Please use this identifier to cite or link to this item:
Title: New 3-Ethynylaryl Coumarin-Based Dyes for DSSC Applications: Synthesis, Spectroscopic Properties, and Theoretical Calculations
Authors: Sarrato, João
Pinto, Ana Lucia
Malta, Gabriela
Röck, Eva G
Pina, João 
Lima, João Carlos 
Parola, A. Jorge 
Branco, Paula Sério 
Keywords: dye-sensitized solar cells; coumarin dyes; thieno [3,2-b] thiophene; charge transfer; ethynylaryl
Issue Date: 14-May-2021
Publisher: MDPI
Serial title, monograph or event: Molecules
Volume: 26
Issue: 10
Abstract: A set of 3-ethynylaryl coumarin dyes with mono, bithiophenes and the fused variant, thieno [3,2-b] thiophene, as well as an alkylated benzotriazole unit were prepared and tested for dye-sensitized solar cells (DSSCs). For comparison purposes, the variation of the substitution pattern at the coumarin unit was analyzed with the natural product 6,7-dihydroxycoumarin (Esculetin) as well as 5,7-dihydroxycomarin in the case of the bithiophene dye. Crucial steps for extension of the conjugated system involved Sonogashira reaction yielding highly fluorescent molecules. Spectroscopic characterization showed that the extension of conjugation via the alkynyl bridge resulted in a strong red-shift of absorption and emission spectra (in solution) of approximately 73-79 nm and 52-89 nm, respectively, relative to 6,7-dimethoxy-4-methylcoumarin (λabs = 341 nm and λem = 410 nm). Theoretical density functional theory (DFT) calculations show that the Lowest Unoccupied Molecular Orbital (LUMO) is mostly centered in the cyanoacrylic anchor unit, corroborating the high intramolecular charge transfer (ICT) character of the electronic transition. Photovoltaic performance evaluation reveals that the thieno [3,2-b] thiophene unit present in dye 8 leads to the best sensitizer of the set, with a conversion efficiency (η = 2.00%), best VOC (367 mV) and second best Jsc (9.28 mA·cm-2), surpassed only by dye 9b (Jsc = 10.19 mA·cm-2). This high photocurrent value can be attributed to increased donor ability of the 5,7-dimethoxy unit when compared to the 6,7 equivalent (9b).
ISSN: 1420-3049
DOI: 10.3390/molecules26102934
Rights: openAccess
Appears in Collections:I&D CQC - Artigos em Revistas Internacionais
FCTUC Química - Artigos em Revistas Internacionais

Show full item record


checked on Apr 1, 2024


checked on Apr 2, 2024

Page view(s)

checked on Apr 9, 2024


checked on Apr 9, 2024

Google ScholarTM




This item is licensed under a Creative Commons License Creative Commons