Pub Date : 2025-03-05DOI: 10.1021/acs.jpcc.5c00330
Mikhail Fonin, Vivien Enenkel, Iva Šrut Rakić, Yuriy Dedkov, Elena Voloshina
Two-dimensional planar antiferromagnets on the basis of transition metal phosphorus trichalcogenides (MPX3) have recently attracted much attention owing to the possibility of exfoliating these materials and potentially implementing them in spintronic heterostructures. For the purpose of designing particular interfaces with graphene or other two-dimensional materials, knowledge of the real-space atomic distributions in the MPX3 layers is essential. Here, by using scanning probe microscopy in combination with ab initio calculations, we investigate the real-space structure of van der Waals material CoPS3 down to the atomic level. We observe that the voltage dependence of scanning tunneling microscopy imaging shows distinct atomic signatures, which, upon comparison to the density functional theory results, can be directly attributed to different orbital contributions. The observed orbital fingerprints suggest the high spin ground state for Co2+ ions (S = 3/2) and energy-dependent hybridization effects between atomic orbitals of Co, P, and S, thus providing valuable insight into the magnetic and electronic states of this van der Waals material.
{"title":"Orbital Analysis of Electronic States for vdW Material CoPS3 by Scanning Probe Microscopy","authors":"Mikhail Fonin, Vivien Enenkel, Iva Šrut Rakić, Yuriy Dedkov, Elena Voloshina","doi":"10.1021/acs.jpcc.5c00330","DOIUrl":"https://doi.org/10.1021/acs.jpcc.5c00330","url":null,"abstract":"Two-dimensional planar antiferromagnets on the basis of transition metal phosphorus trichalcogenides (MPX<sub>3</sub>) have recently attracted much attention owing to the possibility of exfoliating these materials and potentially implementing them in spintronic heterostructures. For the purpose of designing particular interfaces with graphene or other two-dimensional materials, knowledge of the real-space atomic distributions in the MPX<sub>3</sub> layers is essential. Here, by using scanning probe microscopy in combination with <i>ab initio</i> calculations, we investigate the real-space structure of van der Waals material CoPS<sub>3</sub> down to the atomic level. We observe that the voltage dependence of scanning tunneling microscopy imaging shows distinct atomic signatures, which, upon comparison to the density functional theory results, can be directly attributed to different orbital contributions. The observed orbital fingerprints suggest the high spin ground state for Co<sup>2+</sup> ions (<i>S</i> = 3/2) and energy-dependent hybridization effects between atomic orbitals of Co, P, and S, thus providing valuable insight into the magnetic and electronic states of this van der Waals material.","PeriodicalId":61,"journal":{"name":"The Journal of Physical Chemistry C","volume":"84 1","pages":""},"PeriodicalIF":4.126,"publicationDate":"2025-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143546859","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-03-05DOI: 10.1021/acs.jpcc.5c00119
Arkaprava Chowdhury, Anindya Datta
Microscopic insights into molecular aggregation have been obtained using R1, a model solvatochromic fluorophore in DMF–water mixtures. Fluorescence quantum yield (ϕf) and lifetime (τf) of R1 decrease monotonically up to a rather high molar ratio of water (). Near invariance of the hydrodynamic radius, estimated using fluorescence correlation spectroscopy, assigns this to the progressive increase in polarity of the medium and not aggregation. An abrupt increase in ϕf beyond a critical marks the onset of aggregation of R1. Concomitantly, fluorescence decays become bimodal, with the emergence of a longer component associated with the aggregates. Significant heterogeneity is observed in the distribution of lifetimes, indicating the existence of aggregates of different kinds. Fluorescence quenching, observed upon further increase in , is assigned to the breakdown of aggregates into smaller ones. A qualitative correlation between the size of aggregates and τf is obtained by using fluorescence lifetime imaging microscopy.
