bluuebunny/crossref_metadata_2025 huggingface dataset:
(Invited) Charge Carrier Relaxation, Recombination and Extraction Dynamics in Metal Halide Perovskite Nanocrystals
Authors: Samanta Anunay
Published: September 2023

Charge Carrier Relaxation, Recombination and Extraction Dynamics in Metal Halide Perovskite Nanocrystals

Anunay Samanta

School of Chemistry, University of Hyderabad, Hyderabad 500046

(anunay@uohyd.ac.in)

The lead halide-based all-inorganic and hybrid perovskites are under intense investigation due to their immense potential in solar photovoltaic and light emitting applications.1,2 As realization of the full potential of these materials in various applications requires a clear understanding of the relaxation pathways and dynamics of the photo-generated charge carriers, we have been studying these key photo-processes in a wide range of perovskite nanocrystals.3-10 In this talk, we would like to present some of our recent results highlighting how a combination of femtosecond pump-probe and single-particle fluorescence techniques can be used to obtain valuable information on the nature and energy states of the photogenerated species, pathways and dynamics of relaxation of the charge carriers, location and nature of the trap states and their role in fluctuation of the photoluminescence of different caesium lead halide (CsPbX3) perovskite nanocrystals.

References

Dey, A. et. al. ACS Nano
2021, 15, 10775.

Green, M.A.; Ho-Baillie, A.; Snaith, H.J. Nature Photonics
2014, 8, 506.

Mondal, N; De, A.; Das, S.; Paul, S.; Samanta, A. Nanoscale
2019, 4, 9796.

Mondal, N; De, A.; Samanta, A. ACS Energy Letts.
2019, 4, 32.

Seth, S.; Ahmed, T.; Samanta, A. J. Phys. Chem. Lett.
2018, 9, 7007.

Mondal, N; De, A.; Samanta, A. J. Phys. Chem. Lett.
2018, 9, 3673.

Ahmed, T; Seth. S.; Samanta, A. ACS Nano
2019, 13, 13537.

De, A.; Das, A.; Samanta, A. ACS Energy Letts.
2020, 5, 2246.

Ahmed, T.; Paul, S.; Samanta, A. J. Phys. Chem. C
2022, 126, 9109.

Paul, S.; Samanta, A. J. Phys. Chem. Lett.
2022, 13, 5742.
Co-Doping SrTi1-2xCoxCrxO3-
δ (0.001 ≤ x ≤ 0.1) Perovskite Photocatalysts for Hydrogen Production
Authors: Liao Yuan , Irvine John Thomas Sirr
Published: September 2023

In this work, a series of Cr/Co co-doped SrTiO3 (STCC) perovskite photocatalysts have been successfully synthesized by a traditional solid state method. Their morphology, crystal structure, light absorption and photocatalytic performance have been studied systematically. UV–vis diffuse reflectance spectra (DRS) showed that only a very small amount (0.5%) of Cr/Co co-doping could drastically extended the absorption edge of STiO3 to visible light region at the wavelength of 533 nm. The 1% co-doped SrTiO3 (STCC-0.01) photocatalyst exhibited optimal H2 evolution, which is almost 7 times higher than that of undoped SrTiO3. Additionally, the photocatalytic hydrogen production increased steadily and reached 47.52 μmol/gcat during long time stability test. Different sacrificial agents have also been studied and results found STCC-0.01 showed maximum activity of 14.5 μmol/gcat/h hydrogen evolution with 15 vol% triethanolamine (TEOA) co-catalyst. The charge balance was kept by co doping, resulting in the suppression of formation of Cr6+ ions and oxygen defects in the lattice which should work as effectively nonradiative recombination centers between photogenerated electrons and holes.
Computational Analysis of Excited-State Properties of MoS2 Nanosheet Modified with a Pyrene Derivative
Authors: Urakami Takumi , Sato Hirofumi , Umeyama Tomokazu , Imahori Hiroshi , Higashi Masahiro
Published: September 2023

MoS2, a representative transition metal dichalcogenides (TMD), is known to undergo the hydrogen evolution reaction in the exfoliated state, and its use as an auxiliary catalyst in place of platinum has been widely reported. Recently, the exfoliation of bulk MoS2 and efficient covalent modification of MoS2 nanosheets with N-bromobenzylmaleimide was successfully achieved using a planetary ball mill. For the photofunctionalization of MoS2, further coupling reaction with a pyrene derivative produced pyrene-benzyl-maleimide-MoS2 (Py-Bn-Mal-MoS2) nanosheet. The absorption spectrum of Py-Bn-Mal-MoS2 shows peaks similar to that of 1-phenylpyrene. On the other hand, the emission spectrum of Py-Bn-Mal-MoS2 is much different from that of 1-phenylpyrene. Furthermore, the emission peak of Py-Bn-Mal-MoS2 is more redshifted with increasing solvent polarity. However, the detailed mechanism is unclear. In this study, we investigated the excited-state properties of Py-Bn-Mal-MoS2 with theoretical methods. First, we constructed model systems of Py-Bn-Mal-MoS2 nanosheet and performed time-dependent density functional theory (TDDFT) calculations. The calculated molecular orbitals and dipole moment changes demonstrated that the emission is a charge transfer transition from the pyrene moiety to MoS2 nanosheet. Next, we performed three-dimensional reference interaction site model (3D-RISM) calculations, which is based on the integral equation theory of molecular liquids, to assess the solvent dependence of emission energies. The calculated results reproduced the experimental solvent dependence well. The distributions of polar solvent molecules showed strong interaction between the excited state of Py-Bn-Mal-MoS2 and solvent molecules. This study supports the potential of covalent modification of MoS2 for photocatalytic applications.
Fine Tuning of Plasmonic Metal Array Structures for Effective Light Manipulation
Authors: Minamimoto Hiro , Murakoshi Kei
Published: September 2023

