Aggregation‐Free Organic Dyes Featuring Spiro[dibenzo[3,4:6,7]cyclohepta[1,2‐b]quinoxaline‐10,9′‐fluorene] (SDBQX) for Dye‐Sensitized Solar Cells

Abstract

Three novel organic dyes coded as FHD4‐1, FHD4‐2, and FHD4‐3 featuring spiro[dibenzo[3,4:6,7]cyclohepta[1,2‐b]quinoxaline‐10,9′‐fluorene] (SDBQX) moieties are designed to inhibit dye aggregation to improve the performance of dye‐sensitized solar cells (DSSCs). The consistent absorption onsets of FHD4‐1, FHD4‐2, and FHD4‐3 in solutions and adsorbed on TiO2 films indicate that these dyes are aggregation‐free dyes. Therefore, coadsorption with chenodeoxycholic acid (CDCA) of these three dyes reduces the performance of DSSCs because no inhibition effect for dye aggregation is needed, but, on the contrary, the dye loading amount is reduced after addition of CDCA.

A route to carbon-sp3 bridging spiro-molecules: synthetic methods and optoelectronic applications

“…[113][114][115][116][117][118][119] Apart from spiro-OMeTAD, novel spiro molecules have been specifically designed for use as dye molecules in DSSCs. [120][121][122] For example, Salbeck et al 123 combined a perylene tetracarboxylic acid derivative and a diphenylamine chromophore based on the SBF core structure. They synthesized the spiroperylene carboximide molecule P1 (Fig.…”

Amphiphilic Indoline-Based Unsymmetrical Squaraine Dyes for Dye-Sensitized Solar Cells: Modulating the Dye-TiO2/Electrolyte Interface for Nonaqueous and Aqueous Electrolytes

“…Furthermore, tunable optical properties by structural modulation make squaraine dyes more specific over the other metal-free organic dye architecture . Squaraine dyes have an inherent character to form highly aggregated structures on solid or metal oxide surfaces and in solutions, thus having a variety of applications. − Aggregation of dyes on the semiconducting TiO 2 surface is facile and known for diminishing the DSSC efficiency; ,, , however, squaraine dyes wrapped with alkyl groups control both the dye aggregation and charge recombination that enhances the device efficiency by boosting V OC and J SC . , Many skeletal changes have been done to the squaraine dyes apart from the donor–acceptor–donor architecture, which gave varying DSSC device efficiencies of 2.4–8.9%. ,,− Furthermore, the directions of pioneer studies on the photovoltaics are naturally oriented toward aqueous media. − DSSCs based on water showed relatively low device efficiency and require low pH of buffer solutions for the dye anchoring process; therefore, aqueous media were replaced immediately with organic solvents. ,, However, organic solvent-based electrolytes and additives are the reasons for high DSSC efficiency, but they are chemically hazardous, volatile, and inflammable, which limits their practical applications; therefore, nonhazardous electrolytes drew researchers’ attention once again toward water-based DSSCs. ,− Furthermore, aqueous DSSCs based on water electrolytic systems, dyes wrapped with alkyl groups to avoid dye desorption from TiO 2 , and the use of additives to prevent mass transport have been well explored to enhance the DSSC device efficiency. ,,,− Therefore, achieving a high device efficiency through 100% of water media is still a big task to accomplish . One of the challenges is tuning the charge transport property at the dye-TiO 2 /electrolyte interface, which is compatible with aqueous electrolytes.…”

Cause, Regulation and Utilization of Dye Aggregation in Dye-Sensitized Solar Cells

“…Dye aggregation is of paramount importance in determining the overall DSSC conversion efficiency [ 23 ], short-circuit current (J sc ) [ 24 , 25 ], open-circuit voltage (V oc ) [ 26 , 27 ] and fill factor (FF) [ 28 ] of each device. In general, aggregation occurs during sensitization and can be classified as H-aggregation and J-aggregation.…”