Lívia P. Matte, Maximilian Jaugstetter, Alisson S. Thill, Tara P. Mishra, Carlos Escudero, Giuseppina Conti, Fernanda Poletto, Slavomir Nemsak, Fabiano Bernardi
Hydrogen holds great promise as a cleaner alternative to fossil fuels, but its efficient and affordable storage remains a significant challenge. Bimetallic systems, such as Pd and Ni, present a promising option for storing hydrogen. In this study, using the combination of different cutting-edge X-ray and electron techniques, we observed the transformations of Pd–Ni nanoparticles, which initially consist of a NiO-rich shell surrounding a Pd-rich core but undergo a major transformation when they interact with hydrogen. During hydrogen exposure, the Pd core breaks into smaller pockets, dramatically increasing its surface area and enhancing the hydrogen storage capacity, especially in nanoparticles with lower Pd content. The findings provide a deep understanding of the morphological changes at the atomic level during hydrogen storage and contribute to designing cost-effective hydrogen storage using multimetallic systems.
{"title":"Direct Observation of Phase Change Accommodating Hydrogen Uptake in Bimetallic Nanoparticles","authors":"Lívia P. Matte, Maximilian Jaugstetter, Alisson S. Thill, Tara P. Mishra, Carlos Escudero, Giuseppina Conti, Fernanda Poletto, Slavomir Nemsak, Fabiano Bernardi","doi":"10.1021/acsnano.4c18013","DOIUrl":"https://doi.org/10.1021/acsnano.4c18013","url":null,"abstract":"Hydrogen holds great promise as a cleaner alternative to fossil fuels, but its efficient and affordable storage remains a significant challenge. Bimetallic systems, such as Pd and Ni, present a promising option for storing hydrogen. In this study, using the combination of different cutting-edge X-ray and electron techniques, we observed the transformations of Pd–Ni nanoparticles, which initially consist of a NiO-rich shell surrounding a Pd-rich core but undergo a major transformation when they interact with hydrogen. During hydrogen exposure, the Pd core breaks into smaller pockets, dramatically increasing its surface area and enhancing the hydrogen storage capacity, especially in nanoparticles with lower Pd content. The findings provide a deep understanding of the morphological changes at the atomic level during hydrogen storage and contribute to designing cost-effective hydrogen storage using multimetallic systems.","PeriodicalId":21,"journal":{"name":"ACS Nano","volume":"36 1","pages":""},"PeriodicalIF":17.1,"publicationDate":"2025-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143546904","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pedram Khakbaz, Dominic Waldhoer, Mina Bahrami, Theresia Knobloch, Mahdi Pourfath, Mohammad Rasool Davoudi, Yichi Zhang, Xiaoyin Gao, Hailin Peng, Michael Waltl, Tibor Grasser
Silicon’s dominance in integrated circuits is largely due to its stable native oxide, SiO2, known for its insulating properties and excellent interface to the Si channel. However, silicon-based FETs face significant challenges when further scaled, which inspires the search for better semiconductors. While 2D materials such as MoS2, WSe2, BP, and InSe are promising, they lack a stable and compatible native oxide. High mobility (812 cm2 V–1 s–1) 2D Bi2SeO2 stands out in this regard, as it can be oxidized into different forms of Bi2SeO5, thereby forming compatible high-κ native oxides. Despite growing interest in this material system, a comprehensive understanding of its fundamental properties is lacking. This study uses density functional theory and molecular dynamics simulations to investigate the intrinsic properties of Bi2SeO2, its native oxides, and its interfaces. Additionally, scanning transmission electron microscopy is employed to complement these theoretical analyses, providing detailed insights into the atomic-scale structure and interfaces of these materials. Building on these findings, we model semiconductor-oxide heterostructures and extract their intrinsic properties. Our results demonstrate that the atomically sharp and clean interface between oxide and semiconductor, the high dielectric constant (>30) of the oxide, and the sufficiently large conduction band offsets between the semiconductor and the most relevant β-phase of its native insulator (1.13 eV for holes and 1.55 eV for electrons) make this material system a strong candidate for future transistor technologies. These properties mitigate the limitations of traditional semiconductors and enhance device performance at the ultimate scaling limit, positioning 2D Bi2SeO2 as a suitable choice for next-generation nanoelectronics.
