bluuebunny/crossref_metadata_2025_split huggingface dataset:
(Invited) Novel Technique to Measure Thermal Diffusivity of Soft Crystal in Micro Scale
Authors: Ryu Meguya , Morikawa Junko 
Published: July 2021

To control thermal properties in nano- and micro scale is one of the important topics with regards to the phonon engineering. Recently, the mechanical molecular crystals have been developed, which have the potential applications of actuators and soft robots. Most of the crystal motions are induced by photoisomerization or mechanical stress.
Thermal phase transition and the photothermal effect are considered as the underlying mechanism for the motions, such as bending, twisting, jumping, and rotating, etc., of the mechanical molecular crystals, called soft crystals. However, due to the lack of the measured data of heat transport properties such as thermal diffusivity or thermal conductivity of single crystals in micro volume size, the quantitative analysis of thermal phenomena in the molecular crystals has not yet been quantitatively analyzed. For example, the photo-thermally induced temperature rise produces the localized temperature distribution near the surface, and thermal diffusivity should be utilized to calculate the temperature distribution in the specimen.
To overcome such situation, we propose a micro scale temperature wave analysis (micro-TWA) method to measure the thermal diffusivity of soft crystals in micro scale. (Figure 1) This method enables to measure the axial orientation in single crystals. Furthermore, coupled with the photo-thermal stimulation, the kinetic measurement of thermal diffusivity under the stress induced and photo induced field has been realized. Demonstration of the super elastic phase transition of soft crystal, 3,5- difluorobenzoic acid (3,5−F2bza) and terephthalamide(TPA) will be presented.
This is a proposal of the new measurement method, because the experimental determination of the thermal diffusivity in micro scale of organic single crystals, under operating the deformation control, is still a challenge. The experimental validity is discussed with the theoretical analysis using the reference sample.

Figure 1
Visible Light Driven Hydrogen Evolution Reactions on Plasmonic Cathode
Authors: Minamimoto Hiro , Sato Daiki , Murakoshi Kei 
Published: July 2021

The efficient light energy usage in the chemical reaction system is an important issue in the field of photoelectrochemical region. The visible light induced hydrogen evolution reaction can be recognized as the one of the promising challenges. For the realization of it, the wide-band semiconductor electrode could be the good candidate. However, semiconductor electrodes often have the limitation to the ultraviolet region because of their wide band gap energy. As the breakthrough for it, the introduction of the plasmonic metal nanostructures has been received much attention because the system which is recognized as the plasmonic photoconversion electrode shows the visible light response characters. Up to now, although various systems have been achieved both the cathodic and anodic reactions by the selection of the materials, the molecular process especially on the plasmonic cathode system has not been fully understood yet. In our previous study, we have established the plasmonic photocathode by using the plasmonic nanostructure and the p-type semiconductor electrode [1]. In this system, the holes excited in the metal structures injected into the valence band of the p-type semiconductor and the remained electron are consumed in the hydrogen evolution reaction. It was interesting that, in the pH dependence examination, the photocurrent generations under the neutral condition was comparable to the acidic condition which is the favorable to the hydrogen evolution. This unique property could derive from the unique molecular process influenced by the plasmonic field excitation. In this study, we have attempted to investigate the kinetic isotope effect on the plasmonic cathode system for the clarification of the molecular process on it. Through the various photoelectrochemical measurements, we have confirmed the unique inverse isotope effect on the plasmonic cathode system under the specific condition. Our current research would provide the novel insight for the accurate design of the high efficient light conversion device.
[1] H. Minamimoto et al., Chem. Lett., 2020, 49, 806.
(Invited) Side-Chain Engineering of Small-Molecular Organic Semiconductors for Organic Electronic Devices
Authors: Yamada Hiroko , Suzuki Mitsuharu 
Published: July 2021

