Solid state dye sensitized solar cells applying conducting organic polymers as hole conductors

Solid-state dye sensitized solar cells (SSDSCs) applying mesoporous TiO electrodes sensitized with Ru complex dye Z907 and conducting organic polymers as the hole transport material (HTM) are prepared. We employ the in-situ photo-electrochemically polymerization technique (PEP)[1-3] in order to obtain, in a single step, the conducting organic polymer on the TiO /Dye electrode. We developed a modification of reported method [2] which allows the polymer poly(3,4-ethylenedioxythiophene) (PEDOT) by different electrochemical techniques applying constant-voltage and constant-current methods. Polymer morphology and its influence on solar cell performance were studied. Overall conversion efficiency above 2% (AM 1.5, 100 mW cm) was obtained

Hydrothermal synthesis of 1D TiO2 nanostructures for dye sensitized solar cells

El pdf del artículo es la versión pre-print.Mono-dimensional titanium oxide nanostructures (multi-walled nanotubes and nanorods) were synthesized by the hydrothermal method and applied to the construction of dye sensitized solar cells (DSCs). First, nanotubes (TiNTs) and nanotubes loaded with titanium oxide nanoparticles (TiNT/NPs) were synthesized with specific surface areas of 253 m2/g and 304 m2/g, respectively. After that, thermal treatment of the nanotubes at 500 °C resulted in their transformation into the corresponding anatase nanorods (TiNT-Δ and TiNT/NPs-Δ samples). X-ray diffraction and Raman spectroscopy data indicated that titanium oxide in the pristine TiNT and TiNT/NP samples was converted into anatase phase TiO2 during the heating. Additionally, specific surface areas and water adsorption capacities decreased after the heat treatment due to the sample agglomeration and the collapse of the inner nanotube channels. DSCs were fabricated with the nanotube TiNT and TiNT/NP samples and with the anatase nanorod TiNT-Δ and TiNT/NPs-Δ samples as well. The highest power conversion efficiency of η = 3.12% was obtained for the TiNT sample, despite its lower specific surface compared with the corresponding nanoparticle-loaded sample (TiNT/NP). © 2011 Elsevier B.V. All rights reserved.This work was funded by the Government of Aragon and La Caixa (project ref. GA-LC-041/2008) and by the Spanish MICINN (projects ref. EUI2008-00152 and ENE2008-04373). We thank the Spanish National Research Council (CSIC) for the JAE-Doc contracts awarded to Y.Y. and A.A. To the Xarxa de Referència en Materials Avanc¸ ats per a l’Energia, XaRMAE (Reference Center for Advanced Materials for Energy) of the Catalonia Government.Peer Reviewe

Study on Thermal Properties and Mechanical Properties of Short-cut Polyimide-Fiber Reinforced Polyphenyl Sulfone Composites

In order to increase the thermal stability and mechanical property of PPSU, two different polyimide (PI) short cut fibers reinforced polyphenyl sulfone (PPSU) composites were prepared by melt extrusion using a threescrew extruder. In addition, the effects of fiber lengths on thermal stability, heat resistance and mechanical properties of the composites was studied. The results indicate that the addition of polyimide chopped fiber can greatly improve the heat resistance of the composites. Comparing with PPSU, with the increasing of fiber content, the heat deformation temperature (HDT) of composites increased from 205 °C to 229 °C, but the addition of polyimide fiber has limited effect on the thermal stability of the composites. Meanwhile, the addition of polyimide chopped fiber can also improve the mechanical properties of the composites. Compared with PPSU, the tensile strength of composites can be increased by 102%, and the bending strength can be raised by 117%

