Article
Nanoscience & Nanotechnology
Zheng Ju, Caitlin Crawford, Jesse Adamczyk, Eric S. Toberer, Susan M. Kauzlarich
Summary: This study successfully synthesized core-shell Bi2Te3/Sb2Te3 nanostructured heterojunctions, which have potential in energy waste harvesting and sustainable energy utilization. The material showed high Seebeck coefficient and overall zT value in the out-of-plane direction, possibly due to the energy filtering effect across the heterojunction interfaces.
ACS APPLIED MATERIALS & INTERFACES
(2022)
Article
Chemistry, Inorganic & Nuclear
Jingwen Zhang, Song Li, Zhengyi Zhu, Zhenwang Wu, Jiuxing Zhang
Summary: The study introduces PbTe@C core-shell nanostructures to enhance the thermoelectric performance of SnTe, achieving a significant increase in ZT value. However, the structure also has some impact on the electrical properties to some extent.
DALTON TRANSACTIONS
(2021)
Article
Nanoscience & Nanotechnology
Kazi M. Alam, Charles E. Jensen, Pawan Kumar, Riley W. Hooper, Guy M. Bernard, Aakash Patidar, Ajay P. Manuel, Naaman Amer, Anders Palmgren, David N. Purschke, Narendra Chaulagain, John Garcia, Phillip S. Kirwin, Lian C. T. Shoute, Kai Cui, Sergey Gusarov, Alexander E. Kobryn, Vladimir K. Michaelis, Frank A. Hegmann, Karthik Shankar
Summary: A potential solution to the extraction of photogenerated holes from CdS nanocrystals and nanowires was presented by constructing CdS-C3N5 heterostructures, which improved photocatalytic degradation and photocatalytic decolorization performance while providing control over the reaction pathways.
ACS APPLIED MATERIALS & INTERFACES
(2021)
Article
Chemistry, Multidisciplinary
Shixuan Liu, Yong Yu, Di Wu, Xiao Xu, Lin Xie, Xiaolian Chao, Michel Bosman, Stephen J. Pennycook, Zupei Yang, Jiaqing He
Summary: The introduction of Sb and Cu2Te into an n-type base material (PbTe)(81)-Sb2Te3 effectively tunes the electron concentration and enhances the overall Seebeck coefficient. The co-precipitation of Sb and Cu2Te forms an interesting Sb/CuTe core/shell structure, showing interface characteristics beneficial for electron transport but adverse to phonon transport. The peak ZT(max) of approximately 1.6 @ 823K and averageZT of approximately 1.0 (323-823 K) are achieved in the (PbTe)(81)Sb2Te3-0.6Sb-2Cu(2)Te sample, representing the current state of the art for n-type PbTe-based thermoelectric materials.
ADVANCED FUNCTIONAL MATERIALS
(2021)
Article
Chemistry, Multidisciplinary
Yu Xiao, Liqing Xu, Tao Hong, Haonan Shi, Sining Wang, Xiang Gao, Xiangdong Ding, Jun Sun, Li-Dong Zhao
Summary: A high average ZT value has been achieved in an n-type PbSe-based thermoelectric material with ultrahigh carrier mobility, optimized carrier effective mass, carrier density, and microstructure. Through synergistic tuning of these factors, the carrier mobility and power factor were significantly enhanced, surpassing previous n-type PbSe-based materials.
ENERGY & ENVIRONMENTAL SCIENCE
(2022)
Article
Materials Science, Ceramics
Junyang Zeng, Jingjing Yan, Bao-Wen Li, Xin Zhang
Summary: This paper presents a method to modify high dielectric constant barium titanate (BTO) nanoparticles with polyimide (PI) polymer shells through an in-situ polymerization process. The PI shell improves the compatibility of the inorganic/organic interface, resulting in a uniform dispersion of nanoparticles in the polyetherimide (PEI) matrix. The resultant PEI/PI@BTO nanocomposite exhibits high energy storage density and charge-discharge efficiency.