Molecular orientation and packing structure of small molecular organic semiconductors are very important for the charge carrier mobility of organic thin-film transistors (OTFT). Furthermore, the miscibility of p-and n-type materials and the grain size of each material in bulk heterojunction are critical for the performance of organic photovoltaics (OPVs). Benzoporphyrins (BPs) are one of the outstanding p-type organic semiconductors and have been studied for OTFT and OPV materials [1]. For practical use of organic electronic devices, solution process is desirable but BPs are not soluble in organic solvents.
To achieve the solution process of BPs, two strategies have been studied in the last two decades. One is a precursor approach: as-spun films of soluble precursors of BPs are in-situ converted into BP thin-films by retro-Diels–Alder reaction. With this method, the film of intact BP is available but the mixed film of edge-on and face-on grains are obtained because of the too-good crystallinity of BPs. The other is a substituent engineering: proper substituents induced to the BP framework can improve the solubility and processability of the film as well as the morphology and orientation of the molecules. Recently we were successful to obtain edge-on dominant film of BP derivatives by a simple dip-coating. 5,15-triisopropylsilyl-ethynyl(TIPS)-BP could make brickwork-type packing to achieve 1.1 cm2 V-1 s-1 FET charge carrier mobility (m
FET) [2].
This side-chain engineering was also effective for the control of packing structure of bulk-hetero junction OPV. The alkyl chain length drastically influenced the miscibility of p- and n-materials and the short-circuit current density [3]. We also found open-circuit-voltage shift of over 0.5 V in organic photovoltaic cells induced by a minor structural difference in alkyl substituents of acene-type p-materials [4]. In this presentation, the relation between control of packing structure and the OPV performance will be discussed.
References
[1] Yamada, H.;* D. Kuzuhara, Suzuki, M.; Hayashi, H.; Aratani, Bull. Chem. Soc. Jpn, 2020, 93, 1234.
[2] Takahashi, K.; Shan, B.; Xu, X.; Yang, S.; Koganezawa, T.; Kuzuhara, D.; Aratani, N.; Suzuki, M.;* Miao, Q.;* Yamada, H.* ACS Appl. Mater. Interfaces, 2017, 9, 8211.
[3] Takahashi, K.; Kumagai, D.; Yamada, N.; Kuzuhara, D.; Yamaguchi, Y.; Aratani, N.; Koganezawa, T.; Koshika, S.; Yoshimoto, N.; Masuo, S.; Suzuki, M.; Nakayama, K.; Yamada, H.* J. Mater. Chem. C., 2017, 5 14003.
[4] Suzuki, M.;* Terai, K.; Quinton, C.; Hayashi, H.; Aratani, N.; Yamada, H.* Chem. Sci.
2020, 11, 1825.
(Invited) In silico Material Design and Realization of Highly-Efficient Organic Light-Emitting Diodes
Authors: Kaji Hironori 
Published: July 2021

Conversion of triplet excitons into light is very important to realize highly efficient organic light-emitting diodes (OLEDs). One solution is the use of transition-metal-based phosphorescent materials.1,2 Thermally activated delayed fluorescence (TADF)3 is another solution. Recently, we have developed various type of excellent TADF emitters using a simple high-throughput screening method. In this talk, I will present the method and the results we have obtained.4-8

The OLED performances are excellent, but further improvements are necessary to overcome efficiency roll-off problem etc. I will also show our recently proposed material design concept,9 named tilted Face-to-Face alignment with Optimal distance (tFFO), to further accelerate reverse intersystem crossing (RISC). Using this design concept, we developed a new material, TpAT-tFFO (Figure), which provided very fast RISC with a rate constant (k
RISC) over 107 s-1.
The results of multiscale charge transport simulations10-13 and dynamic nuclear polarization enhanced solid-state NMR14 will be also presented, if time permits.
We express sincere thanks to my group members, Prof. Adachi, and his group members. This work was supported by JSPS KAKENHI Grant Numbers JP20H05840 (Grant-in-Aid for Transformative Research Areas, “Dynamic Exciton”), JP17H01231, and JP17J09631, and FIRST Program. Computation time was provided by the Super Computer System, Institute for Chemical Research, Kyoto University. NMR measurements were supported by the international Joint Usage/Research Centre (iJURC) at the Institute for Chemical Research, Kyoto University, Japan.

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Figure 1
Achieving Consistent Diffusivity Measurement between GITT and EIS
Authors: Deng Changyu , Lu Wei 
Published: July 2021

Accurate measurement of lithium diffusivity in electrode particles is essential for analyzing and predicting the performance of Li-ion batteries. There are two most widely used techniques: Galvanostatic Intermittent Titration Technique (GITT) and Electrochemical Impedance Spectroscopy (EIS). For GITT, a direct current (DC) pulse is applied to the cell. For EIS, the cell is connected to an alternating current (AC) source. The responses of the batteries are used to calculate diffusivity. GITT and EIS, despite different techniques, measure the same material property and are supposed to yield identical results. However, what has puzzled the community for a long time is that these two techniques often give an order of magnitude difference in the results.
Our research aims to resolve this large discrepancy between these two techniques. By analyzing the diffusion profile and approximation error for various particle geometries, we show that these two techniques are consistent only when the current excitation does not impact deep inside the particles, which corresponds to the condition of short pulse time for GITT or high frequency for EIS. GITT does not depend on particle size by its assumption while EIS does. Thus, we propose an innovative approach to use EIS to determine diffusivity accurately independent of particle size or geometry. We further demonstrate experimentally that the two techniques yield identical results under the right measurement conditions. This work may provide insight on the scattering of measured diffusivity data in literature.

