Article
Nanoscience & Nanotechnology
Anxin Luo, Yixin Xu, Yulong Zhang, Mi Zhang, Xiaoqing Zhang, Yan Lu, Fei Wang
Summary: This paper introduces a spray-coating method to deposit electret layer with enhanced charge stability, proposes a second-order linear model to analyze charge decay process, and designs an electrostatic energy harvester with spray-coated electret, showing effective power generation in harsh environments.
MICROSYSTEMS & NANOENGINEERING
(2021)
Article
Chemistry, Physical
Kenta Ichikawa, Wataru Hijikata
Summary: This study presents the development of a thin-sheet energy harvester for monitoring oral health. By utilizing the biting force and the large deformation of the dielectric elastomer, the harvester can generate high output power from low frequency movements. The experimental results show that this principle is an effective power-generation method for low-frequency movements in a narrow space.
Article
Chemistry, Physical
Zibo Wu, Zeyuan Cao, Rong Ding, Shiwen Wang, Yao Chu, Xiongying Ye
Summary: An electrostatic-electromagnetic hybrid generator is proposed to efficiently harvest mechanical energy in the environment. By utilizing a synchronously controlled voltage multiplier and a two-phase freestanding electret generator, the conversion efficiency is enhanced and energy storage is efficiently achieved.
Article
Physics, Applied
Jianan Pan, Weiyang Qin, Yongfeng Yang, Yaowen Yang
Summary: This study introduces a hybrid energy harvester design to broaden the working bandwidth of vibration energy harvesting by utilizing coupling and collision effects between two piezoelectric polyline beams. The results demonstrate that the proposed harvester, consisting of two polyline beams, achieves a broader bandwidth and can generate an output power of 69.1 mu W under specific excitation conditions. Parameter analysis and theoretical studies further support the effectiveness of the design in extending the working bandwidth.
JOURNAL OF PHYSICS D-APPLIED PHYSICS
(2021)
Article
Engineering, Environmental
Jia Xin Liu, Guoxu Liu, Zi Hao Guo, Weiguo Hu, Chi Zhang, Xiong Pu
Summary: This work presents a stretchable electret-based triboelectric nano-generator (SEB-TENG) for stretchable and wearable electronics. The device exhibits high stretchability, high charge density, and can be used to power electronic devices. A power management module (PMM) is also designed to optimize energy utilization.
CHEMICAL ENGINEERING JOURNAL
(2023)
Article
Engineering, Manufacturing
Wei Feng, Haruo Shimamoto, Tsuyoshi Kawagoe, Ichirou Honma, Masato Yamasaki, Fumitake Okutsu, Takatoshi Masuda, Katsuya Kikuchi
Summary: Wafer warpage adversely affects device yield, performance, and reliability by affecting photolithography resolution, process alignment, and wafer bonding. The increase in metal layers exacerbates the warpage problem. Through experiments and simulation, we investigate the warpage issue induced by the Wafer-to-Wafer (W2W) bonding process. The study reveals that the warpage induced by the W2W bonding process is three times the warpage of a single wafer and can be up to seven times in a multi-stack wafer bonding.
IEEE TRANSACTIONS ON SEMICONDUCTOR MANUFACTURING
(2023)
Review
Chemistry, Multidisciplinary
Jianxiong Zhu, Yaxin Yang, Hui Zhang, Zijing Zhao, Tao Hu, Lei Liu
Summary: This review summarizes the progress of electret-based electronics, focusing on enhanced energy harvesting, multi-functional applications, and machine learning-enabled methodologies. Electrets, which can convert mechanical vibration into electrical power without friction, have the potential to greatly benefit energy harvesters, sensors, and sustainable systems. In addition, the application of machine learning in electret electronics can contribute to the development of reliable and sustainable intelligent systems.
ADVANCED FUNCTIONAL MATERIALS
(2023)
Article
Chemistry, Multidisciplinary
Zisheng Xu, Kunwei Bao, Kui Di, Haojie Chen, Jianbo Tan, Xinjun Xie, Yixin Shao, Jiancheng Cai, Shizhe Lin, Tinghai Cheng, E. Shiju, Kang Liu, Zhong Lin Wang
Summary: This article reports a dielectric elastomer nanogenerator (DENG) for harvesting ambient low frequency mechanical energy. The DENG is capable of converting tensile mechanical energy into electrical power without an external power supply. It works based on the shuttle movement of internal charges in an alternating current (AC) and has the potential application in ocean wave energy harvesting.
Article
Materials Science, Multidisciplinary
Jianan Pan, Weiyang Qin, Chaoyang Zhao, Yaowen Yang
Summary: A hybrid energy harvester integrating piezoelectric and electrostatic effects has been proposed for more efficient vibration energy harvesting. Experimental validation shows that the hybrid harvester is more efficient in harvesting stochastic vibration energy.
