Firmly attached: The short‐circuit photocurrent density and conversion yields of solarcellsbased on pyridine‐containing donor–acceptor π‐conjugated (D‐π‐A) dyes (see scheme) are greater than those for conventional D‐π‐A dye sensitizers that bear a carboxy group as the electron‐withdrawing anchoringgroup. The dyes are attached to the surface by coordinate bonding with the Lewis acid sites of TiO2
A new‐type of donor–acceptor π‐conjugated (D‐π‐A) fluorescentdyes NI3–NI8 with a pyridinering as electron‐withdrawing‐injecting anchoringgroup have been developed and their photovoltaic performances in dye‐sensitized solarcells (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
We have newly designed and synthesized unsymmetrical carbazole-type D-pi-A fluorescent dyes. The dyes show a bathochromic shift-type mechanofluorochromism (MFC): grinding of as-recrystallized dyes induces a bathochromic shift of fluorescent color and the fluorescent color is recovered by heating or exposure to solvent vapor. In order to clarify the MFC mechanism for the carbazole-type D-pi-A fluorescent dyes, time-resolved fluorescence spectroscopy, X-ray powder diffractometry, single-crystal X-ray structural analysis, IR spectroscopy, and differential scanning calorimetry are 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 intermolecular hydrogen bonding and pi-pi interaction. (C) 2011 Elsevier Ltd. All rights reserved.