{"title":"Manifestation of Size Heterogeneity of Molecular Aggregates in the Distribution of Their Fluorescence Lifetimes and Diffusion Coefficients","authors":"Arkaprava Chowdhury, Anindya Datta","doi":"10.1021/acs.jpcc.5c00119","DOIUrl":"https://doi.org/10.1021/acs.jpcc.5c00119","url":null,"abstract":"Microscopic insights into molecular aggregation have been obtained using R1, a model solvatochromic fluorophore in DMF–water mixtures. Fluorescence quantum yield (<i>ϕ</i><sub>f</sub>) and lifetime (<i>τ</i><sub>f</sub>) of R1 decrease monotonically up to a rather high molar ratio of water (<i></i><math display=\"inline\"><msub><mi>χ</mi><mrow><msub><mi mathvariant=\"normal\">H</mi><mn>2</mn></msub><mi mathvariant=\"normal\">O</mi></mrow></msub></math>). Near invariance of the hydrodynamic radius, estimated using fluorescence correlation spectroscopy, assigns this to the progressive increase in polarity of the medium and not aggregation. An abrupt increase in <i>ϕ</i><sub>f</sub> beyond a critical <i></i><math display=\"inline\"><msub><mi>χ</mi><mrow><msub><mi mathvariant=\"normal\">H</mi><mn>2</mn></msub><mi mathvariant=\"normal\">O</mi></mrow></msub></math> marks the onset of aggregation of R1. Concomitantly, fluorescence decays become bimodal, with the emergence of a longer component associated with the aggregates. Significant heterogeneity is observed in the distribution of lifetimes, indicating the existence of aggregates of different kinds. Fluorescence quenching, observed upon further increase in <i></i><math display=\"inline\"><msub><mi>χ</mi><mrow><msub><mi mathvariant=\"normal\">H</mi><mn>2</mn></msub><mi mathvariant=\"normal\">O</mi></mrow></msub></math>, is assigned to the breakdown of aggregates into smaller ones. A qualitative correlation between the size of aggregates and <i>τ</i><sub>f</sub> is obtained by using fluorescence lifetime imaging microscopy.","PeriodicalId":61,"journal":{"name":"The Journal of Physical Chemistry C","volume":"49 1","pages":""},"PeriodicalIF":4.126,"publicationDate":"2025-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143546858","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-03-05DOI: 10.1021/acs.jpcc.4c07662
Gema Navarro-Marín, Yunbin Hu, Antoine Hinaut, Long Zhou, Shuyu Huang, Thilo Glatzel, Akimitsu Narita, Ernst Meyer
The fine control of molecules or atoms in self-assemblies on surfaces is a great challenge for future nanodevices, specially for unidimensional structure formations. In this context, our study explores the adsorption behavior of a benzo-fused double [7]thiahelicene (DT7H) on Cu(111). Using non-contact atomic force microscopy (nc-AFM) at room temperature, we prove their capability in the construction of linear-like shape adlayers. After a gentle annealing of the DT7H-copper interface, the molecules are prone to form non-covalent molecular wires which orientations are influenced by the surface symmetry. Analysis of the coverage-dependence reveals a preference for double wires at lower and intermediate densities. However, this coupling is not strong enough to prevent structural changes caused by surface mobility. Wire enlargements were induced by a further increase in surface coverage, reaching the assembly of 17 parallel molecular wires near full monolayer conditions. Finally, the electronic properties of the interface were characterized by means of Kelvin probe force microscopy (KPFM). The surface potential variations indicate a reduction of the surface work function on the regions covered by molecules, showing the functionality of this interface for optoelectronic applications.