Improvements in light manipulation is the key for effective photoenergy conversions. Herein, we propose a method to improve the quality factor of metal nanostructure array using a relatively low temperature annealing. The method leads to the change in the extinction spectra of Au nanoprisms showing a narrow full width at half-maximum while maintaining structural anisotropy. X-ray diffraction and electrochemical measurements proved the improvement of the crystallinity of the Au nanoprisms as the origin of relatively high quality factor. Moreover, the method was also applied to the well-defined Au lattice structure prepared using electron-beam lithography, which resulted in a 5-fold improvement of the quality factors in the surface lattice resonance mode. We applied these structures to construct strong coupling systems with dye excitons. Ultra-strong coupling states was achieved by the optimization of the lattice modes to the energy of the excitons. The present systems could be applied to create controlled light-matter hybridized materials.
(Invited) Photoluminescence-Based Circular Polarization Convertors for Multiplexing of Optical Information
Authors: Okazaki Yutaka , Shimizu Hayaki , Nakamura Kaito , Sagawa Takashi
Published: September 2023

Polarized light has a great potential to provide a variety of optical information at once such as light intensity (brightness), wavelength (color), and polarization. In particular, circularly polarized (CP) light is expected to be used not only for 3D display but also for optical data encryption and anti-counterfeiting, because the polarization plane of CP light rotates during light propagation resulting in no angular dependence on information transmission. The previously reported approaches for creating CP light from unpolarized light can be roughly classified into the filtration using a circular polarizer, the selective reflection by chiral liquid crystals, and the circularly polarized luminescence (CPL) from chiral luminophores. Meanwhile, we have recently proposed a new approach for creating highly-pure CP light by converting linearly polarized luminescence (LPL) using luminescence-based CP convertor (Figure 1a).[1] The unique advantage of the luminescence-based CP convertor lies in the spectral conversion properties of the LPL films which allows multiplexing of optical information by simply laminating LPL films. In this presentation, we introduce the multilayer-type luminescence-based CP convertors (Figure 1b) fabricated by using two or three LPL films showing different PL wavelength.

In this study, we selected quantum rods (QRs) and π-conjugated luminescent polymers as one-dimensional (1D) luminophores. As a stretchable transparent polymer, poly(ethylene-co-vinyl acetate) (EVA) was used. LPL films were prepared by uniaxial stretching of the luminophore/EVA composite films. When yellow-, orange-, and red-color-emissive QRs were used as a luminophore, yellow-, orange-, and red-LPL were obtained as shown in Figures 1c-e. By laminating LPL film on the quarter-wave film with the angles between polarization plane of LPL and fast-axis of quarter-wave film were -45˚, 0˚, and +45˚, left-handed (LH-), parallel LP, and right-handed (RH-) CP light were produced, respectively. When the yellow-, orange-, and red-LPL films were laminated at three different angles (-45˚, 0˚, and +45˚) against the fast axis of the quarter-wave film, 3×3×3=27 different pieces of optical information were produced as shown in Figure 1f. Furthermore, time information on CP light can also be multiplexed theoretically by laminating several LPL films showing different fluorescence lifetimes. In this presentation, we will also discuss about time-multiplexing of optical information by multilayer-type luminescence-based CP light convertor consisting of multiple LPL films showing different PL lifetimes.

[1] Y. Okazaki et. al., J. Mater. Chem. C, 2022. DOI: 10.1039/d2tc03955a.

Figure 1
An Effective Polysulfide Trapping Strategy for the Development of a Scalable, High Energy Density Lithium-Sulfur Battery
Authors: Hasan Md Wahidul , Huynh Khang , Razzaq Amir Abdul , Sumdani Gulam , Shende Rajesh , Paudel Tula , Xing Weibing
Published: September 2023

Rechargeable lithium-sulfur (Li-S) batteries represent an attractive, “beyond Li-ion”, battery technology because they offer a high specific energy of 2,500 Wh/kg at the material level1 and 550 Wh/kg at the cell level.2 However, Li-S batteries face substantial technical challenges that have thus far prevented the realization of the battery’s tremendous performance potentials.3 One of the major technical challenges is low practical specific capacity and fast performance degradation due to the formation, migration, and shuttling of intermediate lithium polysulfides (PSs). Several strategies have been used to trap the PS species either chemically or physically; however, they either incur increased cost due to the use of expensive catalysts4 or suffer from the reduced battery specific energy due to added inactive weights from the cell design.5,6

We will present a novel strategy to address the PS-shuttle issue using a nanolayer polymer modified high surface area carbon (NPC) as a new type of PS-trapping material.7 When thin films of NPC were coated on sulfur electrodes (NPC-S), we found that our NPC-S based Li-S battery demonstrated a high discharge specific capacity (~1,600 mAh/g) that is nearing sulfur’s theoretical specific capacity. Our molecular dynamics simulation suggests such an excellent performance is attributed to NPC’s strong PS trapping capability via dipole-dipole interactions. We will show that, using a sustainable starting material, our approach is low-cost and economically scalable for the advanced Li-S battery technology.

