Article
Nanoscience & Nanotechnology
Gheorghe Stan, Pradeep Namboodiri
Summary: The open-loop variant of Kelvin probe force microscopy (KPFM) provides access to the voltage response of the electrostatic interaction between a conductive atomic force microscopy (AFM) probe and the investigated sample, while the closed-loop variants solely report on the tip-sample contact potential difference. A new OL AM-KPFM mode was implemented in the single-pass scan of the PeakForce Tapping (PFT) mode, combining topographical and electrical components in a single pass. By applying electrical modulation only during tip-sample separation, contact and tunneling discharges were avoided, leading to improved accuracy in measurements.
BEILSTEIN JOURNAL OF NANOTECHNOLOGY
(2021)
Article
Chemistry, Physical
Jie Mao, Zhenao Gu, Yue Yu, Huijuan Liu, Jiuhui Qu, Xiaoqiang An
Summary: This study integrated visual observation techniques and material synthesis strategies to reveal the structure-activity relationship of a single BiVO4 photocatalyst, confirming the significance of facet engineering for enhancing photocatalytic activity.
ACS APPLIED ENERGY MATERIALS
(2021)
Article
Materials Science, Multidisciplinary
Zhaoxiang Ma, Lin Chen, Zhongli Liu, Yumin Wang, Kunjun Zhu, Yanjing Su
Summary: The behavior of dislocation migration hydrogen was observed through scanning Kelvin probe force microscopy (SKPFM) technique and slow tensile test. The quantitative analysis revealed that dislocation transport of hydrogen did not accelerate hydrogen atom migration, but achieved the uphill transport of hydrogen atoms. In addition, SKPFM has been confirmed as a powerful tool for measuring hydrogen diffusion coefficient in materials with high accuracy.
Article
Chemistry, Multidisciplinary
Devon S. Jakob, Nengxu Li, Huanping Zhou, Xiaoji G. Xu
Summary: This article introduces a novel method to generate Coulombic force in KPFM, increasing the spatial resolution to approximately 25 nm. By integrating PiFM, high spatial resolution chemical distributions and surface potential maps can be obtained concurrently. This is expected to facilitate characterizations of nanoscale electrical properties of photoactive materials, semiconductors, and ferroelectric materials.
Article
Energy & Fuels
Christian Kameni Boumenou, Amala Elizabeth, Finn Babbe, Alice Debot, Harry Moeenig, Alex Redinger
Summary: The study investigated the buried MoSe2/CuInSe2 interface of stoichiometric absorbers in thin film solar cells, revealing differences in local density of states compared to the front-side properties. This sheds new light on the complex interface formation in CuInSe2-based thin film solar cells grown under Cu-rich conditions.
PROGRESS IN PHOTOVOLTAICS
(2021)
Article
Chemistry, Multidisciplinary
Mengkang Xu, Xinpeng Tian, Qian Deng, Qun Li, Shengping Shen
Summary: By introducing nanocracks and applying continuously varying mechanical loading, the evolution of flexoelectricity around the crack tips in SrTiO3, Ba0.67Sr0.33TiO3, and TiO2 samples has been successfully measured. This method provides a reliable way to identify the significance of the flexoelectric effect and may open a new avenue for the study of flexoelectricity involving multiple physics phenomena such as flexoelectronics and the flexo-photovoltaic effect.
Article
Chemistry, Multidisciplinary
Shangzhi Gu, Wenyu Liu, Shuo Mi, Guoyu Xian, Jiangfeng Guo, Fei Pang, Shanshan Chen, Haitao Yang, Hong-Jun Gao, Zhihai Cheng
Summary: In this study, the twist angle-dependent work functions of twisted bilayer graphene (tBLG) were investigated using Kelvin probe force microscopy (KPFM) and Raman spectroscopy. The surface potentials of Bernal-stacked multilayer graphene were measured to determine the relationship between twist angle and surface potential. It was found that the work function of tBLG decreases and tends to saturate with increasing number of layers. Controlled annealing process showed that tBLG transforms into Bernal-stacked bilayer graphene. This research provides valuable insights into the twist angle-dependent surface potentials and electronic properties of tBLG.
Article
Chemistry, Physical
Hwi Je Woo, Seongchan Kim, Young-Jin Choi, Jeong Ho Cho, Seong Heon Kim, Young Jae Song
Summary: The work function of graphene devices on SiO2 substrates is studied using Kelvin probe force microscopy, revealing gate voltage-dependent work-function hysteresis. The inhomogeneous distribution of chemical species at the graphene/SiO2 interface leads to varying degrees of hysteresis across different positions on the graphene.
