bluuebunny/crossref_metadata_2025 huggingface dataset:
(Invited, Digital Presentation) High Quality 2-D Materials Characterized Paradoxically from Broad Diffraction Features
Authors: Tringides Michael C
Published: July 2022

Paradoxically a very broad diffraction background, named the Bell-Shaped-Component (BSC), has been established as a feature of graphene growth. Recent diffraction studies as a function of electron energy on Gr/SiC have shown that the BSC is not related to scattering interference. The broad background is in-phase with the Bragg component of both the (00) and Gr(10) spots. Instead textbook diffraction states it should be out-of-phase since it should originate from destructive interference between adjacent terraces[1]. Additional experiments were carried out as a function of temperature over the range 1200° C-1300° C that single-layer-graphene (SLG) grows. Quantitative fitting of the profiles shows that the BSC follows the increase of the G(10) spot, proving directly that the BSC indicates high quality graphene[2]. The BSC has been also seen in graphene on metals including Gr/Ir(111) and on h-BN/Ir(111)[3,4]. Its presence in such a wide range of 2-materials suggests its origin must be general and fundamental, related to their unusual single layer uniformity. The BSC can be a diagnostic of high quality in the growth of other 2-d materials. One possible explanation of the BSC relates to electron confinement within a single uniform layer, according to the uncertainty principle, which generates spread in their wavevector as confirmed with ARPES[5]. The transfer of the large momentum spread to the diffracted electrons to generate the BSC requires better theoretical understanding of the graphene electron-beam electron interaction.

Work in collaboration with P. A. Thiel (deceased), S. Chen, E. Conrad, M. Horn von Hoegen, M. Petrovic, F.-J. Meyer zu Heringdorf

[1] S. Chen, et al.
Phys. Rev. B. 100, 155307 (2019).

[2] S. Chen, et al.
J. Phys. Chem. Lett. 11, 8937 (2020).

[3] K. Omambac et al , Appl. Phys. Lett. 118, 241902 (2021)

[4]M. Petrovic et al
Nanotechnology 32 505706 (2021)

[5] T. Ohta et al.
Phys. Rev. Lett. 98, 206802 (2007).
Rapid Fabrication of Graphene Derived Micro-Supercapacitors on Flexible Substrates Using Millisecond Photothermal Flash Lamp Carbonization
Authors: Bhardwaj Ayush , Okoroanyanwu Uzodinma , Watkins James J.
Published: July 2022

Graphene offers excellent electrical conductivity and very high surface area, which holds great promise for energy storage applications including supercapacitors. Current preparation methods for graphene require relatively long processing times, extremely high temperatures within controlled atmospheres, and/or involve multi-step reactions that present challenges for high throughput fabrication of graphene-based devices. We report a novel photothermal route to large-scale production of graphene within milliseconds using a commercially available benzoxazine polymer and a high intensity xenon flash lamp on various substrates including carbon fiber, Kapton and stainless steel at ambient conditions. The xenon flash lamp provides large-area illumination and a wide emission band (300 nm –1100 nm) that was used to convert the polymeric material directly into graphene upon millisecond exposures. The absorption spectrum of the precursor overlaps well with the maxima of the xenon flash lamp emission spectrum. The precursor material is heated to extremely high temperatures in a fraction of a second – a duration that is much shorter than the timescale for thermal equilibrium. This enables the conversion of the polymeric material to graphene in air and at room temperature, and without thermally damaging the substrate. Characterization of these graphene composites revealed high porosity, excellent conductivity, and good adhesion. Using carbon fiber as the substrate, we prepared micro-supercapacitors exhibiting a very high areal capacitance of 3.2 mF/cm2. Furthermore, we utilized the mechanically and chemically stable graphene/carbon fiber composite as a substrate for the electrochemical deposition of MnO2 which boosted the energy storage capability of the device. The obtained pseudocapacitor has an exceptional capacitance of 300 mF/cm2 at 1mA/cm2. The device retained more than 88% of its capacitance after charging/discharging for 2000 cycles. The preparation of high-quality graphene via photothermal pyrolysis of appropriate precursors is amenable to roll-to-roll processing, and thus large-scale production of electrochemical energy storage devices can be enabled by this approach.

Figure 1
(Invited) Energy Level Alignment at Monolayer MoS2/Electrolyte Interfaces
Authors: Sambur Justin , Austin Rachelle , Farah Yusef , Krummel Amber
Published: July 2022

The fundamental problem that limits the solar energy conversion efficiency of semiconductors such as CdTe and Si is that all excess solar photon energy above the band gap is lost as heat. Avoiding thermalization energy losses is of paramount significance for solar energy conversion because hot-carrier-based systems theoretically achieve 66% efficiency, which breaks the detailed balance limit of 33%.Of all the candidate materials, 2D semiconductors such as monolayer (ML) MoS2 have unique physical and photophysical properties that could make hot-carrier energy conversion possible. The knowledge gap in the field is that the electronic states of 2D materials move with carrier density, due to either light absorption or an applied electrochemical potential. The energy level movements are significant because the real fundamental driving force for charge transfer (ΔG
0´) is unclear for a given reaction and applied potential. In principle, quantifying ΔG
0´ under working conditions opens up the possibility to tune the hot carrier extraction rate relative to the cooling rate. Our research team has employed photocurrent spectroscopy, steady-state absorption spectroscopy, and in situ femtosecond transient absorption spectroscopy as a function of applied potential to characterize underlying steps in a ML MoS2 photoelectrochemical cell. The rich data set informs us on the timescales for hot-carrier generation/cooling and exciton formation/recombination, as well as the magnitudes of changes in exciton energy levels, exciton binding energies, and the electronic band gap. These findings open the possibility of tuning the hot-carrier extraction rate relative to the cooling rate to ultimately utilize hot-carriers for solar energy conversion applications.
Fundamental Charge Transfer Dynamics in 2D TMDCs for Use in Novel Heterostructures
Authors: Myers Alexis , Blackburn Jeff
Published: July 2022

Efficient transfer of charge carriers and/or excitons between small organic molecules and two-dimensional (2D) semiconductor interfaces is being explored for applications in photovoltaics and quantum information processing.

