Cláudia Costa
Universidade Nova de Lisboa
Network
Latest external collaboration on country level. Dive into details by clicking on the dots.
Publication
Featured researches published by Cláudia Costa.
ACS Applied Materials & Interfaces | 2012
Cláudia Costa; Carlos Pinheiro; Inês Henriques; César A. T. Laia
Tungsten oxide nanoparticles were synthesized via a sol-gel route using metallic tungsten as precursor, and were printed on a flexible electrode using inkjet printing in order to build solid-state electrochromic cells. Several spectroscopic techniques were used to characterize and compare tungsten oxide particles obtained from different origins. FTIR, Raman and X-ray diffraction spectroscopic measurements showed that the sol-gel synthesis described here produces nanoparticles mainly in an amorphous state with hexagonal crystalline domains and allowed the analysis of the hydration extent of those nanoparticles. The size was measured combining dynamic light scattering, sedimentation, and microscopic techniques (AFM), showing a consistent size of about 200 nm. The tungsten oxide nanoparticles were used to produce an ink formulation for application in inkjet printing. Solid-state electrochromic devices were assembled at room temperature, without sintering the tungsten oxide printed films, showing excellent contrast between on/off states. Electrochemical characterization of those films is described using cyclic voltammetry. The devices were then tested through spectroelectrochemistry by Visible/NIR absorption spectroscopy (400-2200 nm range), showing a dual spectroscopic response depending on the applied voltage. This phenomenon is attributed to the presence of two different crystalline states in accordance with results obtained from the spectroscopic characterization of the nanoparticles. The electrochromic cells had a good cycling stability showing high reversibility and a cyclability up to more than 50,000 cycles with a degradation of 25%.
ACS Applied Materials & Interfaces | 2012
Cláudia Costa; Carlos Pinheiro; Inês Henriques; César A. T. Laia
Vanadium oxide gel was synthesized and formulated for the assembly of solid-state electrochromic cells on flexible and transparent electrodes using inkjet printing. FTIR, Raman, and X-ray diffraction spectroscopic measurements showed that the vanadium oxide gel here synthesized consisted of V(2)O(5)·6H(2)O, microstructures similar to orthorhombic V(2)O(5), while Raman spectroscopy also shows the presence of amorphous domains. Atomic force microscopy (AFM) images of the thin films printed using an inkjet shows a ribbonlike structure, which is in accordance with previous results of the vanadium oxide gels in solution. Solid-state electrochromic devices were assembled at room temperature using the inkjet printed films, without any sinterization step. The electrochemical properties of the vanadium oxide gel were characterized by cyclic voltammetry and spectroelectrochemistry by visible/NIR absorption spectroscopy (in both liquid and solid-state). Several redox steps are observed, which gives rise to a variety of color transitions as a function of the applied voltage. The different optical properties of the vanadium oxide gel are assigned to different intercalation steps of Li(+), leading to different crystalline phases of the gel. The final result is a solid-state electrochromic cell showing excellent contrast between the redox states, giving rise to colors such as yellow, green, or blue. Color space analysis was used to characterize the electrochromic transitions, and while absorption spectra showed rather long switching times (up to 100 s), in L*a*b* color space coordinates, the switching time is smaller than 30 s. These electrochromic cells also have an excellent cycling stability showing high reversibility and a cyclability up to more than 30,000 cycles with a degradation of 18%.
Solar Energy Materials and Solar Cells | 2016
Lúcia Isabel Pedro De Gomes; Aida Branco; Tiago Moreira; Filipa Feliciano; Carlos Pinheiro; Cláudia Costa
International Business Review | 2015
Cláudia Costa; Luis Filipe Lages; Paula Hortinha
Displays | 2013
Lúcia Isabel Pedro De Gomes; Ana C. Marques; Aida Branco; Jorge Araújo; Mário M.Q. Simões; S. Cardoso; Fernando de C. da Silva; Inês Henriques; César A. T. Laia; Cláudia Costa
Solar Energy Materials and Solar Cells | 2016
António Califórnia; Ana S. Silva; José Gonçalves; Aida Branco; Carlos Pinheiro; Cláudia Costa
Archive | 2010
I. Ferreira; Cláudia Costa; Elvira Maria Correla Fortunato; Rodrigo Ferrão De Paiva Martins; Inês Henriques
Archive | 2012
Cláudia Costa; Carlos Alberto Pinheiro Baptista; Inês Henriques; César A. T. Laia
Archive | 2017
Ângela Maria Jesus De Sequeira Serra Nunes; Lúcia Isabel Pedro De Gomes; Vítor Vermelhudo; Cláudia Costa
Archive | 2017
Carlos Alberto Pinheiro Batista; Cláudia Costa; César A. T. Laia; Inês Henriques