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Antimony-based perovskite-inspired materials (PIMs) are solution-processable halide absorbers with interesting optoelectronic properties, low toxicity, and good intrinsic stability. Their bandgaps around 2 eV make them particularly suited for indoor photovoltaics (IPVs). Yet, so far only the fully inorganic Cs3Sb2ClxI9−x composition has been employed as a light-harvesting layer in IPVs. Herein, the first triple-cation Sb-based PIM (CsMAFA-Sb) in which the A-site of the A3Sb2X9 structure consists of inorganic cesium alloyed with organic methylammonium (MA) and formamidinium (FA) cations is introduced. Simultaneously, the X-site is tuned to guarantee a 2D structure while keeping the bandgap nearly unchanged. The presence of three A-site cations is essential to reduce the trap-assisted recombination pathways and achieve high performance in both outdoor and indoor photovoltaics. The external quantum efficiency peak of 77% and the indoor power conversion efficiency of 6.4% are the highest values ever reported for pnictohalide-based photovoltaics. Upon doping of the P3HT hole-transport layer with F4-TCNQ, the power conversion efficiency of CsMAFA-Sb devices is fully retained compared to the initial value after nearly 150 days of storage in dry air. This work provides an effective compositional strategy to inspire new perspectives in the PIM design for IPVs with competitive performance and air stability. publishedVersion

In this study, a nanocellulose-based material showing anisotopic conductivity is introduced. The material has up to 1000 times higher conductivity along the dry-line boundary direction than along the radial direction. In addition to the material itself, the method to produce the material is novel and is based on the alignment of cationic cellulose nanofibers (c-CNFs) along the dry-line boundary of an evaporating droplet composed of c-CNFs in two forms and conductive multi-walled carbon nanotubes (MWCNTs). On the one hand, c-CNFs are used as a dispersant of MWCNTs, and on the other hand they are used as an additional suspension element to create the desired anisotropy. When the suspended c-CNF is left out, and the nanocomposite film is manufactured using the high energy sonicated c-CNF/MWCNT dispersion only, conductive anisotropy is not present but evenly conducting nanocomposite films are obtained. Therefore, we suggest that suspending additional c-CNFs in the c-CNF/MWCNT dispersion results in nanocomposite films with anisotropic conductivity. This is a new way to obtain nanocomposite films with substantial anisotropic conductivity. publishedVersion

The O,O-silyl group migrations on a quinic acid-derived cyclitol have been studied, and the ease of migration was observed to be dependent on the silicon substituents and reaction conditions. Conditions were found to improve the formation of a main isomer during the O,O-silyl group migrations that could be integrated into the formal synthesis of vitamin D receptor modulator VS-105 and in the first total synthesis of a metabolite from the African ant Crematogaster nigriceps. acceptedVersion

The excited-state properties of an amphiphilic porphyrin-fullerene dyad and of its porphyrin analogue adsorbed at the dodecane/water interface are investigated by using surface second-harmonic generation. Although the porphyrin is formally centrosymmetric, the second-harmonic spectra of both compounds are dominated by the intense Soret band of the porphyrin. Polarization-selective measurements and molecular dynamics simulations suggest an angle of about 45° between the donor-acceptor axis and the interfacial plane, with the porphyrin interacting mostly with the nonpolar phase. Time-resolved measurements reveal a marked concentration dependence of the dynamics of both compounds upon Q-band excitation, indicating the occurrence of intermolecular quenching processes. The significant differences in dynamics and spectra between the dyad and the porphyrin analogue are explained by a self-quenching of the excited dyad via an intermolecular electron transfer.