Figure 1
Engineering Cells, Membranes and Light Harvesting/Photosystem II Super-Complexes in Bio-Photoelectrochemical Cells
Authors: Adir Noam 
Published: July 2021

Photosynthetic organisms, membranes and complexes are attractive starting materials for solar energy conversion (SEC). Our overall goal is to develop methods to perform SEC using these materials in simple, inexpensive and a fashion that will be non-polluting and will not compete with the growth of food materials. I will describe here how the remarkable photocatalytic activity of the photosynthetic apparatus can provide overall water splitting with oxygen and hydrogen production in Bio-Photo-Electro-Chemical (BPEC) cells via the simplest and cleanest of processes wither in the absence or presence of added electron transport molecules. With plant thylakoids, electrons are shuttled by FeCN to a transparent FTO electrode, yielding a photocurrent density of 0.5 mA·cm-2. Hydrogen evolution occurs at the cathode at a bias as low as 0.8 V. A tandem cell comprising the BPEC cell with the thylakoid membranes and a Si photovoltaic module achieves overall water splitting with solar to hydrogen conversion efficiency of 0.3% (Pinhassi et al. Nature Communications 2016). With cyanobacterial cells, electrons from the respiratory system are energized by the photosynthetic system and transferred directly to a graphite electrode, utilizing endogenous electron carriers, especially NADPH (Saper et al. Nature Communications 2018 and Shlosberg et al.
iScience 2020). The current produced can be used for hydrogen production at low additional bias for significantly longer durations than the plant thylakoids.
Another route is to use isolated photosynthetic complexes and chemically connect them to the electrochemical cell. One of the issues with this strategy is the small number of light absorbing chromophores connected to the complex, lowering the photochemical efficiency. Connection of isolated light harvesting (LH) complexes can help to overcome this deficiency. Photosystem II (PSII) is the only enzyme that catalyzes light-induced water oxidation being the basis for its application as a biophotoanode in various bio-photovoltaics and photo-bioelectrochemical cells. However, the absorption spectrum of PSII limits the quantum efficiency in the range of visible light, due to a gap in the green absorption region of chlorophylls (500 - 600 nm). To overcome this limitation, we have used two strategies: stabilizing the interaction between PSII and Phycobilisomes (PBSs) –LH complex or direct connection to modified gold-nanoparticles (Au-NPs) that serve both as LH and electron conduit. Integration of the PBS-PSII super-complexes within an Os-complex-modified hydrogel on macro-porous indium tin oxide electrodes (MP-ITO) resulted in notably improved, wavelength dependent, incident photon-to-electron conversion efficiencies (Hartmann et al. J. Mat. Chem. A. 2020). With the Au-NPs, record currents were obtained, with strong improvement in the SPR range of wavelengths that are not absorbed by chlorophylls.
Design, Synthesis and Characterization of Molecular Components for Light Induced Molecular Machines
Authors: Bayard Brandon 
Published: July 2021

Molecular machines are systems of molecules that convert chemical energy into mechanical forces. They have a range of potential applications such as transportation of chemicals or use as an arity signal for computation. In literature, most molecular machines are activated through some form of chemical signal. This has a range of drawbacks from limiting the range of environments the machine can function in to the buildup of byproducts of the chemical reaction. The solution to these limitations was found in the synthesis and characterization of various light induced molecular machines. Like the name implies, this subset of molecular machines uses light as the signal that activates the mechanism. The model of molecular machine being worked on in this research is a porphyrin-based molecular shuttle shown in scheme 1.
Upon photoexcitation of the porphyrin acceptor, represented by the symbol A, an electron transfer from naphthyl group to the porphyrin occurs. Following this photoinduced electron transfer, a radical pair is formed between the porphyrin and naphthyl group. The newly generated naphthyl cation is expected to drive the macrocycle situated around the naphthalene towards the aryl group due to the more favourable interactions. Upon relaxation of the radical pair through back electron transfer, the macrocycle is expected to return to the naphthalene group due to the regeneration of the electron density on the naphthyl group. In this context, novel molecular machine components have been synthesized and characterized using various spectroscopic and electrochemical techniques. The goal of which, is to fine tune the chemical, physical and synthetical properties such that they are suitable for future use in a complete molecular machine as described in scheme 1.