JOURNAL OF INTELLIGENT MATERIAL SYSTEMS AND STRUCTURES
(2022)
Article
Engineering, Electrical & Electronic
Mustafa Mert Torunbalci, Hasan Dogan Gavcar, Ferhat Yesil, Said Emre Alper, Tayfun Akin
Summary: The paper introduces a novel and simple all-silicon wafer-level fabrication and hermetic packaging method for MEMS devices. The method achieves hermetic sealing and signal transfer without complex process steps, with a low package vacuum and high bonding strength. MEMS resonators fabricated and packaged using this method show significant enhancements in bias instability and temperature sensitivity compared to traditional technologies.
IEEE SENSORS JOURNAL
(2021)
Article
Chemistry, Physical
Zhixin Wang, Xu Liu, Mengyue Yue, Hongbo Yao, Haotian Tian, Xinru Sun, Yonghui Wu, Zongyin Huang, Dayan Ban, Haiwu Zheng
Summary: Smart agriculture faces challenges of low energy efficiency and lack of low-cost energy harvesting methods. This study presents a hybridized energy harvesting device that captures wind and solar energy for environmental energy collection. The device combines triboelectric nanogenerators and electromagnetic generators to transform motion into energy. A self-powered monitoring system and a farm peripheral security alarm system were established to achieve remote monitoring. This research demonstrates the potential of using triboelectric nanogenerators in smart agriculture applications.
Article
Engineering, Electrical & Electronic
Jumi Deka, Kundan Saha, Raktim Gogoi, Gitish K. Dutta, Kalyan Raidongia
Summary: Metal-water batteries are gaining attention for their environmental compatibility, low cost, and high energy density. A pressure-responsive energy delivery system based on these principles has been developed, showing promising power density. By adjusting parameters such as layer dimensions, applied pressure, and ionic conductivity of the gel membrane, the output power of the devices can be further enhanced. Both gel and V2O5 membranes can be completely regenerated after damage, and the devices can be connected in series or parallel to increase voltage or current values.
ACS APPLIED ELECTRONIC MATERIALS
(2021)
Article
Computer Science, Information Systems
Man Chu, An Liu, Junting Chen, Vincent K. N. Lau, Shuguang Cui
Summary: This article investigates device-to-device transmission powered by radio signals harvested from cellular systems, proposes two transmission policies, and discusses the technical challenges to implement these policies. Numerical simulation results show that introducing a guard zone can significantly improve D2D performance.
IEEE INTERNET OF THINGS JOURNAL
(2022)
Article
Chemistry, Analytical
Yongxin Zhou, Yuandong Gu, Songsong Zhang
Summary: This paper presents a novel wafer scale thin film thickness measurement method using reflected picosecond ultrasonic waves, which is highly efficient and suitable for opaque materials. By studying AlScN thin film and related piezoelectric stacking layers, the method successfully measured the thickness and showed good agreement with SEM data.
Article
Materials Science, Ceramics
Dongyu Xu, Yan Hu, Huaicheng Chen, Hongyu Jia, Peng Liu, Cheng Xin
Summary: This paper develops piezoelectric macro fiber composites (MFCs) for vibration energy harvesting using a hot pressing technique, which has the advantages of high power density, architectural simplicity, and scalability. Microscopic analysis shows good interfacial bonding between the piezoelectric ceramic fibers and epoxy resin matrix. Mechanical testing results demonstrate a maximum tensile stress of 71.27 MPa along the direction of the piezoelectric ceramic fibers in MFCs. Research results indicate that increasing vibration acceleration, interdigital electrode space, and volume fraction of piezoelectric ceramic fibers can improve the open circuit voltage amplitude of MFCs harvesters. Application validation shows that one MFC cantilever harvester can generate enough electric power to supply 88 LEDs and a small calculator.
CERAMICS INTERNATIONAL
(2023)
Article
Nanoscience & Nanotechnology
Alireza Assar, Filipe Martinho, Jes Larsen, Nishant Saini, Denver Shearer, Marcos V. Moro, Fredrik Stulen, Sigbjorn Grini, Sara Engberg, Eugen Stamate, Jorgen Schou, Lasse Vines, Stela Canulescu, Charlotte Platzer-Bjorkman, Ole Hansen
Summary: Multijunction solar cells in a tandem configuration using crystalline silicon as the bottom cell can reduce electricity costs. However, only a limited number of top and bottom cell architectures are compatible for direct integration on silicon. By using polySi/SiOx passivating contacts, degradation can be minimized and the lifetime of the bottom cell can be increased. Applying this concept to low-cost top cell chalcogenides, the efficiency and resilience of the tandem solar cells can be improved.