{"title":"Two-dimensional Bi2SeO2 and Its Native Insulators for Next-Generation Nanoelectronics","authors":"Pedram Khakbaz, Dominic Waldhoer, Mina Bahrami, Theresia Knobloch, Mahdi Pourfath, Mohammad Rasool Davoudi, Yichi Zhang, Xiaoyin Gao, Hailin Peng, Michael Waltl, Tibor Grasser","doi":"10.1021/acsnano.4c12160","DOIUrl":"https://doi.org/10.1021/acsnano.4c12160","url":null,"abstract":"Silicon’s dominance in integrated circuits is largely due to its stable native oxide, SiO<sub>2</sub>, known for its insulating properties and excellent interface to the Si channel. However, silicon-based FETs face significant challenges when further scaled, which inspires the search for better semiconductors. While 2D materials such as MoS<sub>2</sub>, WSe<sub>2</sub>, BP, and InSe are promising, they lack a stable and compatible native oxide. High mobility (812 cm<sup>2</sup> V<sup>–1</sup> s<sup>–1</sup>) 2D Bi<sub>2</sub>SeO<sub>2</sub> stands out in this regard, as it can be oxidized into different forms of Bi<sub>2</sub>SeO<sub>5</sub>, thereby forming compatible high-κ native oxides. Despite growing interest in this material system, a comprehensive understanding of its fundamental properties is lacking. This study uses density functional theory and molecular dynamics simulations to investigate the intrinsic properties of Bi<sub>2</sub>SeO<sub>2</sub>, its native oxides, and its interfaces. Additionally, scanning transmission electron microscopy is employed to complement these theoretical analyses, providing detailed insights into the atomic-scale structure and interfaces of these materials. Building on these findings, we model semiconductor-oxide heterostructures and extract their intrinsic properties. Our results demonstrate that the atomically sharp and clean interface between oxide and semiconductor, the high dielectric constant (>30) of the oxide, and the sufficiently large conduction band offsets between the semiconductor and the most relevant β-phase of its native insulator (1.13 eV for holes and 1.55 eV for electrons) make this material system a strong candidate for future transistor technologies. These properties mitigate the limitations of traditional semiconductors and enhance device performance at the ultimate scaling limit, positioning 2D Bi<sub>2</sub>SeO<sub>2</sub> as a suitable choice for next-generation nanoelectronics.","PeriodicalId":21,"journal":{"name":"ACS Nano","volume":"4 1","pages":""},"PeriodicalIF":17.1,"publicationDate":"2025-03-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143546679","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In recent years, DNA has emerged as a promising molecule for the construction of molecular computing systems. In the research field of DNA logic circuits, enzyme-driven DNA logic circuits, which offer faster reactions and lower complexity, have become the key focus in the field. However, it remains a significant drawback that it lacks the capability of being reused. Reusability is essential to enhance the computational capacity, correct errors, and reduce costs in DNA circuits. In this study, we propose a method for achieving high reuse in enzyme-driven DNA logic circuits using exonuclease III. By selectively digesting ds-DNA while preserving gate strands, our system highly restores the circuit to its initial state, which contains no waste-strand. This reuse method has demonstrated good performance in the converted-input reuse experiment of single-gate, multilayer cascades. Finally, we achieve four times converted-input reuse in a relatively complex circuit and three times multiple reuse in a square root DNA circuit.