CERAMICS INTERNATIONAL
(2022)
Article
Nanoscience & Nanotechnology
Xinyu Wang, Honghao Yao, Zongwei Zhang, Xiaofang Li, Chen Chen, Li Yin, Kangning Hu, Yirui Yan, Zhou Li, Bo Yu, Feng Cao, Xingjun Liu, Xi Lin, Qian Zhang
Summary: This study demonstrates the effectiveness of high entropy alloying in reducing lattice thermal conductivity and improving Seebeck coefficient of thermoelectric materials. By introducing various elements at the cationic site, both the configurational entropy and phonon scattering are enhanced. Additionally, Ga doping further optimizes carrier concentration and results in a peak ZT value of approximately 1.52 at 823 K for the Ga-0.025(Sn0.25Pb0.25Mn0.25Ge0.25)(0.975)Te alloy.
ACS APPLIED MATERIALS & INTERFACES
(2021)
Article
Chemistry, Inorganic & Nuclear
Muhammad Waqas
Summary: A delicate synthesis strategy of Fe2TiO5/Fe2O3 heterostructures was proposed to achieve efficient photocatalytic water oxidation, with the hierarchical structure increasing light absorption depth and promoting the separation of photoinduced excitons, while the high surface area and adequate porosity facilitated the diffusion of electrolyte and adsorption at active sites. Furthermore, the coating of Fe2TiO5/Fe2O3 with graphitic carbon nitride subunits improved photocatalytic water reduction by accelerating the separation of electrons and holes at the contact interface.
INORGANIC CHEMISTRY
(2021)
Article
Chemistry, Physical
Xingzhong Liu, Yue Zhang, Yanshuang Meng, Mingjun Xiao, Tai Kang, Hongfu Gao, Liangbiao Huang, Fuliang Zhu
Summary: A core-shell structured lithium iron phosphate (LFP) material with LFP as the core and LiCoxFe1-xO4 as the shell was prepared using the solvothermal method. Doping of cobalt widened the diffusion channel of Li+ and improved the electronic conductivity of LFP. In addition, cobalt on the surface inhibited electrolyte corrosion and protected the material's structure. The core-shell structure material exhibited good interface and cycle stability, as well as excellent cycle and rate performance.
JOURNAL OF ALLOYS AND COMPOUNDS
(2022)
Article
Chemistry, Physical
Xingzhong Liu, Yue Zhang, Yanshuang Meng, Mingjun Xiao, Tai Kang, Hongfu Gao, Liangbiao Huang, Fuliang Zhu
Summary: A core-shell structured lithium iron phosphate (LFP) material was successfully prepared using the solvothermal method, with LiCoxFe1-xPO4 serving as the shell and enhancing the diffusion of Li+ in combination with the doped Co. The Co-doped core-shell structure exhibited improved electronic conductivity, cycle stability, and rate performance, maintaining a capacity of 165.1mAh g(-1) over 300 cycles at 0.1 C.
JOURNAL OF ALLOYS AND COMPOUNDS
(2022)
Article
Chemistry, Multidisciplinary
M. Almasoudi, Numan Salah, Ahmed Alshahrie, Abdu Saeed, Mutabe Aljaghtham, M. Sh. Zoromba, M. H. Abdel-Aziz, Kunihito Koumoto
Summary: Core shell nanocomposites based on SWCNT/PPy were fabricated and the optimum formula for maximum TE performance was determined. The core shell nanocomposite showed significantly enhanced TE power factor and figure of merit compared to pure PPy. This enhancement was attributed to the good interaction between PPy polymer chains and walls of the SWCNT.
Article
Chemistry, Inorganic & Nuclear
You Zi, Jun Zhu, Mengke Wang, Lanping Hu, Yulin Hu, Swelm Wageh, Omar A. Al-Hartomy, Ahmed Al-Ghamdi, Weichun Huang, Han Zhang
Summary: Uniform and well-defined cadmium sulfide@cadmium selenide core/shell quantum dots (CdS@CdSe QDs) were successfully synthesized for the first time using a solvothermal method and chemical bath growth. The as-synthesized CdS@CdSe QDs exhibit superior self-powered photoresponse behavior, excellent stability, and significantly improved current densities and photoresponsivity compared to individual CdS QDs or CdSe QDs. These properties are mainly attributed to the built-in electric field, suggesting great potential in the fields of renewable energy and carbon neutrality target achievement.