Article
Nanoscience & Nanotechnology
Ryo Izumi, Masato Miyazaki, Yan Jun Li, Yasuhiro Sugawara
Summary: The recently proposed high-low Kelvin probe force microscopy (KPFM) allows for the evaluation of semiconductor interface states with high spatial resolution using high and low AC bias frequencies. This is important for assessing the energy spectrum of interface state density in semiconductor devices. In this study, a method called high-low Kelvin probe force spectroscopy (high-low KPFS) is proposed, which measures the interface state density inside semiconductors using high and low-frequency AC bias voltages. Preliminary experiments on ion-implanted silicon surfaces confirmed the dependence of electrostatic force on AC bias voltage frequency and obtained the interface state density.
BEILSTEIN JOURNAL OF NANOTECHNOLOGY
(2023)
Article
Nanoscience & Nanotechnology
Jill Serron, Albert Minj, Valentina Spampinato, Alexis Franquet, Yevhenii Rybalchenko, Marie-Emmanuelle Boulon, Steven Brems, Henry Medina Silva, Yuanyuan Shi, Benjamin Groven, Renan Villarreal, Thierry Conard, Paul van der Heide, Thomas Hantschel
Summary: This study investigates the rapid intercalation of water vapor at the interface of transition metal dichalcogenides (TMDs) and sapphire, as well as between two TMD monolayers, and examines its impact on their electrical properties. The findings reveal that water vapor can intercalate rapidly within a few minutes and show partial reversibility under (ultra)-high vacuum conditions. Complete desorption of intercalated water clusters significantly enhances the electronic properties of TMDs, but also indicates that the characterization of TMD samples is significantly affected by the presence of water intercalation in air, inert environments, and even vacuum. Moreover, the study highlights a correlation between water intercalation and the presence of defects, contributing to the gradual degradation of TMDs as they age.
ACS APPLIED MATERIALS & INTERFACES
(2023)
Article
Nanoscience & Nanotechnology
Woongbin Yim, Van Tu Nguyen, Quynh Thi Phung, Hwan Sik Kim, Yeong Hwan Ahn, Soonil Lee, Ji-Yong Park
Summary: The spatial distribution of photogenerated carriers in atomically thin MoS2 flakes and their correlation with photocurrent generation is investigated using Kelvin probe force microscopy. The study reveals that surface potential changes can image the vertical redistribution of photogenerated carriers, and the trapping of photogenerated holes at the interface between MoS2 and the substrate is the main mechanism for the photoresponse.
ACS APPLIED MATERIALS & INTERFACES
(2022)
Article
Chemistry, Physical
Chin Chyi Loo, Sha Shiong Ng, Wei Sea Chang
Summary: The recent progress in piezotronics and piezo-phototronics has revealed new methods for adjusting/enhancing the performance of GaN-based devices, and the photostrictive effect in GaN samples with InGaN/GaN MQWs can be elucidated through the combination of light-induced surface electric field and converse piezoelectric effect. The enhanced piezoelectric coefficient under laser illumination suggests the potential for adjustable photostrictive responses in optomechanical sensors/actuators by manipulating the strain state of MQWs.
Article
Nanoscience & Nanotechnology
Jason I. Kilpatrick, Emrullah Kargin, Brian J. Rodriguez
Summary: Quantitative expressions governing the performance of single and multifrequency Kelvin probe force microscopy (KPFM) techniques in both air and water are derived and compared in this paper. The study concludes that open-loop multifrequency KPFM modes operated with the first harmonic of the electrostatic response on the first eigenmode offer the best performance in liquid environments.
BEILSTEIN JOURNAL OF NANOTECHNOLOGY
(2022)
Article
Chemistry, Physical
Yuuki Adachi, Yasuhiro Sugawara, Yan Jun Li
Summary: Probing CO on a rutile TiO2(110) surface using atomic force microscopy and Kelvin probe force microscopy enables the resolution of the interatomic dipole moment and charge state of CO at atomic resolution. The results suggest that both charge state and on-surface dipole interaction play a significant role in the reaction of CO on rutile TiO2(110) surface.
Article
Chemistry, Multidisciplinary
Minwoo Lee, Eunyoung Choi, Arman Mahboubi Soufiani, Jihoo Lim, Moonyong Kim, Daniel Chen, Martin Andrew Green, Jan Seidel, Sean Lim, Jincheol Kim, Xinchen Dai, Robert Lee-Chin, Bolin Zheng, Ziv Hameiri, Jongsung Park, Xiaojing Hao, Jae Sung Yun
Summary: This study presents an effective strategy to improve the performance of halide perovskite-based PV devices by using a hole-selective layer formed by PEAI salt, achieving high efficiency and stability under different light conditions.
