Through elongating the end or side alkyl chains of dye molecules, we decorate anatase nanocrystals with a thicker organic assembly featuring a smaller tilt angle of the D–π-A backbone with respect to the surface normal, which retards the interfacial charge recombination and confers a higher photovoltage output on mesoscopic cobalt solar cells displaying an over 10% power conversion efficiency at the AM1.5G conditions.

Diverse thiophene-containing blocks have been employed as the π-conjugated spacers of organic D-π-A dyes. In the case that multiple segments with distinguishable electronic features are applied, their conjugation sequence could potently affect optoelectric behaviors of photosensitizers in mesoscopic titania solar cells. In this work, we address this issue by designing three organic dyes (C225, C226, and C227), wherein the dihexyl-substituted cyclopentadithiophene moiety is stepwise shifted from the electron acceptor side to the donor one, along with the additional use of two 3-hexylthiophene rings as the conjugated spacing unit. With respect to C225 and C226, C227 presents a relatively inefficient photoinduced electron injection as indicated by photoluminescence measurements, which accounts for its lower efficiencies of converting incident monochromatic photons to collected electrons. Transient absorption measurements suggest that the charge recombination between oxidized dye molecules and titania electrons gradually decelerates from C225 to C227, while the interception of oxidized dye molecules by iodide ions exhibits an apparent driving force dependent, Marcus normal region behavior.

Through elongating the end or side alkyl chains of dye molecules, we decorate anatase nanocrystals with a thicker organic assembly featuring a smaller tilt angle of the D–π-A backbone with respect to the surface normal, which retards the interfacial charge recombination and confers a higher photovoltage output on mesoscopic cobalt solar cells displaying an over 10% power conversion efficiency at the AM1.5G conditions.

Through elongating the end or side alkyl chains of dye molecules, we decorate anatase nanocrystals with a thicker organic assembly featuring a smaller tilt angle of the D–π-A backbone with respect to the surface normal, which retards the interfacial charge recombination and confers a higher photovoltage output on mesoscopic cobalt solar cells displaying an over 10% power conversion efficiency at the AM1.5G conditions.

Through elongating the end or side alkyl chains of dye molecules, we decorate anatase nanocrystals with a thicker organic assembly featuring a smaller tilt angle of the D–π-A backbone with respect to the surface normal, which retards the interfacial charge recombination and confers a higher photovoltage output on mesoscopic cobalt solar cells displaying an over 10% power conversion efficiency at the AM1.5G conditions.

A series of D−π–A organic dyes, X72–75, containing novel triarylamine electron donors have been synthesized for dye-sensitized solar cells (DSCs). The superiority of the asymmetric design of the triphenylamine electron donor over the symmetrical triphenylamine when applied in organic dyes for cobalt cells has been observed. Using X72 with the cobalt(II/III) redox shuttle resulted in an overall power conversion efficiency (PCE) of 9.18%, outperforming the state-of-the-art dye C218 under the same conditions.