ACS APPLIED MATERIALS & INTERFACES
(2022)
Article
Materials Science, Multidisciplinary
Mungunshagai Gansukh, Alireza Assar, Filipe Martinho, Simon Lopez Marino, Moises Espindola-Rodriguez, Sara Engberg, Eugen Stamate, Jorgen Schou, Ole Hansen, Stela Canulescu
Summary: In this study, a barrier layer consisting of an ultrathin layer of Al between two TiN films is introduced to prevent Cu diffusion into Si in CZTS-Si tandem solar cells. The nature of the precursors is found to affect the chemical composition of the barrier layer, and CZTS/Si tandem solar cells based on oxide precursors demonstrate superior performance compared to those based on sulfide precursors.
APPLIED PHYSICS A-MATERIALS SCIENCE & PROCESSING
(2022)
Article
Materials Science, Ceramics
Sara Engberg, Mungunshagai Gansukh, Filipe Martinho, Eugen Stamate, Ole Hansen, Jorgen Schou, Stela Canulescu
Summary: This study successfully incorporated silver into the CZTS lattice using cation substitution, which reduced the disorder and band tailing effects. The best efficiency was achieved with 13% Ag/(Ag+Cu), reaching 4.9%. In addition, silver incorporation also improved grain growth and increased the band gap.
CERAMICS INTERNATIONAL
(2022)
Article
Engineering, Multidisciplinary
Benny Guralnik, Ole Hansen, Andreas R. Stilling-Andersen, Soren E. Hansen, Kasper A. Borup, Besira M. Mihiretie, Braulio Beltran-Pitarch, Henrik H. Henrichsen, Rong Lin, Lior Shiv, Bo B. Iversen, Peter F. Nielsen, Dirch H. Petersen
Summary: Micro four-point probing is an electrical metrology technique that accurately measures the electrical and electromagnetic properties of charge carriers at the micrometer scale. In this study, we propose and demonstrate a new application of micro four-point probe for quantifying the thermoelectric properties of a sample. We show that the voltage drop across the sensing electrodes is proportional to the ratio of the Seebeck coefficient to thermal conductivity, and our measurements on various semiconductor materials exhibit high accuracy and precision, indicating a novel in-situ metrology of thermoelectric properties at the micrometer scale.
MEASUREMENT SCIENCE AND TECHNOLOGY
(2022)
Article
Nanoscience & Nanotechnology
Ganapathi Prabhu Sai Balasubramanian, Elizaveta Lebedkina, Nebile Isik Goktas, Jakob Birkedal Wagner, Ole Hansen, Ray LaPierre, Elizaveta Semenova, Kristian Molhave, Marco Beleggia, Elisabetta Maria Fiordaliso
Summary: Off-axis electron holography was used to observe remote doping in GaAs nanowires during in situ annealing in a transmission electron microscope. Dynamic changes in electrostatic potential caused by carbon dopant diffusion upon annealing were measured, and the electrostatic potential profiles were extracted from GaAs nanowires with radial p-p+ core-shell junctions. The experiment showed that the built-in potentials remained nearly constant and the depletion layer widths slightly increased, contrary to the predictions made in the absence of remote doping. A depression in the potential profile of the core upon annealing was also observed, which was attributed to carbon diffusion from the shell to the core through the nanowire sidewalls.
Article
Materials Science, Ceramics
Gaoqiang Niu, Mingxiang Zhang, Bo Wu, Yi Zhuang, Rajendran Ramachandran, Changhui Zhao, Fei Wang
Summary: Nanocomposites of pre-oxidized Ti3C2Tx MXene and SnO2 nanosheets are synthesized and annealed for formaldehyde sensors. The pre-oxidized Ti3C2Tx MXene prevents further degradation, and its effects are verified through various characterizations. The SnO2/MXene nanocomposites exhibit high response, low detection limit, good selectivity, excellent reproducibility, and superior long-term stability. The sensing properties are attributed to the synergistic effect between the pre-oxidized Ti3C2Tx MXene and the SnO2 nanosheets.
CERAMICS INTERNATIONAL
(2023)
Article
Chemistry, Physical
Andrea Crovetto, Thomas Unold, Andriy Zakutayev
Summary: Through thin-film experiments, electronic structure calculations, and semiclassical Boltzmann transport theory, we find that Cu3P is an intrinsic semimetal, while experimentally realizable Cu3-xP films are p-type semimetals due to copper vacancy doping. Small-sized Cu3-xP samples may become semiconductors as a result of quantum confinement effects. This study demonstrates the suitability of reactive sputter deposition for detailed high-throughput studies of emerging metal phosphides.
CHEMISTRY OF MATERIALS
(2023)
Article
Engineering, Electrical & Electronic
Mingjie Li, Anxin Luo, Wenxin Luo, Xiaojiang Liu, Fei Wang
Summary: The electrostatic vibration energy harvester (e-VEH) is designed and fabricated with built-in silicon tips and perforated electrode based on MEMS technology. The integrated micro-tips effectively recharge the electret surface without separating the assembled device. Through-holes on the fixed electrode also optimize the energy harvesting performance. After self-charging, the fabricated device yields an output voltage of 6.2 V at a low driving frequency of 75 Hz, suggesting promising applications for self-powered electronics.
