Impact of Nitroxyl Radicals on Photovoltaic Conversion Properties of Dye-Sensitized Solar Cells.

Nitroxyl radicals, characterized by unique redox properties, have been investigated for their potential influence on the photovoltaic conversion properties of dye-sensitized solar cells (DSSCs). In this study, we investigated the influence of nitroxyl radicals as donor sites in DSSCs. We observed that the redox activity of nitroxyl radicals significantly enhanced the photovoltaic conversion efficiency of DSSCs; this finding can offer new insights into the application of these radicals in solar energy conversion.

Circulating Syndecan-1 Levels Are Associated with Chronological Coagulofibrinolytic Responses and the Development of Disseminated Intravascular Coagulation (DIC) after Trauma: A Retrospective Observational Study.

Background: The purpose of this study was to evaluate the association between endotheliopathy represented by high levels of circulating syndecan-1 (SDC-1) and coagulofibrinolytic responses due to trauma, which can lead to disseminated intravascular coagulation (DIC).

Methods: We retrospectively evaluated 48 eligible trauma patients immediately admitted to our hospital and assessed SDC-1 and coagulofibrinolytic parameters for 7 days after admission. We compared the longitudinal changes of coagulofibrinolytic parameters and SDC-1 levels between two groups (high and low SDC-1) according to median SDC-1 value on admission.

Cricotracheostomy for patients with severe COVID-19: A case control study.

Background: Tracheostomy is an important procedure for the treatment of severe coronavirus disease-2019 (COVID-19). Older age and obesity have been reported to be associated with the risk of severe COVID-19 and prolonged intubation, and anticoagulants are often administered in patients with severe COVID-19; these factors are also related to a higher risk of tracheostomy. Cricotracheostomy, a modified procedure for opening the airway through intentional partial cricoid cartilage resection, was recently reported to be useful in cases with low-lying larynx, obesity, stiff neck, and bleeding tendency.

Dynamic coagulofibrinolytic responses under long-term VV-ECMO management without anticoagulation in a COVID-19-ARDS patient: A case report.

Rationale: Venovenous extracorporeal membrane oxygenation (ECMO) is recommended for the treatment of critically ill patients with acute respiratory distress syndrome due to coronavirus disease 2019 (COVID-19). However, ECMO management can cause both bleeding and thrombotic complications. There are insufficient coagulofibrinolytic data for appropriate ECMO management in patients with COVID-19.

Laryngeal complications after endotracheal intubation and prone positioning in patients with coronavirus disease 2019.

Objectives: Laryngeal complications have been reported after endotracheal intubation and prone positioning in patients with critical coronavirus disease 2019 (COVID-19), but their association is unclear. In this study, we investigated the rate of laryngeal complications in patients with COVID-19 compared to an alternative condition (control group).

Methods: We retrospectively analyzed the data of 40 patients who underwent endotracheal intubation for either COVID-19 or an alternative condition (control group).

Thoracoscopic radical surgery for a morbidly obese patient with early lung cancer after laparoscopic sleeve gastrectomy: a case report.

Background: We experienced a case of early stage lung cancer involving a morbidly obese patient. Obesity is associated with a higher incidence of surgical complications. We examined the effectiveness of laparoscopic sleeve gastrectomy as a primary weight loss procedure in a morbidly obese patient who required oncological surgery.

Seebeck coefficients of regioregular poly(3-hexylthiophene) correlated with doping levels.

Thermoelectric properties of regioregular poly(3-hexylthiophene) (P3HT) were investigated in correlation with doping level measured by a potential-step chronocoulometry (PSC) method. It was found that the log-log plot of Seebeck coefficients against doping levels showed a good linearity, whose slope value was around -1.

Impact of the molecular structure and adsorption mode of D-π-A dye sensitizers with a pyridyl group in dye-sensitized solar cells on the adsorption equilibrium constant for dye-adsorption on TiO surface.

D-π-A dyes NI-4 bearing a pyridyl group, YNI-1 bearing two pyridyl groups and YNI-2 bearing two thienylpyridyl groups as the anchoring group on the TiO surface have been developed as dye sensitizers for dye-sensitized solar cells (DSSCs), where NI-4 and YNI-2 can adsorb onto the TiO electrode through the formation of the coordinate bond between the pyridyl group of the dye and the Lewis acid site (exposed Ti cations) on the TiO surface, but YNI-1 is predominantly adsorbed on the TiO electrode through the formation of the hydrogen bond between the pyridyl group of the dye and the Brønsted acid sites (surface-bound hydroxyl groups, Ti-OH) on the TiO surface. The difference in the dye-adsorption mode among the three dyes on the TiO surface has been investigated from the adsorption equilibrium constant (K) based on the Langmuir adsorption isotherms. It was found that the K values of YNI-1 and YNI-2 are higher than that of NI-4, and more interestingly, the K value of YNI-2 is higher than that of YNI-1.