References

Zhang, S. S., Journal of Power Sources
2013,
231, 153-162.

Manthiram, A.; Fu, Y.; Su, Y.-S., Accounts of Chemical Research
2013,
46 (5), 1125-1134.

Chen, Z. X.; Zhao, M.; Hou, L. P.; Zhang, X. Q.; Li, B. Q.; Huang, J. Q., Advanced Materials
2022, 2201555.

Hamal, D.; Awadallah, O.; El-Zahab, B., Catalysis in Lithium-Sulfur Cathodes for Improved Performance and Stability. In 242nd The Electrochemical Society Meeting, Atlanta, GA, USA, 2022.

Chung, S.-H.; Han, P.; Singhal, R.; Kalra, V.; Manthiram, A., Advanced Energy Materials
2015,
5 (18).

Singhal, R.; Chung, S.-H.; Manthiram, A.; Kalra, V., Journal of Materials Chemistry A
2015,
3 (8), 4530-4538.

Hasan, W.; Hyynh, K.; Razzaq, A.; Smdani, G.; Shende, R.; Paudel, T.; Xing, W., "Scalable, High Energy Density Lithium-Sulfur Batteries". In NASA Battery Workshop, November 15-17, 2022
, Huntsville, AL, USA, 2022.

Acknowledgment

This work was supported by the Larry and Linda Pearson Endowed Chair at the Department of Mechanical Engineering, South Dakoda School of Mines and Technology and by the South Dakota Governor’s Research Center for Electrochemical Energy Storage.

Figure 1
A Big Data Approach to Rational Design and Discovery of Electrolytes
Authors: Kumar Ritesh , Vu Canh , Amanchukwu Chibueze
Published: September 2023

Lithium-metal batteries (LMBs) have much higher energy densities than the current state-of-the-art lithium-ion batteries that drive the green energy landscape. However, their wide-scale commercialization is hampered by the lack of desirable electrolytes that suffer from stability and cyclability issues. The discovery of electrolytes for LMBs has been mainly guided by chemical intuition and trial-and-error experiments. While the emerging machine learning (ML)-based initiatives for electrolyte discovery are promising, most studies have been carried out on limited datasets of ionic conductivity, they remain experimentally unvalidated, and lack in design principles governing performance of efficient electrolytes. The present work addresses these problems by curating exhaustive datasets of the most critical parameters affecting the LMB electrolytes – ionic conductive, oxidative stability, and Coulombic efficiency and by developing highly accurate ML and deep learning (DL) models. The models were consistent with the known chemical principles of ionic conductivity and pinpointed few non-trivial trends. After undergoing stringent checks on out-of-distribution (OOD) in-house data sets for the three target properties, the ML models were finally deployed on large unlabeled datasets to identify new and promising electrolytes, and a score was devised to rank the molecules in terms of the predicted target properties. The subsequent experimental investigations led to an entirely new class of LMB electrolytes, establishing the efficacy of our heuristic approach. The proposed “multi-pronged” strategy for LMB electrolyte discovery will also enable researchers to find extraordinary electrolytes for other battery chemistries.
Developing Tin Anodes for Aqueous Batteries
Authors: Wang Jianbo , Catalina Sofia K. , Chueh William C. , Mefford J. Tyler
Published: September 2023

Aqueous batteries based on metal anodes present an attractive alternative to lithium-ion for long-duration energy storage due to their low-cost, high-safety, and theoretically high energy density. Still, despite many efforts towards development and commercialization, metal anode systems remain hampered by irreversible hydrogen evolution (HER), detrimental shape change, and passivation during cycling. Recognizing the immediacy required to enable the renewable energy transition, our research is focused on developing alternative anode chemistry based on Tin (Sn) for aqueous batteries.

Sn metal has been used in aqueous battery systems as additives or current collectors to mitigate side reactions due to its high overpotential for HER. However, little attention was paid to its potential use as a redox active material in aqueous electrolytes. In this talk, we will discuss our efforts to develop Sn as an aqueous anode with high capacity and cyclability. We will first present our development of pouch cells to enable aqueous cells while minimizing the side reactions from cell components other than the active materials. Preliminary data demonstrate the feasibility of using Sn as anode active materials via a 4-electron process in aqueous systems. To investigate the mechanism and improve the Coulombic efficiency, we perform operando X-ray diffraction (XRD), rotating ring disk electrochemistry (RRDE), electrochemical quartz crystal microbalance (EQCM), and 117Sn nuclear magnetic resonance (Sn-NMR) on the Sn system. Lastly, we will show our improvement based on the mechanistic understanding that enables Sn-based full cells with high Coulombic efficiency, high areal capacity, high utilization rate and long capacity retention.
(Digital Presentation) Mathematical Approximations for Monitoring the State of Charge and Computing Electrolyte Volume in Vanadium Redox Flow Battery Systems
Authors: Santana Jordy , Villegas Victor , Espinoza Andaluz Mayken , Andersson Martin
Published: September 2023

During the last years, several attempts have been carried out to provide clean energy storage as an alternative to overcome the energy demand. Vanadium redox flow batteries (VRFBs) appear as a suitable device that converts the chemical energy present in the electrolyte into electrical energy in a noiseless and clean manner. In the mentioned device, the electrolyte is polarized by using renewable energy, and later the stored energy is used in several applications from mobile to stationary scenarios. There are two fundamental design parameters to be considered in the sizing of a VRFB: the state of charge (SoC), and the electrolyte volume. The mentioned parameters are related to two independent parameters of great importance, the energy consumption per unit of time (power delivered by the device), and the amount of energy that can be stored in the system (energy capacity).