{"title":"Non-covalent Molecular Wires of Double Thiahelicene on Cu(111): A nc-AFM Study at Room Temperature","authors":"Gema Navarro-Marín, Yunbin Hu, Antoine Hinaut, Long Zhou, Shuyu Huang, Thilo Glatzel, Akimitsu Narita, Ernst Meyer","doi":"10.1021/acs.jpcc.4c07662","DOIUrl":"https://doi.org/10.1021/acs.jpcc.4c07662","url":null,"abstract":"The fine control of molecules or atoms in self-assemblies on surfaces is a great challenge for future nanodevices, specially for unidimensional structure formations. In this context, our study explores the adsorption behavior of a benzo-fused double [7]thiahelicene (DT7H) on Cu(111). Using non-contact atomic force microscopy (nc-AFM) at room temperature, we prove their capability in the construction of linear-like shape adlayers. After a gentle annealing of the DT7H-copper interface, the molecules are prone to form non-covalent molecular wires which orientations are influenced by the surface symmetry. Analysis of the coverage-dependence reveals a preference for double wires at lower and intermediate densities. However, this coupling is not strong enough to prevent structural changes caused by surface mobility. Wire enlargements were induced by a further increase in surface coverage, reaching the assembly of 17 parallel molecular wires near full monolayer conditions. Finally, the electronic properties of the interface were characterized by means of Kelvin probe force microscopy (KPFM). The surface potential variations indicate a reduction of the surface work function on the regions covered by molecules, showing the functionality of this interface for optoelectronic applications.","PeriodicalId":61,"journal":{"name":"The Journal of Physical Chemistry C","volume":"22 1","pages":""},"PeriodicalIF":4.126,"publicationDate":"2025-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143561239","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-03-05DOI: 10.1021/acs.jpcc.5c00660
Lars G.M. Pettersson
The concept of “bond strength” is of essence for modeling every kind of reactive chemistry. Particularly within the field of catalysis and surface science, the interaction strength of adsorbates to surfaces affects the activity, selectivity, and stability of intermediates and transition states. Here, we introduce a simple approach to chemical reactions through an analogy with business. We regard rehybridization as the investment a molecule makes to prepare its electronic and geometrical structure to form new bonds. The resulting bond strength is the total proceeds from bond formation, and the difference (exothermicity) is the profit. The predictive power lies in the fact that any change in the electronic structure to prepare for bond formation requires the involvement of specific excited states. Thus, with knowledge of the energy needed for this excitation (investment) and the strength of the resulting interaction one can predict whether a specific reaction or bonding mode will be favored. We apply this concept to rationalize observed binding modes at surfaces and the often observed large structural changes even for “weakly” chemisorbed systems and finally to justify using small metal clusters to correct chemisorption energies from periodic DFT calculations.
{"title":"Capitalistic Chemistry","authors":"Lars G.M. Pettersson","doi":"10.1021/acs.jpcc.5c00660","DOIUrl":"https://doi.org/10.1021/acs.jpcc.5c00660","url":null,"abstract":"The concept of “bond strength” is of essence for modeling every kind of reactive chemistry. Particularly within the field of catalysis and surface science, the interaction strength of adsorbates to surfaces affects the activity, selectivity, and stability of intermediates and transition states. Here, we introduce a simple approach to chemical reactions through an analogy with business. We regard rehybridization as the <i>investment</i> a molecule makes to prepare its electronic and geometrical structure to form new bonds. The resulting bond strength is the total <i>proceeds</i> from bond formation, and the difference (exothermicity) is the <i>profit</i>. The predictive power lies in the fact that any change in the electronic structure to prepare for bond formation requires the involvement of specific excited states. Thus, with knowledge of the energy needed for this excitation (investment) and the strength of the resulting interaction one can predict whether a specific reaction or bonding mode will be favored. We apply this concept to rationalize observed binding modes at surfaces and the often observed large structural changes even for “weakly” chemisorbed systems and finally to justify using small metal clusters to correct chemisorption energies from periodic DFT calculations.","PeriodicalId":61,"journal":{"name":"The Journal of Physical Chemistry C","volume":"67 1","pages":""},"PeriodicalIF":4.126,"publicationDate":"2025-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143546861","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-03-05DOI: 10.1021/acs.jpcc.5c00622
Shichang Han, Hanfang Zhang, Huaqiang Chu
High carbon content, good liquidity, and low cost endow coal tar with great potential in the field of advanced carbon cathode materials. Herein, honeycomb porous carbon nanosheet cathodes were prepared by the synergistic activation method of an alkali- and salt-coupled system. The obtained coal tar-derived carbon (CTPC) with a unique porous honeycomb-like microstructure significantly enhances the migration rate of electrolyte ions and electron conduction within the cathode. Besides, the valence bond variation on the CTPC has been detected via in situ infrared spectroscopy to demonstrate the mechanism of reversible chemisorption and desorption of Zn2+. The constructed zinc ion capacitors with the CTPC4 cathode can achieve a high discharge capacity of 104.9 mA h g–1 at 0.05 A g–1 and an impressive energy density up to 80.6 W h kg–1 at a power density of 93.1 W kg–1. Notably, CTPC4 maintains excellent performance stability during 10,000 cycles. The novel alkali- and salt-coupled synergistic activation method can provide a new perspective for the preparation of advanced carbon materials.
