Quirina Ferreira

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In this article, we present a denoising algorithm to improve the interpretation and quality of scanning tunneling microscopy (STM) images. Given the high level of self-similarity of STM images, we propose a denoising algorithm by reformulating the true estimation problem as a sparse regression, often termed sparse coding. We introduce modifications to the(More)
We report on the efficiency improvement of organic solar cells (OPVs) based on the low energy gap polyfluorene derivative, APFO-3, and the soluble C60 fullerene PCBM, upon addition of a residual amount of poly (4-vinylpyridine) (PVP). We find that the addition of 1% by weight of PVP with respect to the APFO-3 content leads to an increase of efficiency from(More)
Biocellulose and biocellulose composites are being investigated as substrates and as gate dielectrics for organic field effect transistors. Spin coated films of regioregular poly(3-hexylthiophene) (RR-P3HT) and thermally evaporated pentacene were used as semiconducting materials. Preliminary results on device characteristics are reported.
We report on organic photovoltaic cells (OPVs) with columnar-grain active layers consisting in cross-linked semiconducting (conjugated) polymers as electron-donors and PCBM as the electron-acceptor and compare with OPVs based either on blends or on planar bilayers made with the same components. Although the columnar-grain layers have morphologic(More)
This article reports on the measurement of the electrical properties of a single molecule, a first step for the functionalization of surfaces towards nanoelectronics applications. The study includes the preparation and characterization of monolayers of cobalt (II) porphyrin (CoOEP) self-assembled on highly oriented pyrolitic graphite (HOPG). These molecules(More)
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