The purpose of the current study is, based on collected data and theoretical approximations, analyze the SoC and the required electrolyte volume for several applications. To estimate the SoC for the different VRFB, a Nernst-modified equation is used. In this case, the number of cells was a key part of achieving the desired results. A correction factor (λ) was introduced to visualize the trend of the generated curve family in a better manner. On the other hand, to calculate the volume of electrolyte, an equation derived from the definition of electric charge is implemented. Similarly, due to the power applications range covering the study, a correction factor (γ) was also introduced. Considering the obtained results, as the correction factor increases the load state in the system will tend to present higher values of open circuit voltage and nevertheless constant values of load state. Based on the energy capacity calculations, and considering common vanadium concentrations among the electrolytes, it was found that the higher the vanadium concentration the required electrolyte volume will tend to be minor. In addition, on a large scale, there is a greater convergence of the required electrolyte volume to values greater than 10 000 m3.

Figure 1. Trend of the open circuit voltage (OCV) when the state of charge (SoC) is increasing. Due to the wide range of output power analyzed in the current study, all the OCV presented values have been determined by using a correction factor (λ).

Figure 1
Photoinduced Processes in Molecular and Supramolecular Arrays Based on Porphyrins and Acridinium Units
Authors: Ruani Federica , Sánchez Resa Daniel , Edo-Osagie Amy , Jacquot de Rouville Henri-Pierre , Heitz Valérie , Armaroli Nicola , Ventura Barbara
Published: September 2023

Multichromophoric arrays based on porphyrins are of high interest for their mimicry of naturally occurring photoinduced energy and electron transfer processes leading to energy collection and conversion. [1] Moreover, the rich photophysics and electrochemistry of porphyrins make them suitable components of molecular wires, switches or chemical sensors. [2] In this perspective, it is interesting to pursue the combination of porphyrins with units that can act as multiresponsive components by modifying their chemical and electronic structure upon chemical or redox stimuli. N-acridinium ions have been recently explored as a new class of switches that respond to various orthogonal stimulations (pH or electrochemical/photochemical inputs) that trigger their reversible conversion into the non-aromatic acridane form. [3] Few examples reporting the association of acridinium units and porphyrins indicate that these systems are characterized by fast photoinduced electron transfer reactions between the porphyrin donor and the acridinium acceptor. [4,5]

We recently investigated the photophysical properties of molecular and supramolecular arrays based on porphyrins and acridinium units, where the type of porphyrin (free-base or metallated) and/or the form of the switchable component (acridinium or acridane) has been varied (Figure 1). We found that the association of porphyrins and acridinium ions always leads to ultrafast electron transfer processes, and that these reactions can be altered by changing the temperature or by converting the acridinium electron acceptor into an acridane energy donor. Moreover, the combination of two Zn-porphyrins with two acridinium/acridane units results in switchable molecular receptors able to coordinate suitable hosts. The photophysics of the arrays and of the complexes, analyzed by means of steady-state and time-resolved luminescence techniques and ultrafast transient absorption spectroscopy, will be herein presented and discussed.

The work is supported by the H2020-MSCA-ITN-2017-765297 project “NOAH” and by the H2020-LC-SC3-2020-RES-RIA-101006839 project “CONDOR”.

[1] M. Beyler, L. Flamigni, V. Heitz, J.-P. Sauvage, B. Ventura, Photochem.
Photobiol.
2014, 90, 275-286.

[2] Beletskaya I, Tyurin VS, Tsivadze AY, Guilard R, Stern C. Chem. Rev.
2009, 109, 1659-1713.

[3] H.-P. J. de Rouville, J. Hu, V. Heitz, ChemPlusChem, 2021, 86, 110-129.

[4] A. Edo-Osagie, D. Sánchez-Resa, D. Serillon, E. Bandini, C. Gourlaouen, H.-P. Jacquot de Rouville, B. Ventura, V. Heitz, C. R. Chim.
2021, 24, 1-9.

[5] H. Kotani, K. Ohkubo, M. J. Crossley, S. Fukuzumi, J. Am. Chem. Soc., 2011, 133, 11092-11095.

Figure 1. Structures of the studied arrays and schemes of the occurring photoinduced processes: a) bisacridinium-Zn(II) porphyrin conjugate, b) bisacridinium-diphenylporphyrin conjugate, c) bis(acridinium/acridane)-Zn(II) porphyrin receptors.

Figure 1
Porphyrins Derivatives Grafted on Chiral Nanoplatforms for Enantioselective Recognition
Authors: Oda Reiko , Anfar Zakaria , Scalabre Antoine , Okazaki Yutaka , Buffeteau Thierry , Stefanelli Manuela , Magna Gabriele , Monti Donato , Pouget Emilie , Nlate Sylvain , Paolesse Roberto
Published: September 2023

There are many reports on biologically inspired helical structure obtained by polymers, foldamers and low molecular-weight molecules. Indeed, helices with controllable pitches at nanometrical level are attractive not only to mimic nature, but also for the wide range of applications in materials sciences, chemical and biomaterial sensing, and enantioselective catalysis. Here we report the synthesis of inorganic nanohelices based on the transcription of supramolecular helical assemblies,2 which can be used to induce chiroptical properties to a large variety of host molecules grafted on their surface, which can then be used as sensors for enantioselective recognition for the chiral guests.