Photoinduced intra- and interlayer electron transfer (ET) of doubly bridged donor–acceptor molecule, porphyrin–fullerene dyad (PF), was studied in single- and multi-layered Langmuir–Schäfer (LS) films and in LS films, where PF and an efficient electron donating polymer polyhexyltiophene (PHT) formed a bilayer PHT/PF and multi-layered PHT/PF structures. The ET through layers were investigated by a method, which measures the photovoltaic (PV) response proportional to the number of charge-separated (CS) states and to the CS distance between the electrons and holes formed in pulsed photo-excitation. Primary conclusions were, that ET starts as formations of CS dyads (P+F−) in single-layers, continues as long-range intra-layer charge migrations following interlayer CS between two adjacent monolayers. Quantitative conclusions were, that the interlayer ET efficiency is 100% in the bi-layered PF structure (2PF), where two CS dyads in adjacent layers forms CS complexes (P+F/PF−) and that the probability to form longer or higher order of CS complexes follows an expression of a convergent geometric series, with a converting factor of 2/3. In the PHT/PF bilayer structure the ET efficiency was one order of magnitude higher, than that for the 2PF structure due to the ET from the CS dyads to ground state electron donor PHT, with an acceptor density, much higher than that of (P+F−). acceptedVersion

For long-term live-cell fluorescence imaging and biosensing, it is crucial to work with a dye that has high fluorescence quantum yield and photostability without being detrimental to the cells. In this paper, we demonstrate that neutral boron-dipyrromethene (BODIPY)-based molecular rotors have great properties for high-light-dosage demanding live-cell fluorescence imaging applications that require repetitive illuminations. In molecular rotors, an intramolecular rotation (IMR) allows an alternative route for the decay of the singlet excited state (S1) via the formation of an intramolecular charge transfer state (CT). The occurrence of IMR reduces the probability of the formation of a triplet state (T1) which could further react with molecular oxygen (3O2) to form cytotoxic reactive oxygen species, e.g., singlet oxygen (1O2). We demonstrate that the oxygen-related nature of the phototoxicity for BODIPY derivatives can be significantly reduced if a neutral molecular rotor is used as a probe. The studied neutral molecular rotor probe shows remarkably lower phototoxicity when compared with both the non-rotating BODIPY derivative and the cationic BODIPY-based molecular rotor in different light dosages and dye concentrations. It is also evident that the charge and localization of the fluorescent probe are as significant as the IMR in terms of the phototoxicity in a long-term live-cell imaging. Graphical abstract

Studies of extracellular vesicles (EVs), their trafficking and characterization often employ fluorescent labelling. Unfortunately, little attention has been paid thus far to a thorough evaluation of the purification of EVs after labelling, although the presence of an unbound dye may severely compromise the results or even lead to wrong conclusions on EV functionality. Here, we systematically studied five dyes for passive EV labelling and meticulously compared five typical purification methods: ultracentrifugation (UC), ultracentrifugation with discontinuous density gradient (UCG), ultrafiltration (UF), size exclusion chromatography (SEC), and anion exchange chromatography (AEC). A general methodology for evaluation of EV purification efficiency after the labelling was developed and tested to select the purification methods for the chosen dyes. Firstly, we found that some methods initially lead to high EV losses even in the absence of the dye. Secondly, the suitable purification method needs to be found for each particular dye and depends on the physical and chemical properties of the dye. Thirdly, we demonstrated that the developed parameter