Electrical Characteristics of Pentacene Films on Cross-Linked Polymeric Insulators of Varying Thicknesses.

Pentacene films vacuum-sublimed on a cross-linked polymeric insulator (CPVP-C) prepared using poly(4-vinylphenol) (PVP) and 1,6-bis(trichlorosilyl)hexane (C) were studied with a special concern on possible influences of the CPVP-C thickness on the electrical characteristics of the pentacene films. It was found that the conductivities of the pentacene films on a thin CPVP-C film (10 nm) were approximately 2 orders of magnitude higher than those on a glass substrate and increased slightly with the increase in the thickness of the underlying CPVP-C film. In addition, the X-ray diffraction measurements showed that the stacking structure of pentacene molecules was remarkably enhanced by increasing the thickness of the CPVP-C film, suggesting that the increase in conductivity is due, at least in part, to the improvement in carrier mobilities caused by the growth of large pentacene grains.

Dye-sensitized solar cells based on D-π-A fluorescent dyes with two pyridyl groups as an electron-withdrawing-injecting anchoring group.

D-π-A fluorescent dye with two pyridyl groups as an electron-withdrawing-injecting anchoring group possessing a high coordinate bonding ability to Lewis acid sites on the TiO2 surface, which can lead to high dye loading on the TiO2 film and efficient electron injection, has been developed as a new type of D-π-A dye sensitizer for dye-sensitized solar cells.

Intermolecular distances of carboxylated TEMPO derivatives on TiO2 evaluated by spin-probe ESR.

Nearest-neighbor intermolecular distances of molecules adsorbed on the surface of nanocrystalline TiO(2) particles were evaluated by the electron spin resonance (ESR) technique with molecules having a nitroxide radical and a carboxyl group as a spin probe to clarify their aggregation behaviors on TiO(2) and the influence of coadsorbates.

Development of a simple method for fabrication of transparent conductive films with high mechanical strength.

We have developed a simple method of fabricating transparent conductive films with a high mechanical strength on glass and indium tin oxide substrates. It does not require a large excess of organic solvents and polymerization catalysts and can yield smooth films by spin-coating of a mixture of a commercially available aqueous dispersion of poly(3,4-ethylenedioxythiophene)-poly(4-styrene sulfonate) and a neat liquid of tetraethyl orthosilicate. Preparation conditions such as feed ratio, kinds of additives, and annealing temperature and time were optimized to give highly conductive, transparent and mechanically strong films.

Photophysical and electrochemical properties, and molecular structures of organic dyes for dye-sensitized solar cells.

Dye-sensitized solar cells (DSSCs) based on organic dyes adsorbed on oxide semiconductor electrodes, such as TiO(2), ZnO, or NiO, which have emerged as a new generation of sustainable photovoltaic devices, have attracted much attention from chemists, physicists, and engineers because of enormous scientific interest in not only their construction and operational principles, but also in their high incident-solar-light-to-electricity conversion efficiency and low cost of production. To develop high-performance DSSCs, it is important to create efficient organic dye sensitizers, which should be optimized for the photophysical and electrochemical properties of the dyes themselves, with molecular structures that provide good light-harvesting features, good electron communication between the dye and semiconductor electrode and between the dye and electrolyte, and to control the molecular orientation and arrangement of the dyes on a semiconductor surface. The aim of this Review is not to make a list of a number of organic dye sensitizers developed so far, but to provide a new direction in the epoch-making molecular design of organic dyes for high photovoltaic performance and long-term stability of DSSCs, based on the accumulated knowledge of their photophysical and electrochemical properties, and molecular structures of the organic dye sensitizers developed so far.

Dye-sensitized solar cells based on donor-π-acceptor fluorescent dyes with a pyridine ring as an electron-withdrawing-injecting anchoring group.

A new-type of donor-acceptor π-conjugated (D-π-A) fluorescent dyes NI3-NI8 with a pyridine ring as electron-withdrawing-injecting anchoring group have been developed and their photovoltaic performances in dye-sensitized solar cells (DSSCs) are investigated. The short-circuit photocurrent densities and solar energy-to-electricity conversion yields of DSSCs based on NI3-NI8 are greater than those for the conventional D-π-A dye sensitizers NI1 and NI2 with a carboxyl group as the electron-withdrawing anchoring group. The IR spectra of NI3-NI8 adsorbed on TiO(2) indicate the formation of coordinate bonds between the pyridine ring of dyes NI3-NI8 and the Lewis acid sites (exposed Ti(n+) cations) of the TiO(2) surface.

Fluorescence PET (photo-induced electron transfer) sensors for water based on anthracene-boronic acid ester.

Anthracene-boronic acid ester as a new class of fluorescence PET sensors for detection of a trace amount of water in organic solvents has been designed and developed.

Detection of water in organic solvents by photo-induced electron transfer method.

A new class of fluorescence sensor for detection of water in organic solvents based on photo-induced electron transfer (PET) of anthracene coupled with an amino acid has been designed and developed.