{"title":"Highly Reusable Enzyme-Driven DNA Logic Circuits","authors":"Xiao Liu, Zhuo Chen, Kaixuan Wan, Yangkang Luo, Jingge Yang, Longjie Li, Kaixiong Tao, Xianjin Xiao, Mingxia Zhang","doi":"10.1021/acsnano.4c15176","DOIUrl":"https://doi.org/10.1021/acsnano.4c15176","url":null,"abstract":"In recent years, DNA has emerged as a promising molecule for the construction of molecular computing systems. In the research field of DNA logic circuits, enzyme-driven DNA logic circuits, which offer faster reactions and lower complexity, have become the key focus in the field. However, it remains a significant drawback that it lacks the capability of being reused. Reusability is essential to enhance the computational capacity, correct errors, and reduce costs in DNA circuits. In this study, we propose a method for achieving high reuse in enzyme-driven DNA logic circuits using exonuclease III. By selectively digesting ds-DNA while preserving gate strands, our system highly restores the circuit to its initial state, which contains no waste-strand. This reuse method has demonstrated good performance in the converted-input reuse experiment of single-gate, multilayer cascades. Finally, we achieve four times converted-input reuse in a relatively complex circuit and three times multiple reuse in a square root DNA circuit.","PeriodicalId":21,"journal":{"name":"ACS Nano","volume":"20 1","pages":""},"PeriodicalIF":17.1,"publicationDate":"2025-03-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143539279","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Justin L. Lee, Noreen Elizabeth Gentry, Jennifer L. Peper, Staci Hetzel, Christine Quist, Fabian S. Menges, James M. Mayer
Redox transformations at metal oxide (MOx)/solution interfaces are broadly important, and oxygen atom transfer (OAT) is one of the simplest and most fundamental examples of such reactivity. OAT is a two-electron transfer process, well-known in gas/solid reactions and catalysis. However, OAT is rarely directly observed at oxide/water interfaces, whose redox reactions are typically proposed to occur in one-electron steps. Reported here are stoichiometric OAT reactions of organic molecules with aqueous colloidal titanium dioxide and iridium oxide nanoparticles (TiO2 and IrOx NPs). Me2SO (DMSO) oxidizes reduced TiO2 NPs with the formation of Me2S, and IrOx NPs transfer O atoms to a water-soluble phosphine and a thioether. The reaction stoichiometries were established and the chemical mechanisms were probed using typical solution spectroscopic techniques, exploiting the high surface areas and transparency of the colloids. These OAT reactions, including a catalytic example, utilize the ability of the individual NPs to accumulate many electrons and/or holes. Observing OAT reactions of two different materials, in opposite directions, is a step toward harnessing oxide nanoparticles for valuable multi-electron and multi-hole transformations.
{"title":"Oxygen Atom Transfer Reactions of Colloidal Metal Oxide Nanoparticles","authors":"Justin L. Lee, Noreen Elizabeth Gentry, Jennifer L. Peper, Staci Hetzel, Christine Quist, Fabian S. Menges, James M. Mayer","doi":"10.1021/acsnano.4c17955","DOIUrl":"https://doi.org/10.1021/acsnano.4c17955","url":null,"abstract":"Redox transformations at metal oxide (MO<sub><i>x</i></sub>)/solution interfaces are broadly important, and oxygen atom transfer (OAT) is one of the simplest and most fundamental examples of such reactivity. OAT is a two-electron transfer process, well-known in gas/solid reactions and catalysis. However, OAT is rarely directly observed at oxide/water interfaces, whose redox reactions are typically proposed to occur in one-electron steps. Reported here are stoichiometric OAT reactions of organic molecules with aqueous colloidal titanium dioxide and iridium oxide nanoparticles (TiO<sub>2</sub> and IrO<sub><i>x</i></sub> NPs). Me<sub>2</sub>SO (DMSO) oxidizes reduced TiO<sub>2</sub> NPs with the formation of Me<sub>2</sub>S, and IrO<sub><i>x</i></sub> NPs transfer O atoms to a water-soluble phosphine and a thioether. The reaction stoichiometries were established and the chemical mechanisms were probed using typical solution spectroscopic techniques, exploiting the high surface areas and transparency of the colloids. These OAT reactions, including a catalytic example, utilize the ability of the individual NPs to accumulate many electrons and/or holes. Observing OAT reactions of two different materials, in opposite directions, is a step toward harnessing oxide nanoparticles for valuable multi-electron and multi-hole transformations.","PeriodicalId":21,"journal":{"name":"ACS Nano","volume":"45 1","pages":""},"PeriodicalIF":17.1,"publicationDate":"2025-03-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143546909","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Yazgan Tuna, Amer Al-Hiyasat, Anna D. Kashkanova, Andreas Dechant, Eric Lutz, Vahid Sandoghdar