INORGANIC CHEMISTRY
(2021)
Article
Chemistry, Multidisciplinary
Shijia Zeng, Zhenbo Li, Wenjiang Tan, Jinhai Si, Yuren Li, Xun Hou
Summary: This study compares the ultrafast carrier dynamics in InP/ZnSe/ZnS core/shell/shell quantum dots (CSS-QDs) and InP/ZnS core/shell QDs (CS-QDs), revealing the impact of the ZnSe midshell on carrier dynamics. The results show that the ZnSe midshell enhances electron delocalization, prolongs the in-band relaxation time of electrons and holes, and reduces defect emissions. Additionally, the ZnSe midshell leads to an increased density of higher-energy hole states, which may decrease the probability of Auger recombination.
Article
Metallurgy & Metallurgical Engineering
Zhao Li-Dong, Wang Sining, Xiao Yu
Summary: This review summarizes the methods to optimize carrier mobility in thermoelectric materials, including crystal defect manipulations and multiple coupling parameter manipulations, and discusses their applications in various TE material systems. The importance of carrier mobility optimization in improving TE performance over a wide temperature range is highlighted as a new research idea for developing high-efficiency TE materials.
ACTA METALLURGICA SINICA
(2021)
Article
Chemistry, Physical
Lin-Yuan Cheng, Kai-Cheng Zhang, Yong-Feng Li, Yong Liu, Yan Zhu
Summary: The study reveals the influence of SnSe thickness on its thermoelectric properties, showing changes in electron mobility and thermal conductivity with increasing thickness. Thicker films of SnSe exhibit higher carrier mobility and lower thermal conductivity, leading to better thermoelectric performance.
JOURNAL OF ALLOYS AND COMPOUNDS
(2022)
Article
Materials Science, Multidisciplinary
Maksim Naumochkin, Gyu-Hyeon Park, Kornelius Nielsch, Heiko Reith
Summary: This study presents the full TE characterization of sputtered Bi2Te3 thin films for micro-TE device fabrication, revealing the influence of thickness and annealing conditions on their ZT values.
PHYSICA STATUS SOLIDI-RAPID RESEARCH LETTERS
(2022)
Article
Materials Science, Multidisciplinary
Shiyang He, Amin Bahrami, Xiang Zhang, Ignacio Gonzalez Martinez, Sebastian Lehmann, Kornelius Nielsch
Summary: This study introduces a strategy of interface modification based on powder atomic layer deposition to control and modify the phase boundary of pure bismuth, resulting in a substantial increase in thermoelectric performance and a significant decrease in thermal conductivity, with a maximum figure of merit of 0.15. This method shows great potential for practical application in developing high-performance thermoelectric materials.
ADVANCED MATERIALS TECHNOLOGIES
(2022)
Article
Physics, Applied
Sami Alajlouni, David Alberto Lara Ramos, Kerry Maize, Nicolas Perez, Kornelius Nielsch, Gabi Schierning, Ali Shakouri
Summary: We introduce a noncontact experimental method for estimating the thermal conductivity of nanoscale thin films by fitting high spatial resolution thermoreflectance images of surface spot heating. The method offers advantages of easy sample preparation, rapid in situ measurement, and applicability to a broad range of thin-film materials.
JOURNAL OF APPLIED PHYSICS
(2022)
Article
Chemistry, Multidisciplinary
Jun Yang, Amin Bahrami, Xingwei Ding, Sebastian Lehmann, Nadine Kruse, Shiyang He, Bowen Wang, Martin Hantusch, Kornelius Nielsch
Summary: This study investigates the deposition of ZnO thin films using atomic layer deposition (ALD) with diethylzinc as the zinc source and H2O and H2O2 as oxygen sources. The results show that H2O2 provides an oxygen-rich environment, suppressing the oxygen vacancies and resulting in lower carrier concentration and higher resistivity. Additionally, the lower growth rate leads to ZnO thin films growing along the lower surface energy direction, leading to lower Hall mobility. Furthermore, ZnO thin films are integrated into thin film transistor (TFT) devices and their electrical properties are analyzed, demonstrating promising results for potential application in metal-oxide electronics optimization.
