Journal of Photochemistry and Photobiology C: Photochemistry Reviews最新文献

The volatility of noble metals prices, globally increasing demands, and its limited resources drive chemists to find alternatives in the place of expensive transition metal catalysts. So, this is a time for the scientific community to find alternative sources to replace Nobel metals, and it is making genuine changes in developing sustainable synthetic methods. Photoexcited transition-metal catalysis is revitalizing the research area for functionalizing diverse π-bond systems. The massive progression of the two conventional photochemical reactivity modes, photoredox catalysis, and synergetic photocatalyst/transition-metal catalysis, has fueled the search for a next-level mechanistic paradigm visible-light initiated excited-state transition-metal catalysis (Cu, Pd, Fe, Au, Co, Ni, W, and Mn), which can be deployed to harvest light energy and convert it into chemical energy in a single catalytic cycle. This review summarizes early examples of the visible-light-induced photocatalytic activities of conventional transition metals employed in C-H activation, π-bond functionalization, and annulation reactions of unsaturated compounds, and excluding the commonly used expensive photocatalysts (i.e., Ir-, and Ru-based pyridyl complexes). Unlike the other two classical photochemical approaches, the discrete inner-sphere mechanism associated with photoexcited transition metals facilitates reactive substrate-metal-complex interactions. It enables the direct involvement of excited-state catalysts in bond-forming or-breaking processes.

In this account, the reactive oxygen species (ROS) in photodynamic therapy (PDT) were deliberately reviewed. First, the specific definition of ROS and PDT were readily clarified. Afterward, this review focuses on the fundamental principles and applications of PDT. Due to strong oxidation ability of radicals (e.g., •OH and O₂^•-) and non-radical (e.g., ¹O₂ and H₂O₂), these ROS would attack the in vitro and in vivo tumor cells, thus achieving the goal of cancer treatment. Then, ROS in PDT for cancer treatment was thoroughly reviewed, including the mechanism and photosensitizer (PS) selection (i.e., nanomaterials). Ultimately, emphasis was made on the challenges, research gap, and prospects of ROS in cancer treatment and critically discussed. Hopefully, this review can offer detailed theoretical guidance for the researchers who participate in the study regarding ROS in PDT.

I–III–VI multinary semiconductors, which have low toxicity, are attracting much attention as quantum dot (QD) materials for replacing conventional binary semiconductors that contain highly toxic heavy metals, Cd and Pb. Recently, the inherent design flexibility of multinary QDs has also been attracting attention, and optoelectronic property control has been demonstrated in many ways. Besides size control, the electronic and optical properties of multinary QDs can be changed by tuning the chemical composition with various methods including alloying with other semiconductors and deviation from stoichiometry. Due to significant progress in synthetic methods, the quality of such multinary QDs has been improved to a level similar to that of Cd-based binary QDs. Specifically, increased photoluminescence quantum yield and recently narrowed linewidth have led to new application fields for multinary QDs. In this review, a historical overview of the solution-phase synthesis of I–III–VI QDs is provided and the development of strategies for better control of optoelectronic properties, i.e., electronic structures, energy gap, optical absorption profiles, and photoluminescence feature, is discussed. In addition, applications of these QDs to luminescent devices and light energy conversion systems are described. The performance of prepared devices can be improved by controlling the optical properties and electronic structures of QDs by changing their size and composition. Clarification of the unique features of I–III–VI QDs in detail will be the base for further development of novel applications by utilizing the complexity of multinary QDs.

Light possesses momentum, and hence, force is exerted on materials if they absorb and/or scatter light. Laser techniques that use optical forces are currently attracting considerable attention. Optical manipulation for trapping, transporting small particles, and measuring the interparticle force is a representative technique. In addition, photoinduced force microscopy is a promising scanning type of microscopy using optical force. Optical force techniques have recently been used in various fields of research, such as molecular bioscience, organic photochemistry, materials engineering, and molecular fluid dynamics. In these techniques, several types of optical forces such as scattering, absorption, and gradient forces play their respective roles. In this article, we summarize the basics of optical forces and present their elementary expressions for using simplified models of light and matter systems. This will help the readers of this Special Issue to understand how different types of forces are distinguished in the basic expressions used for analyzing the optical force phenomena that appear depending on the light geometry and matter systems. After observing simplified cases of scattering and absorption forces, we introduce general formulae for the optical force and then discuss how different components appear in particular cases of laser geometry and materials.