{"title":"Construction of Coal Tar-Derived 3D Porous Carbon with KOH–K2CO3 Synergistic Activation for Advanced Zinc Ion Capacitors","authors":"Shichang Han, Hanfang Zhang, Huaqiang Chu","doi":"10.1021/acs.jpcc.5c00622","DOIUrl":"https://doi.org/10.1021/acs.jpcc.5c00622","url":null,"abstract":"High carbon content, good liquidity, and low cost endow coal tar with great potential in the field of advanced carbon cathode materials. Herein, honeycomb porous carbon nanosheet cathodes were prepared by the synergistic activation method of an alkali- and salt-coupled system. The obtained coal tar-derived carbon (CTPC) with a unique porous honeycomb-like microstructure significantly enhances the migration rate of electrolyte ions and electron conduction within the cathode. Besides, the valence bond variation on the CTPC has been detected via in situ infrared spectroscopy to demonstrate the mechanism of reversible chemisorption and desorption of Zn<sup>2+</sup>. The constructed zinc ion capacitors with the CTPC4 cathode can achieve a high discharge capacity of 104.9 mA h g<sup>–1</sup> at 0.05 A g<sup>–1</sup> and an impressive energy density up to 80.6 W h kg<sup>–1</sup> at a power density of 93.1 W kg<sup>–1</sup>. Notably, CTPC4 maintains excellent performance stability during 10,000 cycles. The novel alkali- and salt-coupled synergistic activation method can provide a new perspective for the preparation of advanced carbon materials.","PeriodicalId":61,"journal":{"name":"The Journal of Physical Chemistry C","volume":"36 1","pages":""},"PeriodicalIF":4.126,"publicationDate":"2025-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143546860","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Transport properties of heterostructures differ from those of the constituent two-dimensional materials due to van der Waals (vdW) interactions and the strength of the interlayer coupling. In this work, we investigated the effect of interfacial configurations on vdW interactions and the electronic transport properties of graphene-hBN heterostructures using density functional theory (DFT) and a tight-binding approximation. The surface charges are redistributed in the heterostructures depending on the strength of the vdW interactions that drive interfacial configurations. It is noted that the interfacial configuration with the maximum charge redistribution has the maximum inter- and intralayer electronic transport characteristics. As a consequence, the transport properties are found to be strongly dependent on the interfacial configuration of the heterostructures. The results provide valuable insights into interfacial configurations in designing heterostructures from 2D materials for electronic devices based on the transport properties such as transistors and sensors.
{"title":"Interfacial Configuration-Driven Transport Properties in Graphene-hBN Heterostructures","authors":"Renu, Konstantin Katin, Sabarna Chakraborti, Abhishek Sharma, Manoharan Muruganathan, Rakesh Kumar","doi":"10.1021/acs.jpcc.5c00841","DOIUrl":"https://doi.org/10.1021/acs.jpcc.5c00841","url":null,"abstract":"Transport properties of heterostructures differ from those of the constituent two-dimensional materials due to van der Waals (vdW) interactions and the strength of the interlayer coupling. In this work, we investigated the effect of interfacial configurations on vdW interactions and the electronic transport properties of graphene-hBN heterostructures using density functional theory (DFT) and a tight-binding approximation. The surface charges are redistributed in the heterostructures depending on the strength of the vdW interactions that drive interfacial configurations. It is noted that the interfacial configuration with the maximum charge redistribution has the maximum inter- and intralayer electronic transport characteristics. As a consequence, the transport properties are found to be strongly dependent on the interfacial configuration of the heterostructures. The results provide valuable insights into interfacial configurations in designing heterostructures from 2D materials for electronic devices based on the transport properties such as transistors and sensors.","PeriodicalId":61,"journal":{"name":"The Journal of Physical Chemistry C","volume":"426 1","pages":""},"PeriodicalIF":4.126,"publicationDate":"2025-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143561242","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-03-05DOI: 10.1021/acs.jpcc.4c08571
Conor Waldt, Rajeev Kumar, David Hibbitts