[1] a) Oda, R., Huc, I., Schmuts, M. Candau, S. J., Mackintosh, F. C. Nature, 1999, 399, 566 ; b) Brizard, A., Aimé, C., Labrot, T., Huc, I., Berthier, D., Artzner, F., Desbat, B., Oda, R. J. Am. Chem. Soc., 2007, 129¸ 3754. c) R. Tamoto, N. Daugey, T. Buffeteau, B. Kauffmann, M. Takafuji, H. Ihara and R. Oda Chem commun, 2015, 51, 3518-3521

2 a) Delclos, T.; Aimé, C.; Pouget, E.; Brizard, A.; Huc, I.; Delville, M.-H.; Oda, R., Nano Letters 2008, 8 (7), 1929-1935 ; b) Okazaki, Y.; Cheng, J.; Dedovets, D.; Kemper, G.; Delville, M.-H.; Durrieu, M.-C. Ihara, H.; Takafuji, M.; Pouget, E.; Oda R.; Acs Nano, 2014. 8(7): 6863-6872; c) Y Okazaki, J Cheng, D Dedovets, G Kemper, MH Delville, MC Durrieu, H Ihara, M Takafuji, E Pouget, R Oda, ACS Nano, 2014 (6) PMID: 24883981

Figure 1
Calix[3]Pyrrole and Related Macrocycles: Synthesis and Properties
Authors: Inokuma Yasuhide
Published: September 2023

Calix[4]pyrrole is a porphyrinogen-like macrocycle in which four pyrrole units are linked by four sp3-hybridized carbon atoms at the α-positions. While such tetrapyrrolic macrocycles are readily synthesized by acid-catalyzed condensation reactions of pyrrole monomer and carbonyl compound, analogous macrocycles composed of three pyrrole units are always not observed. Calix[3]pyrrole is a ring-contracted analogue of calix[4]pyrrole, and has been missing in porphyrin-related chemistry. In this presentation, the first synthesis of calix[3]pyrrole and its furan-embedded analogues is reported, and their unique reactivity derived from their macrocyclic ring strain will be discussed.

Synthesis of calix[3]pyrrole started with a linear trimer of 3,3-dimethylpentane-2,5-dione. Intramolecular cyclization of the linear hexaketone was accomplished in 5 steps to give a cyclic hexaketone precursor. Paal–Knorr type pyrrole formation reaction of cyclic hexaketone gave calix[3]pyrrole in 41% yield (Scheme 1). Using similar strategies, analogous calix[3]-type macrocycles, namely, calix[1]furan[2]pyrrole, calix[2]furan[1]pyrrole, and calix[3]furan, were successfully synthesized. Single crystal X-ray diffraction analysis of calix[3]pyrrole revealed its strained structure, and the theoretical calculations showed the strain energy of calix[3]pyrrole is 22.1 kcal/mol per unit higher than that of calix[4]pyrrole. Such strain energy tends to decrease as the number of pyrrole unit decreased.

Calix[3]pyrrole exhibited unique reactivity derived from macrocyclic ring strain under acidic (Rothemund–Lindsey) conditions that are frequently used for porphyrin synthesis. When calix[3]pyrrole was dissolved in 10 mM solution of trifluoroacetic acid in dichloromethane, calix[6]pyrrole was quantitatively formed within 30 seconds (Scheme 1). Similar strain-induced ring expansion was observed for calix[1]furan[2]pyrrole, but full conversion took approximately 5 minutes. On the other hand, calix[2]furan[1]pyrrole and calix[3]furan did not show ring expansion. Detailed mechanistic analysis revealed that protonation at a pyrrole unit in calix[3]pyrrole triggers irreversible ring-cleavage to give a linear tripyrrane moiety which undergoes cyclodimerization under acidic conditions.

The strain-induced ring expansion reaction of calix[3]pyrrole solved a long-standing question in porphyrin-related chemistry. Tripyrrolic macrocycles such as calix[3]pyrrole are, even formed, not isolable from pyrrole condensation reaction using acid, because the strain-induced conversion to calix[6]pyrrole is too fast. Besides, this reaction provided a novel approach to ring-expanded calix-type macrocycles.

Figure 1
Coordination Chemistry of Open-Ring Hemiporphyrazines
Authors: Muranaka Atsuya
Published: September 2023

Hemiporphyrazines, phthalocyanine analogues consisting of two isoindoline subunits and two pyridine or other aromatic subunits, have attracted considerable interest not only from the viewpoint of their fundamental properties but also in materials science. Since the first report on hemiporphyrazine about 70 years ago, various types of hemiporphyrazines have been synthesized to date. However, when comparing the rich chemistry of porphyrins and other porphyrinoids, the structural diversity of hemiporphyrazines and azaporphyrinoids is still limited. In particular, much less attention has been paid for acyclic hemiporphyrazines, which is in sharp contrast to many reports on acyclic porphyrinoids. Herein we report synthesis of open-ring hemiporphyrazines and their coordination chemistry. Helical metal complexes (1M
) and dinuclear metal complexes ((2M)2
) were obtained depending on the terminal subunit of the open-hemiporphyrazine ligands. The effects of the central metal ion on molecular and electronic structures will be discussed in the presentation.