Interfaces of small molecules and 2D semiconductors such as graphene, nanocrystals, quantum dots and transition metal dichalcogenides (TMDCs) are capable of charge, energy, and spin singlet transfer. The long excited state lifetimes of spin triplet excitons makes triplet exciton transfer across such interfaces advantageous for exciton harvesting and photon upconversion. However, to date, triplet energy transfer between physisorbed small molecules and monolayer TMDCs has only been reported in a single study. To our knowledge, the process where photoexcitation of a TMDC/organic interface yields triplet excitons in the TMDC layer has not been reported. In quantum dot (QD) systems, direct covalent attachment of organic molecules to QD surfaces has shown to facilitate triplet energy transfer across the QD/molecule interface, but this covalent approach has not been widely applied to TMDC/molecule interfaces.

Here we present a systematic study of covalently functionalized TMDC/molecule interfaces employing synthetically tailored thiolated acenes. We create tunable amounts of sulfur vacancies, which allows for subsequent covalent acene functionalization. We study the impact of covalent bonding on the charge transfer (CT) dynamics of TMDC/organic interfaces with energy level offsets suitable for charge and energy transfer (ET) as well as triplet acceptance and sensitization. We characterize the interfaces with a variety of steady-state and time-resolved spectroscopic techniques and initial results show success in selective isolation of CT vs ET pathways.

Figure 1
Low Temperature WS2 Metal-Organic Chemical Vapor Deposition Using n-Bunc-W(CO)5
for W Precursor
Authors: Cho Kirito , Machida Hideaki , Ishikawa Masato , Sudoh Hiroshi , Wakabayashi Hitoshi , Yokogawa Ryo , Sawamoto Naomi , Ogura Atsushi
Published: July 2022

Tungsten disulfide (WS2) is one of the representative two-dimensional layered materials, and its applications in various fields have been actively studied due to its preferable properties such as reasonably wide band gap (monolayer: 2.03 eV, bulk: 1.32 eV) [1] and excellent stability. In particular, large area, a few layer WS2 has a high potential as channel material for MOSFET in the next generation LSI. In most of the WS2 CVD reported so far, WF6 or W(CO)6 has been widely used for tungsten precursor as well as H2S for S precursor. However, there are critical problems for the precursors: WF6 is toxic, and W(CO)6 is solid and hard to supply to the reaction chamber. Sublimation supply of solids is not stable in terms of transport volume, and sometime clogging of pipes is also a concern. H2S is also highly toxic.

In this study, a tungsten precursor of n-BuNC-W(CO)5 was investigated for WS2 deposition. One of its favorable characteristics is that it is liquid above 35 °C with stable vapor supply. It is also expected to interact with the substrate efficiently due to its polarity in the molecule. The vapor pressure is 1.2 torr at 115 °C, which is an appropriate for a CVD precursor. As a sulfur precursor, (t-C4H9)2S2 [2], which is non-toxic in contrast to H2S, was employed. WS2 thin films were grown by MOCVD in a cold-wall reactor, using the organic compounds introduced above as precursors for W and S, respectively, on silicon (001) or sapphire (0001) substrates. The deposited films were evaluated by X-ray photoelectron spectroscopy (XPS), Raman spectroscopy (wavelength: 355 nm), and transmission electron microscopy (TEM).

As a result, the continuous films were successfully obtained at the deposition temperature over 250 °C. XPS measurements showed the S/W ratio were slightly larger than the stoichiometric value of two (Fig. 1(a) and (b)). Residual C contamination was significantly reduced by elevating the deposition temperature over 300 °C. The Raman spectra confirmed the film was multi-layer WS2 with peak at 356 cm-1 (E1
2g) and 419 cm-1 (A1g) (Fig. 1(c)). TEM observation also revealed the film had a layered structures as is shown in the typical 2D materials (Fig. 1(d)).

This study was partly supported by JST CREST Number JPMJCR16F4, Japan.

Reference

[1] J. Gusakova, X. Wang, L. L. Shiau, A. Krivosheeva, V. Shaposhnikov, V. Borisenko, V. Gusakov, and B. K. Tay, Phys Status Solidi.
214, 12 (2017).

[2] C. Kirito, K. Yamazaki, Y. Hibino, Y. Hashimoto, H. Machida, M. Ishikawa, H. Sudoh, H. Wakabayashi, R. Yokogawa and A. Ogura, ECS Trans.
104, 3 (2021).

Figure 1
(Invited) Influence of Materials and Processing on Edge Contacts to 2D Semiconductors
Authors: Franklin Aaron D
Published: July 2022

The most common approach for establishing electrical contacts to 2D semiconductors, such as MoS2, is by fabricating metal contacts on top of the inert crystal surface. From an electron transport perspective, these top-contact interfaces can be awkward, with a van der Waals gap or some difficult-to-control form of interfacial bonding. Pure edge contacts (where the interface between the metal and 2D semiconductor occurs completely along the open bonds of the 2D crystal edge) provide a more natural bonding structure and potentially better carrier transport behavior; however, edge contacts have proven more difficult to realize. In this talk, recent success with establishing clean, pure edge contacts between metals and 2D semiconductors will be discussed, including an approach involving an in situ ion beam within a thin-film deposition system. Evaluation of these edge contacts compared to other approaches will be provided, along with demonstration of how edge-contact scaling affects the performance of 2D transistors compared to top-contact scaling. While there remains much to be learned about these interesting metal-2D edge interfaces, results thus far show significant promise for yielding a more scalable and potentially reproducible contact for 2D-based devices.
(Invited) Long-Life Sodium-Sulfur Batteries Enabled By a Localized High Concentration Electrolyte
Authors: Bhargav Amruth , He Jiarui , Shin Woochul , Manthiram Arumugam
Published: July 2022

The high abundance of both sulfur and sodium on earth makes room-temperature sodium-sulfur (Na-S) batteries a low-cost, environmentally benign, sustainable energy storage technology.1 High reactivity and instability of the Na-metal anode and the formation and migration of sodium polysulfides (NaPSs) at the sulfur cathode need to be mitigated to make this technology viable. The root cause of these issues can be the traced to the electrolytes that are conventionally used.