AuPd is a miscible metal alloy that is often used in catalysis. Supported AuPd catalysts, at high Au/Pd ratios, form single-atom alloys (SAAs) that have been shown to enhance rates and/or selectivities for many catalytic reactions, including (de)hydrogenations, hydrogenolysis, and C–C and C–O coupling reactions. While many computational studies have examined the stability of AuPd structures (the arrangement of atoms within the miscible alloy), most focused on generic alloys rather than SAAs and those that have closely investigated SAAs focused on single crystal surfaces. In this work, we use density functional theory (DFT) to calculate exchange energies (swapping an Au atom with a Pd atom) in a 201-atom truncated octahedral nanoparticle model with a focus on particles with high Au/Pd ratios. We calculate these exchange energies as a function of Pd location within the nanoparticle, the number of Pd atoms neighboring and near those exchange sites, and the total Pd content in the nanoparticle. These DFT-calculated exchange energies are also used to inform simple physics-based models (in contrast to cluster expansion or neural network models) that show good agreement with DFT-calculated values with relatively few regressed parameters. These models are then implemented into Monte Carlo (MC) simulations to predict the nanoparticle structure as a function of composition and temperature. The results show that Pd prefers to be in the subsurface of nanoparticles and that Pd prefers to be isolated from itself within Au. Both observations agree well with prior experimental and computational studies of single-crystal systems. We also show that the overall composition of the nanoparticle influences exchange energies by changing the electronic properties (e.g., Fermi level) of the system, which is relevant as Pd has one fewer valence electron than Au. MC simulations show that, in a vacuum, Pd begins to populate the surface of these ∼2 nm nanoparticles at around 20 mol % Pd (at 298 K) and that the number of Pd surface monomers, desired for SAA applications, goes through a maximum near 40 mol % Pd. As the temperature increases, Pd is more prevalent at the surface, but the influence of temperature is relatively muted. While AuPd structures are known to change in the presence of reactive gases (e.g., CO or O2), these studies characterize the baseline thermodynamic arrangements that can be used to understand surface restructuring during catalyst characterization and reaction studies.
{"title":"Understanding AuPd Alloy Nanoparticle Structure under Vacuum Using DFT and Monte Carlo Methods","authors":"Conor Waldt, Rajeev Kumar, David Hibbitts","doi":"10.1021/acs.jpcc.4c08571","DOIUrl":"https://doi.org/10.1021/acs.jpcc.4c08571","url":null,"abstract":"AuPd is a miscible metal alloy that is often used in catalysis. Supported AuPd catalysts, at high Au/Pd ratios, form single-atom alloys (SAAs) that have been shown to enhance rates and/or selectivities for many catalytic reactions, including (de)hydrogenations, hydrogenolysis, and C–C and C–O coupling reactions. While many computational studies have examined the stability of AuPd structures (the arrangement of atoms within the miscible alloy), most focused on generic alloys rather than SAAs and those that have closely investigated SAAs focused on single crystal surfaces. In this work, we use density functional theory (DFT) to calculate exchange energies (swapping an Au atom with a Pd atom) in a 201-atom truncated octahedral nanoparticle model with a focus on particles with high Au/Pd ratios. We calculate these exchange energies as a function of Pd location within the nanoparticle, the number of Pd atoms neighboring and near those exchange sites, and the total Pd content in the nanoparticle. These DFT-calculated exchange energies are also used to inform simple physics-based models (in contrast to cluster expansion or neural network models) that show good agreement with DFT-calculated values with relatively few regressed parameters. These models are then implemented into Monte Carlo (MC) simulations to predict the nanoparticle structure as a function of composition and temperature. The results show that Pd prefers to be in the subsurface of nanoparticles and that Pd prefers to be isolated from itself within Au. Both observations agree well with prior experimental and computational studies of single-crystal systems. We also show that the overall composition of the nanoparticle influences exchange energies by changing the electronic properties (e.g., Fermi level) of the system, which is relevant as Pd has one fewer valence electron than Au. MC simulations show that, in a vacuum, Pd begins to populate