In the past decades, many techniques have been explored for trapping microscopic and nanoscopic objects, but the investigation of nano-objects under arbitrary forces and conditions remains nontrivial. One fundamental case concerns the motion of a particle under a constant force, known as force clamping. Here, we employ metallic nanoribbons embedded in a glass substrate in a capacitor configuration to generate a constant electric field on a charged nanoparticle in a water-filled glass nanochannel. We estimate the force fields from Brownian trajectories over several micrometers and confirm the constant behavior of the forces both numerically and experimentally. Furthermore, we manipulate the diffusion and relaxation times of the nanoparticles by tuning the charge density on the electrode. Our highly compact and controllable setting allows for the trapping and force-clamping of charged nanoparticles in a solution, providing a platform for investigating nanoscopic diffusion phenomena.
{"title":"Electrostatic All-Passive Force Clamping of Charged Nanoparticles","authors":"Yazgan Tuna, Amer Al-Hiyasat, Anna D. Kashkanova, Andreas Dechant, Eric Lutz, Vahid Sandoghdar","doi":"10.1021/acsnano.4c17299","DOIUrl":"https://doi.org/10.1021/acsnano.4c17299","url":null,"abstract":"In the past decades, many techniques have been explored for trapping microscopic and nanoscopic objects, but the investigation of nano-objects under arbitrary forces and conditions remains nontrivial. One fundamental case concerns the motion of a particle under a constant force, known as <i>force clamping</i>. Here, we employ metallic nanoribbons embedded in a glass substrate in a capacitor configuration to generate a constant electric field on a charged nanoparticle in a water-filled glass nanochannel. We estimate the force fields from Brownian trajectories over several micrometers and confirm the constant behavior of the forces both numerically and experimentally. Furthermore, we manipulate the diffusion and relaxation times of the nanoparticles by tuning the charge density on the electrode. Our highly compact and controllable setting allows for the trapping and force-clamping of charged nanoparticles in a solution, providing a platform for investigating nanoscopic diffusion phenomena.","PeriodicalId":21,"journal":{"name":"ACS Nano","volume":"67 1","pages":""},"PeriodicalIF":17.1,"publicationDate":"2025-03-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143546907","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Platinum (Pt)-based chemotherapeutic agents, known for their potent cytotoxicity, are extensively used in clinical oncology. However, their therapeutic efficacy is severely limited by a variety of factors, particularly the hypoxic tumor microenvironment (TME), which not only impedes effective drug delivery but also triggers immune suppression, further diminishing the antitumor effects of Pt drugs. In response to these challenges, we have developed a biotin receptor (BR)-targeting oxaliplatin (OXA)-based PtIV prodrug, named Lipo-OPtIV-BT, which could encapsulate hemoglobin (Hb) as an oxygen carrier, forming PtIV-loaded lipid nanoparticles (Hb@BTOPtIV). The design of the Hb@BTOPtIV aims to address the dual issues of poor drug delivery and immune suppression by effectively increasing local oxygen tension in the TME. Notably, our findings demonstrate that the cytotoxic effects of the BR-targeting PtIV prodrug and increased oxygen levels synergistically reverse the tumor immune microenvironment, leading to improved antitumor efficacy. We observed that Hb@BTOPtIV significantly improved the biodistribution of the drug, enabling it to preferentially accumulate in tumor regions. Importantly, the enhanced oxygenation within the TME also plays a critical role in reshaping the immune landscape of the tumor, promoting a more favorable immune environment for effective chemotherapy. This reversal of immune suppression is evidenced by increased infiltration of cytotoxic T cells and reduced levels of regulatory T cells (Tregs) within the tumor. These findings highlight the promising potential of using BR-targeting lipid PtIV prodrug amphiphiles to improve drug accumulation at tumor sites and counteract immunosuppression induced by tumor hypoxia.