To simultaneously solve the issues mentioned above, we utilize a localized high concentration electrolyte (LHCE).2 LHCE is prepared by diluting a concentrated salt solution with an inert solvent. The resulting unique solvation structure of the electrolyte favors the decomposition of the sodium salt to yield a thin, robust, ion-conducting SEI on both the anode and the cathode. This enables highly efficient and reversible stripping and plating at the Na-metal anode. At the sulfur cathode, this SEI changes the sulfur redox pathway by preventing the formation of NaPSs and steers it towards a quasi-solid-state conversion reaction. These benefits significantly prolong the life of the battery and bring the Na-S technology a step closer to viability.

References

A. Manthiram and X. Yu, Small, 11, 2108–2114 (2015).

J. He, A. Bhargav, W. Shin, and A. Manthiram, J. Am. Chem. Soc., 143, 20241–20248 (2021).

Figure 1
(Invited) Synthesis and Properties of Fluorinated Cubanes
Authors: Akiyama Midori , Sugiyama Masafumi , Komaguchi Kenji , Nozaki Kyoko , Okazoe Takashi
Published: July 2022

Electron acceptor molecules play an important role in the design of organic functional materials. The electron acceptor molecules reported so far are limited to π-conjugated molecules, which stabilize the accepted electrons by delocalizing them in the extended π-orbitals. In contrast, in perfluorocubane, in which eight carbons of the box-shaped molecule are fluorinated, the eight σ* orbitals of the C-F bonds overlap inside the box and are expected to accept and stabilize electrons there.[1] Since perfluorocubane is expected to accept electrons by overlapping σ* orbitals, it will probably show different physical properties from those of π-conjugated electron acceptor molecules.

In the present study, we have succeeded in introducing multiple fluorine atoms into the carbon of cubane derivatives by using an original synthetic technique using fluorine gas,[2] which cannot be used in conventional synthetic organic chemistry. Using this key reaction, perfluorocubane (1), heptafluorocubane (2), and hexafluorocubane (3) were synthesized. Electrochemical and spectroscopic measurements demonstrated that the electron affinity increased with increasing the number of fluorine atoms. Furthermore, the successful observation of perfluorocubane radical anion by ESR measurement will be reported.

[1] Irikura, K. K. J. Phys. Chem. A
2008, 112, 983–988. [2] Okazoe, T. J. Fluorine Chem.
2015, 174, 120–131.

Figure 1
(Invited, Digital Presentation) Synthesis, Aromaticity and Application to OFET and OLED of Peri-Pentacenopentacene
Authors: Mamada Masashi , Jousselin-Oba Tanguy , Wright Karen , Marrot Jérome , Adachi Chihaya , Yassar Abderrahim , Frigoli Michel
Published: July 2022

Recently, there has been increasing interest in a class of polycyclic aromatic hydrocarbons (PAHs) with peri-extension of acenes. These peri-fused systems, referred to as peri-acenes and acenoacenes, are considered to be nanographenes.[1–3] Thus, the compounds based on tetracene and larger acenes show singlet biradical nature at the zigzag edge, offering unique and interesting properties.

However, the synthesis schemes for these compounds are generally complicated, which hinder the extensive development of these derivatives and application to organic optoelectronics such as organic field-effect transistors (OFETs) and organic light-emitting diodes (OLEDs). A pentacene derivative with two triisopropylsilylethynyl groups at the central ring (TIPS-PEN) was developed in 2001. It shows good solubility, stability, and semiconducting property, resulting in being one of the most studied organic semiconductors. In contrast, the peri-extended compound of TIPS-PEN has not been developed because of the difficulty in synthesis using the same method as TIPS-PEN.[4] Here, we found the synthetic conditions to avoid the competition between 1,2- and 1,4-addition of lithium acetylide on large aromatic dione and succeeded in synthesizing TIPS-ethynyl-substituted peri-pentacenopentacene (TIPS-PPP).[5]

The stability of TIPS-PPP was 16 times superior to that of TIPS-PEN, which is attributed to higher aromaticity as shown in an electronic structure of two-fused anthracene. TIPS-PPP shows the crystal packing of the 2D-brickwall motif like TIPS-PEN. The high mobility of up to 1 cm2 V−1 s−1 was obtained in OFET fabricated by wet process owing to large transfer integrals and low reorganization energies. In addition, TIPS-PPP showed high quantum yield in near-infrared (NIR) region. Thus, it was used as an emitter for NIR-OLED devices, resulting in high external quantum efficiency at 800 nm. These results suggest that acene-like materials are very promising for developing NIR emitters.

References

[1] M. Mamada, R. Nakamura, C. Adachi, Chem. Sci.
2021, 12, 552.

DOI: 10.1039/D0SC04699J

[2] T. Jousselin-Oba, M. Mamada, J. Marrot, A. Maignan, C. Adachi, A. Yassar, M. Frigoli, J. Am. Chem. Soc.
2019, 141, 9373.

DOI: 10.1021/jacs.9b03488

[3] Y. Gu, Y. G. Tullimilli, J. Feng, H. Phan, W. Zeng, J. Wu, Chem. Commun.
2019, 55, 5567.

DOI: 10.1039/c9cc01986c

[4] X. Zhang, J. Li, H. Qu, C. Chi, J. Wu, Org. Lett.
2010, 12, 3946.

