Li-Lin Tan

Highly efficient and stable organic sensitizers with duplex starburst triphenylamine and carbazole donors for liquid and quasi-solid-state dye-sensitized solar cells

Two new D–D–π–π–A type stable organic sensitizers, DT3 and DW3, were successfully synthesized for dye-sensitized solar cells (DSSCs). DT3 displayed η values of 10.03% and 8.05% in liquid and quasi-solid-state DSSCs, respectively, under standard global 1.5 solar conditions, offering an example achieving the highest efficiency to date in quasi-solid-state DSSCs based on pure organic dyes.

Starburst triarylamine based dyes bearing a 3,4-ethylenedioxythiophene linker for efficient dye-sensitized solar cells.

Starburst triarylamine-based organic dyes (D1, D2, and D3) have been synthesized. For the three designed dyes, the starburst triarylamine group, thiophene (or 3,4-ethylenedioxythiophene), and cyanoacetic acid take the role of electron donor, π-conjugation bridge, and electron acceptor, respectively. These compounds are characterized by photophysical, electrochemical, and theoretical computational methods. Nanocrystalline TiO2-based dye-sensitized solar cells were fabricated using these molecules as light-harvesting sensitizers. The overall efficiencies of the sensitized cells range from 5.48 to 6.15%. It was found that the introduction of the EDOT group in D3 bathochromically extended the absorption spectra, resulting in a leap in the photovoltaic performance in comparison to D2. Incorporation of a hydrophobic carbazole-containing segment at D2 relative with D1 retarded the electron transfer from TiO2 to the oxidized dye or electrolyte, leading to an increase of electron lifetime.

Stable organic dyes based on the benzo[1,2-b:4,5-b′]dithiophene donor for efficient dye-sensitized solar cells

Two novel arylamine-free organic compounds (CYF1 and CYF2) incorporating a substituted benzo[1,2-b:4,5-b′]dithiophene unit as the electron donor were synthesized and used as sensitizers for dye-sensitized solar cells (DSSCs). The relationship between the chemical structure and photovoltaic performance was investigated. A higher molar absorption coefficient, longer electron lifetime, and larger adsorption amount were observed for sensitizer CYF1, which contains a single π bridge and anchoring unit, compared with CYF2 with twin π bridges and anchoring units. As a result, under standard global AM 1.5 solar conditions, the device based on CYF1 sensitizer gave a higher conversion efficiency of 8.02% than that based on CYF2. This is the highest value for amine-free organic sensitizers with no strong donor units. Moreover, the CYF1- and CYF2-sensitized DSSCs exhibited excellent stability under 1000 W m2 light soaking at 60 °C for 600 h. This is the first example of organic sensitizers based on benzo[1,2-b:4,5-b′]dithiophene donors for efficient dye-sensitized solar cells.

Dye‐Sensitized Solar Cells with Improved Performance using Cone‐Calix[4]Arene Based Dyes

Three cone-calix[4]arene-based sensitizers (Calix-1-Calix-3) with multiple donor-π-acceptor (D-π-A) moieties are designed, synthesized, and applied in dye-sensitized solar cells (DSSCs). Their photophysical and electrochemical properties are characterized by measuring UV/Vis absorption and emission spectra, cyclic voltammetry, and density functional theory (DFT) calculations. Calix-3 has excellent thermo- and photostability, as illustrated by thermogravimetric analysis (TGA) and dye-aging tests, respectively. Importantly, a DSSC using the Calix-3 dye displays a conversion efficiency of 5.48 % in under standard AM 1.5 Global solar illumination conditions, much better than corresponding DSSCs that use the rod-shaped dye M-3 with a single D-π-A chain (3.56 %). The dyes offer advantages in terms of higher molar extinction coefficients, longer electron lifetimes, better stability, and stronger binding ability to TiO2 film. This is the first example of calixarene-based sensitizers for efficient dye-sensitized solar cells.

Fluorescent calix[4]arene chemosensor for acidic and basic amino acids in pure aqueous media

A modified calix[4]arene based receptor 2, conjugated with four bithiophene–cyanoacrylic acid groups, not only recognizes acidic amino acids (Asp and Glu) by quenching fluorescence, but also shows highly selective sensing for basic amino acids (Lys and Arg) by turning on fluorescence in sodium phosphate buffer solution without any organic solvent. The UV-Vis spectroscopy binding analysis and ESI-MS studies indicate that the above complexes have a 1 : 1 stoichiometry. 1H NMR and molecular modeling studies suggest a supramolecular complex structure like the relationship between a lid and cup, but not a typical host-guest relationship of the cavity. A plausible mechanism involving intramolecular charge transfer (ICT) is proposed.

Performance Improvement for Dye-sensitized Solar Cells with Cone-calix[4]arene Based Dyes

Invited for the cover of this issue is the group of Jun-Min Liu and Cheng-Yong Su at Sun Yat-Sen University. The image shows that cone-calix[4]arene-based dye flowers can develop in the field of dye-sensitized solar cells as sunflowers thrive under sunshine. The Full Paper itself is available at 10.1002/cssc.201402401