{"title":"Biotin Receptor-Targeting PtIV Oxygen Carrying Prodrug Amphiphile for Alleviating Tumor Hypoxia Induced Immune Chemotherapy Suppression","authors":"Kaichuang Sun, Xiaodan Wei, Shangcong Han, Yong Sun, Haihua Xiao, Dengshuai Wei","doi":"10.1021/acsnano.5c00691","DOIUrl":"https://doi.org/10.1021/acsnano.5c00691","url":null,"abstract":"Platinum (Pt)-based chemotherapeutic agents, known for their potent cytotoxicity, are extensively used in clinical oncology. However, their therapeutic efficacy is severely limited by a variety of factors, particularly the hypoxic tumor microenvironment (TME), which not only impedes effective drug delivery but also triggers immune suppression, further diminishing the antitumor effects of Pt drugs. In response to these challenges, we have developed a biotin receptor (BR)-targeting oxaliplatin (OXA)-based Pt<sup>IV</sup> prodrug, named Lipo-OPt<sup>IV</sup>-BT, which could encapsulate hemoglobin (Hb) as an oxygen carrier, forming Pt<sup>IV</sup>-loaded lipid nanoparticles (Hb@BTOPt<sup>IV</sup>). The design of the Hb@BTOPt<sup>IV</sup> aims to address the dual issues of poor drug delivery and immune suppression by effectively increasing local oxygen tension in the TME. Notably, our findings demonstrate that the cytotoxic effects of the BR-targeting Pt<sup>IV</sup> prodrug and increased oxygen levels synergistically reverse the tumor immune microenvironment, leading to improved antitumor efficacy. We observed that Hb@BTOPt<sup>IV</sup> significantly improved the biodistribution of the drug, enabling it to preferentially accumulate in tumor regions. Importantly, the enhanced oxygenation within the TME also plays a critical role in reshaping the immune landscape of the tumor, promoting a more favorable immune environment for effective chemotherapy. This reversal of immune suppression is evidenced by increased infiltration of cytotoxic T cells and reduced levels of regulatory T cells (Tregs) within the tumor. These findings highlight the promising potential of using BR-targeting lipid Pt<sup>IV</sup> prodrug amphiphiles to improve drug accumulation at tumor sites and counteract immunosuppression induced by tumor hypoxia.","PeriodicalId":21,"journal":{"name":"ACS Nano","volume":"40 1","pages":""},"PeriodicalIF":17.1,"publicationDate":"2025-03-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143538336","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Tinglian Yuan, Xiaofei Guo, Stephen Anthony Lee, Sadie Brasel, Amrita Chakraborty, David J. Masiello, Stephan Link
Plasmon-induced interfacial charge separation is a promising way to efficiently extract energetic carriers through direct plasmon decay. This mechanism of charge transfer has been investigated by single-particle scattering spectroscopy, which measures the homogeneous plasmon line width. The line width is broadened by charge transfer, generally known as chemical interface damping. However, conflicting reports exist regarding the effect of chemical interface damping on the corresponding single-particle absorption spectrum, which is needed to accurately determine absolute light conversion efficiencies. This work aims to resolve this question by directly correlating absorption and scattering spectra of individual gold nanorods in the presence and absence of a charge-accepting interface. We find that for TiO2 coated nanorods, the absorption line width is indeed broadened due to chemical interface damping but is overall narrower than the scattering line width. Chemical interface damping is furthermore found to increase with larger resonance energies. The observed differences in line widths between absorption and scattering are elucidated within the context of an analytically tractable model describing the lowest energy optically bright and higher-order optically dark plasmon modes of the nanorod, including bulk, radiative, and chemical interface damping effects. Taken together, these results establish that single-particle absorption spectroscopy is capable of revealing interfacial charge injection by direct plasmon decay.