DOI: 10.1021/ol101720e

[5] T. Jousselin-Oba, M. Mamada, K. Wright, J. Marrot, C. Adachi, A. Yassar, M. Frigoli, Angew. Chem. Int. Ed.
2021,

DOI: 10.1002/anie.202112794.
(Invited) Energy Transfer in Stimuli-Responsive Multiblock Nanofibers from Organic Electronic Materials
Authors: Hudson Zachary M.
Published: July 2022

Techniques for the assembly of hierarchical nanostructures from soft matter have opened the door to many new applications of nanotechnology. Despite these achievements, nanoscale syntheses that rely on self-assembly can be highly dependent on conditions such as solvent and temperature if the integrity of the nanomaterial is to be maintained. Bottlebrush copolymers provide a compelling bottom-up approach to the synthesis of hierarchical nanostructures from soft material, allowing for the preparation of multicompartment structures that remain nanosegregated by virtue of their covalent chemistry. Here we describe methods for the preparation of fiber-like nanomaterials that mimic the multilayer structure of organic electronic devices on individual polymer chains. Narrowly dispersed fibers are prepared from materials commonly used as the hole transport, electron transport, and host materials in organic electronics, with molecular weights on the order of 106 Da. Energy transfer interactions can be regulated by the reversible expansion and collapse of polymer chains, creating dramatic fluorescence changes or activating thermaly activated delayed fluorescence (TADF).
(Invited) Pi-Extended Porphyrins: Synthesis, Functionalization and Applications in Dye-Sensitized Solar Cells
Authors: Wang Hong , Hu Yi , Thomas Michael , Alsaleh Ajyal , D'Souza Francis
Published: July 2022

pi-Extended porphyrins are of broad interest due to their unique combination of photophysical, optoelectronic, and physicochemical properties, and their potential applications in many areas ranging from biomedicine to organic electronics.1,2 In this talk, three series of beta-functionalized push-pull pi-extended porphyrins as sensitizers for dye-sensitized solar cells will be presented.3-5 Our studies show significant push-pull effects for these porphyrins. DFT calculations suggest that the inclusion of ethynylphenyl bridge between the donating group and the porphyrin core significantly segregate the frontier orbitals. It has also been found that dimethylaminophenyl group cause dye decomposition on solar cells. To solve the dye degradation problem, porphyrin dyes with tertiary arylamine groups serving as the donor groups were prepared. Our studies show that tertiary arylamine groups are able to stabilize the dyes adsorbed on the solar cells. Their photovoltaic performances were tested in dye-sensitized solar cells. In this talk, the synthesis and characterization of pentacene-fused (linearly conjugated) and pentaquinone-fused (cross-conjugated) porphyrin oligomers will also be presented.6 These pentacene-fused porphyrins are much more stable than their corresponding pentacene derivatives. The electronic absorption spectra and transit spectroscopy of these porphyrins indicate highly interactive multiple p-systems. The electronic and optical properties of these p-extended porphyrins were measured using UV-Vis spectroscopy, life-time and steady state fluorescence spectroscopy, and cyclic voltammetry. DFT calculations were also performed for these porphyrins.
(Invited) Metalation Effect on Diketopyrrolopyrrole-Tetrabenzoporphyrin Conjugate As p-Type Material in BHJ Organic Photovoltaics
Authors: Vats Ajendra Kumar , Matsuo Kyohei , Yamada Hiroko
Published: July 2022

Organic photovoltaics have attracted much attention for the next generation of photovoltaics. Tetrabenzoporphyrin (BP) is a p-type organic semiconductor characterized as the large, rigid p-framework, excellent stability, and good photoabsorption capability. Because of the low solubility, thermal precursor approach is necessary for the deposition of BP by solution process, where a soluble precursor (CP) of BP is spin-coated on the substrate, followed by annealing of CP film to make BP film by in-situ retro-Diels-Alder reaction of CP.[1,2] In 2017, we reported side-chain engineering for efficient photocurrent generation using a series of diketopyrrolopyrrole (DPP)–tetrabenzoporphyrin (BP) conjugates named Cn-DPP–BP (n = 4, 6, 8 or 10 depending on the length of n-alkyl groups on the DPP unit) as p-type materials in BHJ OPVs in combination with PC61BM as a n-type material by the thermal precursor approach.[3] The comparative study shows that the short-circuit current density largely depends on the length of alkyl substituents, ranging from 0.88 mA cm-2 with C10-DPP–BP to 15.2 mA cm-2 with C4-DPP–BP. C10-DPP–BP in the film is edge-on orientation dominant while that of C4-DPP–BP is face-on orientation dominant.

Encouraged with the results, we synthesized a zinc complex of C4-DPP-CP (C4-DPP-ZnCP) as a soluble precursor of C4-DPP-ZnBP to investigate the effect of metalation of the porphyrin cavity for the BHJ OPV performance. BHJ OPV was prepared by thermal precursor approach: spin-coating of a mixed solution of the precursor, C4-DPP-ZnCP, and PC61BM, followed by annealing at 200 ºC to make a blend film of C4-DPP-ZnBP and PC61BM. Interestingly, the energy gap and ionization potential of C4-DPP-ZnBP film and C4-DPP-BP film are similar to each other, but the Jsc of C4-DPP-ZnBP is 1.5 times larger than that of C4-DPP-BP. We will discuss the relationship between film morphology and OPV performance by studying the blend film of C4-DPP-ZnBP/PC61BM by atomic force microscopy (AFM), X-ray diffraction (XRD) analysis and p-polarized multiple-angle incidence resolution spectrometry (p-MAIRS).

