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

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-3-{5-[8-(2-ethylhexyl)-8H-thieno[2,3- b]indol-2-yl]thiophen-2-yl}acrylic acid (IK 3), 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. © 2017 Arkat. All rights reserved

A facile and convenient synthesis and photovoltaic characterization of novel thieno[2,3-b]indole dyes for dye sensitized solar cells

Two novel dyes IK-1,2 bearing the 8-alkyl-8H-thieno[2,3-b]indole unit as an electron-donating part of the push–pull system have been designed and prepared, as promising sensitizers for solar cells. The key steps of the synthesis involve the crotonic condensation of 1-alkylisatins with 2-acetylthiophene, followed by reduction of the Cdouble bond; length as m-dashC double bond and further cyclization through the Paal–Knorr reaction with the Lawesson reagent, thus leading to the formation of 2-(thien-2-yl) substituted thieno[2,3-b]indole derivatives. The optical and electrochemical properties of these dyes have been investigated by using spectrophotometry and cyclic voltammetry respectively, while their photovoltaic performance was evaluated by a device fabrication study. The DSSCs based on IK-1 and IK-2 have demonstrated an efficiency of η = 0.37% (FF = 73%) and η = 0.79% (FF = 69%) under 100 mW cm−2 simulated AM 1.5 G solar irradiation, respectively

A facile and convenient synthesis and photovoltaic characterization of novel thieno[2,3-b]indole dyes for dye sensitized solar cells

Two novel dyes IK-1,2 bearing the 8-alkyl-8H-thieno[2,3-b]indole unit as an electron-donating part of the push–pull system have been designed and prepared, as promising sensitizers for solar cells. The key steps of the synthesis involve the crotonic condensation of 1-alkylisatins with 2-acetylthiophene, followed by reduction of the Cdouble bond; length as m-dashC double bond and further cyclization through the Paal–Knorr reaction with the Lawesson reagent, thus leading to the formation of 2-(thien-2-yl) substituted thieno[2,3-b]indole derivatives. The optical and electrochemical properties of these dyes have been investigated by using spectrophotometry and cyclic voltammetry respectively, while their photovoltaic performance was evaluated by a device fabrication study. The DSSCs based on IK-1 and IK-2 have demonstrated an efficiency of η = 0.37% (FF = 73%) and η = 0.79% (FF = 69%) under 100 mW cm−2 simulated AM 1.5 G solar irradiation, respectively

Pyrimidine-Based Push–Pull Systems with a New Anchoring Amide Group for Dye-Sensitized Solar Cells

New donor–π–acceptor pyrimidine-based dyes comprising an amide moiety as an anchoring group have been designed. The dyes were synthesized by sequential procedures based on the microwave-assisted Suzuki cross-coupling and bromination reactions. The influence of the dye structure and length of π-linker on the photophysical and electrochemical properties and on the photovoltaic effectiveness of dye-sensitized solar cells was investigated. An increase in efficiency with a decrease in the length of π-linker was revealed. The D1 dye with only one 2,5-thienylene-linker provided the highest power conversion efficiency among the fabricated dye sensitized solar cells