The role of π bridges in high-efficiency DSCs based on unsymmetrical squaraines
| Autor: | Elisa Dell'Orto, Jared H. Delcamp, Tissa Sajoto, Mohammad Khaja Nazeeruddin, Stephen Barlow, Yanrong Shi, Jun-Ho Yum, Michael Grätzel, Seth R. Marder |
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| Rok vydání: | 2012 |
| Předmět: |
Squaraine dye
Organic Chemistry Energy conversion efficiency 02 engineering and technology General Chemistry Molar absorptivity Chromophore 010402 general chemistry 021001 nanoscience & nanotechnology Photochemistry 01 natural sciences Catalysis 3. Good health 0104 chemical sciences chemistry.chemical_compound Delocalized electron chemistry 0210 nano-technology HOMO/LUMO |
| Zdroj: | Chemistry (Weinheim an der Bergstrasse, Germany). 19(5) |
| ISSN: | 1521-3765 |
| Popis: | A series of squaraine-based sensitizers with various π bridges and anchors were prepared and examined in dye-sensitized solar cells. The carboxylic anchor group was attached onto a squaraine dye through π bridges with and without an ethynyl spacer. DFT studies indicate that the LUMO is delocalized throughout the dyes, whilst the HOMO resides on the squaraine core. The dye that incorporates a 4,4-di-n-hexyl-cyclopentadithiophene group that is directly attached onto the π bridge, JD10, exhibits the highest power conversion efficiency in a DSC; this result is attributed, in part, to the deaggregative properties that are associated with the gem-di-n-hexyl substituents, which extend above and below the π-conjugated dye plane. Dye JD10 demonstrates a power-conversion efficiency of 7.3% for liquid-electrolyte dye-sensitized solar cells and 7.9% for cells that are co-sensitized by another metal-free dye, D35, which substantially exceed the performance of any previously tested squaraine sensitizer. A panchromatic incident-photon-to-current-conversion efficiency curve is realized for this dye with an excellent short-circuit current of 18.0 mA cm(-2). This current is higher than that seen for other squaraine dyes, partially owing to a high molar absorptivity of5,000 M(-1) cm(-1) from 400 nm to the long-wavelength onset of 724 nm for dye JD10. |
| Databáze: | OpenAIRE |
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