{"title":"Chemical Interface Damping Revealed by Single-Particle Absorption Spectroscopy","authors":"Tinglian Yuan, Xiaofei Guo, Stephen Anthony Lee, Sadie Brasel, Amrita Chakraborty, David J. Masiello, Stephan Link","doi":"10.1021/acsnano.4c17894","DOIUrl":"https://doi.org/10.1021/acsnano.4c17894","url":null,"abstract":"Plasmon-induced interfacial charge separation is a promising way to efficiently extract energetic carriers through direct plasmon decay. This mechanism of charge transfer has been investigated by single-particle scattering spectroscopy, which measures the homogeneous plasmon line width. The line width is broadened by charge transfer, generally known as chemical interface damping. However, conflicting reports exist regarding the effect of chemical interface damping on the corresponding single-particle absorption spectrum, which is needed to accurately determine absolute light conversion efficiencies. This work aims to resolve this question by directly correlating absorption and scattering spectra of individual gold nanorods in the presence and absence of a charge-accepting interface. We find that for TiO<sub>2</sub> coated nanorods, the absorption line width is indeed broadened due to chemical interface damping but is overall narrower than the scattering line width. Chemical interface damping is furthermore found to increase with larger resonance energies. The observed differences in line widths between absorption and scattering are elucidated within the context of an analytically tractable model describing the lowest energy optically bright and higher-order optically dark plasmon modes of the nanorod, including bulk, radiative, and chemical interface damping effects. Taken together, these results establish that single-particle absorption spectroscopy is capable of revealing interfacial charge injection by direct plasmon decay.","PeriodicalId":21,"journal":{"name":"ACS Nano","volume":"13 1","pages":""},"PeriodicalIF":17.1,"publicationDate":"2025-03-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143546908","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Light elements or compounds with an average atomic number (Z) of less than 10 are difficult to detect due to their weak interactions with electrons and photons. Here, we introduce a direct thermal absorbance measurement platform for scanning electron microscopy. The technique, named ZEM, is particularly sensitive to low Z materials, including hydrogen (Z = 1) and vacancy (Z = 0). We use Pd as an example to explore ZEM’s potential in characterizing hydrogen storage materials. ZEM reveals that hydrogen storage is highly inhomogeneous, concentrating on grain boundaries and defects. ZEM also unveils a large defect density created by hydrogenation, uncovering abundant voids beneath the surface. ZEM’s nondestructive detection method allows us to investigate multiple hydrogen charging–discharging cycles, revealing two distinct hydrogen uptake phenomena accompanied by unusual defect healing processes. We further establish the causality between hydrogenation and defect formation, quantifying distinct correlations between hydrogen-induced defect generation and defect-mediated hydrogen trapping. The rich phenomena discovered by the ZEM underscore its potential in material characterizations, particularly for light elements or compounds.
