Molecular Designs and Syntheses of Organic Dyes for Dye‐Sensitized Solar Cells

Abstract

Dye‐sensitized solar cells (DSSCs) based on organic dyes adsorbed on nanocrystalline TiO2 electrodes have received considerable attention because of their high incident solar light‐to‐electricity conversion efficiency and low cost of production. A number of organic dyes have so far been developed, and the relationship between their chemical structures and the photovoltaic performances of DSSCs based on the dyes has been examined. To create high‐performance DSSCs, it is important to develop effective organic dye sensitizers, which should be optimized for the chemical structures to possess good light‐harvesting features, to provide good electron communication between the dyes and a TiO2 electrode, and to control the molecular arrangements on the TiO2 electrode. The aim of this microreview is to highlight the design and synthesis of organic dyes for DSSCs based on recent work of organic chemists. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)

Photo-induced intramolecular charge transfer from antenna to anchor groups in phenoxazine dyes

“…In particular, donor-acceptor p-conjugated (D-p-A) dyes are considered one of the most promising classes of metal-free organic sensitizers [3][4][5][6]. Zhang et al [7] reported that DSSCs based on a D-p-A dye (C217) show a power conversion efficiency of 9.8%.…”

“…The most useful donor group is triphenylamine (TPA), but other donor groups have also been reported [2][3][4][5][6]. The widely used acceptor and anchor group is cyanoacrylic acid.…”

Synthesis and optical and photovoltaic properties of dithienosilole–dithienylpyridine and dithienosilole–pyridine alternate polymers and polymer–B(C6F5)3 complexes

“…As B(C 6 F 5 ) 3 was added to the solutions of pDTSTPyT and pDTSPy in benzene, the solution changed color from red to purple. Simultaneously, the absorbance of the UV-Vis bands of the parent polymers decreased, and new bands appeared at longer wavelengths, which became more intense with increasing concentration of B(C 6 F 5 ) 3 . This result is in good agreement with the previously reported [15][16][17][18] optical properties of similar complexes of pyridinecontaining polymers with borane, and it clearly indicates that complex formation reduces the polymer band gap, thereby potentially allowing for fine tuning of the electronic states.…”

“…Complex formation with B(C 6 F 5 ) 3 Complex formation between the polymers and B(C 6 F 5 ) 3 was monitored by UV-Vis absorption spectrophotometry, as shown in Figure 2. As B(C 6 F 5 ) 3 was added to the solutions of pDTSTPyT and pDTSPy in benzene, the solution changed color from red to purple.…”

“…Donor-acceptor (D-A)-type compounds and polymers have been studied extensively as key materials for OPVs. [1][2][3] Their broad, redshifted absorptions arising from a low bandgap make it possible to utilize the wide range of sunlight wavelengths, and their polar structures facilitate photo-induced charge separation in this system.…”