References

H. Yamada, T. Okujima, N. Ono, Chem. Commun. 2008, 2957-2974.

H. Yamada, D. Kuzuhara, M. Suzuki, H. Hayashi, N. Aratani, Bull. Chem. Soc. Jpn.
2020, 93, 1234-1267.

K. Takahashi, D. Kumagai, N. Yamada, D. Kuzuhara, Y. Yamaguchi, N. Aratani, T. Koganezawa, S. Koshika, N. Yoshimoto, S. Masuo, M. Suzuki, K. Nakayama, H. Yamada, J. Mater. Chem. A
2017, 5, 14003-14011.
(Invited) Development of Benzene-Annelated Quinoidal Systems for Acceptor Applications
Authors: Ie Yutaka
Published: July 2022

Quinoidal oligothiophenes have attracted great attention as promising electron-transporting semiconductors. However, the use of quinoidal molecules as nonfullerene acceptors (NFAs) in organic solar cells has not been reported so far. We hypothesized that control of diradical characteristics to fine-tune the electronic properties of quinoidal oligothiophenes is important for the application to NFAs. Since the representative approach to increase the contribution of the quinoid character is the utilization of aromatic stabilization in a quinoidal form, we designed and developed new quinoidal oligothiophenes that contain benzene annelation. As a result, we revealed that quinoidal terthiophenes having fully benzene annelation functioned as NFAs. Furthermore, the quinoidal thiophene 5-mer showed acceptor characteristics in NIR organic phototransistors. In this presentation, we also discuss the influence of benzene annelation on the diradical character and physical properties.
(Invited) Structural Analysis of Organic Semiconducting Materials By Solid State NMR
Authors: Suzuki Katsuaki , Kaji Hironori
Published: July 2022

Recently, our group have successfully developed several blue and green thermally activated delayed fluorescence (TADF) emitters showing high external quantum efficiencies in OLEDs through high-throughput screening based on quantum chemical calculations. Although a number of highly efficient TADF emitters have been reported, the study about their conformation and aggregated structure in an amorphous states, which is expected to be the origin of high device performance, is still limited. Thus we have carried out multiscale simulations and solid-state NMR (ssNMR) analysis of organic amorphous thin films. The ssNMR is one of the powerful technique to acquire the structural information of amorphous aggregated materials, which has been difficult by diffraction techniques due to the lack of long range order for amorphous state. In this presentation, we demonstrate ssNMR analysis of amorphous organic semiconducting materials.

Reference

(1) “Analysis of Molecular Orientation in Organic Semiconducting Thin Films Using Static Dynamic Nuclear Polarization Enhanced Solid-State NMR Spectroscopy”, Suzuki, K.; Kubo, S.; Aussenac, F.; Engelke, F.; Fukushima, T.; Kaji, H. Angew. Chem. Int. Ed. 2017, 56, 14842.

(2) “Efficient blue thermally activated delayed fluorescence emitters showing very fast reverse intersystem crossing”, Ren, Y., Wada, Y., Suzuki, K., Kusakabe, Y., Geldsetzer, J. and Kaji, H.

Appl. Phys. Express, 2021, 14, 071003.

(3) “Solution-processable thermally activated delayed fluorescence emitters for application in organic light emitting diodes”, Suzuki, K.; Adachi, C.; Kaji, H. J. Soc. Inf. Disp.
2017, 25, 480.

(4) “Combined Inter- and Intramolecular Charge-Transfer Processes for Highly Efficient Fluorescent Organic Light-Emitting Diodes with Reduced Triplet Exciton Quenching”, Moon, C.-K.; Suzuki, K.; Shizu, K.; Adachi, C.; Kaji, H.; Kim, J.-J. Adv. Mater.
2017, 131, 6614.

(5) “Triarylboron-based Fluorescent Organic Light-emitting Diodes with External Quantum Efficiencies Exceeding 20%”, Suzuki, K.; Kubo, S.; Shizu, K.; Fukushima, T.; Wakamiya, A.; Murata, Y.; Adachi, C.; Kaji, H.; Angew. Chem. Int. Ed. 2015, 54, 15231.

(5) “Purely organic electroluminescent material realizing 100% conversion from electricity to light”, Kaji, H.; Suzuki, H.; Fukushima, T.; Shizu, K.; Suzuki, K.; Kubo, S.; Komino, T.; Oiwa, H.; Suzuki, F.; Wakamiya, A.; Murata, Y.; Adachi, C. Nat. Commun. 2015, 6, 8476.
Directing Energy and Electron Transfer Processes in Perovskite Nanocrystals
Authors: Kamat Prashant V , DuBose Jeffrey , Kipkorir Anthoni
Published: July 2022

The flow of energy and electron transfer processes in semiconductor nanocrystal based light harvesting assemblies is dictated by the nature of the excited state interactions. Surface interactions of chromophore or redox active molecule which dictate the efficiency of energy/electron transfer thus plays an important role in realizing their photocatalytic and optoelectronic applications. In this presentation we will two specific examples to show the flow of energy and electrons in CsPbBr3 nanocrystals. In the first case, the excited state interactions in the CsPbBr3-Rhodamine B (RhB) hybrid assembly are probed using photoluminescence (PL) and transient absorption measurements. PL studies reveal quenching of the CsPbBr3 emission with a concomitant enhancement of the fluorescence of RhB, indicating a singlet energy transfer mechanism. In the second case we will discuss the factors dictating the electron transfer between CsPbBr3 and surface bound viologen. The implications of electron transfer in photocatalytic applications will be discussed.
(Invited) Functional Materials and Sustainable Process for Commercialization of Perovskite Solar Cells
Authors: Jung Hyun Suk
Published: July 2022

All solid-state solar cells based on organometal trihalide perovskite absorbers have already achieved distinguished power conversion efficiency (PCE) to over 25% and further improvements are expected up to 27%. Now, the research on perovskite solar cells (PSCs) has been moving toward commercialization. To facilitate commercialization of these great solar cells, some technical issues such as long-term stability, large scale fabrication process, and Pb-related hazardous materials need to be solved. Also, flexible perovskite solar cell using plastic substrate can be used in niche applications such as portable electrical chargers, electronic textiles, and large-scale industrial roofing.

