Alexi Cosmos Arango

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BACKGROUND The first cases of multiple sclerosis (MS) in Panama were notified in the 1980s and it was considered a low-risk region for this disease. Between 2000 and 2005, a prevalence study was conducted to characterize MS in Panama. METHODS An instrument was developed to gather information from clinical files and interviews with previous informed(More)
We fabricate PbS colloidal quantum dot (QD)-based solar cells using a fullerene derivative as the electron-transporting layer (ETL). A thiol treatment and oxidation process are used to modify the morphology and electronic structure of the QD films, resulting in devices that exhibit a fill factor (FF) as high as 62%. We also show that, for QDs with a band(More)
were grown was revealed to be almost identical to the stoichiometry determined by EPMA of the obtained crystal, the mixing ratio of the anions in the solution was adopted in the chemical formula of the crystal. The results of EPMA of k-(BETS)2FexGa1±xBr1.0Cl3.0 are: for x = 0.50, Fe/Ga/Br/Cl = 0.51:0.49:1.13:2.85 (0.50:0.50:1.00:3.00); for x = 0.40,(More)
We demonstrate a bilayer photovoltaic device consisting of a heterojunction between colloidal cadmium selenide (CdSe) quantum dots (QDs) and a wide band gap organic hole-transporting thin film of N,N'-diphenyl-N,N'-bis(3-methylphenyl)[1,1'-biphenyl]-4,4'-diamine (TPD) molecules. The active light-absorbing film of QDs is nondestructively printed onto TPD(More)
Citation Osedach, Tim P. et al. " Lateral heterojunction photodetector consisting of molecular organic and colloidal quantum dot thin films. Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use. The MIT Faculty has made this article openly available.(More)
Thin fi lms of organic semiconductors and colloidal nanocrystal quantum dots (QDs) have attracted considerable interest for a variety of electronic device applications due to the tunability of their electronic structure as well as the potential for scalable device fabrication across large-area substrates. QDs are especially interesting due to the freedom(More)
We study the effect of blended and layered titanium dioxide (TiO2) nanoparticles on charge transfer processes in conjugated polymer photovoltaics. A two order of magnitude increase in photoconductivity and sharp saturation is observed for layered versus blended structures, independent of the cathode work function. Using electrodes with similar work(More)