bluuebunny/crossref_metadata_2025 huggingface dataset:
(Invited) Manipulation of Locally-Excited, Charge-Transfer, and Charge-Separated States at Organic-Inorganic Heterointerfaces
Authors: Imahori Hiroshi
Published: August 2024

Precise engineering of excited-state interactions between an organic conjugated molecule and a two-dimensional semiconducting inorganic nanosheet, specifically the manipulation of locally-excited (LE), charge-transfer (CT), and charge-separated (CS) states, still remains a challenge for state-of-the-art photochemistry. In this study we successfully observed a long-lived, highly emissive CT state at structurally well-defined hetero-nanostructure interfaces of photoactive pyrene and two-dimensional (2D) MoS2 nanosheet via N-benzyl succinimide bridge (Py-Bn-MoS2). Spectroscopic measurements revealed that the LE state of pyrene in Py-Bn-MoS2 efficiently generates an unusual emissive CT state without further yielding the CS state. Theoretical studies supported the interaction of MoS2 vacant orbitals with the pyrene excited state to form a CT state. This is the first example of realizing a mixing luminescence property of organic–inorganic 2D hetero-nanostructures by an accurate design of bridge structure, and therefore represents an important step in their applications for energy conversion and optoelectronic devices and sensors.

[1] J. Baek, T. Umeyama, W. Choi, Y. Tsutsui, H. Yamada, S. Seki, H. Imahori, Chem. Eur. J., 24, 1561 (2018).

[2] T. Umeyama, T. Ohara, Y. Tsutsui, S. Nakano, S. Seki, H. Imahori, Chem. Eur. J., 26, 6726 (2020).

[3] T. Umeyama, H. Xu, T. Ohara, Y. Tsutsui, S. Seki, and H. Imahori, J. Phys.
Chem. C, 125, 13954 (2021).

[4] T. Umeyama, D. Mizutani, Y. Ikeda, W. R. Osterloh, F. Yamamoto, K. Kato, A. Yamakata, M. Higashi, T. Urakami, H. Sato, H. Imahori, Chem. Sci., 14, 11914 (2023).
(Invited) Ion Migration Influencing Perovskite Solar Cell Performance and Stability
Authors: Szabo Gabor , Mathew Preethi Susan , Kamat Prashant V
Published: August 2024

The thermodynamic and redox properties of halide perovskites provide a strong driving force for hole trapping and oxidation of iodide species. When in contact with a non-polar solvent, the migration of iodine species is further extended to expulsion of iodine from the perovskite film. Thus, the mobility of halides and their susceptibility to hole-induced oxidation play a crucial role in determining the long-term stability of metal halide perovskite solar cells. When Ruddlesden-Popper 2D mixed-halide perovskite films with spacer cations such as butylammonium are introduced into three-dimensional (3D) perovskite films, they can stabilize them against moisture-induced degradation at room temperature. While such passivation of 3D perovskites using 2D perovskites has been reported widely, the instability of the 2D/3D interface during long term solar cell operation can be problematic, especially at higher temperatures. The cation migration under light and heat can significantly alter the 2D/3D interface, thus affecting the solar cell performance. We have now probed the cation migration between 2D and 3D perovskites by physically pairing X PbI (X=butylammonium BA, oleylammonium OA, or phenethylammonium PEA) 2D film and (CH3)PbI3 3D film at different temperatures by recording changes in the absorption and emission spectra. Thus, suppression of halide ion migration as well as cation migration remains a key factor in achieving long term stability and improving efficiency of perovskite solar cells and light emitting devices.
A Lanthanide-Based Supramolecular Nanotube and Its Photochemistry
Authors: Yakuwa Kotaro , Yuasa Junpei
Published: August 2024

Lanthanide complex including Europium ion (Eu3+) is one of the fascinating photoluminescent compound. However, most of lanthanide complexes are used as a mononuclear-based material without void space. Here, we developed lanthanide-based assemblies including a supramolecular nanotube. Their photophysical properties related to dynamic exciton was investigated.
Perovskite Quantum Dots for Solar Cells and Beyond
Authors: Wang Lianzhou
Published: August 2024

Halide perovskite solar cells have witnessed great successes recently while their instability is a big hurdle for practical application. Herein we discuss our recent progress in addressing the stability of perovskite solar cells, including introduction of capping layers to improve the stability against moisture and heat, and perovskite size engineering to suppress phase segregation. In particular, quantum dots (QDs) have the advantages of quantum confinement effect, defect-tolerant nature, and processability for flexible devices. We discuss a new surface ligand engineering strategy in designing new hybrid perovskite QDs with controllable compositions and sizes The QDs have been used as building blocks in quantum dot solar cells delivering a certified record efficiency of 16.6% with excellent long-term operation stability. By using QDs as light absorbing materials, the QD based photocatalysts also exhibited good stable performance in photocatalytic hydrogen production. The combination of perovskite QDs with Metal-Organic Framework (MOF) materials to form new composites led to ultrastable photoluminescent property for > 10,000 hours. The integration of perovskite solar cells and rechargeable batteries have led to a single module type rechargeable solar batteries with an overall storable solar energy conversion efficiency of >12%.

References:

Nature Energy, 2020, 5, 79-88.

Science, 2021, 374, 621.