Triplet-triplet annihilation upconversion (TTAUC) is a power density-dependent process where photons of low energy are transformed into high energy ones. The most important attributes of efficient TTAUC are quantum yield φTTAUC, power density threshold Ith (photon flux at which 50% of φTTAUC is achieved), and the upconversion shift of emitted photons (anti-Stokes shift). To date, approaches to balance these parameters have remained unclear. Herein, the cumulative effect of sensitizer triplet lifetime (τ0 S), sensitizer-annihilator triplet energy gap (ΔET), and the total concentration of the sensitizer on the power density threshold at high TTAUC quantum yields is evaluated experimentally using Pt, Pd, and Zn tetraphenylporphyrin derivatives and a tetra-tert-butylperylene annihilator, and by kinetic rate modeling. The results suggest that a large energy gap (ΔET ≥ 4 kBT) and long sensitizer triplet lifetime make the triplet-triplet energy transfer (TTET) extremely efficient and allow the utilization of high sensitizer concentrations for low Ith. However, for large upconversion shifts, the triplet energy gap should be as small as possible. Smaller energy gap values result in slower forward TTET and faster reverse TTET, which together with high total sensitizer concentration can lead to a quenching of annihilator's triplet state and therefore elevate the Ith. In this regard, low concentration of a sensitizer is beneficial, making sensitizers with high molar extinction coefficients preferential. Sensitizers with a long living triplet state and a high molar extinction coefficient can work efficiently and have low Ith at 0 kBT or even negative ΔET. Kinetic rate modeling further helps to optimize the parameters for best possible TTAUC performance. Thus, the findings of the study pave the way for the design of TTAUC systems with superior performance, such as high φTTAUC at low excitation power densities with large anti-Stokes shift, for, for example, solar-driven photovoltaics, photocatalysis, bioimaging, and safe light-triggered drug-delivery systems. publishedVersion

Zn phthalocyanine with improved synthesis suitable for bulk production shows extremely high antimicrobial efficacies even under weak indoor light. The dye-impregnated cellulose material inactivates over 99.996% of drug-resistant C. albicans, S. aureus and E. faecalis in just one hour exposure with consumer-grade fluorescent lamps and diodes. publishedVersion

Reduced graphene oxide (rGO) integrated nano-fibrillated cellulose (NFC) grafted poly(ionic liquid) (PIL) composite paper with enhanced hydrophobicity, ductility and toughness was fabricated by vacuum filtration of an aqueous dispersion of rGO/NFC-graft-PIL (NFC-g-PIL). The NFC-g-PIL was synthesized by growing PIL chains from the NFC surface using free radical polymerization of a pyridinium acrylate-based ionic liquid monomer. publishedVersion

Contemporary world with constantly increasing speed of change and rapid development of technologies is challenging companies to accustom to existing complexity. This led to the fact that various methodologies change accordingly. Practitioners and researchers are seeking the ways to ameliorate processes using emerging technologies. One of the methodologies is Six Sigma that has always been connected with technologies necessary for data collection and analysis. The emergence of new technologies might benefit or challenge Six Sigma. In this paper an attempt has been performed to analyze the trends in research output of the conjunction of Industry 4.0 technologies and Six Sigma methodology. This paper is based on the bibliometric analysis. In the process of analysis, it was found that the combination of Six Sigma methodology and Industry 4.0 technology has positive potential, however, not all of the technologies have been analyzed., Internal Grant Agency of Tomas Bata University in Zlin [IGA/FaME/2020/009]; znalostni informacni systemy jako podpora podniku v Industry 4.0"

Four clay materials, namely, bentonite, bleaching earth, attapulgite and sepiolite, were shaped into the cylindrical body by extrusion. Clays were characterized in depth by TEM, SEM-EDX, N2 physisorption, pyridine FTIR, pH measurements, contact angle measurements, 27Al MAS NMR, and the crush test. Catalytic properties were investigated in the citronellal cyclization as a model reaction. The reaction was performed in the trickle-bed reactor at 70 °C, 10 bar of Ar with 0.086 M initial citronellal concentration in cyclohexane. The best results were obtained over attapulgite with isopulegols yield of 24% and stereoselectivity to the desired isopulegol isomer of 61%. Attapulgite had the highest meso-to-micropore volume ratio, the highest basicity, a low Brønsted-to-Lewis acid sites ratio, and the lowest amount of Brønsted acid sites compared to other extrudates. In addition, same clay exhibited the highest mechanical strength of extrudates. publishedVersion

Correction for ‘Addressing challenges in the removal of unbound dye from passively labelled extracellular vesicles’ by Kaisa Rautaniemi et al., Nanoscale Adv., 2022, DOI: 10.1039/d1na00755f.