This talk is dealing with our recent efforts to facilitate commercialization of perovskite solar cells. For examples, we introduce a recycling technology of perovskite solar cells, which covers the regeneration process of Pb contained perovskite layer as well as recycling process of Au electrodes and transparent conducting oxide glass. Also, simple fabrication technologies for realizing large scale perovskite module are introduced and recent effort for achieving high efficiency module is going to be presented. Precursor technology is of great importance for yielding high efficiency and reproducibility of PSC, which is one of topics in this talk.
(Invited, Digital Presentation) Transformations of Ionic Nanocrystals Via Ion Exchange Reactions
Authors: Teranishi Toshiharu
Published: July 2022

Elaborate chemical synthesis methods allow the production of various types of inorganic nanocrystals (NCs) with uniform shape and size distributions. Then, how can we synthesize NCs with thermodynamically metastable phases or very complex structures? The transformation of already-synthesized NCs via elemental substitutions, such as ion exchange reactions for ionic NCs [1,2] and galvanic replacement reactions for metal NCs [3], can overcome the difficulties facing conventional one-step syntheses. In particular, NC ion exchange reactions have been studied with numerous combinations of foreign ions and ionic NCs with various shapes. The functionality of the resulting ionic NCs, including semiconducting and plasmonic properties, can be easily tuned in a wide range, from the visible to near-infrared. Here we focus on the full and partial ion exchange reactions involving ionic NCs, highlighting important aspects such as the preservation of appearance and dimensions [4,5]. Finally, visible-to-near infrared light energy conversion systems using partially exchanged ionic NCs are provided [6,7].

[1] Saruyama, M.; Sato, R.; Teranishi, T. Acc. Chem. Res.
2021, 54, 765.

[2]Saruyama, M.; Teranishi, T. et al., J. Am. Chem. Soc.
2011, 133, 17598.

[3] Sato, R.; Teranishi, T. et al., to be submitted.

[4] Wu, H.-L.; Teranishi, T. et al., Science
2016, 351, 1306.

[5] Li, Z.; Saruyama, M.; Asaka, T.; Tatetsu, Y.; Teranishi, T. Science
2021, 373, 332.

[6] Lian, Z.; Teranishi, T. et al., Nat. Commun.
2018, 9, 2314.

[7] Lian, Z.; Teranishi, T. et al., J. Am. Chem. Soc.
2019, 141, 2446.
(Invited) Preparation and Characterization of WS2–TiO2–Au Nanohybrid System Using Hydrothermal Synthesis for Photocatalysis Under Visible Light
Authors: Furube Akihiro , Wu Kejun , Pankaj Koinkar
Published: July 2022

We have developed a new visible light responsive photocatalytic material by combining tungsten disulfide (WS2), a nanosheet semiconductor material that has attracted much attention in recent years, gold nanoparticles that strongly absorb visible light, and titanium dioxide (TiO2), a highly active photocatalyst1. Ultrasonic milling and hydrothermal synthesis methods were utilized to successfully synthesize the ternary nanohybrid materials and improve their visible light photocatalytic performance. The mechanism was elucidated based on the detailed characterization of structural properties, spectroscopic properties, photocatalytic reaction properties, and electron transfer reaction dynamics using femtosecond transient absorption spectroscopy.

Reference

Kejun Wu, Pankaj Koinkar, and Akihiro Furube, International Journal of Modern Physics B, 35, 2140046 (2021)
(Digital Presentation) Supercapacitors with Prussian Blue Derived Carbon Encapsulated Fe/Fe3c Nanocomposites
Authors: Kumar Ankit , Das Debanjan , Sarkar Debasish , Patil Satish , Shukla Ashok
Published: July 2022

A one-step synthesis of carbon encapsulated Fe/Fe3C nanoparticles by pyrolyzing single source precursor of Prussian Blue (Iron (III) ferrocyanide) for its usage as anode material in high-performance supercapacitors is reported. The synthetic method produces 3D doughnut shaped porous structures comprising numerous interconnected Fe/Fe3C nanoparticles entirely encapsulated within layers of graphitic carbon. Such a porous structure facilitates electrolytic ion diffusion during charge storage on Fe/Fe3C nanoparticles through surface or near surface- based faradaic reactions, while the metallic iron helps enhancing the electronic conductivity of the electroactive material. Accordingly, the charge storage in such carbon encapsulated Fe/Fe3C nanoparticles is governed by capacitive as well as diffusion-controlled processes at lower scan rates and is taken over by capacitive processes at higher scan rates. The material achieves a specific capacitance of 223 F/g at a scan rate of 10 mV/s along with compelling cycling performance exhibiting a little decay in capacitance over 20000 cycles. When coupled with activated-carbon cathode, Fe/Fe3C//activated-carbon asymmetric supercapacitor out-performs many recently reported supercapacitors, which reflects their potential in next-generation storage applications.
(Digital Presentation) Photopolymerization of Tetraazaporphyrin Based Surfactants and Mesogens
Authors: Eichhorn S. Holger , Rondeau-Gagné Simon , Abdulhamied Elmahdy , Tahir M Nazir
Published: July 2022

Intermolecular interactions between tetraazaporphyrin (TAP) macrocycles are less dominated by π-π stacking interactions than interactions between their larger phthalocyanine derivatives. Consequently, the self-organization and -assembly of TAPs is more widely altered by changes to the type of complexed metal ion and substitution pattern. Presented here are different molecular designs for mesomorphic and amphiphilic TAPs that could be cross-linked by “click” chemistry and by the photo and thermal polymerization of diacetylene groups. All compounds were studied by polarized optical microscopy, thermal analysis, and X-ray diffraction to probe their (meso)phase structures and transitions and by the Langmuir-Blodget method to quantify their interfacial properties. Potential applications for these compounds include their use as active materials in sensors, functional coatings for metal oxide nanoparticles, and building blocks for dye nanoparticles.