Synthesis and fluorescence and electrochemical properties of D-pi-A structural isomers of benzofuro[2,3-c]oxazolo[4,5-a]carbazole-type and benzofuro[2,3-c]oxazolo[5,4-a]carbazole-type fluorescent dyes.

Heteropolycyclic donor--acceptor (D--A) structural isomers of benzofuro[2,3-c]oxazolo[4,5-a]carbazole-type (2a-f) and benzofuro[2,3-c]oxazolo[5,4-a]carbazole-type fluorescent dyes (3a-f), which differ in the position of oxygen and nitrogen atoms of the oxazole ring, have been synthesized, and their photophysical and electrochemical properties have been investigated. The fluorescent dyes 2a-f exhibit much stronger intramolecular charge transfer (ICT) absorption and fluorescence bands than 3a-f. Both of the D-pi-A structural isomers showed bathochromic shifts of the fluorescence band and a decrease in the fluorescence quantum yields with increasing solvent polarity (i.

Trapping of atomic hydrogens in cage-shaped silsesquioxanes by electric discharge.

A simple and safe technique which is based on glow discharge is demonstrated for stable encapsulation of H atoms in cage-shaped silsesquioxanes at room temperature, leading to the encapsulation yield of ca. 10(-4) H atoms per molecule for 10-minute discharging, much faster than the conventional gamma-ray irradiation technique.

Influence of phenazine structure on polaron formation in polyaniline: in situ electron spin resonance-ultraviolet/visible-near-infrared spectroelectrochemical study.

The role of the phenazine structure in the stabilization of charged states in polyaniline was studied by in situ electron spin resonance (ESR)-UV/vis-near-infrared (NIR) spectroelectrochemistry of polyaniline and the copolymers of aniline and a phenazine derivative (3,7-diamino-5-phenylphenazinium chloride, phenosafranine). It is shown that the copolymer can be prepared by electropolymerization, and its structure was confirmed by mass spectrometry and IR spectroscopy. The electrochemistry of polyaniline and its copolymer pointed to preferred stabilization of a polaron pair in the charged states at the initial charge transfer reaction instead of polarons that are formed by equilibrium reaction at higher electrode potentials.

New four-band electrode fabrication to measure in situ electrical property of conducting polymers.

A simple and renewable four-band platinum electrode for in situ conductivity measurement of polymers is described. A model is developed to evaluate contact resistance between the electrode and polyaniline film and calibrate the film resistances obtained by two-probe and four-probe methods. The conductivity of the film is calculated from the calibrated resistance.

Photovoltaic performance of dye-sensitized solar cells based on donor-acceptor pi-conjugated benzofuro[2,3-c]oxazolo[4,5-a]carbazole-type fluorescent dyes with a carboxyl group at different positions of the chromophore skeleton.

Donor-acceptor pi-conjugated benzofuro[2,3-c]oxazolo[4,5-a]carbazole-type fluorescent dyes 3a, 3b, 8a, and 8b with a carboxyl group at different positions of the chromophore skeleton have been designed and synthesized. The absorption and fluorescence spectra and cyclic voltammograms of the fluorescent dyes agree very well, showing that the position of the carboxyl group has a negligible influence on the photophysical and electrochemical properties of these dyes. When these dyes are used in dye-sensitized solar cells, however, their photovolatic performances are considerably different.

Influences of self-assembled structure on mobilities of charge carriers in pi-conjugated polymers.

Mobilities of charge carriers in cast and spun films of poly(3-hexylthiophene)s (PHTs) with regioregularities of 97%, 81%, 70%, and 54% (denoted as PHT97%, PHT81%, PHT70%, and PHT54%, respectively) are evaluated as a function of doping level. A common feature of mobility vs doping level plots for all the PHT films is that the mobility decreases initially with the increase of the doping level and then starts to rise drastically at ca. 1% doping level.

Synthesis and photophysical properties of two dual oligothiophene-fullerene linkage molecules as photoinduced long-distance charge separation systems.

To further extend photoinduced charge separation previously observed for oligothiophene-fullerene dyads (nT-C60), we have studied two novel dual oligothiophene-fullerene triads, 8T-4T-C60 and 4T-8T-C60, where quaterthiophene (4T) and octithiophene (8T) are linked by a trimethylene chain and either one is attached to a fullerene (C60). The cyclic voltammograms and electronic absorption spectra of these triad compounds indicated no electronic interactions among the three components. On the other hand, the emission spectra were markedly perturbed by electron transfer and/or energy transfer from the oligothiophene to fullerene.

Changes in electrochemical and optical properties of oligoalkylthiophene film induced by bipolaron formation.

An unusual electrochemical response is found for oligoalkylthiophene (13T) films in acetonitrile. A pristine 13T film exhibits a stable redox wave in cyclic voltammogram when the anodic potential limit is below 0.6 V, whereas the redox peaks shift clearly to the negative side by ca.