14 research outputs found

    Maximized performance of dye solar cells on plastic: a combined theoretical and experimental optimization approach

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    We demonstrate that a combined optimization approach based on the sequential alternation of theoretical analysis and experimental realization gives rise to plastic supported dye solar cells for which both light harvesting efficiency and electron collection are maximized. Rationalized configurations with optimized light trapping and charge extraction are realized to achieve photoanodes on plastic prepared at low temperature, showing a power conversion efficiency of 8.55% and a short circuit photocurrent of 16.11 mA cm 2, unprecedented for plastic based dye solar cell devices. Furthermore, the corresponding fully flexible designs present stable mechanical properties after several bending cycles, displaying 7.79% power conversion efficiency, an average broadband internal quantum efficiency above 90%, and a short circuit photocurrent of 15.94 mA cm 2, which is the largest reported value for bendable cells of this sort to dateEuropean Union 307081, 622533Ministerio de Economía y Competitividad MAT2014-54852-R, MAT2011–2359

    Selective CO2 adsorption and proton conductivity in the two-dimensional Zn(II) framework with protruded water molecules and flexible ether linkers

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    A two-dimensional (2D) Zn(II) metal-organic framework with flexible aryl ether linkers and water molecules exposed to the pores was prepared. The supramolecular three-dimensional (3D) network is generated by the presence of extensive pi-pi contacts, which could be responsible for gas uptake. The water molecules and oxygen atoms from the flexible linkers create a polar environment within the integrated framework, leading to simultaneous selective CO2 adsorption and proton conductivity in the two-dimensional Zn(II) framework

    Photovoltaic properties of high efficiency plastic dye-sensitized solar cells employing interparticle binding agent "nanoglue"

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    An interparticle binding agent, or nanoglue, was synthesized by a sol-gel process, which facilitated the preparation of well-interconnected TiO2 electrodes at low-temperatures for plastic dye-sensitized solar cells. The viscosity of the nanoglue-based pastes was seven times higher than that obtained in pastes without any nanoglue. The increased viscosity was sufficiently high enough for coating thick films to fabricate TiO2 electrodes. The structural and photovoltaic properties of the films were extensively investigated by varying the amounts of nanoglue. A reduced pore size and greatly enhanced surface area were observed in the nanoglue-based films. Improved interparticle connectivity, resulting in faster electron transport, was confirmed by photocurrent transient spectroscopy and electrochemical impedance measurements of the nanoglue-based films. The electron diffusion length and charge collection efficiency were also enhanced in these nanoglue-based films. A maximum conversion efficiency of 5.43% was achieved in films containing 20 wt% nanoglue fabricated on a plastic substrate under one-sun illumination, even without any additional treatment

    pH-Dependent Proton Conducting Behavior in a Metal-Organic Framework Material

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    A porous metal-organic framework (MOF), [Ni-2-(dobdc)(H2O)2]center dot 6H(2)O (Ni-2(dobdc) or Ni-MOF-74; dobdc(4) = 2,5-dioxido-1,4-benzenedicarboxylate) with hexagonal channels was synthesized using a microwave-assisted solvothermal reaction. Soaking Ni-2(dobdc) in sulfuric acid solutions at different pH values afforded new proton-conducting frameworks, H@Ni-2(dobdc). At pH 1.8, the acidified MOF shows proton conductivity of 2.2 x 10(-2) S cm(-1) at 80 degrees C and 95% relative humidity (RH), approaching the highest values reported for MOFs. Proton conduction occurs via the Grotthuss mechanism with a significantly low activation energy as compared to other proton-conducting MOFs. Protonated water clusters within the pores of H@Ni-2(dobdc) play an important role in the conduction process

    Rapid hydrothermal synthesis of cobalt oxyhydroxide nanorods for supercapacitor applications

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    Cobalt oxyhydroxide (CoOOH) nanorods were synthesized by fast hydrothermal process for supercapacitor electrodes. The structural and morphological studies revealed the formation of CoOOH with hexagonal rhomb-centered crystal structure and excellent rod like morphology of approx. 5-10 nm diameter. The electrochemical characterization was performed for both half cell and symmetric full cell configuration using cyclic voltammetry, galvanostatic charge/discharge test and impedance spectroscopy in 3 M KOH aqueous electrolyte. The fabricated CoOOH electrodes showed maximum specific capacitance value of 198 F g−1 for a half cell and 94 F g−1 for a symmetric capacitor of 10 mg cm−2 active material per electrode and showed better energy and power densities. Moreover, the CoOOH electrode exhibits good capacitance retention (83%) after 5000 charge/discharge cycles

    Molecular Engineering of Photosensitizers for Solid‐State Dye‐Sensitized Solar Cells: Recent Developments and Perspectives

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    Abstract Dye‐sensitized solar cells (DSSCs) are a feasible alternative to traditional silicon‐based solar cells because of their low cost, eco‐friendliness, flexibility, and acceptable device efficiency. In recent years, solid‐state DSSCs (ss‐DSSCs) have garnered much interest as they can overcome the leakage and evaporation issues of liquid electrolyte systems. However, the poor morphology of solid electrolytes and their interface with photoanodes can minimize the device performance. The photosensitizer/dye is a critical component of ss‐DSSCs and plays a vital role in the device‘s overall performance. In this review, we summarize recent developments and performance of photosensitizers, including mono‐ and co‐sensitization of ruthenium, porphyrin, and metal‐free organic dyes under 1 sun and ambient/artificial light conditions. We also discuss the various requirements that efficient photosensitizers should satisfy and provide an overview of their historical development over the years

    Synergistic strategies for the preparation of highly efficient dye-sensitized solar cells on plastic substrates: combination of chemical and physical sintering

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    Preparation of well-interconnected TiO2 electrodes at low temperature is critical for the fabrication of highly efficient dye-sensitized solar cells (DSCs) on plastic substrates. Herein we explore a synergistic approach using a combination of chemical and physical sintering. We formulate a binder-free TiO2 paste based on “nanoglue” as the chemical sintering agent, and use it to construct a photoelectrode on plastic by low-temperature physical compression to further improve the connectivity of TiO2 films. We systematically investigated the factors affecting the photovoltaic performance and found the conditions to achieve electron diffusion lengths as long as 25 mm and charge collection efficiencies as high as 95%, as electrochemical impedance spectroscopy measurements indicate. We apply this approach to obtain a DSC deposited on plastic displaying 6.4% power conversion efficiency based on commercial P25 titania particlesEspaña Mineco MAT2011-23593Unión Europea FP7/2007-201

    Rapid sintering of TiO2 photoelectrodes using intense pulsed white light for flexible dye-sensitized solar cells

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    Intense pulsed white light (IPWL) sintering was carried out at room temperature, which is suitable dye-sensitized solar cells (DSSCs) fabrication process on plastic substrates for the mass production. Five seconds irradiation of IPWL on TiO2 electrode significantly improves the photocurrent density and power conversion efficiency of DSSCs by more than 110% and 115%, respectively, compared to the DSSCs without IPWL treatment. These improvements were mainly attributed to the enhanced interconnection between the TiO2 nanoparticles induced by IPWL illumination, which is confirmed by the impedance spectra analysis