Topochemical Polymerization of a Nematic Tetraazaporphyrin Derivative to Generate Soluble Polydiacetylene Nanowires. M. Nazir Tahir, et al., 2019, Langmuir, 35(47) 15158−15167.

Self-organization of Porphyrins and Phthalocyanines in two and three dimensions by S. Holger Eichhorn and Elmahdy Abdulhamied, in “Handbook of Porphyrin Science: Towards Tuned Properties of Porphyrinoids”, Vol. 42, Karl M. Kadish, Kevin M. Smith, Roger Guilard, Eds., World Scientific, Singapore, 2016, 173-232.

Cross-linking of discotic tetraazaporphyrin dyes in 2 and 3 dimensions by “click” chemistry. Himadri Kayal, et al., 2013, J. Mater. Chem. C, 1(42), 7064-7072.

Face- and edge-on orientations of octa-acid and -alcohol substituted tetraazaporphyrins in langmuir and Langmuir-Blodgett monolayers. M. M. Ahmida, et al., 2013, Soft Matter 9 (3), 811-9.
Isoindoline-Based Open Macrocycles
Authors: Ziegler Christopher J.
Published: July 2022

Diiminoisoindoline (DII) continues to be a useful reagent for the synthesis of phthalocyanine-inspired macrocycles and chelate systems. When combined with pyrazole, indazole, and benzimidazole-based heterocycles, DII forms a chelate that can undergo a template reaction at metal sites to produce phthalocyanine analog compounds. These analogs are ring open macrocycles, where the ring either closes via a non-covalent interaction (biliazine and subbiliazine) or forms a helical structure, the new heliphyrin chelates. This talk will present recent developments and the electrochemical properties of these new phthalocyanine analogs, as well as introduce new isoindoline and phthalazine-based bidentate chelates.
Triarylcorrole Vs Octaalkylcorrole: Similar but Different
Authors: Paolesse Roberto , Nardis Saar , Naitana Mario L. , Di Zazzo Lorena
Published: July 2022

The chemistry of corroles is still an open field of investigation able to deliver new and unexpected results especially when they a peculiar reactivity, different from the parent porphyrins.

The genesis of corrole is derived from the Johnson attempt to elaborate a synthetic route for the preparation vitamin B12 and the corrole name is due to the molecular skeleton of this macrocycle, similar to that of the corrin nucleus. The interest on this macrocycle has been boosted by the definition of synthetic routes for the preparation of 5,10,15-triarylcorroles, which make facile to prepare and consequently investigated the chemistry of this macrocycle. As a consequence, the chemistry of b-octaalkylcorroles has been shadowed by the expansion of the triaryl congeners.

However, the chemistry of these two types of corrole show some interesting differences and in this contribution we want to show some examples of this different behavior.
Porphyrin Based Supramolecular Scaffolds
Authors: Weiss Jean
Published: July 2022

The design and synthesis of supramolecular assemblies derived from poprhyrins which are ranging from new hemoprotein models to self-assembled porphyrin wires and functional rotaxanes will be discussed. The properties of wires and light-responsive rotaxanes architectures as well as molecular break junctions derived from phenanthroline and bipyridine strapped porphyrins will be detailed, emphasizing the importance of weak interactions in the design and the properties of functional self-assemblies

Figure 1
Use of Porphyrin Containing Porous Materials in Heterogeneous Catalyst
Authors: Lee Suk Joong , Yoon Jong Ho
Published: July 2022

Due to their potential applications in catalysis, separation, gas storage, drug delivery, and biosensing, porous materials (PMs) such as porous organic polymers (POPs), polymers with intrinsic microporosity (PIMs), porous coordination polymers (PCPs), and metal–organic frameworks (MOFs), have received much attention. Various building blocks have been prepared and demonstrated various functional materials. Among the various organic building blocks, porphyrin has become one of the most important building blocks for the construction of such materials witnessed by a wide range of molecular architectures using porphyrin derivatives with various applications. Mn(III)- and Fe(III)-containing metalloporphyrins are often used to fabricate various functional molecular architectures and to mimic the extraordinary behavior of enzymes in both homogeneous and heterogeneous catalytic systems. In the case of homogeneous catalysis, Mn(III)- and Fe(III)-containing metalloporphyrins have frequent trouble with fast catalytic degradation because of µ-oxo dimer formation or ligand oxidation. To avoid the catalyst degradation, the immobilization and/or site-isolation of homogeneous catalysts using supporters such as polymers, membranes, and MOFs, are widely used strategy. In addition, they are often used to modify the surface of porous silica materials such as SBA-15, MCM-41 and MCM-48, because these porous silica materials exhibit narrow pore size distributions, high thermal stability and easy accessibility.

In this presentation, we like to show the use of metalloporphyrins in various porous materials and their use as heterogeneous catalysts.

References

D. Y. Shin, J. H. Yoon, S. H. Kim, H. Baik, S. J. Lee,* "Immobilization of Porphyrinic Mn(III) Catalyst on a New Class of Silica Support Comprising Three-Dimensionally Interconnected Network with Two Different Sizes of Pores",
Catal. Sci. Technol. 2018, 8, 6306-6310.

J. Yi, H. Y. Jeong, D. Y. Shin, C. Kim, S. J. Lee,* "Mn(III)-Porphyrin Containing Heterogeneous Catalyst based on Microporous Polymeric Constituents as a New Class of Catalyst Support",
ChemCatChem 2018, 10, 3974-3977.

J. Yoon, H. M. Choi, S. J. Lee,* "Cu(II)Cl2 containing bispyridine-based porous organic polymer support prepared via alkyne–azide cycloaddition as a heterogeneous catalyst for oxidation of various olefins",
New J. Chem. 2020, 44, 9149-9152.