A aplicação de tecnologia de blockchain na campanha anticorrupção na China

Mestrado Bolonha em Desenvolvimento e Cooperação InternacionalO rápido desenvolvimento económico da China a partir da década de 1980 trouxe a prosperidade política e cultural através de política de reforma e abertura, mas também trouxe o crescimento da corrupção no Partido Comunista Chinês. O governo chinês iniciou uma série de investigação de corrupção desde o 18º Congresso Nacional do Partido Comunista Chinês em 2012 e tentou aplicar a tecnologia da informação ao trabalho anticorrupção. Propõe-se a observar a atualidade da campanha anticorrupção por meio de tecnologia da informação, segundo as políticas atuais, analisando as insuficiências dessa forma na luta contra corrupção. As observações mostram-nos a falta de regulações formais e a falta de proteção de privacidade pessoal são obstáculos para a promoção de campanha anticorrupção através de tecnologia de informação. Por meio de estudo de legislação pertinente e de tecnologia de blockchain com metodologia qualitativa, procede-se a comparação e a combinação entre a tecnologia de blockchain e aplicação de tecnologia de informação na campanha anticorrupção. O estudo descobriu a semelhança entre as duas tecnologias e a possibilidade de aplicação de tecnologia de blockchain na campanha anticorrupção chinesa para resolver o problema de segurança dos dados, privacidade pessoal e legislações. Concluiu que a tecnologia de blockchain é aplicável para a campanha anticorrupção chinesa e que para tal, é necessário também, o governo possui uma legislação e regulação forte, de modo que as tecnologias novas podem promover o desenvolvimento do sistema governamental.China's rapid economic development since the 1980s has brought political and cultural prosperity through policy reform and opening up, but it has also brought the growth of corruption in the Chinese Communist Party. The Chinese government has launched a series of corruption investigations since the 18th National Congress of the Chinese Communist Party in 2012 and has tried to apply information technology to anticorruption campaign. This dissertation proposes to observe the actuality of the anticorruption campaign through information technology, according to current policies, analyzing the insufficiencies in this way in the fight against corruption. The observations show us that the lack of formal regulations and the lack of protection of personal privacy are obstacles to promoting an anti-corruption campaign through information technology. Through a study of relevant legislation and blockchain technology with a qualitative methodology, a comparison and combination between blockchain technology and the application of information technology in the anti-corruption campaign is carried out. The study found the similarity between the two technologies and the possibility of applying blockchain technology in the Chinese anti-corruption campaign to solve the problem of data security, personal privacy and legislation. The dissertation concluded that blockchain technology is applicable to the Chinese anti-corruption campaign and that for this, it is also necessary, the government has strong legislation and regulation, so that new technologies can promote the development of the government system.info:eu-repo/semantics/publishedVersio

Solid state dye sensitized solar cells applying conducting organic polymers as hole conductors

Solid-state dye sensitized solar cells (SSDSCs) applying mesoporous TiO electrodes sensitized with Ru complex dye Z907 and conducting organic polymers as the hole transport material (HTM) are prepared. We employ the in-situ photo-electrochemically polymerization technique (PEP)[1-3] in order to obtain, in a single step, the conducting organic polymer on the TiO /Dye electrode. We developed a modification of reported method [2] which allows the polymer poly(3,4-ethylenedioxythiophene) (PEDOT) by different electrochemical techniques applying constant-voltage and constant-current methods. Polymer morphology and its influence on solar cell performance were studied. Overall conversion efficiency above 2% (AM 1.5, 100 mW cm) was obtained

A phenyl-capped aniline tetramer for Z907/tert-butylpyridine-based dye-sensitized solar cells and molecular modelling of the device

Z907-sensitized solar cells incorporating a phenyl-capped aniline tetramer (EPAT) as a substitute of the iodine/iodide redox couple in the electrolytes produce an enhanced open-circuit voltage and short circuit photocurrent density when tert-butylpyridine (TBP) is added to the electrolyte. © 2013 The Royal Society of Chemistry.One of the authors (K.M.) acknowledges the support from The Koshiyama Research Grant and The Advancing Researcher Support Program (Gifu University, Faculty of Engineering).Peer Reviewe

A general approach for fabrication of nitrogen-doped graphene sheets and its application in supercapacitors

In this paper, a general and efficient strategy has been developed to produce nitrogen-doped graphene sheets (NGs) based on hard and soft acids and bases (HSAB) theory. Under hydrothermal conditions, any salt with amphiprotic character have a strong tendency to hydrolysis, it is possible to provide reducing agent and nitrogen source simultaneously. It is worth noting that, NGs can be prepared under hydrothermal conditions by using some common ammonium salts with hard acid-soft base pairs as nitrogen-doping agents. The morphology, structure and composition of the as-prepared NGs were studied in detail. The results demonstrated that large amount of nitrogen was incorporated into the nanocarbon frameworks at the same time as the graphene oxide (GO) sheets were reduced. The electrochemical behavior of the synthesized NGs as supercapacitor electrodes was evaluated in a symmetric two-electrode cell configuration with 1 M H2SO4 as the electrolytes. It was found that the nitrogen groups making the as-prepared NGs exhibited remarkably enhanced electrochemical performance when used as electrode materials in supercapacitors. The supercapacitor based on the NGs exhibited a high specific capacitance of 242 F g(-1), at a current density of 1 A g(-1), and remains a relatively high capacitance even at a high current density. This work will put forward to understand and optimize heteroatom-doped graphene in energy storage systems. (C) 2013 Elsevier Inc. All rights reserved