ADVANCED FUNCTIONAL MATERIALS
(2021)
Article
Chemistry, Physical
Jonghee Yang, Diana K. LaFollette, Benjamin J. Lawrie, Anton V. Ievlev, Yongtao Liu, Kyle P. Kelley, Sergei V. Kalinin, Juan-Pablo Correa-Baena, Mahshid Ahmadi
Summary: Mixed cesium- and formamidinium-based metal halide perovskites (MHPs) are promising photovoltaic materials, but high cesium ratios result in chemical complexities and local inhomogeneities, compromising the optoelectronic performance.
ADVANCED ENERGY MATERIALS
(2023)
Article
Chemistry, Multidisciplinary
Boxiao Fu, Vasileios Tzitzios, Qiancheng Zhang, Brian Rodriguez, Michael Pissas, Maria Veronica Sofianos
Summary: In this study, manganese mono-boride nanoflakes were synthesized using a simple one-pot chemical reduction method at room temperature. The influence of specific surface area and boron content on the magnetic and electrocatalytic properties of the synthesized nanoflakes was investigated. The sample with the highest specific surface area and boron content showed the best magnetic and electrocatalytic properties in the HER, while the sample with the lowest specific surface area and boron content exhibited the best electric conductivity and electrocatalytic properties in the OER.
Article
Chemistry, Multidisciplinary
Wei-Jian Xu, Mao-Fan Li, Ana R. Garcia, Konstantin Romanyuk, Josee M. G. Martinho, Pavel Zelenovskii, Alexander Tselev, Luis Verissimo, Wei-Xiong Zhang, Xiao-Ming Chen, Andrei Kholkin, Joao Rocha
Summary: The design and synthesis of a new metal-nitrosyl ferroelectric crystal (DMA)(PIP)[Fe(CN)(5)(NO)] with potential phototunable polarization via a dual-organic-cation molecular design strategy is reported. The crystal exhibits a large polarization and a high Curie temperature, and the reversible photoisomerization of the nitrosyl ligand is accomplished by light irradiation. The optical accessibility and controllability of different ferroelectric states via photoinduced nitrosyl linkage isomerization present a new and attractive route to optically controllable macroscopic polarization.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Review
Materials Science, Multidisciplinary
Jonghee Yang, Sergei V. Kalinin, Ekin D. Cubuk, Maxim Ziatdinov, Mahshid Ahmadi
Summary: Low-dimensional hybrid perovskites combine the physical functionalities of inorganic materials and complexity of organic molecules to form self-organized complex structures. These materials offer high-performance optoelectronics and versatile applications, and can be produced cost-effectively.
Letter
Chemistry, Physical
Andrew R. Akbashev, Sergei V. Kalinin
Article
Chemistry, Multidisciplinary
Muammer Y. Yaman, Sergei V. Kalinin, Kathryn N. Guye, David S. Ginger, Maxim Ziatdinov
Summary: The application of machine learning is demonstrated for rapidly and accurately extracting plasmonic particles cluster geometries from hyperspectral image data using a dual variational autoencoder (dual-VAE). This approach shares information between the latent spaces of two VAEs, one handling particle shape data and the other handling spectral data, while enforcing a common encoding for shape-spectra pairs. The results show that this approach can establish the relationship between the geometric characteristics of nanoparticles and their far-field photonic responses, allowing for accurate prediction of the geometry of multiparticle assemblies below the diffraction limit using hyperspectral darkfield microscopy in an automated manner.
Article
Chemistry, Physical
Yongtao Liu, Rama K. K. Vasudevan, Kyle P. Kelley, Hiroshi Funakubo, Maxim Ziatdinov, Sergei V. V. Kalinin
Summary: We developed automated experiment workflows for identifying the best predictive channel in spectroscopic measurements. The approach combines ensembled deep kernel learning for probabilistic predictions and reinforcement learning for channel selection. The implementation in multimodal imaging of piezoresponse force microscopy (PFM) showed that the amplitude is the best predictive channel for polarization-voltage and frequency-voltage hysteresis loop areas. This workflow and code can be applied to other multimodal imaging and local characterization methods.
NPJ COMPUTATIONAL MATERIALS
(2023)
Article
Chemistry, Physical
Denis Alikin, Kiryl Zakharchuk, Wenjie Xie, Konstantin Romanyuk, Maria J. Pereira, Blanca I. Arias-Serrano, Anke Weidenkaff, Andrei Kholkin, Andrei V. Kovalevsky, Alexander Tselev
Summary: Thermoelectric conversion could play a significant role in future energy technologies. Oxide-based thermoelectric composite ceramics have attracted attention as a promising approach to control electrical and thermal conductivity for improved thermoelectric performance. However, the variability of composite properties, even with identical preparation routes, requires detailed studies of thermal transport at the local scale in order to be understood.