H. M. Choi, Y. J. Kim, E. T. Choi, S. J. Lee,*
"Selective Photocatalytic Oxidative Detoxification of a Chemical Warfare Agent Simulant by Porphyrin-Containing Polymers of Intrinsic Microporocity."
ACS Appl. Polym. Mater.2021,
submitted
.
Electrocatalytic Reduction of Furfural Using Single-Atom Molecular Catalysts
Authors: Mukadam Zamaan , Liu Sihang , Scott Søren , Luo Hui , Pedersen Angus , Li Alain , Chan Karen , Titirici Magda , Stephens Ifan Erfyl Lester , Mezzavilla Stefano
Published: July 2022

The electrochemical conversion of bio-based platform chemicals is an effective way of moving away from a crude oil reliant chemical source. Lignocellulosic biomass such as hemicellulose provides a sustainable chemicals source which can yield important platform chemicals including furfural, which can be upgraded into higher valued chemicals for biofuels, renewable polymers, and pharmaceuticals. In this study, we investigate the electrochemical reduction of furfural using Cu and Co single-atom molecular catalysts on carbon electrodes in a mild basic electrolyte (pH 10) for selective production of hydrofuroin, a promising precursor to sustainable drop-in jet fuels. Using density functional theory, we show that the selectivity of furfural reduction products on transition metals could be generally described by the adsorption energies of furfural and hydrogen (Fig 1a). In particular, we predict that the weak-binding molecular catalysts could give rise to a facile reaction path towards coupling product. Based on theoretical calculations, we synthesized Cu and Co-doped phthalocyanines and show that those single-atom molecular catalysts display up to 92% Faradaic efficiency for hydrofuroin production with suppressed hydrogen evolution in pH 10 at -0.50 V vs. the reversible hydrogen electrode (RHE). Combining experiment and theory, we show that the rate-determining step for hydrofuroin formation on single-atom molecular catalysts is the first proton-coupled electron transfer rather than the chemical coupling step. Furthermore, a single-atom molecular design principle is briefly proposed by tuning the adsorption strength of furfural.

Figure 1
Electrosynthesis and Electrochemistry of Porphyrins with Redox Active Substituents
Authors: Osterloh William Ryan , Kadish Karl
Published: July 2022

Electrosynthesis, when combined with classical electrochemical measurements, can often provide unique insights into the mechanism and intermediates involved in formation of the desired product. This is described in the current work which investigates the redox properties of electrosynthesis and electrochemistry of porphyrins with redox active substituents.
Application of Lever’s Electrochemical EL Parameters Scale Toward Fe(II)/Fe(III) Versus Pc(2-)/Pc(1-) Oxidation Process Crossover Point in Axially Coordinated Iron(II) Phthalocyanine Complexes and Its Relation to the MLCT1 Energy Derived from MCD Spectroscopy
Authors: Nemykin Viktor , Nevonen Dustin , Ferch Laura , Osterloh William Ryan , Marx Benjamin , Kadish Karl
Published: July 2022

The electronic structures, and, particularly, the nature of the HOMO in a series of the low-spin PcFeL2, PcFeL′L″, and [PcFeX2]2- iron(II) phthalocyanine complexes were probed by electrochemical, spectroelectrochemical and chemical oxidation approaches and complimented by MCD spectroscopy as well as theoretical (DFT and TDDFT) studies. In general, energies of the metal-centered occupied orbitals in the various six-coordinate iron phthalocyanine complexes correlate well with Lever’s electrochemical parameter, EL, and intercross the phthalocyanine-centered a1u
orbital in several compounds with moderate-to-strong p-accepting axial ligands. In these cases, an oxidation of the phthalocyanine macrocycle (Pc(2-)/Pc(1-)) rather than the central metal ion (Fe(II)/Fe(III)) was theoretically predicted and experimentally confirmed. The experimentally derived using MCD spectroscopy or theoretically predicted using TDDFT calculations energy of the MLCT1 transition (dπ→Pc(π*)) on iron(II) phthalocyanines also follows the trend expected for the EL properties of the axial ligands.
Synthesis and Electrochemical Investigation of π Expanded Vitamin B12 Derivative, Pyrocobester
Authors: Shichijo Keita , Hisaeda Yoshio , Shimakoshi Hisashi
Published: July 2022

Vitamin B12 is a unique metal complex which has the cobalt ion and the corrin as a centered metal and a ligand, respectively. The Co(I) state of the vitamin B12 reacts alkyl halide to form alkylated complex by the SN2 type reaction and proceed the several catalytic reactions via alkyl radicals formed by homolysis of the cobalt-carbon bond.[1] Based on these properties of the vitamin B12, many B12-inspired reactions have been developed.[2] In general, many researchers have used the cobyrinate complex (1) as the B12 derivatives. Here, we report the synthesis and characterization of the Co(II) state of pyrocobseter (2) with π-expanded structure and the reactivities of the complex will be discussed.

The pyrocobester was synthesized by the pyrolysis of the cobyrinate.[3] The absorption of the pyrocobester showed efficiently red-shift compared to the cobyrinate because of the conjugated corrin ligand. Furthermore, Co(II)/Co(I) redox potentials were +0.3 V shifted (Figure 1). In addition, the spectrum was dramatically changed after adding the CH3I as the substrate. It is suggested that Co(I) state of pyrocobester reacted with CH3I and alkylated complex (CH3-Co(III)) was formed. In this presentation, we will report experimental detail of pyrocobester chemistry.

References

[1] D. Gryko et al., Chem. Soc. Rev., 2015, 44, 3391.

[2] H. Shimakoshi, Y. Hisaeda, Chem. Rec., 2021, 21, 2080.

[3] B. Kraütler et al., Helv. Chim. Acta., 1983, 66, 1493.

Figure 1