Novel push-pull thieno[2,3-b]indole-based dyes for efficient dye-sensitized solar cells (DSSCs)

Abstract

New metal-free sensitizers (IK 3-6), based on the thieno [2,3-b]indole ring system, bearing various aliphatic substituents at the nitrogen atom (electron-donating part), several thiophene units (π-bridge linker) and 2-cyanoacrylic acid (the electron-accepting and anchoring group) have been synthesized for application in dye-sensitized solar cells (DSSCs). The relationship between the IK dye structure and efficiency of the corresponding DSSC has been elucidated. Power conversion efficiency (PCE) up to 6.3% (short-circuit photocurrent density (JSC) 19.0 mA cm -2 , open-circuit voltage (VOC) 0.59 V, and fill factor (FF) 56.4%) were obtained for the DSSC, based on 2-cyano-, which proved to be a highly synthetic available compound, under simulated AM 1.5 G irradiation (100 mW cm -2 ), thus indicating that thieno [2,3-b]indole-based organic dyes are perspective candidates for DSSCs.

Dye-Sensitized Solar Cells: Fundamentals and Current Status

“…To suppress a charge-recombination process at the dye interface, they introduced long alkyl chains, which specifically interact with the radical mediator [ 229 ]. Recently in 2017, Irgashev et al synthesized a novel push-pull thieno[2,3-b]indole-based metal-free dyes and investigated their application in DSSCs [ 230 ]. They designed IK 3–6 dyes based on the thieno[2,3-b]indole ring system, bearing various aliphatic substituents such as the nitrogen atom as an electron-donating part, several thiophene units as a π-bridge linker, and 2-cyanoacrylic acid as the electron-accepting and anchoring group.…”

“…The LUMO energy levels are more negative than the conduction edge of the TiO 2 (− 3.9 eV), and their HOMO energy levels of all four dyes were found to be more positive than the I − /I 3 − redox couple (− 4.9 eV), making possible regeneration of oxidized dye molecules after injection of excited electrons into TiO 2 electrode (as shown in Fig. 19 ) [ 230 ]. The less efficiency of other dyes was contributed by the intermolecular π-stacking and aggregation processes in these dyes, proceeding on the photoanode surface.…”

Characterization and electrochemical properties of conducting nanocomposites synthesized from p-anisidine and aniline with titanium carbide by chemical oxidative method

“…Conducting polymers are 10 combined with metal oxides because of their enhanced physical 11 and electronic properties and find useful applications in different 12 devices, such as sensors, electrodes, batteries, and photovoltaics 13 [1,2]. Conducting-polymer-based solar cells have gained much 14 importance in the last decade because of their low cost, easy 15 processability, low toxicity, and high environmental stability [3,4].…”

“…16 Among conducting polymers, polyaniline (PANI) is unique because 17 it can be easily doped with various acids and it also exhibits good 18 thermal and environmental stabilities [5,6]. Metal oxides can also 19 replace fullerenes (electron-acceptor materials) in bulk hetero- 20 junction solar cells because of their high electron mobilities [1,2]. 21 Organic-inorganic hybrid materials, which combine excellent 22 performances of the two materials, are extremely innovative, and 23 such materials promise new applications in many fields, such as 24 electronics, optics, electrochemistry, supercapacitor, mechanics 25 and biology [7][8][9][10].…”

Indole fused heterocycles as sensitizers in dye-sensitized solar cells: an overview

“…35). [68][69] They introduced a new synthetic route for constructing thieno [3,2-b]indole from 1-alkylisatin and 2-acetylthiophene. Among the dyes, 108 with thiophene as the -bridge and ethyl hexyl as the alkyl group contributed towards the highest PCE of 6.3%.…”