Novel Oxindole Based Sensitizers: Synthesis and Application in Dye-Sensitized Solar Cells

Abstract

Two novel oxindole sensitizers have been synthesized for dye-sensitized solar cell applications. These new dyes can provide an additional pathway to inject electrons into the photoanode through the partial chelation of their amide carbonyl groups to the TiO2 surface. Incorporation of an electron deficient pyridine in the acceptor of the TI125 dye was found to enhance the photovoltage and conversion efficiency of the cell.

New Oxindole-Bridged Acceptors for Organic Sensitizers: Substitution and Performance Studies in Dye-Sensitized Solar Cells

“…Scheme 1 depicts the syntheses of new sensitizers TI111-TI115 that started with a Knoevenagel condensation reaction using amides 1a-d and 5-[4-(diphenylamino)phenyl]thiophene-2-carbaldehyde (2) [54] to yield condensed compounds 3a-d as single Z-isomers. Oxindoles 3a-d were then alkylated with methyl bromoacetate in the presence of base and tetrabutylammonium bromide (TBAB) to afford esters 4a-d.…”

“…We unprecedentedly visualize oxindoles as new acceptors for the organic sensitizers. It is our speculation that the amide group of the oxindole dye will not only act as an electron acceptor but also can direct the electron injection because of its chelation to the TiO 2 surface [54]. Furthermore, it is located near the anchoring group which will help to accelerate the electron transfer to the TiO 2 due to the shorter distance.…”

“…The oxindoles are natural indole alkaloids and can be isolated from the plants [50]. Although oxindoles are ubiquitous within the pharmaceutical industry [51][52][53], the potential of oxindoles to act as sensitizing materials [54] has not been investigated by other groups and need to be studied thoroughly. We unprecedentedly visualize oxindoles as new acceptors for the organic sensitizers.…”

Development of indanones and isatins as non-cytotoxic inhibitors of cholinesterases

“…Thus, isatins 15a-15r were obtained in yields ranging between 9 and 94% 8 . Compounds 16a-16h and 17a-17d were prepared similarly; the starting materials (brominated at C-5 or C-5 and C-7) were obtained adapting the procedure reported 9 by Tingare et al…”

Computational Prediction of Electronic and Photovoltaic Properties of Anthracene-Based Organic Dyes for Dye-Sensitized Solar Cells

“…However, solution of the instability of devices and pollution for environment caused from raw materials are still a challenge [18][19][20]. Metal-free organic dyes are characterized by low cost, ease of purification, and flexible molecular design [21], and metal-free sensitizers are designed with donor-π-acceptor (D-π-A), D-π-A-A, or D-A-π-A, which can lead to light-induced charge separation, improvement in stability, and optimization of the energy level of the dye from structure modifications [22][23][24][25]. To date, PCE of such kind of organic dyes has reportedly reached 14% [26].…”