Figure 1
Synthesis and Properties of a Fused Antiaromatic Hydrocarbon By Oxidative Transformation of Carbacorrole Analogue
Authors: Ishida Masatoshi
Published: September 2023

Polycyclic aromatic hydrocarbons (PAHs) containing fused pyrrole moieties are known as unique nitrogen-doped pi-conjugated molecules, e.g., azacoronenes, which possess a large π-conjugated planar structure and show rich redox properties. The related molecules are thus expected to be applied to redox-responsible optoelectronic materials. Furthermore, PAH-based compounds containing [4n]π-electron antiaromatic segments, such as pentalene and indacene are contributed to the ambipolar semiconducting material applications due to the distinct high HOMO and low LUMO energy levels.

In this work, we have synthesized and characterized a novel N-doped poly-antiaromatic hydrocarbon (PAH) by the oxidative transformation of a dibenzocarbacorrole isomer, namely, dibenzocorrorin (1). X-ray crystal structure of the fused product (2) revealed a highly planar pi-conjugated structure containing a unique diaza-dicyclopentaazulene moiety. The distinct 12pi antiaromatic resonance structure led to the emergence of a near-infrared band beyond 1000 nm in the absorption spectrum and facile redox properties determined in the cyclic voltammetry. Furthermore, crystalline compound 2 showed carrier mobility in the single-crystal organic field effect transistor.
Molecular Electrochemical Reduction of COx-to-Methanol with Cobalt Phthalocyanines Combined Electrochemical and Spectroscopic Studies
Authors: Robert Marc
Published: September 2023

Reduction of carbon dioxide has as main objective the production of useful organic compounds and fuels - renewable fuels - in which solar energy would be stored. Molecular catalysts can be employed to reach this goal, either in photochemical or electrochemical (or combined) contexts. They may in particular provide excellent selectivity thanks to easy tuning of the electronic properties at the metal and of the ligand second and third coordination sphere. Hybridization of the catalysts with conductive or semi-conductive materials may lead to enhance stability and new catalytic properties, as well as the development of devices (electrolyzers).

Recently, we have found that Co phthalocyanine adsorbed at carbon nanotubes can convert CO2 to CO, and CO to methanol, opening the path to a cascade process for the production of CH3OH. Upon combining electrochemical and spectroscopic studies (IR, XAS), we have uncovered the reasons for such remarkable reactivity. Our most recent results will be discussed, including the insertion of this catalyst into a flow cell.

References

1. E. Boutin, M. Robert et al., Angew. Chem. Int. Ed. 2019, 58, 16172-16176

2. E. Boutin, M. Robert et al. Chem. Eur. J. 2022, e202200697

3. B. Liu, M. Robert et al., submitted
Kinetics of Oxygen Coordination to a Graphite Supported Cobalt Porphyrin
Authors: Hipps K. W. , Johnson Kristen Nicole , Mazur Ursula
Published: September 2023

Single molecule level time-dependent binding of O2 to cobalt(II) octaethylporphyrin [CoOEP] supported on graphite at the solution-solid interface was observed with scanning tunneling microscopy (STM). Using STM movies of the surface and a stochastic kinetic analysis it was possible to extract both the binding and dissociation rate constants for this reversible equilibrium process. This study was the first of its kind and has opened the way for kinetic analysis if reversible surface reactions at the single molecule level by STM methodology. These results are transformative for STM based studies because they demonstrate both the possibility of, and the methodology for, performing kinetic binding studies at the solution solid interface at room temperature.
The on-Surface Supramolecular Chemistry of Porphyrins, Phthalocyanines and Sub-Phthalocyanines: How Shape and Functionalization Change the Game
Authors: Jung Thomas A. , Ahsan Aisha , Sk Rejaul , Heydari Mehdi , Baljozovic Milos , Nowakowska Sylwia K. , Waeckerlin Aneliia , Mousavi Fatemeh S. , Popova Olha , Decurtins Silvio , Stoehr Meike , Waeckerlin Christian , Hill Jonathan P. , Shah Zaman Sameena , Liu Shi Xia
Published: September 2023

By their role in biochemistry, porphyrins have played a central role for “Chemistry beyond the molecule”, long before the term ‘supramolecular chemistry’ has been coined. It is interesting that the bio-chemical functions of porphyrins predominantly derive from the center metal atom, its coordination shell and the coordination-site specific properties. The integration of porphyrins into bio-molecules is safeguarded by covalent chemistry and not ‘supra-molecular’ as such. Nevertheless, square planar porphyrins and pthalocyanines take a decisive role in the development of on-surface supra molecular chemistry: This for their excellent stability and for the many ways they can be functionalized with ligands. Thereby, porphyrin and phthalocyanine chemistry paved the way towards the systematic investigation of many different functional groups known to direct self-assembly and their influence on the formation of on-surface supramolecular layers and chains. I will review the results of on-surface supramolecular assembly experiments performed at the solid-vacuum interface with CN-[1], CN-phenyl, alkoxy [1], fluoro [2] and fluorophenyl [3] and di-methylene-aniline derived functional groups and discuss the supramolecular ordering in terms of estimated binding energies and formation kinetics. It is also interesting to compare the supramolecular ordering in fluids with the constrained ordering of molecules confined to surface substrates. Further insight into the directing power of the individual functional groups derives from a fresh look at the three-fold symmetric pyramidal sub-Phthalocyanines.

