Molecular Engineering of Simple Metal-Free Organic Dyes Derived from Triphenylamine for Dye-Sensitized Solar Cell Applications.

Two new metal-free organic sensitizers, L156 and L224, were designed, synthesized, and characterized for application in dye-sensitized solar cells (DSCs). The structures of the dyes contain a triphenylamine (TPA) segment and 4-(benzo[c][1,2,5]thiadiazol-4-yl)benzoic acid as electron-rich and -deficient moieties, respectively. Two different π bridges, thiophene and 4,8-bis(4-hexylphenyl)benzo[1,2-b:4,5-b']dithiophene, were used for L156 and L224, respectively.

Electron-Affinity-Triggered Variations on the Optical and Electrical Properties of Dye Molecules Enabling Highly Efficient Dye-Sensitized Solar Cells.

The synthesis, characterization, and photovoltaic performance of a series of indacenodithiophene (IDT)-based D-π-A organic dyes with varying electron-accepting units is presented. By control of the electron affinity, perfectly matching energy levels were achieved with a copper(I/II)-based redox electrolyte, reaching a high open-circuit voltage (>1.1 V) while harvesting a large fraction of solar photons at the same time.

Planar Perovskite Solar Cells with High Open-Circuit Voltage Containing a Supramolecular Iron Complex as Hole Transport Material Dopant.

In perovskite solar cells (PSCs), the most commonly used hole transport material (HTM) is spiro-OMeTAD, which is typically doped by metalorganic complexes, for example, based on Co, to improve charge transport properties and thereby enhance the photovoltaic performance of the device. In this study, we report a new hemicage-structured iron complex, 1,3,5-tris(5'-methyl-2,2'-bipyridin-5-yl)ethylbenzene Fe(III)-tris(bis(trifluoromethylsulfonyl)imide), as a p-type dopant for spiro-OMeTAD. The formal redox potential of this compound was measured as 1.

Molecular Design of Efficient Organic D-A-π -A Dye Featuring Triphenylamine as Donor Fragment for Application in Dye-Sensitized Solar Cells.

A metal-free organic sensitizer, suitable for the application in dye-sensitized solar cells (DSSCs), has been designed, synthesized and characterized both experimentally and theoretically. The structure of the novel donor-acceptor-π-bridge-acceptor (D-A-π-A) dye incorporates a triphenylamine (TPA) segment and 4-(benzo[c][1,2,5]thiadiazol-4-ylethynyl)benzoic acid (BTEBA). The triphenylamine unit is widely used as an electron donor for photosensitizers, owing to its nonplanar molecular configuration and excellent electron-donating capability, whereas 4-(benzo[c][1,2,5]thiadiazol-4-ylethynyl)benzoic acid is used as an electron acceptor unit.

11% efficiency solid-state dye-sensitized solar cells with copper(II/I) hole transport materials.

Solid-state dye-sensitized solar cells currently suffer from issues such as inadequate nanopore filling, low conductivity and crystallization of hole-transport materials infiltrated in the mesoscopic TiO scaffolds, leading to low performances. Here we report a record 11% stable solid-state dye-sensitized solar cell under standard air mass 1.5 global using a hole-transport material composed of a blend of [Cu (4,4',6,6'-tetramethyl-2,2'-bipyridine)](bis(trifluoromethylsulfonyl)imide) and [Cu (4,4',6,6'-tetramethyl-2,2'-bipyridine)](bis(trifluoromethylsulfonyl)imide).

A small electron donor in cobalt complex electrolyte significantly improves efficiency in dye-sensitized solar cells.

Photoelectrochemical approach to solar energy conversion demands a kinetic optimization of various light-induced electron transfer processes. Of great importance are the redox mediator systems accomplishing the electron transfer processes at the semiconductor/electrolyte interface, therefore affecting profoundly the performance of various photoelectrochemical cells. Here, we develop a strategy-by addition of a small organic electron donor, tris(4-methoxyphenyl)amine, into state-of-art cobalt tris(bipyridine) redox electrolyte-to significantly improve the efficiency of dye-sensitized solar cells.

Copper Bipyridyl Redox Mediators for Dye-Sensitized Solar Cells with High Photovoltage.

Redox mediators play a major role determining the photocurrent and the photovoltage in dye-sensitized solar cells (DSCs). To maintain the photocurrent, the reduction of oxidized dye by the redox mediator should be significantly faster than the electron back transfer between TiO and the oxidized dye. The driving force for dye regeneration with the redox mediator should be sufficiently low to provide high photovoltages.

Novel Blue Organic Dye for Dye-Sensitized Solar Cells Achieving High Efficiency in Cobalt-Based Electrolytes and by Co-Sensitization.

Blue and green dyes as well as NIR-absorbing dyes have attracted great interest because of their excellent ability of absorbing the incident photons in the red and near-infrared range region. A novel blue D-π-A dye (Dyenamo Blue), based on the diketopyrrolopyrrole (DPP)-core, has been designed and synthesized. Assembled with the cobalt bipyridine-based electrolytes, the device with Dyenamo Blue achieved a satisfying efficiency of 7.