Nature Commun, 2023, articles/s41467-023-35830-8
(Invited) Light Emission from Single Plasmonic Nanoparticles
Authors: Link Stephan
Published: August 2024

A surface plasmon in a metal nanoparticle is the coherent oscillation of the conduction band electrons leading to both absorption and scattering as well as strong local electromagnetic fields. These fundamental properties have been exploited in many different ways, including surface enhanced spectroscopy and sensing, photothermal cancer therapy, and color display generation. The performance of plasmonic nanoparticles for a desired application not only depends on the particle size and shape, but is tunable through nanoparticle interactions on different length scales that support near- and far-field coupling. Chemical synthesis and assembly of nanostructures are able to tailor plasmonic properties that are, however, typically broadened by ensemble averaging. Single particle spectroscopy together with correlated imaging is capable of removing heterogeneity in size, shape, and assembly geometry. In this talk I will discuss our recent work on understanding the radiative properties of individual plasmonic nanostructures including its time dependence, illustrating that light emission provides a unique window into the dynamics of hot carriers.
Photoactive Porphyrin-Based Covalent Organic Frameworks for Photocatalytic Applications
Authors: Zhao Yanli
Published: August 2024

The incorporation of porphyrin units into covalent organic frameworks (COFs) brings new photoelectrochemical properties to the resulted systems. We have developed a bottom-up strategy to prepare a series of tailor-made chiral COFs. The porphyrin subunits act as antennae to harvest visible light. Meanwhile, various secondary amine-based chiral functional groups are immobilized on the pore walls of COFs as catalytic sites. As a result, the COFs that are elaborately designed to merge photoactive building blocks and chiral catalytic sites achieve high production yields with good enantiomeric excess in photocatalytic asymmetric alkylation of aldehydes. In further studies, we have also prepared isostructural porphyrin-based COFs with high crystallinity and porosity, and investigated their photocatalytic N2 fixation performance. The porphyrin building blocks act as not only light-harvesting antennae, but also docking sites for anchoring Au single atoms. Moreover, the microenvironment of Au sites and optoelectronic properties of photocatalysts could be finely tuned by designing the functional groups on proximal and distal position of porphyrin units. The structure-activity relationship has been studied in detail by combining experimental results and theoretical calculations. The introduction of electron-withdrawing groups facilitates the separation and transportation of photogenerated electrons within the entire framework, thus promoting the adsorption of N2 on Au sites for achieving high performance of N2 conversion into NH3.
Insights into the Activity and Stability of Dual-Site Single Atom Catalysts for Oxygen Reduction Reaction Using a 2D Phthalocyanine-MOF
Authors: Hossain Md Delowar , Wei Lingze , Chen Gan , Bao Zhenan , Burke Stevens Michaela , Jaramillo Thomas F. , Bajdich Michal
Published: August 2024

Hydrogen fuel cells have been considered as an effective strategy to shift fossil-fuel based economy to hydrogen economy. The performance of the fuel cells is often limited by the slow kinetics of the cathodic oxygen reduction reaction (ORR). Metal-organic frameworks (MOFs) based on 2D Phthalocyanine offer dual-site single atom catalyst (SAC) where M1 site typically amine coordinated node and M2 site is the phthalocyanine center (M1/M2 = Co, Cu, Ni). Here we conduct both computational studies and experimental measurements to elucidate the site selectivity and activity of two- and four-electron ORR process for pure (contains same element on both sites) and mixed (different M1 and M2) MOF system, and their overall stability. Using density functional theory (DFT), we find that regardless of site, Cobalt (Co) element shows better four-electron ORR activity than other elements in the mixed MOF system. Our integrated crystal orbital Hamilton population (ICOHP) calculations indicate that for pure MOF system, M1(d)-4N(2p) bonds are stronger than M2(d)-4N(2p), which raises d-band center of M2 sites closer to Fermi level, hence improves its activity towards four-electron ORR process. For mixed systems, M2 sites activity largely depends on the geometrical effects caused by M1 site elements. Our activity calculations reveal that Co (as M2) in the Ni-Co mixed MOF systems predicts lowest overpotential for ORR among all studied MOF system. Our dissolution mechanism and stability calculations show that Cu (as M1) causes stress/strain within the mixed MOF system denoting least stable among all studied during ORR process. In experiment, we found Co-based MOF, particularly Ni-Co demonstrates the highest kinetic activity and Cu is the least stable element, showing excellent agreement with computational studies. We hope this study will help in understanding the insight into the rational design of highly active and stable MOF for electrochemical processes. This research was supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, Chemical Sciences, Geosciences, and Biosciences Division, Catalysis Science Program to the SUNCAT Center for Interface Science and Catalysis.
Quantum Dots and Molecular Junctions as Energy Filters for Thermal-to-Electric Energy Conversion
Authors: Linke Heiner
Published: August 2024

The thermoelectric conversion of heat into electricity requires a form of energy filtering, that allows hot electrons to pass while blocking cold electrons. The energy conversion efficiency is determined by the details of the energy filtering, with an infinitely sharp (delta function) transmission spectrum allowing near ideal (Carnot) efficiency. [1]

I will introduce this concept and report on a proof-of-performance experiment based on a quantum dot embedded into a single, semiconductor nanowire. This near-ideal quantum-dot heat engine realized power production at maximum power with Curzon-Ahlborn efficiency as well more than 70% of Carnot efficiency at maximum efficiency settings [2].