the surface of these ∼2 nm nanoparticles at around 20 mol % Pd (at 298 K) and that the number of Pd surface monomers, desired for SAA applications, goes through a maximum near 40 mol % Pd. As the temperature increases, Pd is more prevalent at the surface, but the influence of temperature is relatively muted. While AuPd structures are known to change in the presence of reactive gases (e.g., CO or O<sub>2</sub>), these studies characterize the baseline thermodynamic arrangements that can be used to understand surface restructuring during catalyst characterization and reaction studies.","PeriodicalId":61,"journal":{"name":"The Journal of Physical Chemistry C","volume":"30 1","pages":""},"PeriodicalIF":4.126,"publicationDate":"2025-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143546857","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-03-05DOI: 10.1021/acs.jpcc.4c08584
Sebastian Lindenthal, Daniel Rippel, Lucas Kistner, Angus Hawkey, Jana Zaumseil
Despite its comparatively low electron affinity, tris(pentafluorophenyl)borane (BCF) has been widely explored as an efficient molecular p-dopant for semiconducting polymers through the formation of Brønsted acidic complexes as well as its high affinity toward Lewis-basic nitrogen moieties. Many conjugated polymers that are used for selective wrapping and dispersion of semiconducting single-walled carbon nanotubes (SWCNTs) such as poly[(9,9-di-n-octylfluorenyl-2,7-diyl)-alt-(6,6′-(2,2′-bipyridine))] (PFO-BPy) contain nitrogen moieties that should promote interaction with BCF. Here, we demonstrate that BCF indeed efficiently p-dopes even small-diameter (6,5) SWCNTs that are wrapped with large-bandgap PFO-BPy as corroborated by bleaching of the main absorption peaks and the appearance of red-shifted trion absorption and emission. In contrast, SWCNTs that are wrapped with poly(9,9-di-n-octylfluorenyl-2,7-diyl) (PFO) without any Lewis-basic nitrogen moieties are only mildly doped. UV–Vis–NIR absorption, 19F NMR, and 11B NMR spectra confirm that BCF dopes the bipyridine-containing PFO-BPy but not PFO, thus leading to a proposed doping mechanism that relies on the unique interactions between BCF, the bipyridine moieties in PFO-BPy, and the nanotubes. Since BCF doping of PFO-BPy-wrapped (6,5) SWCNTs is more efficient than doping with F4TCNQ and more stable than doping with AuCl3, it provides a reliable alternative for spectroscopic studies of the interactions of charge carriers and excitons in SWCNTs.
{"title":"Synergistic p-Doping of Polymer-Wrapped Small-Diameter Single-Walled Carbon Nanotubes by Tris(pentafluorophenyl)borane","authors":"Sebastian Lindenthal, Daniel Rippel, Lucas Kistner, Angus Hawkey, Jana Zaumseil","doi":"10.1021/acs.jpcc.4c08584","DOIUrl":"https://doi.org/10.1021/acs.jpcc.4c08584","url":null,"abstract":"Despite its comparatively low electron affinity, tris(pentafluorophenyl)borane (BCF) has been widely explored as an efficient molecular p-dopant for semiconducting polymers through the formation of Brønsted acidic complexes as well as its high affinity toward Lewis-basic nitrogen moieties. Many conjugated polymers that are used for selective wrapping and dispersion of semiconducting single-walled carbon nanotubes (SWCNTs) such as poly[(9,9-di-<i>n</i>-octylfluorenyl-2,7-diyl)-<i>alt</i>-(6,6′-(2,2′-bipyridine))] (PFO-BPy) contain nitrogen moieties that should promote interaction with BCF. Here, we demonstrate that BCF indeed efficiently p-dopes even small-diameter (6,5) SWCNTs that are wrapped with large-bandgap PFO-BPy as corroborated by bleaching of the main absorption peaks and the appearance of red-shifted trion absorption and emission. In contrast, SWCNTs that are wrapped with poly(9,9-di-<i>n</i>-octylfluorenyl-2,7-diyl) (PFO) without any Lewis-basic nitrogen moieties are only mildly doped. UV–Vis–NIR absorption, <sup>19</sup>F NMR, and <sup>11</sup>B NMR spectra confirm that BCF dopes the bipyridine-containing PFO-BPy but not PFO, thus leading to a proposed doping mechanism that relies on the unique interactions between BCF, the bipyridine moieties in PFO-BPy, and the nanotubes. Since BCF doping of PFO-BPy-wrapped (6,5) SWCNTs is more efficient than doping with F<sub>4</sub>TCNQ and more stable than doping with AuCl<sub>3</sub>, it provides a reliable alternative for spectroscopic studies of the interactions of charge carriers and excitons in SWCNTs.","PeriodicalId":61,"journal":{"name":"The Journal of Physical Chemistry C","volume":"30 1","pages":""},"PeriodicalIF":4.126,"publicationDate":"2025-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143546684","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-03-04DOI: 10.1021/acs.jpcc.4c07872