Article
Biochemistry & Molecular Biology
Sawsan Almohammed, Mohammed Benali Kanoun, Souraya Goumri-Said, Mir Waqas Alam, Agata Fularz, Abdullah Alnaim, James H. H. Rice, Brian J. J. Rodriguez
Summary: Self-assembling nanostructured peptide gels, particularly Fmoc-FF gels, offer promising applications in sensing, drug delivery, and energy harvesting. By controlling the water content and temperature, the structure tunability of Fmoc-FF gels can be achieved. Incorporating metal nanoparticles in the gel formation allows for optical sensing applications. The observations also suggest the potential use of these peptide materials in bioimaging and sensing applications.
Article
Chemistry, Physical
Arwa Bazaid, Fengyuan Zhang, Qiancheng Zhang, Sabine Neumayer, Denise Denning, Stefan Habelitz, Ana Marina Ferreira, Brian J. Rodriguez
Summary: Since the discovery of piezoelectricity in bone in 1957, there has been a debate about the functional role of collagen piezoelectricity. The investigation of piezoelectricity in collagen has generated interest in bone remodeling, but there are conflicting reports about its presence in a humid environment. This study used lateral piezoresponse force microscopy to investigate the electromechanical properties of type I collagen from a rat tail tendon at the nanoscale, and found that collagen retains its piezoelectric behavior even in a biologically relevant humidity range.
Article
Computer Science, Artificial Intelligence
Maxim Ziatdinov, Chun Yin (Tommy) Wong, Sergei Kalinin
Summary: Recent advances in scanning tunneling and transmission electron microscopies have generated large volumes of imaging data containing information on the structure and functionality of materials. However, automatic extraction and classification of patterns in the images is non-trivial. To address this problem, the authors propose a shift-invariant variational autoencoder approach and demonstrate its effectiveness on 1D, synthetic, and experimental data. The shift VAE analysis shows promise for pattern discovery, but also has limitations.
MACHINE LEARNING-SCIENCE AND TECHNOLOGY
(2023)
Article
Chemistry, Multidisciplinary
Srikanth Kolagatla, Gearoid A. Collins, Jason I. Kilpatrick, Emrullah Kargin, Kevin M. Ryan, Brian J. Rodriguez
Summary: A systematic study was conducted on lithium-silicon nanowire electrodes in charged and discharged states, with and without the solid electrolyte interphase (SEI) layer. Kelvin probe force microscopy in air was used to characterize the pristine and cycled nanowires. By correlating the changes in morphology with contact potential difference mapping, insights into SEI layer formation, growth, and its effect on battery performance were obtained.
CHEMICAL COMMUNICATIONS
(2023)
Article
Materials Science, Biomaterials
Niamh Geoghegan, Mark O'Loughlin, Colm Delaney, Keith D. Rochfort, Meabh Kennedy, Srikanth Kolagatla, Lucia Podhorska, Brian J. Rodriguez, Larisa Florea, Susan M. Kelleher
Summary: In this study, we demonstrate the fabrication of micropillar arrays using a combination of direct laser writing and nanoimprint lithography. By using two diacrylate monomers, polycaprolactone dimethacrylate (PCLDMA) and 1,6-hexanediol diacrylate (HDDA), we were able to create copolymer formulations that could be controllably degraded in the presence of base. The topography of the micropillars could be varied over a short period of time, and their degradation was attributed to the presence of PCL. These materials showed compatibility with mammalian cells, making them potentially useful for biomedical applications in microfabrication contexts.
BIOMATERIALS SCIENCE
(2023)
Article
Multidisciplinary Sciences
Marti Checa, Addis S. Fuhr, Changhyo Sun, Rama Vasudevan, Maxim Ziatdinov, Ilia Ivanov, Seok Joon Yun, Kai Xiao, Alp Sehirlioglu, Yunseok Kim, Pankaj Sharma, Kyle P. Kelley, Neus Domingo, Stephen Jesse, Liam Collins
Summary: Unraveling local dynamic charge processes is essential for progress in various fields. Researchers have developed high-speed sparse scanning Kelvin probe force microscopy, enabling sub-second imaging of nanoscale charge dynamics and enhancing understanding of material heterogeneities.
NATURE COMMUNICATIONS
(2023)
Article
Engineering, Electrical & Electronic
Sabine M. Neumayer, Anton Ievlev, Alexander Tselev, Sergey A. Basun, Benjamin S. Conner, Michael A. Susner, Petro Maksymovych
Summary: This research demonstrates the volatile ferroelectric switching of Sn2P2S6 at room temperature and reveals the strong influence of initial polarization orientation on the switching properties. The existence and mechanism of domain walls can control the shape of the hysteresis loop, enabling controlled volatile ferroelectric switching.
NEUROMORPHIC COMPUTING AND ENGINEERING
(2023)