ADVANCED MATERIALS INTERFACES
(2022)
Article
Nanoscience & Nanotechnology
Jun Yang, Jianzhu Li, Amin Bahrami, Noushin Nasiri, Sebastian Lehmann, Magdalena Ola Cichocka, Samik Mukherjee, Kornelius Nielsch
Summary: This work demonstrates a high-performance and self-powered photodetector that is compatible with silicon. A wide detection range from visible to near infrared light is achieved by the vertical p-n heterojunction. The photodetectors have low dark current, high responsivity, peak detectivity, and quick rise time. The devices also exhibit long-term air stability and efficient switching behavior, making them suitable for various applications in optoelectronics.
ACS APPLIED MATERIALS & INTERFACES
(2022)
Article
Crystallography
Vladimir Ciobanu, Veaceslav V. Ursaki, Sebastian Lehmann, Tudor Braniste, Simion Raevschi, Victor V. Zalamai, Eduard V. Monaico, Pascal Colpo, Kornelius Nielsch, Ion M. Tiginyanu
Summary: New aeromaterials are proposed in this paper, which are based on titania thin films deposited using atomic layer deposition (ALD) on a sacrificial network of ZnO microtetrapods. The morphology, composition, and crystal structure of the aeromaterials are investigated depending on the temperature of annealing and the sequence of the technological steps. Photoluminescence analysis suggests that these aeromaterials have potential for photocatalytic applications.
Article
Materials Science, Multidisciplinary
Kangfa Deng, Qihao Zhang, Yangxi Fu, Andres Fabian Lasagni, Heiko Reith, Kornelius Nielsch
Summary: This article presents a novel fabrication technique named PowderMEMS for high-performance, low-cost TE films and micro-patterns. The TE film is composed of agglomerated micro-sized N-type Bi2Te2.5Se0.5 powders with a molten binder of bismuth (Bi). The influence of key process parameters on TE performance is investigated, and the TE film exhibits a maximum power factor of 1.7 mW m-1K-2 at room temperature, the highest value reported so far.
ADVANCED ENGINEERING MATERIALS
(2023)
Article
Chemistry, Physical
Ruben Bueno Villoro, Duncan Zavanelli, Chanwon Jung, Dominique Alexander Mattlat, Raana Hatami Naderloo, Nicolas Perez, Kornelius Nielsch, Gerald Jeffrey Snyder, Christina Scheu, Ran He, Siyuan Zhang
Summary: By using scanning transmission electron microscopy and atom probe tomography, this study revealed the structural differences of hexagonal close-packed lattice phases at grain boundaries in Ti-doped NbFeSb half-Heusler compounds. It was found that the enrichment of Fe leads to high electrical resistivity in Nb0.95Ti0.05FeSb, while the accumulation of Ti dopants results in good electrical conductivity in Nb0.80Ti0.20FeSb. This resistive to conductive grain boundary phase transition provides a new design space for decoupling the intertwined electronic and phononic transport in thermoelectric materials.
ADVANCED ENERGY MATERIALS
(2023)
Article
Materials Science, Multidisciplinary
Sebastian Lehmann, Fanny Mitzscherling, Shiyang He, Jun Yang, Martin Hantusch, Kornelius Nielsch, Amin Bahrami
Summary: In this study, a water-free atomic layer deposition (ALD) process was used to deposit SbOx on the surface of Bi2Te3 particles for the first time. The coating improved the thermoelectric properties through interface engineering. The results showed that the ALD coating enhanced the electrical conductivity and Seebeck coefficient of the thermoelectric material.
