{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,3,6]],"date-time":"2026-03-06T20:42:32Z","timestamp":1772829752595,"version":"3.50.1"},"reference-count":78,"publisher":"MDPI AG","issue":"1","license":[{"start":{"date-parts":[[2021,12,28]],"date-time":"2021-12-28T00:00:00Z","timestamp":1640649600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Coatings"],"abstract":"<jats:p>Three heterocyclic dyes were synthesized having in mind the changes in the photovoltaic, optical and redox properties by functionalization of 5-aryl-thieno[3,2-b]thiophene, 5-arylthiophene and bis-methylpyrrolylthiophene \u03c0-bridges with different donor, acceptor\/anchoring groups. Knoevenagel condensation of the aldehyde precursors with 2-cyanoacetic acid was used to prepare the donor-acceptor functionalized heterocyclic molecules. These organic metal-free dyes are constituted by thieno[3,2-b]thiophene, arylthiophene, bis-methylpyrrolylthiophene, spacers and one or two cyanoacetic acid acceptor groups and different electron donor groups (alkoxyl, and pyrrole electron-rich heterocycle). The evaluation of the redox, optical and photovoltaic properties of these compounds indicate that 5-aryl-thieno[3,2-b]thiophene-based dye functionalized with an ethoxyl electron donor and a cyanoacetic acid electron acceptor group\/anchoring moiety displays as sensitizer for DSSCs the best conversion efficiency (2.21%). It is mainly assigned to the higher molar extinction coefficient, long \u03c0-conjugation of the heterocyclic system, higher oxidation potential and strong electron donating capacity of the ethoxyl group compared to the pirrolyl moiety.<\/jats:p>","DOI":"10.3390\/coatings12010034","type":"journal-article","created":{"date-parts":[[2021,12,28]],"date-time":"2021-12-28T06:55:03Z","timestamp":1640674503000},"page":"34","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":15,"title":["Push-Pull Heterocyclic Dyes Based on Pyrrole and Thiophene: Synthesis and Evaluation of Their Optical, Redox and Photovoltaic Properties"],"prefix":"10.3390","volume":"12","author":[{"given":"Sara S. M.","family":"Fernandes","sequence":"first","affiliation":[{"name":"Centro de Qu\u00edmica, Universidade do Minho, Campus de Gualtar, 4710-057 Braga, Portugal"}]},{"given":"Maria Cid\u00e1lia R.","family":"Castro","sequence":"additional","affiliation":[{"name":"Centro de Qu\u00edmica, Universidade do Minho, Campus de Gualtar, 4710-057 Braga, Portugal"}]},{"given":"Dzmitry","family":"Ivanou","sequence":"additional","affiliation":[{"name":"LEPABE, Departamento de Engenharia Qu\u00edmica, Faculdade de Engenharia, Universidade do Porto, 4200-465 Porto, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-2472-3265","authenticated-orcid":false,"given":"Ad\u00e9lio","family":"Mendes","sequence":"additional","affiliation":[{"name":"LEPABE, Departamento de Engenharia Qu\u00edmica, Faculdade de Engenharia, Universidade do Porto, 4200-465 Porto, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-7996-1626","authenticated-orcid":false,"given":"Maria Manuela M.","family":"Raposo","sequence":"additional","affiliation":[{"name":"Centro de Qu\u00edmica, Universidade do Minho, Campus de Gualtar, 4710-057 Braga, Portugal"}]}],"member":"1968","published-online":{"date-parts":[[2021,12,28]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"3","DOI":"10.1016\/j.jphotochem.2004.02.023","article-title":"Conversion of sunlight to electric power by nanocrystalline dye-sensitized solar cells","volume":"164","year":"2004","journal-title":"J. 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