Efficient Electronic Coupling in Perylenediimide Multilayered Films on Indium Tin Oxide

Autor(es)

Silva, Barbara P. G. ^[1] ; Tosco, Bruna ^[1] ; de Florio, Daniel Z. ^[1] ; Stepanenko, Vladimir ^{[2, 3]} ; Wuerthner, Frank ^{[2, 3]} ; Rey, Jose Fernando Q. ^[1] ; Brochsztain, Sergio ^[1]

Afiliação do(s) autor(es)

^[1] Univ Fed ABC, BR-09210580 Santo Andre, SP - Brazil

^[2] Univ Wurzburg, Inst Organ Chem, D-97074 Wurzburg - Germany

^[3] Univ Wurzburg, Ctr Nanosyst Chem, D-97074 Wurzburg - Germany

• Tipo de documento: Artigo Científico
• Fonte: Journal of Physical Chemistry C; v. 124, n. 10, p. 5541-5551, MAR 12 2020.
• Citações Web of Science: 0

Resumo

Layer-by-layer thin films with up to 11 layers of N,N'-bis(2-phosphonoethyl)-3,4,9,10-perylenediimide (PPDI) were deposited on indium tin oxide (ITO) substrates by the zirconium phosphonate method. Film growth was studied by UV-visible absorption spectroscopy, X-ray photoelectron spectroscopy (XPS), X-ray reflectivity (XRR), and atomic force microscopy (AFM). It was found that the films grow in a linear fashion, with the same amount of dye incorporated in each deposition cycle, and the dye molecules were pi-stacked within the films. For a 10-layer film, film thickness was estimated as 20 nm, giving 2 nm per layer. Electrochemical characterization of the films was performed using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). CV measurements showed that peak currents were proportional to the number of layers, for both the first and second reductions of PPDI. The effect of applied bias on the EIS response was studied in both the impedance (Bode plots) and capacitance (Cole-Cole plots) complex planes. The width of the semicircles in the Cole-Cole plots was proportional to the number of layers when the electrode was biased at -0.6 V, which is within the redox window for PPDI reduction. The pseudocapacitance of the films was obtained from the width of the semicircles, allowing the calculation of electroactive surface coverages and electrontransfer rates. Surface coverages of ca. 1 x 10(-10) mol/cm(2) per layer were obtained, whereas electron transfer rates decreased with film thickness, from 41 s(-1) in a monolayer to 1.3 s(-1) in a 10-layer film. The present study shows that compact PPDI films were formed, with efficient electronic coupling between the PPDI units, rendering the films attractive as electron transport layers for organic electronics. (AU)

• Processo FAPESP: 15/24999-2 - Novos compostos cerâmicos para células a combustível de óxidos sólidos protônicas
• Beneficiário: Daniel Zanetti de Florio
• Modalidade de apoio: Auxílio à Pesquisa - Regular
• Processo FAPESP: 16/05496-2 - Síntese e caracterização de organosílicas mesoporosas contendo imidas aromáticas e suas aplicações na área de energia
• Beneficiário: Sergio Brochsztain
• Modalidade de apoio: Auxílio à Pesquisa - Regular