The properties and antimicrobial efficacies of zinc complexes of tetrakis(N-methylpyridinium-4-yl) tetraiodide porphyrin and tetrakis(N-methylpyridinium-4-yl) tetraiodide phthalocyanine impregnated to paper were evaluated. Photo-inactivation of microbes using inexpensive consumer light-emitting diode lamp was assessed on surface of dyed papers. Antimicrobial experiments of phthalocyanine-dyed paper by live cell assessment through colony forming units counting demonstrated 3.72 and 4.01 log reduction against Escherichia coli (E. coli) and Acinetobacter baylyi (A. baylyi) respectively after 1 h of illumination with 35 mW/cm2 light. The porphyrin-dyed paper exhibited 1.66 and 2.01 log reduction in colony forming units against E. coli and A. baylyi respectively after 1 h exposure with 4 mW/cm2 light. Both dyed papers were photo-stable after 64 h of continuous exposure with 42 mW/cm2 light, while phthalocyanine-dyed paper exhibited superior leaching stability in phosphate-buffered saline.

The pulp and paper industry together with lignocellulosic biofuel production provides plentiful streams of lignin and lignin-derived molecules (LDMs) that currently remain underutilized. The heterogeneity and complexity of lignin along with the lack of convenient tools significantly hamper its utilization. Selective separation of these LDMs from streams using specific tools would allow the recovery of aromatic compounds, as well as facilitate biological processes aiming at lignin valorization. To this end, here we report the isolation and characterization of single-chain variable fragment (scFv) antibodies against ferulate, coumarate, and caffeate, which are the molecular representatives of LDMs. Binders for the target LDMs were enriched by interrogating a synthetic scFv library with the phage display technique. As a result, scFv binders specific against each of the target molecules were obtained with affinities in the micromolar range. The selectivity of scFvs towards specific LDMs was proved by recovering caffeate from simulated LDM solution, Kraft lignin, and rice straw hydrolysate samples. Further proof of concept studies with model compounds demonstrated the applicability of antibody-based binders as a detection tool for monitoring microbial LDM conversion. Overall, this study demonstrates the potential of scFv binders as a specific toolset for lignin compound recovery and analysis. publishedVersion

Polyurethane/polyhydroxyurethane (PU/PHU) hybrid materials are potential alternatives to PU materials in adhesive use, when the user needs to be protected from free di-isocyanates. PU/PHU materials have promising mechanical and adhesive properties, but they are susceptible to a higher water uptake than corresponding PU materials. In adhesive use, water and temperature are typically responsible for environmental ageing, which can cause unexpected bond failure. Therefore, the effect of water uptake on mechanical and adhesive strength is crucial. In this study, the water uptake of PU/PHU at various temperatures was studied and the contribution of absorbed water to material properties was investigated. The highly crosslinked amorphous PU/PHU was synthesized from a multifunctional polyethyleneimine (PEI) and a cyclic carbonate terminated prepolymer made from a hexamethylene di-isocyanate (HDI) based isocyanate prepolymer. High water uptake of PU/PHU originated from the hydrophilic amine used as well as the pendant hydroxyl groups in the hydroxy urethane. After the high initial water absorption, a quasi-equilibrium was reached at room temperature. Water immersion at elevated temperature introduced a second water absorption step which eventually caused PU/PHU to become a water-soluble gel. Considering the potential applications of PU/PHU, the cohesive strength had increased after water immersion cycles, but the adhesive strength was irreversibly reduced resulting in total bond failure after five water immersion cycles. In contrast, longer storage at dry elevated temperature improved the cohesive and adhesive strength. Thus, a careful design of the application is required for PU/PHU adhesives to fully utilize the advantage of the high lap shear strength in dry condition.