To further enhance efficiency at maximum power one wishes to shape the transmission function to allow a spectrum of warmer electrons to pass while still completely blocking cold electrons. This may be achieved by exploiting quantum interference phenomena to block low-energy electron transmission by destructive interference, and to thus sculpt the transmission function of quantum dots or molecular junctions.[4] In contrast to quantum dots, molecular junctions have the advantage that they can be used at room temperature and can be produced, in principle, cheaply and scalable. To systematically explore the effect of quantum interferences, we designed and synthesized a new class of porphyrins that are expected to feature destructive quantum interference in single molecule junctions with gold electrodes and may thus show high thermopower, as well as a control that does not. We performed detailed experimental single-molecule break-junction studies of conductance and thermopower on porphyrin molecular junctions. We find a somewhat better thermoelectric performance for the porphyrin where we expect destructive interference. However, the predicted large difference in conductance and thermopower is not supported by our experimental findings.[4]

Finally, I will also briefly discuss the potential application of the concepts and systems presented here in hot-carrier photovoltaics, as an approach to increasing photovoltaic energy conversion efficiency beyond current limits.

[1] T.E. Humphrey et al., Reversible Quantum Brownian Heat Engines for Electrons. Phys. Rev. Lett., 89, 116801 (2002)

[2] M. Josefsson et al. A quantum-dot heat engine operated close to thermodynamic efficiency limits. Nature Nanotechn. 13, 920 (2018)

[3] O Karlström et al. Increasing thermoelectric performance using coherent transport. Phys. Rev. B 84, 113415 (2011)

[4] H. Xu et al. Electrical Conductance and Thermopower of β-Substituted
Porphyrin Molecular Junctions Synthesis and Transport. JACS
145

,
23541 (2023)

Figure 1
Solvent-Porphyrin Pseudo-Polymorphs: A DFT and Statistical Mechanical Study
Authors: Hipps K. W. , Mazur Ursula
Published: August 2024

Well defined monolayers of solvent incorporated cobalt(II) octaethylporphyrin (CoOEP) on Au(111) can be formed in toluene (TOL) and in 1,2,4 trichlorobenzene (TCB). These structures are pseudo rectangular and one-to-one in composition (REC). These structures only form when the initial exposure of Au is to very dilute solutions of CoOEP. When the initial Au exposure is to high CoOEP concentration solution, only the porphyrin adsorbs in the well-known pseudo hexagonal (HEX) structure. Attempts to convert the REC structure to HEX by the addition of concentrated CoOEP at 298K were never observed for the TCB case, and occurred slowly in the TOL case. Density functional theory (DFT) and statistical mechanics are used to investigate the rates of desorption and the equilibrium concentrations for the TOL-REC, TCB-REC, and HEX system. Two different DFT functional types (GGA and meta-GGA), both with corrections for van der Waals forces, were used. In order to address both the energies of the activated states and the kinetics of desorption in contact with liquid solvent, we will use a method proposed by Charlie Campbell for estimating the difference in adsorption energy of a molecule in the presence and absence of a liquid solvent, which assumes pairwise interfacial bond additivity. The results of these calculations indicate that the REC forms only exist because of the rapid adsorption and desorption of the solvents and the slow desorption and diffusion of the porphyrin. We note that computed desorption rates are extremely sensitive to the actual activation energy and, based on the difference in values produced by the two computational methods, are not quantitively reliable. The computed equilibrium state at 298K, on the other hand, is predicted to be the HEX form independent of computational method and solution concentration for all practical values of the concentration. Thus the REC structures are kinetically controlled while the HEX structure is the equilibrium structure.
Fused Porphyrin-Graphene Nanoribbons, One-Dimensional Porphyrinoid Polymers, and Subphthalocyanine-Based 2D-Polymers: On-Surface Synthetic Approaches
Authors: Torres Tomas , Bottari Giovanni , Labella Jorge , Urbani Maxence
Published: August 2024

On-surface synthesis offers a versatile approach to fabricate novel carbon-based nanostructures that cannot be obtained via conventional solution chemistry. Within the family of such nanomaterials, graphene nanoribbons (GNRs) hold a privileged position due to their high potential for different applications. One of the key issues for their application in molecular electronics lies in the fine-tuning of their electronic properties through structural modifications, such as heteroatom doping or the incorporation of non-benzenoid rings. In this context, the covalent fusion of GNRs and porphyrins (Pors) represents a highly appealing strategy.
On-Surface Chemistry: Probing the Presence of Adatoms on Differently Terminated Surfaces by Porphyrin Metalation
Authors: Nowakowski Jan , Ahsan Aisha , Nowakowska Sylwia K. , Siewert Dorota , Baljozovic Milos , Girovsky Jan , Wäckerlin Christian , Ballav Nirmalya , Jung Thomas A.
Published: August 2024

Reactive adsorbates in on-surface reactions and in heterogeneous catalysis on different substrates are of emerging importance. This is for the crucial roles they take in reaction pathways and for their decisive influence on reaction kinetics. [1] The thermally activated 2D mobility [2] of reaction precursors and reactive adatoms as well as their spatial and temporal coincidence at reaction sites is of mechanistic importance for many interface-specific reactions. In our work, we use the well-studied metalation reaction of H2-porphyrins to investigate the action of adatoms on metallic and passivated surface substrates. Porphyrin metalation has been established on atomically clean metallic substrates [3] as well as on metal-oxides [4] and metallic surfaces modified by oxygen [5].

