The Surface-Functionalized Materials group, led by Dr. Amin Bahrami, specializes in the precise surface modification or functionalization of materials using Atomic Layer Deposition (ALD). The team's expertise extends across a range of materials, including energy materials like thermoelectrics and active components in metal-ion batteries, biomaterials, textiles, and catalysts.
With years of experience, the group excels in depositing diverse compounds, including but not limited to metals such as Bi, Sb, Cu, semiconductors like Bi2Te3, Sb2Te3, Sb2Se3, and oxides such as ZnO, Al2O3, HfO2, TiO2, and Sb2O3.
Our capabilities go beyond surface functionalization. Utilizing the high conformality of ALD thin films, we can encapsulate 3D objects such as powders, implants, and electronic devices. Moreover, the team is actively involved in investigating the mechanical properties of these thin films. If you have specific compounds in mind, the group is open to discussing the possibilities of their deposition using ALD.
Head of Research Group "Surface-Functionalized Materials "
Room: D 1E.10
Phone: +49 351 4659 664
Postdocs:
Dr. Jorge Luis Vazquez-Arce (Ph.D.: UNAM-Mexico)
Ph.D. Students:
Jun Li (M.Sc.: Friedrich-Alexander-Universität Erlangen-Nürnberg, Germany)
Master Students:
Alessio Amoroso (Università di Napoli Federico II, Italy)
Bachelor Student:
Niels Stolzenburg (Hochschule für Technik und Wirtschaft-Dresden, Germany)
Alumni:
Ms. Moriom Akter (TU Dresden, research stay)
Ms. Ying Lu (TU Chemnitz, Master thesis)
S. He, S. Lehmann, A. Bahrami, K. Nielsch, Advanced Energy Materials 11 (37), 2101877 (2021)
URL
Thermoelectric (TE) materials are prominent candidates for energy converting applications due to their excellent performance and reliability. Extensive efforts for improving their efficiency in single-/multi-phase composites comprising nano/micro-scale second phases are being made. The artificial decoration of second phases into the thermoelectric matrix in multi-phase composites, which is distinguished from the second-phase precipitation occurring during the thermally equilibrated synthesis of TE materials, can effectively enhance their performance. Theoretically, the interfacial manipulation of phase boundaries can be extended to a wide range of materials. High interface densities decrease thermal conductivity when nano/micro-scale grain boundaries are obtained and certain electronic structure modifications may increase the power factor of TE materials. Based on the distribution of second phases on the interface boundaries, the strategies can be divided into discontinuous and continuous interfacial modifications. The discontinuous interfacial modifications section in this review discusses five parts chosen according to their dispersion forms, including metals, oxides, semiconductors, carbonic compounds, and MXenes. Alternatively, gas- and solution-phase process techniques are adopted for realizing continuous surface changes, like the core–shell structure. This review offers a detailed analysis of the current state-of-the-art in the field, while identifying possibilities and obstacles for improving the performance of TE materials.
Niloofar Soltani, Syed Muhammad Abbas, Martin Hantusch, Sebastian Lehmann, Kornelius Nielsch, Amin Bahrami*, Daria Mikhailova, Advanced Materials Interfaces 9 (34), 2201598 (2022)
The electrochemical performances of CoSn2 and Ni3Sn4 as potential anode materials in lithium-ion batteries (LIBs) are investigated using varying thicknesses of an alumina layer deposited by the atomic layer deposition (ALD) technique. Rate capability results showed that at high current densities, Al2O3-coated CoSn2 and Ni3Sn4 electrodes after 10-ALD cycles outperformed uncoated materials.
S He, A Bahrami, X Zhang, J Julin, M Laitinen, K Nielsch, Materials Today Chemistry 32, 101650 (2023)
Antimony (Sb) has distinct physical properties that make it a promising candidate for use in integrated phase-change photonics and tunable optical absorbers. In this work, we present atomic layer deposition (ALD) of Sb metal thin films using new precursor combinations produced from comproportionation reactions of antimony ethoxide (Sb(OEt)3) and Tris (dimethylamido)antimony (Sb(NMe2)3) with Tris (trimethylsilyl)antimony ((SiMe3)3Sb). The growth behaviors of the Sb thin films made from the Sb(OEt)3/(SiMe3)3Sb and Sb(NMe2)3/(SiMe3)3Sb precursor combinations showed different temperature dependencies at low deposition temperatures (60–80 °C). Furthermore, the deposition temperature had a significant impact on the oxidation of the deposited Sb film after exposure to air. XRD and Raman spectroscopy confirmed the high purity of the Sb films made with the Sb(OEt)3/(SiMe3)3Sb combination and deposited at 75 °C. The presence of a Sb2O3 phase deteriorated the electrical properties of deposited Sb films. However, the electrical conductivities of the purest Sb films prepared in this study were slightly higher than those previously reported for Sb-ALD films. This approach of Sb ALD can speed up actual applications of pure metals in electronic device fabrication and can potentially be extended to other main group metals.
A Bahrami, G Schierning, K Nielsch, Advanced Energy Materials 10 (19), 1904159 (2020)
Thermoelectric (TE) technology enables the efficient conversion of waste heat generated in homes, transport, and industry into promptly accessible electrical energy. Such technology is thus finding increasing applications given the focus on alternative sources of energy. However, the synthesis of TE materials relies on costly and scarce elements, which are also environmentally damaging to extract. Moreover, spent TE modules lead to a waste of resources and cause severe pollution. To address these issues, many laboratory studies have explored the synthesis of TE materials using wastes and the recovery of scarce elements from spent modules, e.g., utilization of Si slurry as starting materials, development of biodegradable TE papers, and bacterial recovery and recycling of tellurium from spent TE modules. Yet, the outcomes of such work have not triggered sustainable industrial practices to the extent needed. This paper provides a systematic overview of the state of the art with a view to uncovering the opportunities and challenges for expanded application. Based on this overview, it explores a framework for synthesizing TE materials from waste sources with efficiencies comparable to those made from raw materials.
Interface Engineering of Thermoelectric Materials Through Powder Atomic Layer Deposition (DFG research grant)
Amin Bahrami (BA 8109/1-1), since 2023
