Tomohiro Higashino

Dye-sensitized solar cells (DSSCs) have attracted much attention as an alternative to silicon-based solar cells because of their low-cost production and high power conversion efficiency. Among various sensitizers, numerous research activities have been focused on porphyrins due to their strong absorption bands in the visible region, versatile modifications of their core, and facile tuning of the electronic structures. In 2005-2007, Officer and Grätzel et al. had achieved a rapid increase in the

Aromaticity with a twist: The reversal of Möbius aromaticity occurs by changing the number of π electrons between [4n+2] and [4n] in monophosphorus complexes of [28]hexaphyrins and bisphosphorus complexes of [30]hexaphyrins. The 30π Möbius antiaromatic bisphosporus[30]hexaphyrins (see picture) were determined to be the first structurally characterized Möbius antiaromatic systems, which are rigid, neutral, and stable. Detailed facts of importance to specialist readers are published as ”Supporting

A tropolone group has been employed for the first time as an anchoring group for dye-sensitized solar cells (DSSCs). The DSSC based on a porphyrin, YD2-o-C8T, with a tropolone moiety exhibited a power-conversion efficiency of 7.7 %, which is only slightly lower than that observed for a reference porphyrin, YD2-o-C8, with a conventional carboxylic group. More importantly, YD2-o-C8T was found to be superior to YD2-o-C8 with respect to DSSC durability and binding ability to TiO2 . These results una

The unprecedented dependence of final charge separation efficiency as a function of donor-acceptor interaction in covalently-linked molecules with a rectilinear rigid oligo-p-xylene bridge has been observed. Optimization of the donor-acceptor electronic coupling remarkably inhibits the undesirable rapid decay of the singlet charge-separated state to the ground state, yielding the final long-lived, triplet charge-separated state with circa 100% efficiency. This finding is extremely useful for the

To evaluate the effects of substituent bulkiness around a porphyrin core on the photovoltaic properties of porphyrin-sensitized solar cells, long alkoxy groups were introduced at the meso-phenyl group (ZnPBAT-o-C8) and the anchoring group (ZnPBAT-o-C8Cn, n = 4, 8) of an asymmetrically substituted push-pull porphyrin with double electron-donating diarylamino groups and a single electron-withdrawing carboxyphenylethynyl anchoring group. The spectroscopic and electrochemical properties of ZnPBAT-o-

Dyes play a crucial role in the cell performance of dye-sensitized solar cells (DSSCs), and versatile synthetic strategies towards well-tailored porphyrins for DSSCs have been developed for achieving high photovoltaic performances.

Redox shuttles play a crucial role in the photovoltaic performance of dye-sensitized solar cells (DSSCs). A traditional iodide/triiodide (I–/I3–) redox shuttle has been widely utilized in the first generation, but it suffers from intrinsic disadvantages such as a limited open-circuit voltage (VOC). On the other hand, cobalt(II/III) complexes with polypyridyl ligands have been established as second-generation redox shuttles and have achieved a power conversion efficiency (η) of up to 13%. Since 2

Aromatizität mit Dreh: Die Umkehr von Möbius-Aromatizität wurde in Mono-Phosphorkomplexen von [28]Hexaphyrinen und Bis-Phosphorkomplexen von [30]Hexaphyrinen durch eine Änderung der Anzahl der π-Elektronen zwischen [4n+2]π und [4n]π nachgewiesen. Bis-Phosphor[30]hexaphyrine (siehe Bild) sind die ersten strukturell charakterisierten Möbius-antiaromatischen Systeme, die formtreu, neutral und stabil sind. Detailed facts of importance to specialist readers are published as ”Supporting Information”.

In recent years, copper(I/II) complexes have emerged as alternative redox shuttles in dye-sensitized solar cells (DSSCs), exhibiting more positive redox potential than iodine- and cobalt-based redox shuttles. In particular, copper(I/II) complexes with 1,10-phenanthroline- or 2,2'-bipyridyl-based ligands attained moderate to high power conversion efficiencies (6-11%) with a high open-circuit voltage (<i>V</i>_OC) over 1.0 V due to the positive potentials. Although copper(I/II) complexes

Singly twisted Möbius antiaromatic [34]heptaphyrin A and doubly twisted Hückel aromatic [34]heptaphyrin B were formed by a phosphorus insertion reaction. A rearranges thermally to give the more stable B with P=O migration from NNN to NNC, and thus A is a rare case of a kinetically controlled Möbius antiaromatic molecule.

Abstract A phosphole‐fused porphyrin dimer, as a representative of a new class of porphyrins with a phosphorus atom, was synthesized for the first time. The porphyrin dimer exhibits remarkably broadened absorption, indicating effective π‐conjugation over the two porphyrins through the phosphole moiety. The porphyrin dimer possesses excellent electron‐accepting character, which is comparable to that of a representative electron‐accepting material, [60]PCBM. These results provide access to a new c

Abstract A tropolone group has been employed for the first time as an anchoring group for dye‐sensitized solar cells (DSSCs). The DSSC based on a porphyrin, YD2‐o‐C8T, with a tropolone moiety exhibited a power‐conversion efficiency of 7.7 %, which is only slightly lower than that observed for a reference porphyrin, YD2‐o‐C8 , with a conventional carboxylic group. More importantly, YD2‐o‐C8T was found to be superior to YD2‐o‐C8 with respect to DSSC durability and binding ability to TiO 2 . These

A hydroxamic acid group has been employed for the first time as an anchoring group for cobalt-based dye-sensitized solar cells (DSSCs). The porphyrin dye YD2-o-C8HA including a hydroxamic acid anchoring group exhibited a power conversion efficiency (η) of 6.4 %, which is close to that of YD2-o-C8, a representative porphyrin dye incorporating a conventional carboxylic acid. More importantly, YD2-o-C8HA was found to be superior to YD2-o-C8 in terms of both binding ability to TiO₂ and du

Treatment of an N-fused [24]pentaphyrin with POCl3 in the presence of triethylamine gave a triply-fused pentaphyrin PO complex through an N-fusion reaction and oxidative C–C bond formation between the pyrrolic β-positions. This complex displays strong antiaromatic character due to its 24π-electronic network as evinced by its 1H NMR chemical shifts, absorption spectrum, and NICS calculation. The PO complex was reduced with BH3·SMe2 to provide P–BH3 complex with concurrent hydrogenation at the pyr

Peripherally hexaarylated subporphyrazines (SubPzs) have been prepared through a Pd-catalyzed, CuTC-mediated coupling of a hexaethylsulfanylated subporphyrazine with arylboronic acids. The introduced aryl substituents strongly influence the electronic properties of the subporphyrazine through effective conjugative interaction. Aryl rings endowed with π-electron-donating groups at the para positions produce a remarkable perturbation of the electron density of the SubPz macrocycle. This is reflect