sc. Fanny Reichmayr                                                                                          Project B08 , "Raman Marker Bands for In-situ Quality Control During Synthesis of Two-Dimensional Conjugated Metal-Organic Frameworks"
• Second Place : M. Sc. Anupam Prasoon                                                                                 Project A01 "On-Water Programmable Assembly: Discovering Emergent Interfaces in 2D Polymer Heterostructures"
• Third Place : M. Sc. Mohammadreza Daqiqshirazi                                                              Project C02 "Novel Electronic Effects in Strained 2D Materials"

• 1. Platz: M. Sc. Ankita De                                                                                          Teilprojekt A02 , "Manipulation of Covalent Organic Framework by Side Chain Functionalization – Towards Few Layer Nanosheets"
• 2. Platz: M. Sc. Andrei Mitrofanov                                                                                 Teilprojekt A08 "Multiple-Ring Aromatic Cations for Low-Dimensional Perovskites"
• 3. Platz: M. Sc. Mohammadreza Daqiqshirazi                                                                        Teilprojekt C02 "Electronic Effect in Wrinkled 2D Transition Metal Dichalcogenides"

• Best student poster: M. Sc. Albrecht Wäntig                                                    Teilprojekt A01, "2D Conjugated Polymers for the Photoelectrochemical Oxidation of Nitrogen"
• Second best student poster: M. Sc. Suchetana Sarkar                                                        Teilprojekt B05, "Challenges in 2D On-Surface Synthesis: Experimental Perspective"
• Third best student poster: M. Sc. Ying-Ying Zhang                                                            Teilprojekt C06, "The Influence of Stacking on Properties of Layered COFs"

• 1. Platz: M. Sc. Paula Kalenczuk                                                                            Teilprojekt A03, "Soft-Template-Assisted On-Water Surface Synthesis of 2D Polymers"
• 2. Platz: M. Sc. Ankita De                                                                                         Teilprojekt A02, "Gas Adsorption Properties of Delaminated Layered 2D Covalent Organic Frameworks"
• 3. Platz: M. Sc. Friedrich Schwotzer                                                                            Teilprojekt A04, "The Chemistry of 2D Metal-Organic Framework
  Monolayers (MOFene)"

• Thesis titel: "Chemical Exfoliation of Bismuth-Rich Weak 3D Topological Insulators"
• Former scientific staff in research project A05

• Thesis title: "Broadband Coherent Anti-Stokes Raman Spectroscopy: A Comprehensive Approach to Analyzing Crystalline Materials"
• Former scientific staff in research project B06