Structure-property relationship of different electron donors: new organic sensitizers based on bithiazole moiety for high efficiency dye-sensitized solar cells

Abstract

Three metal-free bithiazole organic dyes (BTT-I-III) based on D-A-p-A building blocks were designed and synthesized for dye-sensitized solar cells (DSSCs) to study the influence of different electron donors on photovoltaic properties, in which the electron donors of BTT-I-III were carbazole, triphenylamine and indoline moieties, respectively. The UV/Vis absorption spectra of BTT-III containing indoline as electrondonor displayed red-shifted absorption compared to the other two dyes with an onset close to 700 nm.The incident photon-to-current conversion efficiency (IPCE) spectra of BTT-III showed a wide region and kept a value higher than 10-15% during 580-650 nm. Electrochemical measurement data indicated that the HOMO and LUMO energy levels could be tuned through introducing different electron-donors in the dye molecule. It was found that the overall conversion efficiency of indoline donor based dye BTT-III showed the highest efficiency of 7.86% under AM 1.5 irradiation (100 mW cm 22 ). The electron lifetime calculated from electrochemical impedance spectroscopy (EIS) measurement demonstrated the reduced charge recombination and the higher open-circuit voltage.

Multichromophoric sensitizers based on calix[4]arene scaffold and 4 H -pyranylidene moiety for DSSCs application

“…The lifetimes were calculated following the equation [45] τ = 1/2 π f (f: frequency at the maximum of the curve in the intermediate frequency region in the Bode plot). The lifetime of electrons are 3, 7, 5 ms for the dyes (P), (Cx-2-P) and (Cx-P-TPA), respectively [46]. This suggests that the calixarene scaffold reduces the recombination process on the TiO 2 surface.…”

Synthesis and characterization of a triphenylamine-dibenzosuberenone-based conjugated organic material and an investigation of its photovoltaic properties

“…Molecular engineering of donor groups has advanced from the use of a basic moiety of TPA to a moiety based on starburst phenylene, to regulate electronic grades or molecular configuration, and to provide efficient movement of charge. 28 A π-tunneling device is a modern design function, affecting the highest energy occupied molecular orbital (HOMO)/lowest energy unoccupied molecular orbital (LUMO) energy levels or otherwise spectroscopic characteristics. 29 Herein, we report on the synthesis of 3,7-bis[4-(diphenylamino)phenyl]-5H-dibenzo[a,d] [7]annulen-5-one (3) which has a D-A-D-based system and a high level of conjugation.…”

Thiophene-bithiazole based metal-free dye as DSSC sensitizer: Effect of co-adsorbents on photovoltaic efficiency

“…Literature reports suggest that metal-free, thiophene based systems exhibited enhancement in efficiency by incorporating co-adsorbents. 20,25,[44][45][46][47][48] A Triphenylamine based sensitizer containing thiophene as a π-bridge exhibited an increase in efficiency of 45% in the presence of CDCA. 25 Multifunctional co-adsorbents with naphthalene and anthracene as π-conjugated aryl unit exhibited significant enhancement in photovoltaic parameters by suppressing charge recombination and increasing electron lifetime.…”