No abstract

A series of meso-tetraphenylzincporphyrins have been prepared to examine the effects of the porphyrin substituents and adsorption conditions on photovoltaic properties of the porphyrin-sensitized TiO 2 cells. The cell performance strongly depended on the linking bridge between the porphyrin core and the TiO 2 surface, the bulkiness around the porphyrin core, and the immersing solvents and times for the porphyrin adsorption. In particular, the high cell performance of the porphyrin-sensitized TiO 2 cells was achieved when protic solvent (i.e., methanol) and short immersing time (0.5-1 h) were used for the conditions of the dye adsorption on TiO 2 , which is in sharp contrast with Ru dye-sensitized TiO 2 cells. The highest cell performance was obtained with 5-(4-carboxyphenyl)-10,15,20-tris(2,4,6-trimethylphenyl)porphyrinatozinc(II) as a sensitizer and methanol as an immersing solvent with an immersing time of 1 h: a maximal incident photon-to-current efficiency of 76%, a short circuit photocurrent density of 9.4 mA cm -2 , an open-circuit voltage of 0.76 V, a fill factor of 0.64, and a power conversion efficiency of 4.6% under standard AM 1.5 sunlight. These results will provide basic and valuable information on the development of dye-sensitized solar cells exhibiting a high performance.

Novel perylene imide derivatives with both electron-donating and bulky substituents have been synthesized for dye-sensitized solar cells. The power conversion efficiency reached 2.6%, which is the highest value among perylene-sensitized TiO2 solar cells.

A novel strategy for constructing a vertical arrangement of bicontinuous donor-acceptor arrays on a semiconducting electrode has been developed. The relationship between the film structure and the photoelectrochemical properties has been elucidated as a function of the number of donor layers for the first time. The maximum incident photon-to-current efficiency value (21%) is comparable to the highest value (20%) reported for vertical arrangements of bicontinuous donor-acceptor arrays on electrodes.

King of the spins is provided by the mixed‐valent Mn19 aggregate as reported by A. K. Powell et al. in their Communication on page 4926 ff. The use of bridging azido ligands leads to a completely ferromagnetically coupled system with a record ground spin state of 83/2. This remarkable molecule has been investigated and characterized by scientists from three laboratories working together in the European Network of Excellence “MAGMANet”, the logo of which provides the background to the cover picture.