{"title":"Quantitatively Profiling the Evolution of Hydrogen Storage and Defect Healing Processes in Palladium at the Nanoscale","authors":"Yu-Cheng Chiu, Bo-Yi Chen, Chin-Chia Hsu, Chia-Wei Tsai, Shih-Ming Wang, I-Ling Chang, Chih-Wei Chang","doi":"10.1021/acsnano.4c16841","DOIUrl":"https://doi.org/10.1021/acsnano.4c16841","url":null,"abstract":"Light elements or compounds with an average atomic number (<i>Z</i>) of less than 10 are difficult to detect due to their weak interactions with electrons and photons. Here, we introduce a direct thermal absorbance measurement platform for scanning electron microscopy. The technique, named ZEM, is particularly sensitive to low <i>Z</i> materials, including hydrogen (<i>Z</i> = 1) and vacancy (<i>Z</i> = 0). We use Pd as an example to explore ZEM’s potential in characterizing hydrogen storage materials. ZEM reveals that hydrogen storage is highly inhomogeneous, concentrating on grain boundaries and defects. ZEM also unveils a large defect density created by hydrogenation, uncovering abundant voids beneath the surface. ZEM’s nondestructive detection method allows us to investigate multiple hydrogen charging–discharging cycles, revealing two distinct hydrogen uptake phenomena accompanied by unusual defect healing processes. We further establish the causality between hydrogenation and defect formation, quantifying distinct correlations between hydrogen-induced defect generation and defect-mediated hydrogen trapping. The rich phenomena discovered by the ZEM underscore its potential in material characterizations, particularly for light elements or compounds.","PeriodicalId":21,"journal":{"name":"ACS Nano","volume":"36 1","pages":""},"PeriodicalIF":17.1,"publicationDate":"2025-03-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143546680","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Victor Vanpeene, Olga Stamati, Cyril Guilloud, Rémi Tucoulou, Benjamin Holliger, Marion Chandesris, Sandrine Lyonnard, Julie Villanova
Improving battery materials calls for nondestructive techniques capable of delivering high-resolution microstructural information in real time. In this context, X-ray phase contrast nano-tomography is a technique of choice as it enables multiscale 3D characterization. In this study, we propose a feedback loop-integrated workflow for X-ray nano-tomography, based on systematic evaluation of six state-of-the-art battery anode and cathode materials to benchmark key procedures ensuring reliable, reproducible, quality-assessed characterization and subsequent 3D morphological quantification, thus avoiding potential bias in the scientific conclusions. As a result for this phase contrast technique, the sample size and energy used appear as key factors for the final resolution, which enhances imaging capabilities for separating the different material phases of the electrode microstructures. But, it is crucial to adapt these parameters to the materials in order to mitigate errors in the morphological parameter estimation. Moreover, an empirical law based on the heterogeneity and the average particle size distribution has been established to calculate the minimum representative elementary volume to be imaged, showing that volumes of 102 × 102 × 102 μm3 (50 nm voxel size) are sufficiently representative for the six microstructures studied. Ultimately, guidelines have been established for in situ/operando X-ray nano-tomography measurements, with a proposed/validated in-house setup and cell design that preserve both the image resolution and electrochemistry. A detailed evaluation of the X-ray beam interaction is also presented, exploring the relationship between the dose received by the electrolyte and material and the reliable monitoring of electrochemistry and tomography.
{"title":"Comparative Study of the Quantitative Analysis of Battery Materials with X-ray Nano-tomography: From Ex Situ toward Operando Measurements","authors":"Victor Vanpeene, Olga Stamati, Cyril Guilloud, Rémi Tucoulou, Benjamin Holliger, Marion Chandesris, Sandrine Lyonnard, Julie Villanova","doi":"10.1021/acsnano.4c16419","DOIUrl":"https://doi.org/10.1021/acsnano.4c16419","url":null,"abstract":"Improving battery materials calls for nondestructive techniques capable of delivering high-resolution microstructural information in real time. In this context, X-ray phase contrast nano-tomography is a technique of choice as it enables multiscale 3D characterization. In this study, we propose a feedback loop-integrated workflow for X-ray nano-tomography, based on systematic evaluation of six state-of-the-art battery anode and cathode materials to benchmark key procedures ensuring reliable, reproducible, quality-assessed characterization and subsequent 3D morphological quantification, thus avoiding potential bias in the scientific conclusions. As a result for this phase contrast technique, the sample size and energy used appear as key factors for the final resolution, which enhances imaging