IEEE ELECTRON DEVICE LETTERS
(2023)
Article
Chemistry, Physical
Anxin Luo, Weihan Xu, Jiangyong Sun, Kunling Xi, Siyao Tang, Xinge Guo, Chengkuo Lee, Fei Wang
Summary: This paper proposes a vibration energy harvester with a double frequency-up conversion mechanism, which is capable of harvesting energy from ultra-low-frequency vibrations. The device can convert external vibrations from sub-Hertz to tens of Hertz and further to hundreds of Hertz, achieving a high conversion ratio of 8400. The comprehensive dynamic model proposed in this paper has been verified through theoretical analysis and COMSOL simulation, effectively analyzing the frequency conversion process and output voltage. When excited by a frequency of 0.2 Hz, the device can generate an average output power of 75 mu W with a compact size. Its non-contact design allows for application in sealed scenarios for smart city construction.
Article
Materials Science, Multidisciplinary
Braulio Beltran-Pitarch, Benny Guralnik, Neetu Lamba, Andreas R. Stilling-Andersen, Lars Norregaard, Torben M. Hansen, Ole Hansen, Nini Pryds, Peter F. Nielsen, Dirch H. Petersen
Summary: In order to develop materials with higher thermoelectric efficiency, a new method based on micro four-point probe (M4PP) was developed to determine the thermal diffusivity of a bulk material using the phase delay of the second harmonic voltage. The method was tested on two relevant thermoelectric materials, skutterudite and bismuth telluride, and showed good agreement with independent estimates. The M4PP method also demonstrated the ability to characterize materials with nonuniform and erratic electrical resistivity, such as bismuth telluride.
MATERIALS TODAY PHYSICS
(2023)
Article
Chemistry, Physical
Mirjana Dimitrievska, Alexander P. Litvinchuk, Andriy Zakutayev, Andrea Crovetto
Summary: In this work, a reference Raman spectrum of CuP2 was provided, and all Raman active modes were analyzed from both experimental and theoretical perspectives. The phonon density of states and phonon dispersions were also calculated, providing a microscopic understanding of the phonon lines. The agreement between the experimental and DFT-calculated Raman spectra of CuP2 was found, which can be used as a reference for future investigations on this material.
JOURNAL OF PHYSICAL CHEMISTRY C
(2023)
Article
Optics
Arnhold Simonsen, Gyeong Cheol Park, Thor Ersted Ansbaek, Ole Hansen, Kresten Yvind
Summary: In this letter, we introduce a 2D mirror design that offers a large optical bandwidth and high reflection. This design is also more rigid than 1D mirrors. We specifically study the impact of rounded corners of rectangles during the transfer from CAD to the wafer using lithography and etching.
Proceedings Paper
Acoustics
Stine Lovholt Grue Pedersen, Andreas Spandet Havreland, Ole Hansen, Erik Vilain Thomsen
Summary: This article introduces the importance of the resonance frequency of ultrasound transducers in the field of ultrasound, and proposes a new expression for deriving the resonance frequency in immersion. By considering the influence of the immersion medium, an approximation of the radiation impedance is obtained using the Taylor expansion, and the use of the Fade approximant is suggested for higher precision at smaller aspect ratios.
2022 IEEE INTERNATIONAL ULTRASONICS SYMPOSIUM (IEEE IUS)
(2022)
Article
Chemistry, Physical
Rasmus Nielsen, Tomas H. Youngman, Hadeel Moustafa, Sergiu Levcenco, Hannes Hempel, Andrea Crovetto, Thomas Olsen, Ole Hansen, Ib Chorkendorff, Thomas Unold, Peter C. K. Vesborg
Summary: Research on selenium solar cells is gaining momentum again due to its potential for integration with existing photovoltaic technology and its low cost. However, there are still voltage deficiencies in single-junction selenium devices, calling for further study on the material properties.
JOURNAL OF MATERIALS CHEMISTRY A
(2022)
Article
Automation & Control Systems
Wenjie Ren, Changhui Zhao, Gaoqiang Niu, Yi Zhuang, Fei Wang
Summary: This study investigates the doping effects of gallium on In2O3 nanotubes and develops a four-component sensor array for detecting TMA. The results show that Ga-In2O3 sensors with 5 mol% gallium doping exhibit the highest sensitivity and selectivity to TMA at a specific operating temperature, and they can display unique response patterns in different gas backgrounds. Additionally, neural network models and linear regression models trained with gas-sensing data can accurately classify different gases and predict the concentrations of target gases.
ADVANCED INTELLIGENT SYSTEMS
(2022)
