We designed a dimeric porphyrin dye (LDD1) based on an efficient push–pull zinc porphyrin (LD14) with extended π-conjugation through coupling of two zinc porphine cores via an acetylene bridge at the meso position of the porphyrin to extend the absorption spectrum effectively into the near infrared region. The effect of dye aggregation among porphyrin molecules was significantly suppressed when the LDD1 and LD14 dyes were co-sensitized on a nanocrystalline TiO₂ film in a dye-sensitized photovoltaic system. The light-harvesting ability of the device exhibits a panchromatic feature covering a broad spectral region from 400 nm to 900 nm, which results in a short-circuit current density of 21.3 mA cm⁻² and a power conversion efficiency of 10.4% in an iodine-based solar cell.

The conducting polymer of poly(3,4 ethylenedioxythiophene):poly(4-styrenesulfonate) (PEDOT:PSS) is one of the most important and intensively investigated organic conducting materials. The PEDOT:PSS water dispersions with various concentrations of poly (4-styrenesulfonic acid) solution (PSSAS) were synthesized by 3,4-ethylenedioxythiophene (EDOT) in the presence of water. The fabrication of the solvent-treated PEDOT:PSS films through spin coating and solvent treatment processes was achieved with a solvent of pure water mixed with acetone (or MeOH, EtOH) in a ratio of 50:50. Moreover, both the organic solvent and water have synergetic effects while the PSS and PEDOT-attached PSS segments will form a coil-like and a linear (or extended-coil) structure, respectively. That may induce a stacking of the linear and planar PEDOT-attached PSS segments, which favors the formation of a crystalline phase. Finally, the maximum electrical conductivity of the PEDOT:PSS thin films with solvent treatment was investigated by means of X-ray diffraction (XRD) patterns and scanning electron microscope (SEM) images. Furthermore, we aimed to explain the synergetic effects of phase separation of the PEDOT:PSS thin films by both the organic solvent and water.

Cyclic electro-deposition (CED) is a cost-effective tool to synthesize nanostructures with a solution process, controllable morphology and high purity. Here we report novel platinum nanostructures fabricated according to CED at room temperature in solution containing H₂PtCl₆ precursor and NaNO₃. Remarkable Pt nanostructures—from nanoclusters, nanosheets, nanograsses to nanoflowers—were produced through morphological control via variation of either period of CED scans or concentration of the precursor. Pt films with uniform nanograss structures have great electro-catalytic performance (electron-transfer resistance = 0.3 Ω) and intrinsic light-scattering (reflectivity ∼50%), perfectly suitable for use as counter-electrodes for dye-sensitized solar cells (DSSCs). The DSSC device made with the Pt-nanograss counter-electrode and N719 dye attained efficiency η = 9.61% of power conversion, which is 12% enhanced from that fabricated according to a conventional thermal decomposition method (η = 8.55%) under similar experimental conditions. When the devices were further optimized with a thick TiO₂ film (17 + 5 μm) sensitized by Z907 dye using the CED-Pt counter-electrode, we obtained J_SC (mA cm⁻²) = 19.44, V_OC (V) = 0.742, and FF = 0.736, giving an exceptional power conversion efficiency of 10.62%.