Josef M. Gallmetzer, Jakob Gamper, Stefanie Kröll, Thomas S. Hofer
The structural and dynamic properties of two polymorphs of the metal–organic framework UMCM-9 (UMCM-9-α and -β) have been studied via molecular dynamics (MD) simulations in conjunction with density functional tight binding (DFTB) as well as the newly developed MACE–MP neural network potential (NNP). Based on these calculations, a novel UMCM-9-β polymorph is proposed that exhibits reduced linker strain and increased flexibility compared to UMCM-9-α, which is shown to be energetically less stable. UMCM-9-β exhibits enhanced diffusion of molecular hydrogen due to weaker host–guest interactions, whereas UMCM-9-α exhibits stronger interactions, leading to improved hydrogen adsorption. The results suggest that synthesis conditions may control the formation of both polymorphs: UMCM-9-β is likely to be the thermodynamic product, forming under stable conditions, while UMCM-9-α may be the kinetic product, forming under accelerated synthesis conditions. This study highlights the potential for optimizing MOFs for specific gas storage applications to achieve the desired structural and associated gas storage properties.
{"title":"Comparative Study of UMCM-9 Polymorphs: Structural, Dynamic, and Hydrogen Storage Properties via Atomistic Simulations","authors":"Josef M. Gallmetzer, Jakob Gamper, Stefanie Kröll, Thomas S. Hofer","doi":"10.1021/acs.jpcc.4c07872","DOIUrl":"https://doi.org/10.1021/acs.jpcc.4c07872","url":null,"abstract":"The structural and dynamic properties of two polymorphs of the metal–organic framework UMCM-9 (UMCM-9-α and -β) have been studied via molecular dynamics (MD) simulations in conjunction with density functional tight binding (DFTB) as well as the newly developed MACE–MP neural network potential (NNP). Based on these calculations, a novel UMCM-9-β polymorph is proposed that exhibits reduced linker strain and increased flexibility compared to UMCM-9-α, which is shown to be energetically less stable. UMCM-9-β exhibits enhanced diffusion of molecular hydrogen due to weaker host–guest interactions, whereas UMCM-9-α exhibits stronger interactions, leading to improved hydrogen adsorption. The results suggest that synthesis conditions may control the formation of both polymorphs: UMCM-9-β is likely to be the thermodynamic product, forming under stable conditions, while UMCM-9-α may be the kinetic product, forming under accelerated synthesis conditions. This study highlights the potential for optimizing MOFs for specific gas storage applications to achieve the desired structural and associated gas storage properties.","PeriodicalId":61,"journal":{"name":"The Journal of Physical Chemistry C","volume":"12 1","pages":""},"PeriodicalIF":4.126,"publicationDate":"2025-03-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143546810","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-03-04DOI: 10.1021/acs.jpcc.4c08560
Henrik S. Jeppesen, Melissa J. Marks, Hamish Cavaye, Marcel Ceccato, Stewart F. Parker, Nina Lock
Bismuth oxyhalides, including Bi24O31X10 and BiOX (X = Cl and Br), are emerging materials for photocatalysis. In this study, we demonstrate the transformation of Bi24O31X10 (X = Br and Cl) into pure-halide and mixed-halide solid solutions (ss) of BiOX by suspending the Bi24O31X10 powder in HX(aq) acid solutions. The photocatalytic activity of all BiOX and Bi24O31X10 materials were screened for the photooxidation of benzylamine to N-benzylidenebenzylamine under UV irradiation, i.e., a reaction involving a hydrogen transfer reaction. The catalytic properties of the acid-derived BiOX were impacted by both the parent Bi24O31X10 precursor the acid concentration used in the transformation and the halide content. BiOBr and BiOCl-ss materials derived from Bi24O31Br10 exhibited better catalytic performance compared to those derived from Bi24O31Cl10, and parent Bi24O31Br10 exhibited the highest catalytic activity of all materials. The superior properties of parent Bi24O31Br10 and all Bi24O31Br10-derived materials were then scrutinized by investigating the mechanism of the light-assisted hydrogen transfer of Bi24O31X10 by using inelastic neutron scattering (INS) and X-ray photoelectron spectroscopy (XPS). Bi24O31Br10 exhibited a remarkably higher capability of abstracting and binding H-atoms in comparison with Bi24O31Cl10, which is essential for reactions involving an H-transfer. We propose that this property explains the difference in the catalytic activity between the two Bi24O31X10 materials.
