Кафедра биофизики

For a long time, starting from pioneering works of M. Irie in the late 80 s and early 90 s of the last century, photochromic diarylethenes were primarily associated with dithienylethenes – diarylethenes possessing thiophene groups. However, about 10 years ago, azole heterocycles (thiazole, oxazole, imidazole) started to be used as aryl moieties instead of common thiophenes, which contributed significantly to the development of diarylethene-based photochromes. In this review, we analyzed in detail the effects of substituting traditional thiophenes in diarylethenes by azoles and revealed amazing examples of functional molecules, materials, and devices based on azole-containing photochromic molecules.

Recent years has witnessed increasing development and exploitation of fluorescence techniques which has been spurred by the discovery, design and synthesis of novel fluorescent molecules. In the realm of nucleic acids, both modest and dramatic structural modification of the nucleobase may engender it with fluorescence. This review focusses on the design, synthesis and applications of purine nucleoside analogs possessing fluorescently modified nucleobases, particularly for detection of nucleic acid sequences or for structural studies on nucleic acids. Thus, fluorescent nucleoside/nucleotide analogs that can be incorporated into oligonucleotides and report changes due to base-pairing/stacking or microenvironmental alterations, such as polarity changes in the grooves, are highlighted. Whenever available, the photophysical mechanism giving rise to the environmental responsiveness of the fluorescent nucleoside/tide is presented.

Energy shortages and global warming are two main problems the world is currently facing. Photocatalytic CO₂ reduction is one of the most promising solutions to the above issues. Among the various photocatalysts, faceted TiO₂ crystals have attracted wide attention due to their excellent photocatalytic performance for CO₂ reduction. This review encompasses the recent advances in the application of facet-engineered TiO₂-based catalysts for CO₂ photocatalytic reduction. The review begins with the fundamentals of CO₂ photocatalytic reduction over TiO₂. In the following section, we discuss the surface atom structure and electronic structure of faceted TiO₂ crystals and the related the CO₂/water adsorption and charge transfer/separation properties. Then, we outline the modification strategies for faceted TiO₂ and their influence on the CO₂ photocatalytic reduction performance. Finally, a summary and the future perspectives of facet-engineered TiO₂ photocatalysts for CO₂ photoreduction are presented.

The phenomenon of metachromasia, which is related to molecular aggregation, leads to significant changes in the photophysical properties of dyes. This review summarizes existing knowledge about molecular aggregation in hybrid systems containing inorganic nanoparticles and metachromatic dyes. The history of metachromasia, physical principles of molecular aggregation, and spectral properties of dye aggregates of various structures are briefly presented. The structure, surface properties, and several types of layered nanomaterials are also described. The main part of the review covers the fundamental properties of nanoparticles, metachromatic dyes, and their hybrid systems, that influence the aggregation of dye molecules. The focus is on the colloidal properties and the surface charge effect of nanoparticles. The importance of the surface charge of layered particles is demonstrated by detailed analysis of current research. The relevance of the phenomenon of molecular aggregation for research and application in the context of layered nanoparticles is then summarized.

Emerging organometal halide solar cells have attracted wide attention as “perovskite solar cells (PSCs)” from very many researchers, and the related articles more than 4000 have been published to date. The power conversion efficiency (PCE) over 22% was achieved within a few years from the advent of the PSCs. In this review article, publications about the PSCs were summarized along their ‘submitted date’, to record the course of the progress. At the first stage, the PSCs were established as nano-structured solar cells. The efficiency up to 15% attracted the researchers in dye-sensitized solar cells and organic thin-film solar cells. After the appearance of planar hetero-junction type PSCs, the power generation mechanism has been argued. Around that time, several issues arose, such as I–V hysteresis and chloride contents. Although there were several severe comments about these issues, the developments of the PSCs progressed steadily, then efficiencies over 20% were reported. At present, the highest PCE in published papers is 22.6%, and the NREL chart records 22.7%. The development history of the PSCs is summarized in this review.

The control of the transmission of the energy transported by optical waves is of extreme importance for the realization of those advanced technologies which require high speed of operation and fast switching. Such a task can be approached through the design and preparation of materials that possess modulable optical properties. In the present review the aspect of material science behind the realization of the effect of optical limiting, OL (or optical power limiting, OPL), will be considered focusing on those materials based on conjugated metallo-macrocycles like porphyrins, phthalocyanines and derivatives. The choice of these molecular materials for OL purposes is motivated by the fact that the optical properties of such annulated systems can be finely modulated in a controlled fashion by changing the chemical structure of the complex. These changes involve the variation of the central metal, the extent of electronic conjugation of the ring, the nature and the number of peripheral ligands, and the eventual introduction of axial ligands coordinated by a central metals with a valence higher than +2. An attempt will be made to establish relationships between the structure of the macrocyclic complex and the relative OL properties taking into account the most recent developments in the field. During this analysis we will also discuss the aspect of optically passivity, i.e. the characteristic of the OL materials of undergoing fast changes of optical properties according to an internal mechanism of self-activation.

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Herein, we review studies on the dynamics of excited radical ions. The enhanced reactivities of excited radical ions are recognized by many researchers based on product analysis studies conducted around 1980. For cases involving fluorescent excited radical ions, lifetime measurements provide information on excited states, and they sometimes lead to confusion owing to emissive byproducts resulting from their higher reactivities. Nanosecond laser flash photolysis studies provide evidence of the reactions of excited radical ions, and analyses of their kinetics reveal properties such as their excited-state lifetimes despite an indirect manner. Recent femtosecond laser flash photolysis studies provide detailed pictures of excited radical ions, though such studies are few. Furthermore, studies on dyad or triad systems, including excited radical ions, show electron transfer dynamics and disclose characteristics of excited radical ions that differ from those in neutral states. Larger electronic coupling and smaller dumping factor are reported as important characteristics of electron transfer systems of excited radical ions. These systematic studies on excited radical ions demonstrate their suitability for applications.

The breakthrough discovery of organic-inorganic hybrid perovskite materials for converting solar energy into electrical energy has revolutionized the third generation photovoltaic devices. Within less than half a decade of rigorous research and development in perovskite solar cells, the efficiency is boosted upto 22%. Aforesaid high PCE is accredited to high optical absorption properties, balanced charge transport properties, and longer diffusion lengths of carriers. Two dominant perovskite solar cell architecture has evolved; n-i-p, and p-i-n with mesoporous or planar heterojunction. In planar heterojunction configuration, perovskite light harvester is layered between hole/electron transport layers and the electrodes. The electron and hole transporting films increase charge collection efficiency and reduce recombination at interfaces. In the following review, we present a critical survey of the recent progress in perovskite absorber and charge transport materials that account for the exceptionally higher PCE of perovskite devices. Furthermore, numerous fabrication techniques and device architectures are summarized.