We perform spectro-microscopy correlation experiments combining X-ray Photoelectron Spectroscopy, Ultraviolet Photoelectron Spectroscopy, Low Energy Electron Diffraction and Scanning Tunnelling Microscopy on Cl- and N terminated Cu(001). Thereby we find extended layers of adsorbate-induced superstructures that have decisive and contrasting impact on the reactivity of the surface, as well as on molecular self-assembly. The O and N termination of Cu facilitates the metalation reaction and self-assembled domains of CuTPP are formed at room temperature. Cl termination on the contrary, fully inhibits the metalation reaction and causes 2HTPP to assemble into small ‘magic’ clusters.

References

[1] Waiz et al., Nature 541, 68–71 (2017). 10.1038/nature20782

[2] Ahsan et al., Nanoscale, 2019, 11, 4895. 10.1021/acs.jpcc.3c03325

[3] Auwärter et al., ChemPhysChem

8
, 250 (2007). 10.1002/cphc.200600675

[4] Wang, C. et al Chem Commun 50, 8291 (2014). 10.1039/C4CC02919D

[5] Nowakowski et al., Chem.
Commun., 49, 2347 (2013). 10.1039/c3cc39134e

[6] Nowakowski et al., ChemistrySelect 2016, 5, 891 –895. 10.1002/slct.201600215

Figure 1
Photoexcited States Dynamics on Cu(II) Porphyrines-Nanographenes Dyads
Authors: Vega Mayoral Victor , Götz Alicia , Garcia Orrit Saül , Müllen Klaus , Narita Akimitsu , Cabanillas Gonzalez Juan Ramon
Published: August 2024

Donor-acceptor systems have garnered significant attention in the fields of semiconducting materials and light harvesting.1 Particularly intriguing are porphyrin diads, wherein porphyrins are covalently bonded to nanographenes, forming a dyad with an expected electron transfer from the porphyrin to the nanographene. In our study, we leverage the excellent charge transport properties of Hexabenzocoronene (HBC) in combination with the superior light harvesting capabilities of Cu(II) porphyrins.

The steady-state absorption spectra of the dyads exhibit a linear combination of HBC and porphyrin spectra, suggesting a low degree of electronic coupling in the ground state. Femtosecond optical transient absorption spectroscopy (TAS) has been employed to investigate the dynamics of photoexcited states. The TAS spectrum of the dyad displays a first derivative shape of the steady-state absorption, indicative of a photoinduced electron transfer within the system.2

These findings underscore the potential application of these systems as donor-acceptor systems, wherein the Cu(II) porphyrine serves as the source, transferring electrons to the HBC nanographene. This points towards promising applications of this system in photovoltaic devices.

Figure 1. A) Cu(II) porphyrine B) Cu (II) porphyrine, HBC and Cu(II) porphyrine-HBC dyad absorption spectra C) Cu (II) porphyrine with C-H chains, HBC and Cu(II) porphyrinewith C-H chains-HBC dyad absorption spectra D)u (II) porphyrine with C-H chains.

______________________________________________

[1] H. Imahori, T. Umevama, Journal of Physical Chemistry C
2009, 113, 9029–9039.

[2] Shengqiang Xiao; Mohamed E. El-Khouly; Yuliang Li; Zhenhai Gan; Huibiao Liu; Li Jiang; Yasuyuki Araki; Osamu Ito; Daoben Zhu J. Phys. Chem. B
2005, 109, 8, 3658–3667

Figure 1
Synthesis, Electrochemistry and Photochemistry of Hypervalent Phosphorus(V) Porphyrin and Antimony(V) Porphyrin Black Dyes
Authors: Poddutoori Prashanth , Hamza Jam Riyan , Sharma Jatan Kumar , D'Souza Francis , Karr Paul
Published: August 2024

In the last few years, our focus has been on push-pull type hypervalent Group 15 porphyrins with intramolecular charge transfer (ICT) properties. Insertion of P(V) or Sb(V) ion in the porphyrin cavity results in a highly electron-deficient porphyrin center, under this condition the presence of electron-rich units in porphyrin meso-positions results in charge transfer within the molecules. Recently, we extended this strategy to 5,10,5,20-tetrakis(triphenylamine)porphyrin derivative where strong electron donor triphenylamine (TPA) units are in meso-positions. Upon insertion of the P(+5) and Sb(+5) ion, the resulting hypervalent Group 15 porphyrins manifested a strong ICT from the TPA units to the central porphyrin ring. The existence of ICT makes the absorption profiles cover the entire visible region with high molar extinction coefficients. Due to this reason, the studied hypervalent Group 15 porphyrins appear as black dyes. Here, I will present these porphyrins and discuss their structural, redox, and remarkable photophysical properties.

Figure 1
Chitin and Cellulose as Constituents of Efficient, Sustainable, and Flexible Zinc-Ion Hybrid Supercapacitors
Authors: Kasprzak Dawid , Liu Jian
Published: August 2024

A zinc-ion hybrid supercapacitor (ZIHS) is a prospective energy storage device featuring cost-effectiveness, operational safety, environmental friendliness, high-power performance, and satisfied energy density.1 The sustainability of this ZIHS technology is even improved by introducing biopolymer constituents into the cell construction.2 Herein, efficient, sustainable, and flexible ZIHSs employing polysaccharide (chitin- or cellulose-based) components are developed.3 Using green ionic liquid solvents, biopolymer-bound, activated carbon-based cathode materials and hydrogel biopolymer electrolytes containing conductive zinc salts are obtained. According to systematical characterization results, the prepared materials possess favorable functional properties. Biopolymer binders provide homogeneity and integrity within the electrode network and high adhesion to the surface of the current collector. Depending on the type of zinc salt, hydrogel biopolymer electrolytes display high ionic conductivity (up to 46 mS cm−1), expanded electrochemical stability window (up to ca. 2.8 V), and zinc dendrites growth suppression. Biopolymer components assembled with zinc foil electrodes operate efficiently in both coin and pouch ZIHS cell configurations, providing satisfactory energy (45–50 Wh kg−1) and high power (10–20 kW kg−1) density combined with excellent cycle stability. Moreover, these ZIHS pouch-type devices exhibit superior durability and flexibility, withstanding mechanical stress up to 150° bending states with at least 90% of capacitance retention. It suggests a prospect for their application in wearable electronics.4

