Design of high-efficiency organic dyes for titania solar cells based on the chromophoric core of cyclopentadithiophene-benzothiadiazole

Dye-sensitized solar cells: Atomic scale investigation of interface structure and dynamics

“…One way to broaden absorption spectrum is to use co-sensitization of two dyes with complementary absorbance. [3][4]30 For instance, the high DSC power conversion efficiency of over 12% is achieved by using modified Zn-porphyrin dye YD2-o-C8 coadsorbed with metal-free dye Y123 (see Fig. 3a and 3b) by Grä tzel et al.…”

“…For instance, by replacing the traditional I -/I 3 -redox couple with cobalt-complex electrolyte, electron recombination with holes in solution is dramatically reduced, increasing the electron collection efficiency of the device. [3][4]30 As the size of the cobalt complex is larger than the I -/I 3 -redox couple, it is difficult for cobalt complexes to make contact with the nanocrystal TiO 2 surface directly, hence retarding the charge recombination in electrolyte. Adsorption of Li + ions from the electrolyte on the semiconductor TiO 2 surface can also slow down both electron transport and charge recombination remarkably.…”

“…In 2013, Wang et al achieved a comparable over 11% efficiency using device made via co-grafting of metal free all-organic dye C258 or C259 with dye C239, which have advantages of non-toxicity, easy synthesis, low cost and high extinction coefficients comparing with the metal-based dyes. 4 Although co-sensitization yields high efficiency in DSC, the fabrication and optimization of these devices can be laborious and technically challenging. The development of a single sensitizer with a panchromatic light harvesting character remains a main objective in the realization of maximum PCEs with standard device fabrication protocols.…”

“…3 Wang et al have achieved comparable efficiency of 12.8% at half irradiance of the AM1.5G sunlight using metal-free all-organic dyes, which possesses large molar absorption coefficient, benign environment impact and low cost, compared with dyes containing heavy metals. 4 The current DSC consists of different layers of components stacked in serial, including transparent conducting glass substrate, transparent conducting layer, TiO 2 nanoparticles, dyes, electrolyte, and counter electrode covered with sealing gasket. The typical configuration is shown in Fig.…”

Effect of Thiophene in Bithiazole-Bridged Sensitizers on the Performance of Dye-Sensitized Solar Cells

“…9 Since then, sensitizers with D-A--A con¯guration have been widely studied. Many electron-withdraw units have been applied to the molecular design of sensitizers, such as benzothiadiazole, [10][11][12] benzotriazole, 13,14 quinoxaline, [15][16][17][18] and diketopyrrolopyrrole. [19][20][21][22] The bithiazole unit, as a good electron-de¯cient unit, has been widely used in the¯elds of transistors, thin-¯lm photovoltaic cells and light-emitting diodes.…”