Alves, L. C.

Barreiros, M. Alexandra

Brites, Maria João

Corregidor, V.

Guimarães, Fernanda

Mascarenhas, João

Sequeira, S.

Barreiros, Maria Alexandra

Guimarães, Fernanda M. G.

Laboratório Nacional de Energia e Geologia Repository

Microscopy techniques for dye distribution in DSCs nanocrystalline TiO2 films

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Microscopy techniques for dye distribution in DSCs nanocrystalline TiO2 films   M. A. Barreiros1, S. Sequeira1, L. C. Alves2,3, V. Corregidor3,4, F. Guimarães5, J. Mascarenhas1, M. J. Brites1  1 Laboratório Nacional de Energia e Geologia, LEN/UES, Estrada do Paço do Lumiar, 22, 1649-038 Lisboa, Portugal. 2 Campus Tecnológico e Nuclear, IST/ITN, Instituto Superior Técnico, Universidade Lisboa, E.N. 10, 2686-953 Sacavém, Portugal 3 CFNUL, Universidade de Lisboa, Av. Prof. Gama Pinto, 2, 1649-003 Lisboa, Portugal 4 IPFN, Instituto Superior Técnico, Universidade de Lisboa, E.N. 10, 2686-953 Sacavém, Portugal 5 Laboratório Nacional de Energia e Geologia, LGM/UCTM, Rua da Amieira, Apartado 1089, 4466-901 S. Mamede de Infesta, Portugal email:  alexandra.barreiros@lneg.pt   Communication type: Poster Communication  Capture of sunlight has attracted an increasing interest in the scientific community and triggered the development of efficient and cheap photovoltaic devices. Amongst recent generation technologies for solar energy conversion, dye-sensitized solar cells (DSCs) show an optimal trade-off between high-conversion efficiency and low-cost manufacturing. For the last two decades, significant progress has been made and best energy conversion efficiency of the DSC at the laboratory scale has surpassed 11%. A lot of work has focused on the enlargement of surface areas to enhance the amount of adsorbed dyes by reduction of nanoparticle sizes or utilization of novel structures. Despite this progress, there remain some crucial details of DSC operation for which limited information is available. One area is the study of dye diffusion, adsorption, and surface coverage as well as the question as to whether the dye is homogeneously spread throughout the nc-TiO2 film. Microprobe techniques can be powerful tools to evaluate the dye load, the dye distribution and dye depth profile in sensitized films. Electron Probe Microanalysis (EPMA) and Ion beam analytical (IBA) techniques using a micro-ion beam, were used to quantify and to study the distribution of the ruthenium organometallic (N719) dye in TiO2 films, profiting from the different penetration depth and beam sizes of each technique. Two different types of films were prepared and sensitized, mesoporous nanoparticles and 1D nanostructured TiO2 films (figure 1). Despite the low concentration of Ru atoms the high sensitive analytical techniques used provided promising results to assess the Ru surface distribution (figure 2) and depth profile (figure 3).  Preliminary data indicate different dye load (Ru/Ti values between 0.4-2 %) depending on the TiO2 film thickness, being the Ru distribution homogenous during the first nanometers from the surface (figure 2).     V. Corregidor acknowledges the funding support from the FCT-Ciência program.         Fig. 1 - SEM image of a) mesoporous nanoparticles TiO2 film and b) 1D nanostructured TiO2 film.     Fig. 2 – 2D PIXE maps for Ru and Ti  (scan size: 1320x1320 mm2) and the  RBS spectra recorded using a 2MeV alpha particle beam.     Figure 3. EPMA/WDS mapping of a mesoporous nanoparticles TiO2 film.  Ru Ti a) b) 

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Microscopy techniques for dye distribution in DSCs nanocrystalline TiO2 films

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