References

(1) Wang, Y.; Sun, S.; Wu, X.; Liang, H.; Zhang, W. Status and Opportunities of Zinc Ion Hybrid Capacitors: Focus on Carbon Materials, Current Collectors, and Separators. Nano-Micro Lett.
2023, 15 (1), 78.

(2) Kasprzak, D.; Mayorga-Martinez, C. C.; Pumera, M. Sustainable and Flexible Energy Storage Devices : A Review. Energy & Fuels
2023, 37, 74–97.

(3) Kasprzak, D.; Liu, J. Chitin and Cellulose as Constituents of Efficient, Sustainable, and Flexible Zinc-Ion Hybrid Supercapacitors. Sustain. Mater. Technol.
2023, 38, e00726.

(4) Dubal, D. P.; Chodankar, N. R.; Kim, D. H.; Gomez-Romero, P. Towards Flexible Solid-State Supercapacitors for Smart and Wearable Electronics. Chem. Soc. Rev.
2018, 47 (6), 2065–2129.

Figure 1. Graphical abstract of the research on biopolymer-based Zn-ion hybrid supercapacitors.

Figure 1
From Invention to Acquisition: Evolution of an Electronic Sensor Startup Catalyzed by Nanotubes
Authors: Franklin Aaron D
Published: August 2024

Nanomaterials have many attractive properties, ranging from electrical to mechanical, that motivate their potential use in diverse applications. Beyond their inherent capabilities, nanomaterials wield a distinctive marketing influence, either catalyzing transformative support or acting as a hindrance for certain applications. Some sectors witness heightened investor and consumer interest when nanomaterials are proposed for product integration, driven by perceived high-tech advantages. Conversely, preconceived notions may diminish enthusiasm in fields citing environmental concerns or scale-up challenges. In this talk, I’ll share two examples of how the marketing dynamics of nanomaterials impacted funding for commercialization. First, I’ll share the story of Tyrata, a tire health sensor company that kicked off in 2017 with a $4.5M Series A investment based on the use of printed carbon nanotubes. While initial interest was enhanced thanks to nanomaterials, the company’s evolution saw a strategic shift in materials and structures. By late 2023, Bridgestone, a goal tire manufacturing giant, acquired Tyrata. I will highlight how a nanotube-based sensor start-up evolved to become a company with sensing systems all over the world, attracting attention from Fortune 500 companies. The second (brief) example I’ll share is regarding the use of nanomaterials in transistors and how the biases and shifting stigmas about their use have impeded progress. Overall, this talk will highlight some practicalities and realities of pursuing commercial applications of nanomaterials in electronic devices.
A New Technology for Industrial Strain Mapping Using Single-Wall Carbon Nanotube Sensors
Authors: Weisman R. Bruce , Bachilo Sergei M. , Meng Wei , Nagarajaiah Satish
Published: August 2024

Measurements of mechanical strain are widely used in heavy industry to design and test new structures and to ensure the safety of installed infrastructure. However, the few practical methods for strain measurement all have serious limitations. To complement these methods, we have developed a new strain technology, called S4 for “strain-sensing smart skin,” which uses single-wall carbon nanotubes (SWCNTs) as microscopic sensors. Nanotubes dilutely embedded in a polymer are applied as a thin film to specimen surfaces of interest. Subsequent strains in the specimen are transmitted by load transfer through the film to the nanotubes, inducing axial compression or extension. Those small structural deformations of the SWCNTs alter the semiconducting band gaps in predictable ways, causing proportional shifts in the peak wavelengths of their near-infrared fluorescence emission. Shifts are quantified by optically exciting the specimen surface and spectrally analyzing the resulting fluorescence to deduce strain values at the probed locations. The S4 method has recently been implemented using hyperspectral imaging. We demonstrate measurements in less than one minute of strain maps containing hundreds of thousands of pixels with 50 microstrain noise levels and 0.2 mm spatial resolution. This technology has promising potential to become a large-scale commercialized application of carbon nanotechnology.
Pulsed Electro-Codeposition of Graphene-Copper Hybrids with Enhanced Conductivity
Authors: Wang Dan , Hall Timothy , Snyder Stephen , Inman Maria , Godwin Jessica , Roberts Nick
Published: August 2024

The development of next generation materials and manufacturing technologies is critical for increasing industrial competitiveness, improving economic strength, and driving economy-wide decarbonization. Thermal and/or electrical conductivity-enhanced materials have been demonstrated as promising elements for the decarbonized industry sector with a wide variety of applications. High thermal conductivity materials enable new capabilities for the applications on sensors, detectors, and accelerators. The sluggish conduction cooling rate of conventional materials, such as copper, aluminum, or graphite, hinders the application of the cryogenic cooling systems. Graphene are two-dimensional nanocarbon materials with excellent physical and chemical properties, such as thermal and electronic conductivity, high mechanical strength, large specific surface area. The intrinsic physiochemical properties of graphene and a metal (copper) matrix, combined with advanced fabrication techniques, could tailor graphene-copper hybrid properties and make the hybrid as ideal thermal strap materials for conduction cooling systems.