We have synthesized novel phthalocyanine with four pyridyl substituents connected to α-phthalo-positions via direct C-C bond. The Zn complex and tetracationic derivatives of phthalocyanine were also synthesized and the dyes were impregnated into filter paper to prepare photoactive antimicrobial surface. The photodynamic antimicrobial efficacy of the dyed paper samples was evaluated by a simple and fast setup using bioluminescent microbes. Escherichia coli and Acinetobacter baylyi ADP1 strains carrying bacterial luciferase genes were used in the screening experiment. The most efficient compound, tetracationic zinc derivative 8, was investigated further. The compound was highly water soluble, had high molar absorptivity and exhibited good adhesion to the filter paper without leaching into the solution. The singlet oxygen quantum yield of tetracationic zinc derivative 8 in water was found out to be 30 ± 20%. According to the cell viability assay test performed on E. coli wild type in solution, the molecule had similar or better photo toxicity as the reference photosensitizer, tetrakis (1-methyl-pyridinium-4-yl)porphyrin (TMPyP). Antimicrobial efficacy of the dye 8 on photoactive surface was studied by live cell assessment through colony forming unit (CFU) counting. The colored surface demonstrated 3 log reduction in CFU against E. coli and A. baylyi ADP1 just after 1 h of illumination with the white light of low intensity.

Novel monoisomeric perylene imide derivatives with terpyridinyl and pyrrolidinyl substituents were synthesized and deposited onto solid substrates, such as a thin film of Al2 O3 and mesoporous TiO2 nanoparticle layer, by using a simple dip-by-dip method. Arrays of up to 33 layers were built on Al2 O3 . In the case of mesoporous TiO2 , the interstitial volume between the particles was filled up with dye assemblies. Deposition could produce either layers of microcrystals or molecular layers if an appropriate washing procedure was used. The resultant arrays were studied by means of scanning electron microscopy, X-ray photoelectron spectroscopy measurements, and UV/Vis absorption.

The preparation of weblike titanium dioxide thin films by atomic layer deposition on cellulose biotemplates is reported. The method produces a TiO2 web, which is flexible and transferable from the deposition substrate to that of the end application. Removal of the cellulose template by calcination converts the amorphous titania to crystalline anatase and gives the structure a hollow morphology. The TiO2 webs are thoroughly characterized using electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy to give new insight into manufacturing of porous titanium dioxide structures by means of template-based methods. Functionality and integrity of the TiO2 hollow weblike thin films were successfully confirmed by applying them as electrodes in dye-sensitized solar cells.

A green-to-blue triplet-triplet annihilation upconversion of 24.5% quantum yield was achieved at a remarkably low 600 μM annihilator concentration in a viscous polymer matrix. This was made possible by utilizing a ZnTPP-based photosensitizer with exceptionally long 11 ms phosphorescence lifetime. Higher 3 mM annihilator concentration resulted in lower 24% upconversion quantum yield. acceptedVersion

Formation of self-assembled monolayers (SAMs) of three porphyrin and one phthalocyanine derivatives on thin ZnO film was studied by monitoring absorption spectra of the samples. The compounds were equipped with carboxylic or phosphate groups to bind to the surface. The SAM formation was found to be fast. The layer was formed in less than 15 min for all studied porphyrins, and 30 min was sufficient to form phthalocyanine layer. For porphyrins with different anchor groups the SAM formation was too fast to see any difference between the anchoring groups. The stability of SAMs was tested then by immersing the samples into neat solvents. Upon immersion the SAMs were gradually losing the absorbance for all the compounds with degradation trends being in line with p[Formula: see text] values of the binding groups of the same type. However, even for the weakest binding group the SAM was relatively stable after a few tens of minutes of washing, which was sufficient to remove physisorbed compounds but the SAM was essentially not destroyed. Comparison of SAMs on thin films with SAMs on ZnO nanorods and TiO2 nanoparticle films indicated the same fast layer formation but relatively weaker SAMs stability, showing 20–40% faster absorption losses during the washing.