capabilities for separating the different material phases of the electrode microstructures. But, it is crucial to adapt these parameters to the materials in order to mitigate errors in the morphological parameter estimation. Moreover, an empirical law based on the heterogeneity and the average particle size distribution has been established to calculate the minimum representative elementary volume to be imaged, showing that volumes of 102 × 102 × 102 μm<sup>3</sup> (50 nm voxel size) are sufficiently representative for the six microstructures studied. Ultimately, guidelines have been established for in situ/<i>operando</i> X-ray nano-tomography measurements, with a proposed/validated in-house setup and cell design that preserve both the image resolution and electrochemistry. A detailed evaluation of the X-ray beam interaction is also presented, exploring the relationship between the dose received by the electrolyte and material and the reliable monitoring of electrochemistry and tomography.","PeriodicalId":21,"journal":{"name":"ACS Nano","volume":"85 4 1","pages":""},"PeriodicalIF":17.1,"publicationDate":"2025-03-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143546678","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Manish Mukherjee, Akshaya Chemmangat, Prashant V. Kamat
Control of forward and back electron transfer processes in semiconductor nanocrystals is important to maximize charge separation for photocatalytic reduction/oxidation processes. By employing methyl viologen as the electron acceptor, we have succeeded in mapping the electron transfer from excited CsPbI3 nanocrystals to viologen as well as the hole trapping process. The electron transfer to viologen is an ultrafast process (ket = 2 × 1010 s–1) and results in the formation of extended charge separation as electrons are trapped at surface-bound viologen sites and holes at iodide sites. The I2─• formation, which is confirmed through the transient absorption at 750 nm, provides a convenient way to probe trapped holes and its participation in the back electron transfer process. By employing a series of mixed halide compositions, we were able to tune the bandgap and valence band energy of the perovskite donor. The back electron transfer rate constant (kbet = 1.3–2.6 × 107 s–1) is nearly three orders of magnitude smaller than that of forward electron transfer, thus extending the lifetime of the charge-separated state. The weak dependence of the back electron transfer rate constant on the valence band energy suggests that trapping of holes at halide (I or Br) sites is involved in the back electron transfer process. The ability to extend the lifetime of the charge-separated pair can offer new strategies to improve the redox properties of semiconductor-based photocatalytic systems.
{"title":"Hole Trapping in Lead Halide Perovskite Nanocrystal–Viologen Hybrids and Its Impact on Back Electron Transfer","authors":"Manish Mukherjee, Akshaya Chemmangat, Prashant V. Kamat","doi":"10.1021/acsnano.5c01423","DOIUrl":"https://doi.org/10.1021/acsnano.5c01423","url":null,"abstract":"Control of forward and back electron transfer processes in semiconductor nanocrystals is important to maximize charge separation for photocatalytic reduction/oxidation processes. By employing methyl viologen as the electron acceptor, we have succeeded in mapping the electron transfer from excited CsPbI<sub>3</sub> nanocrystals to viologen as well as the hole trapping process. The electron transfer to viologen is an ultrafast process (<i>k</i><sub>et</sub> = 2 × 10<sup>10</sup> s<sup>–1</sup>) and results in the formation of extended charge separation as electrons are trapped at surface-bound viologen sites and holes at iodide sites. The I<sub>2</sub><sup>─•</sup> formation, which is confirmed through the transient absorption at 750 nm, provides a convenient way to probe trapped holes and its participation in the back electron transfer process. By employing a series of mixed halide compositions, we were able to tune the bandgap and valence band energy of the perovskite donor. The back electron transfer rate constant (<i>k</i><sub>bet</sub> = 1.3–2.6 × 10<sup>7</sup> s<sup>–1</sup>) is nearly three orders of magnitude smaller than that of forward electron transfer, thus extending the lifetime of the charge-separated state. The weak dependence of the back electron transfer rate constant on the valence band energy suggests that trapping of holes at halide (I or Br) sites is involved in the back electron transfer process. The ability to extend the lifetime of the charge-separated pair can offer new strategies to improve the redox properties of semiconductor-based photocatalytic systems.","PeriodicalId":21,"journal":{"name":"ACS Nano","volume":"2 1","pages":""},"PeriodicalIF":17.1,"publicationDate":"2025-03-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143546910","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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