In this work, Faraday Technology Inc. and Utah State University will discuss an efficient, scalable, manufacturing-ready approach to produce high conductive graphene-copper hybrid foils/coatings and demonstrate their applications in thermal straps for conduction cooling, as well as in electronic devices as low resistance electrical pathways. The innovative electro-codeposition manufacturing process is based on the use of pulsed electric fields, for controlled, reproducible, scalable deposition of Cu and graphene materials simultaneously to form incorporated graphene-Cu hybrid foils. The graphene composition in the hybrid foils was confirmed by Raman spectrometry. The thermal conductivity of fabricated Cu-Graphene foil was ~50% higher than that of commercial Cu foil. Currently. we are scaling up the fabrication process for large scale production of graphene-copper hybrid foils for the thermal strap application.

In summary, a scalable manufacturing process for synthesizing high conductive graphene-copper hybrids has been demonstrated. The work will be continued on thermal straps fabrication and performance evaluation, as well as other applications demonstration, such as low resistance backplanes for electronic devices.

Acknowledgements: The financial support of DOE SBIR program through grant No. DE-SC0021676 (Phase I&II) is acknowledged.
Will 2D Materials Play a Role in the Semiconductor Industry?
Authors: Pop Eric
Published: August 2024

This talk will present my (biased) perspective on whether two-dimensional (2D) materials could play a role in the semiconductor industry. It is important to recognize that 2D materials are good for applications where their ultrathin nature gives them distinct advantages, such as flexible electronics [1] or light-weight solar cells [2]. They may not be good where conventional materials work sufficiently well, like transistors thicker than a few nanometers. I will focus on 2D materials for 3D heterogeneous integration of electronics, which has major advantages for energy-efficient computing [3]. Here, 2D materials could be monolayer transistors with ultralow leakage [4] (due to larger band gaps than silicon), used to access high-density memory [5]. Recent results from our group [6,7] and others [8] have shown monolayer transistors with good performance, which cannot be achieved with sub-nanometer thin conventional semiconductors, and the 2D performance could be further boosted by strain [9]. I will also describe some unconventional applications, using 2D materials as thermal insulators [10], heat spreaders [11], and thermal transistors [12]. These could enable control of heat in “thermal circuits” analogous with electrical circuits. Combined, these studies reveal fundamental limits and some key applications of 2D materials, which take advantage of their unique properties.

Refs: [1] A. Daus et al., Nat. Elec. 4, 495 (2021). [2] K. Nassiri Nazif, et al., Nat. Comm. 12, 7034 (2021). [3] M. Aly et al., Computer 48, 24 (2015). [4] C. Bailey et al., EMC (2019). [5] A. Khan et al. Science 373, 1243 (2021). [6] C. English et al., IEDM, Dec 2016. [7] C. McClellan et al. ACS Nano 15, 1587 (2021). [8] S. Das et al., Nat. Elec. 4, 786 (2021). [9] I. Datye et al., Nano Lett. 22, 8052 (2022). [10] S. Vaziri et al., Science Adv. 5, eaax1325 (2019). [11] C. Koroglu & E. Pop, IEEE Elec. Dev. Lett. 44, 496 (2023). [12] M. Chen et al., 2D Mater. 8, 035055 (2021).
Centrifugal Jet-Spun, Non-Woven Chitin Fiber Separator for High-Performance Aqueous Zinc-Ion Batteries
Authors: Jin Jungho , Song Myeong-Oh , Park Jeong-Ho , Jung Ji-Won
Published: August 2024

Although lithium-ion batteries (LIBs) are key prevailing energy storage devices, alternative battery technologies based on earth-abundant materials are being sought as a viable energy storage systems that could possibly replace LIBs. Among several alternatives is aqueous zinc-ion batteries (AZIBs), which are more eco-friendly, cost-effective, and even safer. Despite their potential advantages, the development of appropriate separators for ZIBs has been elusive, and the issue of zinc metal dendrites on the negative electrode remains a critical challenge.

In this work, we introduces a novel approach to prepare a non-woven spun fiber mat made of chitin, an abundant natural polymer, which could function as a separator for AZIBs. In particular, we use centrifugal jet-spinning (CJS) to fabricate the chitin separator. The use of chitin as a separator offers several advantages over existing ZIB separators, such as high stability, improved capacity, environmental friendliness, and cost-effectiveness. We demonstrate that the chitin separator can be applied in AZIB cells based on symmetric and full cell models, which showed stable cell operation for long-term cycling.

Figure 1
On-Surface Synthesis of 1D and 2D π-Conjugated Polymers from Heterotetrabromo-P-quinodimethanes (HTBQs)
Authors: Jimenez Vicent Diego , Pérez Elvira Elena , Santos Jose , Urgel Jose , Ecija David , Martín Nazario
Published: August 2024

Molecules bearing gem-dibromoolefines functionalities have been employed in wet chemistry as intermediates in the well-known Corey-Fuchs homologation of carbonyls to alkynes. This gem-dibromoolefines can be embedded into tetrabromo-p-quinodimethanes (TBQs), which efficiently undergo dehalogenative homocoupling on coinage metal surfaces, namely Au(111) and Ag(111), forming one-dimensional (1D) acene and periacene π-conjugated polymers able to exhibit non-trivial topological properties.[1,2]

However, the synthesis of more complex π-conjugated polymers to determine the scope of this new reaction, as well as the synthesis of two-dimensional (2D) polymers by following this chemical methodology are still important challenges. In this context, new dimeric TBQs have been synthesized by wet chemical protocols for their further use in the synthesis of double-strand oligomers. Interestingly, the new systems exhibit many defects, due to the intrinsic nature of the synthesized precursors.[3]

In this work, we firstly take advantage of the introduction of heteroatoms at the edges of the monomers in order to grow 1D new π-conjugated polymers which, eventually, collapse into amazing large 2D networks by non-covalent interactions. Moreover, when suitable designed TBQs with both the presence of heteroatoms and steric hindrance, unprecedented 1D and covalently linked 2D π-conjugated polymers are formed. These results have allowed the study of new topologically non-trivial polymers which will be presented and discussed in this communication.