Fig. 1) Supramolecular ordering of substituted porphyrins in networks fromed by CN-phenyl interaction: a) and b) show higher magnification micrographs of c) and d) in two different imaging modes emphasizing the pi orbitals (HOMO) and the alkyl substituants, respectively. e) shows the dynamicity of a network from sterically more demanding alkyl-phenyl substituents. (for further details see [1] and references therein)

[1] N. Wintjes et al. J. Am. Chem. Soc. 2010, 132, 7306–7311

[2] J. Girovsky et al. Nature Communications 2017 8:15388

[3] S. Nowakowska et al. ACS Nano 2018, 12, 768−778.

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Synthesis and Formulation of Ternary Transition Metal Dichalcogenide Alloys for Additive Electronic Manufacturing
Authors: Rajabi Kouchi Fereshteh , Valayil Varghese Tony , Eixenberger Josh , Salehi-Khojin Amin , Estrada David
Published: September 2023

Compared with the most investigated graphene, layered transition metal dichalcogenides (TMDs) have received significant attention due to their various chemical compositions and great potential electronic application. In order to tailor and engineer properties of TMDs and therefore enhance their efficiency toward commercial applications, several methods have been employed including reducing dimensionality, creating inter and intra-heterostructures, introducing inter stain, and alloying. Among these, alloying via chemical vapor transport (CVT) is scalable, cost- efficient, and controllable method of tuning TMD bulk crystal properties. Alloying of TMDs can be categorized into several types including metal replacement, dichalcogenide replacement, and both metal and dichalcogenide replacement. In a typical TMD CVT reaction, high-purity precursors are mixed in a desired stochiometric ratio, vacuumed, and sealed in an ampoule to form a closed system. The resulting TMD crystal can then be used for additional processes, e.g., exfoliation to yield 2D TMD nanosheets. Additive electronics manufacturing is a promising technique for the scalable fabrication of electronic devices, including sensors and energy storage devices. For an ink to be compatible for different printing modalities the ink rheology including viscosity, surface tension, and solid requires to be tuned to obtain suitable fluid dynamic parameters for jetting the ink. This work summarizes the development, synthesis, characterization, and formulation of two-dimensional ternary TMDCs ink for aerosol jet printing (AJP) technology. Ball milling assisted liquid exfoliation is utilized for synthesizing ternary TMDs nanomaterials under controlled condition. The resulting nanomaterial is developed into nanomaterial ink compatible with AJP. Detailed analysis of the material characterization and ink properties are required to optimize the fluid dynamics and properties of the ink. After printing the formulated ink using AJP on various substrates, post-printing process techniques is required to be investigated for printed nanomaterials inks to achieve bulk-like performance for the printed structures. Our results highlight the innovations in synthesis and formulation of ternary transition metal dichalcogenide nanomaterial inks for additive manufacturing of electronic devices such as sensors, solar cells, and energy storage devices.
(Invited) Nanocrystalline Ni-W: The Science, Commercialization and Scaling of an Electrodeposited Coating
Authors: Schuh Christopher Allan
Published: September 2023

Nanocrystalline Ni-W alloy coatings deposited using pulse-reverse electrodeposition were studied as a model nanocrystalline material 20 years ago at MIT, and commercialized by Xtalic Corporation in electronic applications beginning in 2008. Under the trade name Xtronic, these coatings provide exceptional wear resistance and barrier protection due to their extremely fine ~10 nm grain size, and have enabled significant reconfigurations of the electronic connector metallization stack in many applications from enterprise to consumer electronics. This talk will review the basic science of the Ni-W alloy system and its ability to deliver these unique properties by virtue of its nanostructure, as well as some of the electrochemical features of the process that enabled its scaling from the laboratory to hundreds of billions of individual metallized contacts. As a case study in the growth of an electrochemical nanotechnology, the talk will also review elements of technology transfer between MIT and Xtalic Corporation that helped facilitate Xtronic’s commercial emergence, including intellectual property management and ongoing basic research.
Carbon Nanotube Based Broadband Solar Thermal Absorber Coatings
Authors: Wang Dan , Hall Timothy , Snyder Stephen , Inman Maria , Taylor E. Jennings
Published: September 2023

Radiant energy conversion and storage eliminate the mass transfer process induced power output limitation, and open a new vista for energy utilization. An effective system for harvesting radiant energy from both solar and thermal radiation will be beneficial for further radiant energy utilization. On the other hand, space observatory missions require low-reflectivity surfaces/coatings for space-borne instruments, such as seeker telescopes, optical sensors, etc., to minimize stray and reflected light on targeted telescope and baffle materials and construction. The excellent optical, thermal, and mechanical properties of carbon nanotubes (CNTs) make them as ideal coating materials for absorbing the broadband spectrum across UV-Vis-IR regions.

In this presentation, Faraday Technology will discuss an innovative electrophoretic deposition (EPD) manufacturing process, based on the use of pulsed electric fields, for controlled, reproducible, scalable deposition of a wide variety of carbon nanotube based coatings across a broad range of substrates, geometries and sizes (Figure 1 a). The effects of waveforms, electrolytes, substrates, etc. on the formation of robust and uniform coating will be discussed in this talk. The optical properties, and environmental survivability of carbon nanotube coatings will be demonstrated via a variety of testing or characterizations. The CNT coatings show the total hemispherical reflection of 0.5% - 1% across UV-Vis to near infrared (NIR) wavebands, which is much lower than the reflectance of the typically used Z306 black paint (Figure 1 b). These CNT coatings also withstood simulated launch conditions vibrational tests, and demonstrated no weight loss and optical degradation. Furthermore, the CNT coatings were evaluated for atomic oxygen erosion resistance in a simulated low earth orbit (LEO) environment, and showed enhanced resilience when compared to Kapton and HOPG. Faraday will also introduce their applications in low-reflective coatings and solar thermal absorbers for radiant energy harvesting and conversion.