The photoinduced electron transfer processes were studied for hybrid systems consisting of self-assembled monolayer of zinc phthalocyanine (ZnPc) assembled on ZnO nanorods and a film of organic hole transporting material (HTM) atop. Polythiophene (P3HT) or Spiro-OMeTAD were used as HTM. The study was carried out by ultrafast transient absorption spectroscopy technique with selective excitation of ZnPc at 680 nm or P3HT at 500 nm. Data analysis revealed that photoexcitation of ZnPc in the structure ZnO|ZnPc|P3HT results in a fast (1.8 ps) electron transfer from ZnPc to ZnO, which is followed by a hole transfer from the ZnPc cation to P3HT roughly in 30 ps. However, in the case of ZnO|ZnPc|Spiro-OMeTAD structure, the primary reaction upon excitation of ZnPc is a fast (0.5 ps) hole transfer from ZnPc to Spiro-OMeTAD, and the second step is electron injection from the ZnPc anion to ZnO in roughly 120 ps. Thus, we demonstrate two structurally very similar hybrid architectures that implement two different mecha...

Hybrid nanostructures of organic dyes/TiO2 nanoparticles were successfully fabricated by self-assembly method. Compared with pure organic dyes, these hybrid nanostructures showed enhanced performance of light absorption. Extensive high-resolution transmission electron microscopy observations demonstrated that the organic dyes are preferentially attached onto the {101} facets of anatase TiO2 nanoparticles. Density functional theory calculations further confirmed that the preferential attachments are reasonable. These discoveries are very important for the preparation and improvement of the dye-sensitized and hybrid solar cells.

The self-assembled monolayer (SAM) technique was employed to fabricate a two-layer donor-acceptor film on the surface of TiO2. The approach is based on using donor and acceptor compounds with anchoring groups of different lengths. The acceptor, a fullerene derivative, has a carboxyl anchor attached to the fullerene moiety via a short linker that places the fullerene close to the surface. The donor, a porphyrin derivative, is equipped with a long linker that can penetrate between the fullerenes and keep porphyrin on top of the fullerene layer. The two-layer fullerene-porphyrin structures were deposited on a mesoporous film of TiO2 nanoparticles by immersing the TiO2 film sequentially into fullerene and porphyrin solutions. Transient absorption spectroscopy studies of the samples revealed that after the selective photoexcitation of porphyrin a fast (5 ps) intermolecular electron transfer (ET) takes place from porphyrin to the fullerene layer, which confirms the formation of the interlayer donor-acceptor interface. Furthermore, in the second step of ET the fullerene anions donate electrons to the TiO2 nanoparticles. The latter reaction is relatively slow with an average time constant of 230 ps. It involves roughly half of the primary generated charges, and the second half relaxes by the interlayer charge recombination. The resulting state with a porphyrin cation and electron in TiO2 has an extremely long lifetime and recombines with an average time constant of 23 ms.

A new and efficient methodology towards the synthesis of 7-pyrrolidinyl and 7,12-bispyrrolidinyl perylenemonoimide monoanhydrides (PMI monoanhydrides) and their corresponding dicarboxylic acids is devised. The high yields (70–96%) and facile synthesis of PMI monoanhydrides, as compared to traditional methodologies, make the method attractive and versatile. The reported 7,12-bispyrrolidinyl PMI monoanhydrides are a new family of peryleneimides, where both the bay-substituents are located towards the anhydride cycle. The electrochemical and optical properties of target molecules and their precursors were investigated using UV-Vis spectroscopy and differential pulse voltammetry. Atomic charges and electronic properties were calculated using density functional theory (DFT). In addition, self-assembling monolayers of the PMI monoanhydrides and their corresponding diacids were successfully formed over ZnO and TiO2 films. The results of the current study indicate that these molecules are potentially good candidates for various applications in the fields of organic electronics and solar cells.