Article
Materials Science, Multidisciplinary
Klara Luenser, Andreas Undisz, Kornelius Nielsch, Sebastian Faehler
Summary: Understanding and optimizing the martensitic microstructure of nickel-titanium (NiTi) thin films is important for their applications in microsystems. Epitaxial films grown on single-crystalline substrates provide a model system to study the microstructure and exploit the anisotropic mechanical properties of NiTi. By analyzing the growth of NiTi on MgO(100) and Al2O3(0001), we achieve epitaxial films with desired orientations and demonstrate the effect of buffer layers on crystal quality and transformation behavior. Transmission electron microscopy confirms the presence of a martensitic microstructure with Guinier Preston-zone precipitates. This study provides valuable insights into the development of NiTi thin films with optimized properties.
JOURNAL OF PHYSICS-MATERIALS
(2023)
Article
Materials Science, Multidisciplinary
Satyakam Kar, Kornelius Nielsch, Sebastian Faehler, Heiko Reith
Summary: This article investigates different etching techniques for the microfabrication of magnetic shape memory alloys, compares their advantages and disadvantages, and proposes methods to overcome challenges. The results show that wet chemical etching is suitable for large structures, while ion beam etching is suitable for small structures. Finally, a microfabrication process using Si microtechnology to fabricate partially freestanding structures is demonstrated.
ADVANCED ENGINEERING MATERIALS
(2023)
Article
Chemistry, Multidisciplinary
Lukas Fink, Satyakam Kar, Klara Luenser, Kornelius Nielsch, Heiko Reith, Sebastian Faehler
Summary: Magnetic shape memory alloys have multifunctional properties and can be used for high stroke actuation, magnetocaloric refrigeration, and thermomagnetic energy harvesting. This study demonstrates the epitaxial growth of Ni-Mn-based Heusler alloys with single crystal-like properties on silicon substrates using a SrTiO3 buffer. It shows that standard microfabrication technologies can be used to prepare partly freestanding patterns. The approach is versatile and can be applied to NiTi shape memory alloys as well as spintronic and thermoelectric Heusler alloys, paving the way for integrating additional multifunctional effects into state-of-the-art microelectronic and micromechanical technology based on silicon.
ADVANCED FUNCTIONAL MATERIALS
(2023)
Article
Materials Science, Ceramics
Shiyang He, Amin Bahrami, Xiang Zhang, Magdalena Ola Cichocka, Jun Yang, Jaroslav Charvot, Filip Bures, Alla Heckel, Stephan Schulz, Kornelius Nielsch
Summary: In this article, the deposition of BiSe by atomic layer deposition (ALD) using Bi(NMe2)3 and Se(SnMe3)2 as precursors was reported. The growth rate varied from 1.5 to 2.0 angstrom/cycle in the temperature range of 90-120 degrees C. Higher deposition temperatures resulted in larger grain sizes and enhanced crystallinity of the films. The presence of Bi-Bi zigzag bilayers and the formation of the BiSe phase were confirmed by XPS spectra and Raman spectra.
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
(2023)
Article
Multidisciplinary Sciences
Wuyang Ren, Wenhua Xue, Shuping Guo, Ran He, Liangzi Deng, Shaowei Song, Andrei Sotnikov, Kornelius Nielsch, Jeroen van den Brink, Guanhui Gao, Shuo Chen, Yimo Han, Jiang Wu, Ching-Wu Chu, Zhiming Wang, Yumei Wang, Zhifeng Ren
Summary: Studies have shown that vacancy-mediated anomalous transport properties are flourishing in various fields due to their fascinating effects on photoelectric, ferroelectric, and spin-electric behaviors in solid materials. In this study, the authors reveal the multifunctionality of vacancy in tailoring the transport properties of a defective half-Heusler ZrNiBi material, providing insights into the phononic and electronic transport processes. These findings not only demonstrate the potential of this thermoelectric material but also promote further exploration of vacancy-mediated transport properties.
NATURE COMMUNICATIONS
(2023)
Article
Chemistry, Physical
Jonas Wawra, Kornelius Nielsch, Ruben Huehne
Summary: Substrate-induced strains can significantly affect the structural and functional properties of epitaxial thin films. By growing epitaxial Ba0.7Sr0.3TiO3 films on REScO3 substrates with smaller lattice mismatch, the quality of the films was improved compared to SrTiO3. The strain state of the functional layer depended on the substrate and thickness, leading to differences in permittivity and polarization behavior at different temperatures.