Controlling the microstructure and properties of titania nanopowders for high efficiency dye sensitized solar cells

A low temperature hydrothermal process have been developed to synthesize titania nanorods (NRs) and nanoparticles (NPs) with controlled size for dye sensitized solar cells (DSSCs). Effect of calcination temperature on the performance of TiO2 nanoparticles for solar cells was investigated and discussed. The crystallite size and the relative crystallinity of the anatase phase were increased with increasing the calcination temperature. The structures and morphologies of both (TiO2 nanorods and nanoparticles) were characterized using XRD, SEM, TEM/HRTEM, UV-vis Spectroscopy, FTIR and BET specific surface area (SBET) as well as pore-size distribution by BJH. The size of the titania nanorods was 6.7 nm width and 22 nm length while it was 13 nm for nanoparticles. Efficiency of dye-sensitized solar cells (DSSCs) fabricated with oriented TiO2 nanorods was reported to be more superior compared to DSSC based on mesoporous TiO2 nanoparticles due to their high surface area, hierarchically mesoporous structures, low charge recombination and fast electron-transfer rate. With increasing calcination temperature of the prepared nanopowders, the light-electricity conversion efficiency (η) decreased. The efficiency of the assembly solar cells was decreased due to the agglomeration of the particles and difficulty of electron movement. The power efficiency was enhanced from 1.7% for TiO2 nanoparticles cells at hydrothermally temperature 500 °C and 5.2% for TiO2 nanoparticles cells at hydrothermally temperature 100 °C to 7.2% for TiO2 nanorods cells under AM1.5 illumination (100 mW cm -2). © 2012 Elsevier Ltd. All Rights Reserved.This work was financially supported by the Academy of Scientific Research and Technology (ASRT) and Ministry of Scientific Research of Egypt. Ahmed Shalan acknowledges Prof Monica Lira and her lab in Centre de Investigacio en Nanociencia I Nanotecnologia (Cin2, CSIC), ETSE, Campus UAB, Bellaterra (Barcelona), Spain for their support and helping in pursue part of the experimental section.Peer Reviewe

A facile low temperature synthesis of TiO2 nanorods for high efficiency dye sensitized solar cells

Titania (TiO2) nanorods have been synthesized with controlled size for dye-sensitized solar cells (DSSCs) via hydrothermal route at low hydrothermal temperature of 100 C for 24 h. The titania nanorods were characterized using XRD, SEM, TEM/HRTEM, UV-vis Spectroscopy, FTIR and BET specific surface area (S BET), as well as pore-size distribution by BJH. The results indicated that the bulk traps and the surface states within the TiO2 nanorods films have enhanced the efficiency of DSSCs. The size of the titania nanorods was 6.7 nm in width and 22 nm in length. The high surface area can provide more sites for dye adsorption, while the fast photoelectron-transfer channel can enhance the photogenerated electron transfer to complete the circuit. The specific surface area S BET was 77.14 m2 g-1 at the synthesis conditions. However, the band gap energy of the obtained titania nanorods was 3.2 eV. The oriented nanorods with appropriate lengths are beneficial in improving the electron transport property and thus leading to the increase of photocurrent, together enhancing the power conversion efficiency. A nearly quantitative absorbed photon-to-electrical current conversion achieved upon excitation at wave length of 550 nm and the power efficiency was enhanced from 5.6 % for commercial TiO2 nanoparticles Degussa (P25) cells to 7.2 % for TiO2 nanorods cells under AM 1.5 illumination (100 mW cm-2). The TiO2 cells performance was improved due to their high surface area, hierarchically mesoporous structures and fast electron-transfer rate compared with the Degussa (P25). © 2012 Springer-Verlag Berlin Heidelberg.This work was financially supported by the Academy of Scientific Research and Technology (ASRT) and Ministry of Scientific Research of Egypt. Ahmed Shalan acknowledges Prof. Monica Lira and her lab in Centre de Investigacio en Nanociencia I Nanotecnologia (Cin2, CSIC), ETSE, Campus UAB, Bellaterra (Barcelona), Spain for their support and helping in pursue part of the experimental section.Peer Reviewe