Perylenediimides (PDIs) and perylenemonoimide diesters (PMIs) can be selectively substituted at the 1,6- or 7,12- positions of the bay region, respectively, by direct amination reactions. The reactions proceed by the formation of a perylene radical anion and its subsequent oxidation, and the yields range from 20–97 %. The amination can be tuned to obtain either mono- or disubstituted perylenes by varying the oxidants involved. The presence of the imide cycle is crucial for the transformation, although the amination occurs regioselectively at the bay-region positions distant from the imide cycle.

Electron-transfer characteristics of 1,7-dipyrrolidinyl-substituted perylenediimide-fullerene (PyPDI-C60) dyad were studied in solid films by an ultrafast transient absorption technique. The research was further expanded to study a poly(3-hexylthiophene) (P3HT):PyPDI-C60 blend to reveal the charge-transfer processes that take place in bulk heterojunction films, which are potentially suitable for photovoltaic applications. This knowledge is of paramount importance when designing organic photovoltaics since the performance of thin film devices is affected by mechanisms taking place at the molecular level upon photoexcitation. It was demonstrated that the charge- separated state, formed after an electron transfer from the PyPDI to the fullerene moiety of the dyad, has a lifetime of tens of picoseconds. A charge-separated state in which the hole is localized in the P3HT and the electron is in the fullerene moiety with a lifetime of

Synthesis, characterization, molecular modeling, and photovoltage responses of four phthalocyanine–fullerene (Pc-C60) dyads with two polar (−OH) side chains are described. The synthesized dyads have polar tails either on the Pc (electron donor D) side or on the fullerene (electron acceptor A) side of the dyad, providing a possibility to produce oriented donor–acceptor (D–A) monolayers with revised electron transfer direction when deposited on an aqueous subphase or on a solid surface. In the dyads, phthalocyanine and fullerene have different mutual orientations: in the trans-dyads they have face-to-face orientation, while in the cis-dyads the orientation is face-to-edge. Molecular modeling was used to examine and confirm the spatial arrangements of the synthesized dyads. The Pc-C60 dyads were deposited successfully onto solid substrates as highly oriented monolayers using the Langmuir–Schafer method. Formation of a vertically oriented monolayer and the following electron transfer from the photoexcited pht...

Evidence of the Marcus inverted region behavior for the forward electron transfer reaction in a double-linked zinc phthalocyanine–fullerene dyad was found. The charge separation and recombination processes of the dyad were studied in an ionic environment. The chloride ion coordination to the central zinc of the phthalocyanine macrocycle decreases the energy of the charge separated state and increases the energy of the phthalocyanine first singlet excited state, and thus increases the driving force for the charge separation and decreases it for the recombination. The charge separation is slowed down whereas the charge recombination is accelerated upon the chloride coordination.

Americium-241 (²⁴¹Am) is the second most significant radiation hazard after ²³⁹Pu at some of the Mayak Production Association facilities. This study summarizes current data on the accumulation, distribution, and excretion of americium compared with plutonium in different organs from former Mayak PA workers. Americium and plutonium were measured in autopsy and bioassay samples and correlated with the presence or absence of chronic disease and with biological transportability of the aerosols encountered at different workplaces. The relative accumulation of ²⁴¹Am was found to be increasing in the workers over time. This is likely from ²⁴¹Pu that increases with time in reprocessed fuel and from the increased concentrations of ²⁴¹Am and ²⁴¹Pu in inhaled alpha-active aerosols. While differences were observed in lung retention with exposures to different industrial compounds with different transportabilities (i.e., dioxide and nitrates), there were no significant differences in lung retention between americium and plutonium within each transportability group. In the non-pulmonary organs, the highest ratios of ²⁴¹Am/²⁴¹Am + SPu were observed in the skeleton. The relative ratios of americium in the skeleton versus liver were significantly greater than for plutonium. The relative amounts of americium and plutonium found in the skeleton compared with the liver were even greater in workers with documented chronic liver diseases. Excretion rates of ²⁴¹Am in ‘‘healthy’’ workers were estimated using bioassay and autopsy data. The data suggest that impaired liver function leads to reduced hepatic ²⁴¹Am retention, leading to increased ²⁴¹Am excretion.