[1] Cirera, B., Sánchez-Grande, A., de la Torre, B., Santos J. et al. Nat. Nanotechnol.
2020, 15, 437–443.

[2] González-Herrero, H., Mendieta-Moreno, J. I., Edalatmanesh, S., Santos, J. et al. Advanced Materials
2021, 33, 2104495.

[3] Vicent, D. J., Perez-Escribano, M. et al.
Chem. Sci., 2023, 14, 10112-10120.
On-Surface Synthesis of Graphene Nanoribbons and Spin Chains
Authors: Ruffieux Pascal
Published: August 2024

Recent advances in on-surface synthesis has allowed the selective fabrication of a number of prototypical types of graphene nanoribbons. The thereby achieved properties include width-dependent electronic band gaps in armchair graphene nanoribbons, edge-localized states in zigzag graphene nanoribbons and topological band engineering in width-modulated topological graphene nanoribbons. More recently, on-surface synthesis of magnetic nanographenes has been reported. Here, the spin originates from unpaired electrons present in nanographenes with controlled sublattice imbalance or topological frustration. The corresponding magnetic moments live in p-orbitals and are hence largely delocalized, which allows for chemical control over their exchange interaction when covalently linking several molecular building blocks. Here, I will present synthesis of various prototypical magnetic nanographenes and the possibility to covalently link them to form coupled spin systems where exchange coupling can exceed 100 meV. Using halogen-substituted precursors, we achieve the on-surface synthesis-based deterministic bottom-up fabrication of various spin chains including a triangulene spin-1 chain revealing the predicted Haldane gap and fractional excitations at the chain termini or a strictly alternating spin-½ chain with chemically engineered coupling strengths J1
and J2
. Scanning tunneling microscopy and spectroscopy is used to explore length- and site-dependent magnetic excitations. Furthermore, we apply hydrogenation to achieve spin site passivation and controlled tip-based local reactivation to fabricate and characterize specific spin patterns in one-dimensional spin chains and spin clusters.
Enhancing Stability and Activity of Transition Metal Chalcogenides: Development of Carbon-Based Hydrochar Supported Nickel-Cobalt Selenide Electrocatalyst for Oxygen Evolution Reaction
Authors: Soriano Patricia Isabel , Almonte Gio Jerson , Sungcang Chris Ivan , Perez Joaquin Nathaniel , Choi Angelo Earvin Sy , Ortenero Joseph Rempillo
Published: August 2024

Transition metal chalcogenides (TMCs) have long been regarded as cost-substitutes for traditional noble metal electrocatalysts, exhibiting comparable activity in the oxygen evolution reaction (OER). However, stability and activity remain crucial factors influencing the broader applicability of the catalysts. Therefore, enhancing the stability of transition metal chalcogenides is a key area of interest. This study delves into the development of carbon-based hydrochar support, serving as an alternative scaffold for depositing TMCs. Specifically, it aims to explore the application of scaffold for nickel-cobalt selenide (NiCoSe), a TMC exhibiting significant potential in accelerating the OER rate by increasing extrinsic activity through higher catalyst loading, enhanced porosity, and ensuring stability of the supported catalyst. The activity and stability of the NiCoSe/hydrochar are determined from cyclic voltammogram and chronoamperometric curves. Characterization of the synthesized NiCoSe on hydrochar show porous microstructure and well-dispersed electrocatalyst on hydrochar scaffold which allowed enhanced transport of species and aided electron transport through the electrolyte-electrode interface. SEM-EDS spectra show uniform distribution of NiCoSe which is advantageous for enhanced performance of the catalyst. This study elucidated the effect of hydrochar to enhance the extrinsic activity of NiCoSe towards the oxygen evolution reaction.
Influence of Sulfonates on the Interfacial Ion Transfer Kinetics of Cu at Au(111) Surfaces
Authors: Thurman Kira A. , Cannan Caitlyn M. , Kempler Paul A. , Boettcher Shannon W.
Published: August 2024

Corrosion reactions profoundly impact the operational stability of various electrochemical components, such as electrocatalysts, conductive supports, and semiconducting light absorbers. Understanding the kinetics of ion transfer at electrode/electrolyte interfaces is crucial for deciphering the durability of copper-containing electrochemical devices. This study investigates the corrosion and deposition behavior of copper adlayers on gold(111) surfaces in sulfate and sulfonate electrolytes, with a focus on adsorption kinetics influenced by anion structure and Lewis acidity. At low scan rates, the adsorption and desorption capacitance of the broad adsorption region previously assigned to random adsorption of Cu on Au(111) surface in sulfuric acid, were nearly symmetric in E and invariant with ν, indicating reversible kinetics across all four electrolytes. At faster scan rates, the experiments reveal distinct adsorption/desorption responses for different anions, shedding light on the interplay between ion transfer kinetics, corrosion rates, and the microenvironment of electrocatalysts. The results provide valuable insights into the fundamental processes governing interfacial ion transfer and offer implications for the design and optimization of electrochemical systems.