In summary, a scalable EPD manufacturing process for fabricating carbon nanotube based coatings have been developed at Faraday for the applications in the field of low-reflective coatings and broadband solar thermal absorbers.

Acknowledgements: The financial support from NASA SBIR program through contracts No. 80NNSC18P2062 & 80NSSC19C0177, DARPA SBIR program through grant No. W31P4Q-22-C-0014, DOD MDA STTR program through grant No. HQ0147-19-C-7065, and DOD Air Force SBIR program through grant No. FA9550-22-P-0015 are acknowledged.

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Anion-Catalyzed Active Dissolution Model for the Electrochemical Adsorption of Bisulfate, Sulfate, and Oxygen on Gold in H2SO4 Solution
Authors: Ghelichkhah Zahed , Srinivasan Ramanathan , Macdonald Digby D. , Ferguson Gregory S
Published: September 2023

Several plausible mechanisms for the potential-dependent adsorption of bisulfate, sulfate, and oxygen on polycrystalline gold in H2SO4 (0.5 M) were evaluated, based on their fit to the experimental potentio dynamic polarization data using the anion-catalyzed active dissolution model (dc portion). The mechanism giving the best preliminary fit was further analyzed by modelling the electrochemical impedance spectroscopy data collected at various dc potentials in the electric double-layer and pre-oxide formation regions. Electrochemical quartz-crystal microgravimetry and optical ellipsometry provided additional evidence verifying the electrochemical adsorption of solution species on the gold surface. Surprisingly, dissolution was observed throughout the whole potential range under study, despite the electrode surfaces developing significant oxygen surface coverages. Key features of the experimental fractional surface coverages and current density were reproduced by the anion-catalyzed active dissolution model.
Influence of Crack Tip Plasticity on the Microstructure and Corrosion Behavior of CA6NM Stainless Steel Measured Using Scanning Electrochemical Cell Microscopy (SECCM)
Authors: Yassine Sarah , Lacasse Robert , Deschênes Pierre-Antony , Brochu Myriam , Mauzeroll Janine
Published: September 2023

The existence of cracks within ductile materials such as stainless steel induces local plasticity around the crack tip that may cause local changes in the microstructure. Although the plastic deformation and microstructural heterogeneities are expected to influence the electrochemistry of the area around the crack tip, few are the studies that correlate the factors- strain and corrosion- together.

In this work, we analyze the corrosion behavior of pre-cracked CA6NM compact tension stainless steel samples taking into consideration the variations in the microstructure resulting from the local plasticity at the tip of a crack. Multiple surface microstructure analysis are obtained to characterize the surface properties of the plastic zone. The localized corrosion behavior around the crack tip is studied using the scanning electrochemical cell microscopy (SECCM) technique. The acquired micro open circuit potential (OCP) and micro potentiodynamic polarization (PDP) curves were used to generate corrosion potential and corrosion current maps of the scanned area. The electrochemical behavior of the crack tip was compared with that in the un-deformed area of the same sample.

The ability to conduct direct electrochemical measurements at microscopic scale through SECCM allows to correlate the localized corrosion behavior to the microstructure analysis obtained before. This work paves the avenue to studying the synergistic effect of fatigue damage on the local corrosion behavior through monitoring both simultaneously.
Predicting Galvanic Corrosion of Aluminum Using Accelerated Laboratory Electrochemical Experiments
Authors: Srinivasan Raghu , Kollo Toomas
Published: September 2023

Aluminum (Al) alloys are the most commonly used non-ferrous metals (approximately 25 million tons per year) for various technical applications and is the second most commonly used metal alloy after steel. Al alloys are also used in combination with other metals or materials to get specific desirable properties for applications such as transportation, construction, electrical appliances, and consumer goods. However, a system of dissimilar materials can lead to potential corrosion problems such as galvanic and crevice corrosion. In this work, atmospheric galvanic corrosion of Al alloy was predicted by combining electrochemical techniques and accelerated laboratory corrosion tests. Three different galvanic couples were analyzed where 6061-T6 Al alloy was coupled with a passivating metal (304 stainless steel), noble metal (copper), and a carbon fiber-reinforced polymer matrix composite (CFR PMC). The galvanic current flowing between the anode and cathode was measured using the zero-resistance ammeter (ZRA) technique in the humidity-chamber setup, cyclic corrosion test chamber following a modified GM9540P cycle, and an outdoor exposure test site. Electrolytes with varying amounts of chloride contents were used to simulate different atmospheric conditions. Four separate equations based on Faraday's law were developed to calculate the corrosion rate in grams per meter square per day (gmd) by relating the time of wetness (TOW) to the galvanic current measured from the accelerated laboratory experiments. The total exposure time was divided into wet periods (Twet) and dry periods (Tdry). The surface morphology of Al samples from the galvanic couples was studied using a scanning electron microscope (SEM), and elemental surface analysis was conducted using energy-dispersive X-ray Spectroscopy (EDXA).

Figure 1