A First Synthesis of Thiophene Dendrimers

Xia, Chao; Fan, Xiaowu; Locklin, Jason; Advíncula, Rigoberto C.

doi:10.1021/ol025943a

Cited by 156 publications

(129 citation statements)

References 45 publications

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“…All dyes have oxidation potentials between 0.88 and 0.92 V, which are higher than the Co(phen) 3 3+/2+ standard oxidation potential (0.62 V) by at least 260 mV. This difference should create enough driving force for efficient dye regeneration.…”

Section: ■ Results and Discussionmentioning

confidence: 88%

“…, Chloroform-d) δ 165.21, 164.62, 164.39, 160.66, 159.52, 158.45, 156.84 55.44, 45.56, 40.35, 31.94, 31.91, 31.53, 29.71, 29.66, 29.51, 29.48, 29.38, 29.35, 26.47 Dichloromethane-d 2 ) δ 8.98 (s, 1H), 8.88 (s, 1H) for the non-hydrolyzed products are shown, since final products' amount were not enough to obtain NMR signals. DEPT 135 13 3 were synthesized according to the literature methods. 18 …”

Section: 4'-bis(5'-hexyl-[22'-bithiophen]-5-yl)-22'-bipyridine (33)mentioning

confidence: 99%

“…2 In standard DSCs, mesoporous TiO 2 is sensitized by a ruthenium(II) complex or an organic dye, and I 3 − /I − is widely employed as the most effective redox couple. 3,4 Congruence between the dye molecule chemisorbed on a mesoporous oxide and redox pair in the electrolyte in DSCs should be fine-tuned to obtain fast dye regeneration and ideally slow charge recombination. The present certified record power conversion efficiencies (PCEs) of up to 11.1% were achieved with I 3 − /I − and heteroleptic ruthenium dyes.…”

Section: ■ Introductionmentioning

confidence: 99%

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Ligand Engineering for the Efficient Dye-Sensitized Solar Cells with Ruthenium Sensitizers and Cobalt Electrolytes

Aghazada

Gao

Yella³

et al. 2016

Inorg. Chem.

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Over the past 20 years, ruthenium(II)-based dyes have played a pivotal role in turning dye-sensitized solar cells (DSCs) into a mature technology for the third generation of photovoltaics. However, the classic I 3 − /I − redox couple limits the performance and application of this technique. Simply replacing the iodine-based redox couple by new types like cobalt(3+/2+) complexes was not successful because of the poor compatibility between the ruthenium(II) sensitizer and the cobalt redox species. To address this problem and achieve higher power conversion efficiencies (PCEs), we introduce here six new cyclometalated ruthenium(II)-based dyes developed through ligand engineering. We tested DSCs employing these ruthenium(II) complexes and achieved PCEs of up to 9.4% using cobalt(3+/2+)-based electrolytes, which is the record efficiency to date featuring a ruthenium-based dye. In view of the complicated liquid DSC system, the disagreement found between different characterizations enlightens us about the importance of the sensitizer loading on TiO 2 , which is a subtle but equally important factor in the electronic properties of the sensitizers. ■ INTRODUCTIONThe global challenge to develop carbon-neutral renewable energy sources can be addressed by harnessing solar power using photovoltaics. 1 As an alternative to conventional solar cells, third-generation photovoltaic devices with dye-sensitized solar cells (DSCs) at the forefront have been extensively studied. 2 In standard DSCs, mesoporous TiO 2 is sensitized by a ruthenium(II) complex or an organic dye, and I 3 − /I − is widely employed as the most effective redox couple. 3,4 Congruence between the dye molecule chemisorbed on a mesoporous oxide and redox pair in the electrolyte in DSCs should be fine-tuned to obtain fast dye regeneration and ideally slow charge recombination. The present certified record power conversion efficiencies (PCEs) of up to 11.1% were achieved with I 3 − /I − and heteroleptic ruthenium dyes. 5−7 However, regeneration of a ruthenium(II) complex by electron donation from the I 3 − /I − redox couple entails a loss of around 500 mV, with over 300 mV of that being directly related to the complicated sequence of reactions associated with the two-electron oxidation of iodide that do not involve the sensitizer molecule. 8−10 The estimated lowest potential loss for the ruthenium metal complex/iodide system is around 750 mV, which limits the maximum obtainable conversion efficiency to 13.4%. 9,11 To boost the efficiencies further, redox couples with a smaller loss in potential were introduced. Among the one-electron redox pairs, 12,13 cobalt(3+/2+) is the most promising for the following two reasons: (i) DSCs with organic dyes and cobalt electrolytes are more stable in comparison to the cells with other one-electron shuttles; 14 (ii) it is possible to obtain cobalt complexes with various redox potentials just by ligand modification. 15,16 It is worth noting that the recent advances with copper(2+/1+) phenantroline-based electrolytes m...

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Section: ■ Results and Discussionmentioning

confidence: 88%

Section: 4'-bis(5'-hexyl-[22'-bithiophen]-5-yl)-22'-bipyridine (33)mentioning

confidence: 99%

Section: ■ Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Ligand Engineering for the Efficient Dye-Sensitized Solar Cells with Ruthenium Sensitizers and Cobalt Electrolytes

Aghazada

Gao

Yella³

et al. 2016

Inorg. Chem.

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“…Advincula and coworkers were the first to synthesize thiophene dendrimers containing up to 30 thiophene units. [16] Bäuerle and coworkers presented oligothiophene dendrimers with up to 90 thiophene units per molecule showing promising results in organic solar cells. [17,18] Much less is known concerning hyperbranched polythiophenes.…”

Section: Introductionmentioning

confidence: 99%

Design of Soluble Hyperbranched Polythiophenes with Tailor‐Made Optoelectronic Properties

Richter

Link

Hanselmann

et al. 2009

Macromol. Rapid Commun.

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Hyperbranched polythiophenes were prepared via a simple one-pot synthesis approach based on oxidative coupling of branched conjugated monomers. Only small variations in the building unit and architecture lead to large differences of absorption and photoluminescence properties. Interestingly, soluble hyperbranched polythiophenes with relatively small molecular weights show enhanced absorption at low and high wavelengths compared to linear analogues, such as poly(3-hexyl thiophenes) with high molecular weights. With this versatile approach we present a method to design tailor made, functional materials with potential applications in optoelectronics.

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“…Advincula and co-workers reported on the first Th dendrimer synthesis (up to 30 Th rings), 21,22 advances in synthetic approaches enabled the preparation of increasingly larger. Thus, Bäuerle and co-workers 23 synthesized different all-Th dendrimers containing up to 90 Th rings with a divergent/convergent approach to facilitate the inclusion of functionalities in the external surface of the conducting dendrimer.…”

Section: Introductionmentioning

confidence: 99%