Figure 1
Aluminum Current Collector Corrosion Inhibition by a Newly Synthesized 5-Formyl-8-Hydroxyquinoline for Aqueous-Based Battery
Authors: Tekaligne Teshager Mekonnen Mekonnen , Su Wei-Nien , Hwang Bing Joe
Published: August 2024

Aluminum foil is the most frequently used as a cathodic current collector for batteries because of its high electrical conductivity, low cost, robust electrochemical properties, and low density. However, as next-generation batteries are created, serious corrosion poses new challenges to aluminum current collectors, especially with no effective additive in an aqueous electrolyte. A newly 5-formyl-8-hydroxyquinoline (FHQ) additive is designed and synthesized as an effective corrosion inhibitor for aluminum foil. The effect of FHQ on the corrosion of the Al current collector in an aqueous-based electrolyte has been investigated using electrochemical methods and spectroscopy techniques for assessing the corrosion inhibition efficacy and protective film formation on the Al surface. The Potentiodynamic polarization measurements indicated that the corrosion rate in millimeters per year (mmpy) of 1.37×10-3 is much lower in the aqueous electrolyte of 21 m LiTFSI with the FHQ additive than 2.29×10-2 in the electrolyte without an additive. Meanwhile, the Zn//LVPF configuration is developed as an efficient protocol to evaluate the corrosion prevention efficiency of inhibitors in an aqueous-based battery for the first time. The Zn//LVPF cell in the aqueous electrolyte with the FHQ additive provides much higher capacity retention and average Coulombic efficiency than the cell in the electrolyte in the absence of an additive. Interestingly, the Al corrosion prevention efficiency of the developed additive is also observed in an organic electrolyte-based battery. This work paves a new pathway to develop effective Al corrosion inhibitors for applications in lithium-ion batteries, especially in aqueous electrolytes.

Keywords; Corrosion inhibitor; 8-hydroxyquinoline; 5-formyl-8-hydroxyquinoline; Doner/acceptor; HOMO-LUMO; Aluminum corrosion.
Localized Corrosion Behavior and Corrosion Microstructure of LZ91 and LAZ931 Mg Alloys
Authors: Fu Ya-Han , Pan Shi-Yuan , Su Te-Cheng , Chu Peng-Wei
Published: August 2024

LZ91 (Mg-9 wt%Li-1 wt%Zn) and LAZ931 (Mg-9 wt%Li-3 wt%Al-1 wt%Zn) alloys are emerging ultra-lightweight Mg alloys, which can be used in applications that require weight reduction. Although LZ91 alloy has found some success in the 3C industry, the relatively inferior mechanical strength limits its widespread application. To improve the mechanical properties, Al was added to LZ91 alloy to form LAZ931 alloy. However, both LZ91 and LAZ931 alloys are primarily composed of a dual-phase structure with α (HCP) and β (BCC) phases, which form a microgalvanic couple in the corrosion environment. Furthermore, adding Al introduces additional secondary phases, such as AlLi and MgLi2Al, which complicate the corrosion behavior and mechanism. Therefore, this study investigates the corrosion behavior and microstructure of LZ91 and LAZ931 Mg alloys in 3.5 wt% NaCl solution and the relationships to the phase distribution in the alloy substrates.

By in situ optical microscope (OM) observations and open circuit potential (OCP) monitoring, localized corrosion initiates on the LAZ931 alloy earlier than on the LZ91 alloy. The early initiation and propagation of localized corrosion on the LAZ931 alloy result in worse corrosion resistances and faster corrosion rates measured by electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization curves. By scanning Kelvin probe force microscopy (SKPFM), the Li-rich β phase is more active than the Mg-rich α phase. However, interestingly, localized corrosion was found to preferentially propagate inside the α phase, which seems to contradict the SKPFM measurements. The preferential propagation of localized corrosion in the α phase could be related to the difference in the surface corrosion film thicknesses on the α and β phases before localized corrosion propagation. The localized corrosion behavior and corrosion microstructure of the alloys will be discussed based on electrochemical measurements and site-specific microstructure characterizations.

Figure 1
Understanding Ion-Transfer Reactions in Silver Corrosion and Electrodeposition
Authors: Zhao Yang , Kang Richard , Thurman Kira A. , Kempler Paul A. , Head-Gordon Martin , Boettcher Shannon W.
Published: August 2024

The electrified aqueous/metal interface is critical in controlling the performance of energy conversion and storage devices, but an atomistic understanding of even basic interfacial electrochemical reactions challenges both experiment and computation. We report an experiment study of (reversible) ion-transfer reactions involved in anodic Ag corrosion, a model system for interfacial electrochemical processes generating or consuming ions by using temperature-dependent voltage-step measurements. The experimental activation energies (0.4 eV) and transfer coefficients agree with the calculated (equilibrium) free-energy barriers (0.2 eV). The use of Ag nanoclusters eliminates the convolution of the kinetics of Ag+ (aq.) generation and transfer with those of nucleation or etch-pit formation. The work, coupled with theoretical studies, provides molecular-level details on the nascent Ag+ ion formation as well as the primary factors controlling the energetics of the reactions in broad relevance across the energy sciences.