99 research outputs found
Efficient fully blade-coated perovskite solar cells in air with nanometer-thick bathocuproine buffer layer
Fully printed perovskite solar cells (PSCs) were fabricated in air with all constituent layers, except for electrodes, deposited by the blade coating technique. The PSCs incorporated, for the first time, a nanometer-thick printed bathocuproine (BCP) hole blocking buffer using blade coating and deposited at relative humidity up to 50%. The PSCs with a p-i-n structure (glass/indium tin oxide (ITO)/poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS)/CH3NH3PbI3/[6,6]-phenyl-C61-butyric acid methyl ester (PCBM)/BCP/Ag) delivered a maximum power conversion efficiency (PCE) of 14.9% on an active area of 0.5 cm2 when measured under standard test conditions. The PSCs with a blade coated BCP delivered performance of 10% and 63% higher (in relative terms) than those incorporating a spin coated BCP or without any BCP film, respectively. The atomic force microscopy (AFM) showed that blade coated films were more homogeneous and acted also as a surface planarizer leading to a reduction of roughness which improved BCP/Ag interface lowering charge recombination. The demonstration of 15% efficient devices with all constituent layers, including nanometer-thick BCP (⌠10 nm), deposited by blade coating in air, demonstrates a route for industrialization of this technology
Charge transfer complex formation between organic interlayers drives light-soaking in large area perovskite solar cells
Light soaking (LS) is a well-known but poorly understood phenomenon in perovskite solar cells (PSCs) which significantly affects device efficiency and stability. LS is greatly reduced in large-area inverted PSCs when a PC61BM electron transport layer (ETL) is replaced with C60, where the ETL is commonly in contact with a thin bathocuproine (BCP) interlayer. Herein, we identify the key molecular origins of this LS effect using a combination of surface photovoltage, ambient photoemission spectroscopy, Raman spectroscopy, integrated with density functional theory simulations. We find that BCP forms a photoinduced charge-transfer (CT) complex with both C60 and PC61BM. The C60/BCP complex accelerates C60 dimer formation, leading to a favourable cascading energetic landscape for electron extraction and reduced recombination loss. In contrast, the PC61BM/BCP complex suppresses PC61BM dimer formation, meaning that PC61BM dimerisation is not the cause of LS. Instead, it is the slow light-induced formation of the PC61BM/BCP CT complex itself, and the new energetic transport levels associated with it, which cause the much slower and stronger LS effect of PC61BM based PSCs. These findings provide key understanding of photoinduced ETL/BCP interactions and their impact on the LS effect in PSCs
Simple methodology for the quantitative analysis of fatty acids in human red blood cells
In the last years, there has been an increasing
interest in evaluating possible relations between fatty acid
(FA) patterns and the risk for chronic diseases. Due to the
long life span (120 days) of red blood cells (RBCs), their
FA profile reflects a longer term dietary intake and was
recently suggested to be used as an appropriate biomarker
to investigate correlations between FA metabolism and diseases.
Therefore, the aim of this work was to develop and
validate a simple and fast methodology for the quantification
of a broad range of FAs in RBCs using gas chromatography
with flame ionization detector, as a more common
and affordable equipment suitable for biomedical and
nutritional studies including a large number of samples. For
this purpose, different sample preparation protocols were
tested and compared, including a classic two-step method
(Folch method) with modifications and different one-step methods, in which lipid extraction and derivatization were
performed simultaneously. For the one-step methods, different
methylation periods and the inclusion of a saponification
reaction were evaluated. Differences in absolute FA
concentrations were observed among the tested methods,
in particular for some metabolically relevant FAs such as
trans elaidic acid and eicosapentaenoic acid. The one-step
method with saponification and 60 min of methylation time
was selected since it allowed the identification of a higher
number of FAs, and was further submitted to in-house validation.
The proposed methodology provides a simple, fast
and accurate tool to quantitatively analyse FAs in human
RBCs, useful for clinical and nutritional studies.This work received financial support from the
European Union (FEDER funds through COMPETE) and National
Funds (FCT, Fundação para a CiĂȘncia e Tecnologia) through project
PTDC/SAU-ENB/116929/2010 and EXPL/EMS-SIS/2215/2013.
ROR acknowledges PhD scholarship SFRH/BD/97658/2013 attributed
by FCT (Fundação para a CiĂȘncia e Tecnologia).info:eu-repo/semantics/publishedVersio
The Human Serum Metabolome
Continuing improvements in analytical technology along with an increased interest in performing comprehensive, quantitative metabolic profiling, is leading to increased interest pressures within the metabolomics community to develop centralized metabolite reference resources for certain clinically important biofluids, such as cerebrospinal fluid, urine and blood. As part of an ongoing effort to systematically characterize the human metabolome through the Human Metabolome Project, we have undertaken the task of characterizing the human serum metabolome. In doing so, we have combined targeted and non-targeted NMR, GC-MS and LC-MS methods with computer-aided literature mining to identify and quantify a comprehensive, if not absolutely complete, set of metabolites commonly detected and quantified (with today's technology) in the human serum metabolome. Our use of multiple metabolomics platforms and technologies allowed us to substantially enhance the level of metabolome coverage while critically assessing the relative strengths and weaknesses of these platforms or technologies. Tables containing the complete set of 4229 confirmed and highly probable human serum compounds, their concentrations, related literature references and links to their known disease associations are freely available at http://www.serummetabolome.ca
De pivete a funqueiro: genealogia de uma alteridade
Com base na teoria das representaçÔes sociais de Moscovici e a partir de contextualizaçÔes do fenĂŽmeno dos arrastĂ”es, esse texto se propĂ”e a discutir elementos que respondam Ă s questĂ”es: por que discursos criminalizantes, que afirmam a periculosidade do funkeiro, se fizeram tĂŁo presentes desde o inĂcio da dĂ©cada de noventa no Rio de Janeiro? Como esses discursos, que apontam para uma determinada construção social do funkeiro, interferiram na relação do funk com a sociedade? A discussĂŁo passa pela compreensĂŁo dos dispositivos criados na sociedade carioca daquele perĂodo para a solução de problemas com os quais ela se via confrontada. Trata-se de tentar compreender como, em certo momento, o funkeiro ganha um perfil amplamente difundido como problema que requer um tipo de intervenção especĂfica
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