Organic Dyes with Well‐Defined Structures for Highly Efficient Dye‐Sensitised Solar Cells Based on a Cobalt Electrolyte

Abstract

Seven SGT organics dyes, containing bis-dimethylfluoreneyl amino groups with a dialkoxyphenyl unit as an electron donor and a cyanoacrylic acid group as an anchoring group, connected with oligothiophenes, fused thiophenes and benzothiadiazoles as π-bridges, were designed and synthesised for applications in dye-sensitised solar cells (DSSCs). The photovoltaic performance of DSSCs based on organic dyes with oligothiophenes depends on the molecular structure of the dyes, in terms of the length change of the π-bridging units. The best performance was found with a π-bridge length of about 6 Å. To further enhance the photovoltaic performance associated with this concept, cyclopenta[1,2-b:5,4-b']dithiophene (CPDT) and benzothiadiazole were introduced into the π-bridge unit. As a result, the DSSC based on the organic dye containing the CPDT moiety showed the best photovoltaic performance with a short-circuit photocurrent density (Jsc ) of 14.1 mA cm(-2) , an open-circuit voltage (Voc ) of 0.84 V and a fill factor (FF) of 0.72, corresponding to an overall conversion efficiency (η) of 8.61 % under standard AM 1.5 irradiation.

Thiazolo[5,4-d]thiazole-based organic sensitizers with improved spectral properties for application in greenhouse-integrated dye-sensitized solar cells

“…1). In particular, compounds TTZ8-10 featured a benzo-2,1,3-thiadiazole (BTD) unit as an auxiliary acceptor, which in turn is connected to different (hetero)aromatic cycles (benzene, thiophene and furan, respectively); such a modication was expected to cause a red-shi in the absorption spectra of organic D-p-A dyes, [41][42][43] which was anticipated to be more or less pronounced depending on the compound's planarity. 44,45 Dye TTZ11 was instead endowed with a dithieno[3,2-b:2 0 ,3 0 -d] pyrrole (DTP) moiety; in this case a better p-conjugation was expected due to the coplanar bridged p-system, which could possibly lead to an extension of the light absorption range of the sensitizer.…”

Dual-purpose zinc and silicon complexes of 1,2,3-triazole group substituted phthalocyanine photosensitizers: synthesis and evaluation of photophysical, singlet oxygen generation, electrochemical and photovoltaic properties

“…However, the LUMO level of dye 5 is slightly more negative than the CB of TiO 2 and electron injection might be less effective. 44 3.4. Photovoltaic studies Fig.…”

Factors Affecting the Performance of Champion Silyl‐Anchor Carbazole Dye Revealed in the Femtosecond to Second Studies of Complete ADEKA‐1 Sensitized Solar Cells

“…For many years the dominant DSSC systems were based on ruthenium dyes and an iodide electrolyte (containing the pairs I − /I 3 − , with multi‐electron redox reaction mechanism), in which an effective process of dye regeneration required particularly large driving force . Recently, alternative electrolytes based on cobalt ions (with single‐electron redox pair Co 2+ /Co 3+ ) have been developed . Their redox level is energetically lower (has more positive potential) .…”