A series of CdSe quantum dot (QD)–phthalocyanine (Pc) hybrids were synthesized and their photophysics was studied using steady state and time-resolved spectroscopic methods. Emission of QDs was progressively quenched upon increasing the concentration of Pc in the hybrids. A detailed transient absorption study of the hybrids revealed that the mechanism of quenching is charge separation, resulting in the formation of hybrids with negatively charged QDs and the Pc cation. Direct photo-excitation of Pc did not show any detectable interaction between the excited state of Pc and the QD to which it is attached. An explanation is proposed, based on the suggestion that the energy of the lowest unoccupied molecular orbital (LUMO) of Pc is lower than the lower edge of the QD conduction band, while the energy of the highest occupied molecular orbital (HOMO) of Pc is sufficiently higher than the high energy edge of the QD valence band (VB), thus permitting hole transfer from the QD VB to the Pc HOMO after photo-excitation of QDs. acceptedVersion

A series of diaryl-substituted perylene bis(imides) (PBIs) containing electron-donating and -withdrawing aryl groups in the bay region (1-, 6-, 7- and/or 12-positions of the perylene core) were synthesized by Suzuki coupling reaction. The corresponding regioisomers, namely, 1,7- and 1,6-regioisomer, were separated from the mixture by conventional column chromatography without any need of recrystallization. All the individual regioisomers were fully characterized by 1H NMR and HRMS spectroscopy. The compounds were studied by optical spectroscopy and electrochemical techniques. The optical and electrochemical properties of 1,7-regioisomer are slightly different from the 1,6-regioisomer of the respective diaryl-PBI. Significant redshift and broadening of the absorption and emission maxima were observed in all synthesized PBIs depending upon the electronic nature of the attached aryl group. This is very first time such large series of 1,6-diarylperylenetetracarboxydiimides with their corresponding 1,7-regioisomers were synthesized, separated, characterized and studied in detail.

We have synthesized a set of porphyrin and phthalocyanine compounds with two different silane anchors. Syntheses of the anchor-substituted chromophores have been carried out via hydrosilylation of alkene derivatives, catalyzed by platinum complexes. The reduction side-process was suppressed using specific anchor/catalyst pairs, and the silane-containing compounds were successfully isolated from hydrogenated by-products in pure form with good yields. The target porphyrinoids having stable reactive silane anchors possess the ability to self-assemble on metal oxides and quartz surfaces and optical fibers. Covalent attachment is done in one-step, which makes the bonding process fast and easy. Immobilized chromophores were further converted by on-surface reactions into Zn(II) and Mg(II) metal complexes. The metallation time was found to be as fast as 1 min for Zn ion. Bonding densities calculated from the absorbances of the deposited layers give rough estimations for packing of the molecules on various substrates and evidence for monomolecular layers formation.

Dense arrays of zinc oxide nanorods with high specific surface areas were grown by hydrothermal method and functionalized by self-assembled monolayer (SAM) of porphyrins. The growth process was optimized to obtain dense arrays of nanorods with diameter of 60–80 nm and length up to 1.5 μm. The increase in the effective surface area was monitored by comparing the absorbances of SAM deposited both on the flat and nanorod surfaces of ZnO. To alter further semiconductor-organic SAM interactions, a 2 or 5 nm thick layer of either Al2O3 or TiO2 was deposited on the ZnO nanorods. The present results show that both carboxylic acid and triethoxysilane anchors can be used to form porphyrin SAMs on the studied metal oxide substrates, and the electronic interactions between the metal oxide and porphyrin SAM are strongly modified by a thin layer of Al2O3 or TiO2. These hybrid semiconductor-organic SAM constructions present promising model systems for advanced spectroscopy studies of semiconductor-organic interfaces wit...