Inhibiting Charge Recombination in cis-Ru(NCS)(2) Diimine Sensitizers with Aromatic Substituents

Autor(es)

Mueller, Andressa V. ^{[1, 2]} ; de Oliveira, Kleber T. ^[3] ; Meyer, Gerald J. ^[1] ; Polo, Andre S. ^[2]

Afiliação do(s) autor(es)

^[1] Univ North Carolina Chapel Hill, Dept Chem, Chapel Hill, NC 27599 - USA

^[2] Univ Fed ABC UFABC, Ctr Ciencias Nat & Humanas, Ave Estados 5001, BR-09210580 Sao Paulo, SP - Brazil

^[3] Univ Fed Sao Carlos UFSCar, Dept Quim, Rodovia Washington Luis, km 235, BR-13565905 Sao Paulo, SP - Brazil

• Tipo de documento: Artigo Científico
• Fonte: ACS APPLIED MATERIALS & INTERFACES; v. 11, n. 46, p. 43223-43234, NOV 20 2019.
• Citações Web of Science: 0

Resumo

A series of cis-{[}Ru(LL)(dcbH(2))(NCS)(2)] compounds, where dcbH(2) = 2,2'-bipyridine-4,4'-dicarboxylic acid and LL = 1,10-phenanthroline (Ru(phen)), 4,7-dipyrrole-1,10-phenanthroline (Ru(pyr)), 4,7-diindole-1,10-phenanthroline (Ru(ind)), or 4,7-dicarbazole-1,10-phenanthroline (Ru(cbz)), was investigated for application as sensitizers in mesoporous TiO2 dye-sensitized solar cells (DSSCs). A systematic increase in the number of rings of the aromatic substituents at the 4,7-positions of the 1,10-phenanthroline allowed tuning of the molecular size of the sensitizers and the energy stored in the excited state while maintaining the same ground-state Ru3+/2+ reduction potentials. These small structural changes had a significant influence on the rates and/or efficiencies of electron injection, back-electron transfer, recombination to oxidized mediators, lateral self-exchange electron transfer, and regeneration through iodide oxidation that were reflected in distinct photoelectrochemical performance of full operating DSSCs. The global efficiencies, open-circuit voltages, and short-circuit current densities of the DSSCs consistently followed the trend Ru(pyr) < Ru(ind) < Ru(phen) < Ru(cbz), and the most optimal performance of Ru(cbz) was ascribed to dramatically slower recombination to the oxidized redox mediators. Transient photovoltage and transient absorption experiments both revealed significantly slower recombination as the size of the aromatic substituents increased with Ru(cbz) providing the most promising behavior for application in dye sensitization. (AU)

• Processo FAPESP: 18/08038-0 - Investigação de processos de transferência eletrônica para sistemas de conversão de energia baseados em Ru(II)/Re(I)
• Beneficiário: Andressa Vidal Muller
• Modalidade de apoio: Bolsas no Exterior - Estágio de Pesquisa - Doutorado
• Processo FAPESP: 18/00106-7 - Reações Fotocatalisadas por Porfirinas em Condições de Fluxo Contínuo: Arilação de Sistemas Heterocíclicos e de Olefinas Ativadas
• Beneficiário: Kleber Thiago de Oliveira
• Modalidade de apoio: Auxílio à Pesquisa - Regular
• Processo FAPESP: 16/24020-9 - Avaliação de processos fotoassistidos por compostos polipiridínicos de Ru(II) e re(i)
• Beneficiário: Andressa Vidal Muller
• Modalidade de apoio: Bolsas no Brasil - Doutorado
• Processo FAPESP: 16/21993-6 - Avaliação de compostos polipiridínicos de Ru(II) e Re(I) em dispositivos fotoativos
• Beneficiário: André Sarto Polo
• Modalidade de apoio: Auxílio à Pesquisa - Regular