Figure 1
Functionalized Corroles for Sensor Applications
Authors: Paolesse Roberto , Nardis Sara , Caroleo Fabrizio , Di Zazzo Lorena , Mandoj Federica , Magna Gabriele 
Published: July 2021

Corrole continues to attract the interest of different research groups, since this macrocycle shows peculiar and intriguing characteristics, which open its application in different fields.
In the last few years, we have been interested to exploit corrole derivatives as receptors in chemical sensors, because the peculiar coordination chemistry of this contracted macrocycle can allow the preparation of optimized cross sensitive sensor arrays.
For this reason, the functionalization of the corrole is a fundamental step for the optimization of the macrocycle features for the target application.
We have been interested in the introduction at the peripheral positions of the corrole ring of different substituents, because they can allow the preparation of hybrid materials. These hybrid materials have been successfully exploited to develop chemical sensors.
The characterization of these species, together the applications of the functionalized corroles will be presented and discussed.
Solar Energy Conversion Schemes: Photon- and Charge-Management
Authors: Guldi Dirk 
Published: July 2021

In Nature, energy and electron transfer processes in the photosynthetic machinery following light absorption have been perfectionated. To mimic the aforementioned, that is, efficiently utilizing light to separate charges and, in turn, to generate solar fuels, a great variety of multicomponent artificial photosynthetic systems have been designed and synthesized. Incentives for the design build around molecules have been taken from Nature: For example, implementing suitable electrochemical gradients across arrays of several molecular building blocks have enabled the unidirectional transformation of solar energy into electrical energy. A key parameter is the right balance between the reduction / oxidation strengths of the individual building blocks and their spatial arrangements. Both affect the thermodynamic driving forces for each step and, in turn, the overall efficiency. Notably, acceptor-donor1-donor2 or acceptor-donor1-donor2-donor3 types of artificial photosynthetic systems have been reported. Besides an initial charge transfer, charge shifts take place via oxidative electron transfers from donor1 to donor2 and, eventually, to donor3.
Considering the effectiveness of multicomponent systems, in which photoexcitation triggers a cascade of short range electron transfers, we report on two sets of novel multicomponent DA1A2s – Figure 2. These DA1A2 types feature electron transport chains with C60 and C70 of different electron acceptor strengths to create an electrochemical gradient. As a complement to electron accepting C60 / C70 either zinc porphyrins (ZnP) and zinc phthalocyanines (ZnPc) were employed. The motivation for our pump-probe investigations was to establish the role of ZnPc or ZnP as light harvester and electron donor to power unidirectional (reductive) charge shift reactions along a variety of electron transport chains.
In summary, we will demonstrate the control over unidirectional charge shift along electron transport chains en route towards highly energetic, long-lived charge separated states. Key is, however, a charge shift mediating state, whose relative energy determines the overall efficiency. If the energy of the mediating state, on one hand, is higher than the charge separated state, resonance conditions enable efficiencies as high as 50%. If the energy, on the other hand, is lower than the charge separated state, deactivation to the ground state limits the efficiency to 10%.
Development of Efficient Sensitizers Based on Porphyrin Dimers and Fused Porphyrins for Dye-Sensitized Solar Cells
Authors: Higashino Tomohiro , Imahori Hiroshi 
Published: July 2021

In recent years, dye-sensitized solar cells (DSSCs) have attracted much attention as an alternative to silicon-based solar cells owing to their low-cost production and high power-conversion efficiency. Porphyrin sensitizers have made remarkable contribution to performance improvement in DSSCs. The push–pull type porphyrin sensitizers have displayed excellent light-harvesting ability and demonstrated high power conversion efficiencies more than 10% in DSSCs.
We have designed and synthesized various porphyrin sensitizers and evaluated their photovoltaic performances of the dye-sensitized solar cells. Recently, we reported a general synthetic strategy for ABC-ABC-type meso-meso linked porphyrin dimers. A meso-meso directly linked donor-π-acceptor (D-π-A) type porphyrin dimer was prepared and exhibited the high power conversion efficiency. Furthermore, we succeeded in design and synthesis of substituted methylene-bridged thiophene-fused porphyrins. The DSSC with the thiophene-fused porphyrin sensitizer achieved the highest power conversion efficiency ever reported for DSSCs with fused porphyrin sensitizers, which is comparable to that of DSSC with GY50, a representative high-performance push-pull type porphyrin sensitizer.