[신간의 별자리x] 우리/미술, 그리고 ‘슬픔의 박물관’

Dye-sensitized solar cells (DSCs) offer the possibilities to design solar cells with a large flexibility in shape, color, and transparency. DSC research groups have been established around the worl ...

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Dye-Sensitized Solar Cells

Solution-processed bulk-heterojunction solar cells have gained serious attention during the last few years and are becoming established as one of the future photovoltaic technologies for low-cost power production. This article reviews the highlights of the last few years, and summarizes today's state-of-the-art performance. An outlook is given on relevant future materials and technologies that have the potential to guide this young photovoltaic technology towards the magic 10% regime. A cost model supplements the technical discussions, with practical aspects any photovoltaic technology needs to fulfil, and answers to the question as to whether low module costs can compensate lower lifetimes and performances.

https://onlinelibrary.wiley.com/doi/pdf/10.1002/adma.200801283

Polymer‐Fullerene Bulk‐Heterojunction Solar Cells

Dye-sensitized solar cells (DSSC) have attracted considerable attention in recent years as they offer the possibility of low-cost conversion of photovoltaic energy This Review focuses on recent advances in molecular design and technological aspects of metal-free organic dyes for applications in dye-sensitized solar cells Special attention has been paid to the design principles of these dyes and on the effect of various electrolyte systems Cosensitization, an emerging technique to extend the absorption range, is also discussed as a way to improve the performance of the device In addition, we report on inverted dyes for photocathodes, which constitutes a relatively new approach for the production of tandem cells Special consideration has been paid to the correlation between the molecular structure and physical properties to their performance in DSSCs

Metal-Free Organic Dyes for Dye-Sensitized Solar Cells: From Structure: Property Relationships to Design Rules

Rising atmospheric levels of carbon dioxide and the depletion of fossil fuel reserves raise serious concerns about the ensuing effects on the global climate and future energy supply. Utilizing the abundant solar energy to convert CO2 into fuels such as methane or methanol could address both problems simultaneously as well as provide a convenient means of energy storage. In this Review, current approaches for the heterogeneous photocatalytic reduction of CO2 on TiO2 and other metal oxide, oxynitride, sulfide, and phosphide semiconductors are presented. Research in this field is focused primarily on the development of novel nanostructured photocatalytic materials and on the investigation of the mechanism of the process, from light absorption through charge separation and transport to CO2 reduction pathways. The measures used to quantify the efficiency of the process are also discussed in detail.

Photocatalytic reduction of CO2 on TiO2 and other semiconductors.

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.

Photophysical and Electrochemical Properties, and Molecular Structures of Organic Dyes for Dye‐Sensitized Solar Cells

Dye-Sensitized Solar Cells Based On Donor–Acceptor π-Conjugated Fluorescent Dyes with a Pyridine Ring as an Electron-Withdrawing Anchoring Group

Hybrid composites of conductive polyaniline and nanocrystalline titanium oxide prepared via self-assembling and graft polymerization

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. This work demonstrates that the pyridine rings of D-π-A dye sensitizers that form a coordinate bond with the Lewis acid site of a TiO(2) surface are promising candidates as not only electron-withdrawing anchoring group but also electron-injecting group, rather than the carboxyl groups of the conventional D-π-A dye sensitizers that form an ester linkage with the Bronsted acid sites of the TiO(2) surface.

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

Heteropolycyclic donor–acceptor π-conjugated (D–π–A) fluorescent dyes with strong electron-withdrawing substituents show mechanofluorochromism (MFC): grinding of as-recrystallized dyes induces a fluorescent color change accompanying an enhanced fluorescence quantum yield, followed by a reversion to the original fluorescent color by heating or exposure to solvent vapor. Interestingly, both absorption and emission peaks are red-shifted by grinding, and the degrees of the red-shift are dependent on the electron-accepting ability of acceptor, steric sizes of the substituents, and D–π–A system. In order to clarify the mechanism of MFC observed with this new class of D–π–A fluorescent dyes, time-resolved fluorescence spectroscopy, X-ray powder diffractometry, differential scanning calorimetry and density measurements were performed before and after grinding of the solids. On the basis of experimental results and semi-empirical molecular orbital calculations (AM1 and INDO/S), we have revealed that the MFC is attributed to a reversible switching between crystalline and amorphous states with changes of dipole–dipole interaction and intermolecular π–π interaction by changes of the densities of the solids before and after grinding. This study demonstrates that the most important point for developing mechanofluorochromic dyes is to design fluorescent dye molecules of strong D–π–A characters with large dipole moments.

Yutaka Harima

Papers

Photophysical and Electrochemical Properties, and Molecular Structures of Organic Dyes for Dye‐Sensitized Solar Cells

Dye-Sensitized Solar Cells Based On Donor–Acceptor π-Conjugated Fluorescent Dyes with a Pyridine Ring as an Electron-Withdrawing Anchoring Group

Hybrid composites of conductive polyaniline and nanocrystalline titanium oxide prepared via self-assembling and graft polymerization

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

Molecular design of mechanofluorochromic dyes and their solid-state fluorescence properties