Phosphazenes, one of the most important classes of organophosphorus compounds containing phosphorus (V) with double bonds between P and N, can be cyclic molecules or high molecular weight polymers that play an important and dominant role in advanced inorganic materials. Phosphazenes have been the subject of many studies over the past two decades as an excellent synthetic platform for the development of fluorescent materials. This study is conducted to evaluate the contribution of phosphazene chemistry to the preparation of fluorescent materials and to emphasize its importance in development of sophisticated materials. This review provides detailed information about the latest developments in the field of cyclic-, dendrimeric- and polymeric phosphazenes based fluorescent materials and their application examples of sensors (fluorescent and electrochemical) and optoelectronic devices (OLED, OFET and electrochromic devices). The future perspective of fluorescence materials based on phosphazenes is also discussed.

Noninvasive and nondestructive techniques for monitoring and manipulating cells or biomolecules are essential for understanding biological processes. Optical methodologies have been used for the noninvasive and nondestructive monitoring of intracellular molecules and manipulation of cellular activities to elucidate the localization and interactions of these biomolecules. Since the pioneering work of Ashkin, optical trapping has been used to study cellular elasticity and mechanical characteristics of intracellular molecules. In recent years, there has been a substantial amount of research on the optical manipulation of nanometer-sized objects, including the manipulation of the assembly of nanomaterials and the enhancement of optical forces with optical resonance effects. In the study of biomolecular manipulation by optical forces, the functions and roles of biomolecules have been clarified by analyzing the changes in cellular functions induced by manipulation. In this review, we focus on recent studies on optical trapping for the manipulation of living cells or biomolecules and introduce techniques for the manipulation of cellular functions using optical forces.

The reversible photochromic response of tungsten oxide (WO₃) holds promise for solar-related applications as it is capable of photo charging during illumination (color-switching) and spontaneous discharging post-illumination (self-bleaching). Advances in WO₃-based nanostructures synthesis via micro/nanofabrication techniques have created remarkable potential application opportunities. Smart windows represent a typical energy-saving technology; ultraviolet indicators can sense radiation safety limits, and the around-the-clock photocatalysts can be used for pollutant degradation and bacterial disinfection applications. These materials, their distinct properties, and the effects of their application must be comprehensively understood prior to commercialization. In this work, we first summarize the affiliation between the crystallographic properties-optical features-photochromic behavior of WO₃. Several photochromic models and kinetic equations are then presented, accompanied by the related characterization techniques and evaluation methods. The factors affecting photochromic efficiency (e.g., light absorption, surface reaction, and carrier migration) are delineated to clarify the advantages of the specific nanostructured WO₃ and the most efficient available strategies for constructing WO₃-based nanomaterials. The theory, technique, and performance associated with chromogenic applications in smart devices, energy conversion, and environmental remediation are deliberated in detail. Finally, we outline the challenges and emerging trends in this area calling for further innovation to fill various gaps.

Plasmonic catalysis has been recognised as a promising alternative to many conventional thermal catalytic processes in organic synthesis. In addition to their high activity in fine chemical synthesis, plasmonic photocatalysts are also able to maintain control of selectivity under mild conditions by utilising visible-light as an energy source. This review provides an overview of the recent advances in organic transformations with plasmonic metal nanostructures, including selective reduction, selective oxidation, cross-coupling and addition reactions. We also summarize the photocatalysts and catalytic mechanisms involving surface plasmon resonance. Finally, control of reaction pathway and strategies for tailoring product selectivity in fine chemical synthesis are discussed.