{"title":"Surface Properties of High-Performing Bi24O31Br10 and its Acid-Driven Conversion to BiOX Photocatalysts (X = Cl, Br)","authors":"Henrik S. Jeppesen, Melissa J. Marks, Hamish Cavaye, Marcel Ceccato, Stewart F. Parker, Nina Lock","doi":"10.1021/acs.jpcc.4c08560","DOIUrl":"https://doi.org/10.1021/acs.jpcc.4c08560","url":null,"abstract":"Bismuth oxyhalides, including Bi<sub>24</sub>O<sub>31</sub>X<sub>10</sub> and BiOX (X = Cl and Br), are emerging materials for photocatalysis. In this study, we demonstrate the transformation of Bi<sub>24</sub>O<sub>31</sub>X<sub>10</sub> (X = Br and Cl) into pure-halide and mixed-halide solid solutions (ss) of BiOX by suspending the Bi<sub>24</sub>O<sub>31</sub>X<sub>10</sub> powder in HX<sub>(aq)</sub> acid solutions. The photocatalytic activity of all BiOX and Bi<sub>24</sub>O<sub>31</sub>X<sub>10</sub> materials were screened for the photooxidation of benzylamine to <i>N</i>-benzylidenebenzylamine under UV irradiation, i.e., a reaction involving a hydrogen transfer reaction. The catalytic properties of the acid-derived BiOX were impacted by both the parent Bi<sub>24</sub>O<sub>31</sub>X<sub>10</sub> precursor the acid concentration used in the transformation and the halide content. BiOBr and BiOCl-ss materials derived from Bi<sub>24</sub>O<sub>31</sub>Br<sub>10</sub> exhibited better catalytic performance compared to those derived from Bi<sub>24</sub>O<sub>31</sub>Cl<sub>10</sub>, and parent Bi<sub>24</sub>O<sub>31</sub>Br<sub>10</sub> exhibited the highest catalytic activity of all materials. The superior properties of parent Bi<sub>24</sub>O<sub>31</sub>Br<sub>10</sub> and all Bi<sub>24</sub>O<sub>31</sub>Br<sub>10</sub>-derived materials were then scrutinized by investigating the mechanism of the light-assisted hydrogen transfer of Bi<sub>24</sub>O<sub>31</sub>X<sub>10</sub> by using inelastic neutron scattering (INS) and X-ray photoelectron spectroscopy (XPS). Bi<sub>24</sub>O<sub>31</sub>Br<sub>10</sub> exhibited a remarkably higher capability of abstracting and binding H-atoms in comparison with Bi<sub>24</sub>O<sub>31</sub>Cl<sub>10</sub>, which is essential for reactions involving an H-transfer. We propose that this property explains the difference in the catalytic activity between the two Bi<sub>24</sub>O<sub>31</sub>X<sub>10</sub> materials.","PeriodicalId":61,"journal":{"name":"The Journal of Physical Chemistry C","volume":"23 1","pages":""},"PeriodicalIF":4.126,"publicationDate":"2025-03-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143539054","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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