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

Bottom-up strategies have allowed the synthesis of “molecular” nanographenes with full control over size, shape and functionality. In recent years, the progress on wet chemical approaches, oxidative cyclodehydrogenation amongst all, has been the foundation to the synthesis of an impressive number of soluble and well-defined molecular nanographenes. The level of control over nanographene syntheses has allowed a fine-tuning of the photophysical and electrochemical properties and, in turn, has a compelling potential in the field of material science. In this regard, understanding and harnessing the competition between electron transfer and energy transfer in nanographenic systems is of utmost importance. However, a comprehensive structure-property relationship remains still an open aspect. In the present review we describe a large variety of hexa-peri-hexabenzocoronene (HBC)-based nanographenes obtained through wet chemical strategies and linked – either covalently or non-covalently – to porphyrins, rylenes, fullerenes, etc. Particular attention was placed on the optical, electrochemical and excited-state properties.

A review regarding the studies of light-sensitive systems based on bacteriorhodopsin is presented. Briefly given are modern ideas about bacteriorhodopsin and its molecular properties, about the photocycle of its transformation. The possibilities and ways of bacteriorhodopsin modifications are shown, in particular, such as dehydration, modification using chemical additives, changing the primary protein sequence by use of genetic mutants of bacteriorhodopsin, replacing the chromophore with its synthesized analogues. Such modifications can optimize the use of bacteriorhodopsin to create photosensitive recording media. Particular attention is paid to various areas of possible applications of light-sensitive materials of this type, in particular, polymer films based on bacteriorhodopsin and its derivatives, the so-called Biochrome films. The possibilities of using BR-based polymer films not only as a photochromic material for multiple recording, but also as a material for write-once recording and permanent memory (the so-called material for write-once recording of optical information) are also considered.

Spectral microscopy provides information about the spatial distribution and physiological functional states of pigment-protein complexes in photosynthetic organisms. This can be used to complement the newly developed techniques, such as cryogenic electron microscopy and atomic force microscopy, which are less effective in functional analysis of photosynthesis, despite having an excellent spatial resolution. The combination of optical microscopies with various spectroscopic techniques has extended the possibility of a multi-perspective investigation in photosynthesis research. Some of these spectroscopic techniques include fluorescence and absorption spectra, excitation spectra, time-resolved fluorescence measurement, Raman scattering spectroscopy, etc. These techniques can be applied to in vivo investigations of photosynthetic activity without introducing any artificial fluorophore since the photosynthetic pigments are informative probes. In particular, the technique has been effective in clarifying the dynamic physiological responses of photosynthetic organisms to variable environments. In this paper, we review the recent progress in spectral microscopy in the field of in vivo photosynthesis research. We have also introduced and discussed some distinctive spectral microscopies such as anti-Stokes fluorescence spectral microscopy, excitation spectral microscopy, cryo-microscopy, and Raman spectral microscopy.

In the past three decades, dye-sensitized solar cells (DSSCs) have gained increased recognition as a potential substitute for inexpensive photovoltaic (PV) devices, and their maximum efficiency has grown from 7% to 14.3%. Recent developments in DSSCs have attracted a plethora of research activities geared at realizing their full potential. DSSCs have seen a revival as the finest technology for specific applications with unique features such as low-cost, non-toxic, colourful, transparent, ease of fabrication, flexibility, and efficient indoor light operation. Several organic materials are being explored and employed in DSSCs to enhance their performance, robustness, and lower production costs to be viable alternatives in the solar cell markets. This review provides a concise summary of the developments in the field over the past decade, with a special focus on the incorporation of organic materials into DSSCs. It covers all elements of the DSSC technology, including practical approaches and novel materials. Finally, the emerging applications of DSSCs, and their future promise are also discussed.

Room-temperature optical manipulation of small molecules is a challenging issue in the field of material science. To increase optical force for a single molecule trapping, it has been recognized that resonant excitation of molecules should be controlled under the light illumination. Strongly interacting molecules with solid surfaces at electrified interfaces show the exotic behavior of electronic excitation by localized surface plasmon. In this review, we emphases that surface-enhanced Raman scattering can be used to evaluate the resonant excitation of target molecules at interfaces. Under such excitation, the diffusion of small molecules can be controlled by the optical force generated by the intensity gradient of a highly localized electric field.

Open-chain tetrapyrroles are ubiquitous and abundant in living organisms (algae, animals, bacteria, and plants), including examples such as bilirubin, biliverdin, phycocyanobilin, phycoerythrobilin, and urobilin. The open-chain tetrapyrroles, collectively termed bilins, arise from biosynthesis or degradation of tetrapyrrole macrocycles. Bilins are now known to play a wide variety of biological roles encompassing light-harvesting (in phycobiliproteins), photomorphogenesis, signaling, and redox chemistry. The absorption spectra of bilins spans the ultraviolet (UV), visible, to near-infrared (NIR) regions depending on the degree of conjugation, thereby providing a wide range of colors from red/orange to blue/green. The fluorescence intensity of bilins is often quite low and hence fewer spectra are available, but can be increased substantially by structural rigidification, as evidenced by the wide use of biliproteins as fluorescent labels. The present article describes a database of absorption and fluorescence spectra of bilins from natural and synthetic origins for 220 compounds (270 absorption and 13 fluorescence spectral traces). Spectral traces of bilins published over the past ∼50 years have been digitized and assembled along with information concerning solvent, photochemical properties (molar absorption coefficient and fluorescence quantum yield), and literature references. The spectral traces (xy-coordinate data files) can be viewed, downloaded, and accessed at www.photochemcad.com. The accessibility of spectral traces in digital format should facilitate identification and quantitative calculations of interest in diverse scientific areas.

Quantum dot light-emitting diodes (QLEDs) have developed rapidly in the last several decades, in which the maximum external quantum efficiency of the three primary color cadmium (Cd)-based QLEDs have exceeded the theoretical maximum value. However, the presence of Cd element has severely hampered their commercialization. Indium phosphide (InP)-based quantum dots (QDs) without heavy metals have continuously adjustable luminescence range from blue to near infrared, which is a competitive alternative for Cd-based QDs. Especially in the last few years, the synthesis techniques and the device structures of InP-based QLEDs have been greatly improved. In this review, we first introduce the properties of InP-based QDs, carrier dynamics and the early development history. Then, we focus on the development of InP-based red, green and blue primary color QLEDs from their first report in 2011 to the current state of the art. The effects of QDs structure (core/shell or gradient-alloyed QDs and organic ligand modified QDs) and device structure (charge transport layer and interfacial engineering) on the performance of InP-based QLEDs are also summarized.