Density functional theory study of new azo dyes with different pi-spacers for dye-sensitized solar cells

作者：Novir Samaneh Bagheri; Hashemianzadeh Seyed Majid^*

来源：Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy , 2015, 143: 20-34.

DOI：10.1016/j.saa.2015.02.026

• Dye sensitized solar cells
• Charge recombination
• TDDFT
• Lifetime
• Absorption spectra
• Electron injection

Some of new azo-based metal-free dyes with different pi-conjugation spacers, such as carbazole, fluorene, pyrrole, thiophene, furan and thiazole, have been investigated with density functional theory (DFT) and time-dependent DFT (TDDFT) calculations. Theoretical calculations allow us to quantify factors such as light harvesting efficiency (LHE), electron injection driving force (Delta G(inject)) and the weight of the LUMO orbital on the carboxylic group (Q(LUMO)) related to the short-circuit photocurrent density (J(SC)), and to evaluate both charge recombination between the semiconductor conduction band electrons and the oxidized dyes and/or electrolyte, and also the shift of the conduction band of the semiconductor as a result of the adsorption of the dyes onto the semiconductor surface, associated with the open-circuit photovoltage (V-OC). According to the results, we could predict that how the pi-conjugation spacers influence the J(SC) as well as the V-OC of DSSCs. Among these dyes, the carbazole and fluorene-based dyes (dyes 1 and 2) show the highest LHE, Delta G(inject), Q(LUMO), and the slowest recombination rate. Consequently, the obtained results show that the carbazole and fluorene-based dyes could have the better J(SC) and V-OC compared to the other dyes.

• 出版日期2015-5-15