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Bhaskar Dudem, Yeong Hwan Ko, Jung Woo Leem, Joo Ho Lim, Jae Su Yu
We report the hierarchical nano/micro architectured (HNMA)-polydimethylsiloxane (PDMS) film-based hybrid energy cells with multi-functionality to simultaneously harvest mechanical, solar, and wind energies. These films consist of nano/micro dual-scale architectures (i.e., nanonipples on inverted micro pyramidal arrays) on the PDMS surface. The HNMA-PDMS is replicable by a facile and cost-effective soft imprint lithography (SIL) using a nanoporous anodic alumina oxide (AAO) film formed on the micro-pyramidal (MP) structured silicon substrate...
October 19, 2016: ACS Applied Materials & Interfaces
Teng-Fei Lu, Wei Li, Jie Chen, Fu-Quan Bai, Jian Wang, Ling-Jun He, Hong-Xing Zhang
In this work, we designed three dyes (Ru1, Ru2, and Ru3) by modifying the square-planar quadridentate ligand of the experimental Ru(ii) complex K1, [RuL(trans-NCS)2] with L = dimethyl-6,60-bis(methyl-2-pyridylamino)-2,20-bipyridine-4,40-dicarboxylate, from a theoretical viewpoint. As is known, K1 shows obvious advantages over the famous dye N749 in light absorption ability because of its highly conjugated ancillary ligands. Density functional theory and time-dependent density functional theory methods were used to determine the geometrical structures, electronic structures and absorption spectra of the dye complexes...
October 18, 2016: Physical Chemistry Chemical Physics: PCCP
Yasemin Saygili, Magnus Söderberg, Norman Pellet, Fabrizio Giordano, Yiming Cao, Ana B Munoz-Garcia, Shaik Mohammed Zakeeruddin, Nick Vlachopoulos, Michele Pavone, Gerrit Boschloo, Ladislav Kavan, Jacques-E Moser, Michael Grätzel, Anders Hagfeldt, Marina Freitag
Redox mediators play a major role determining the photocurrent and the photovoltage in dye-sensitized solar cells (DSCs). To maintain the photocurrent, the reduction of oxidized dye by the redox mediator should be significantly faster than the back electron transfer between TiO2 and the oxidized dye. The driving force for dye regeneration with the redox mediator should be sufficiently low to provide high photovoltages. With our introduction of new copper complexes as promising redox mediators in DSCs both criteria are satisfied to enhance power conversion efficiencies...
October 17, 2016: Journal of the American Chemical Society
Jongha Lee, Byeongjun Yoo, Hakyong Lee, Gi Doo Cha, Hee-Su Lee, Youngho Cho, Sang Yeon Kim, Hyunseon Seo, Woongchan Lee, Donghee Son, Myungjoo Kang, Hyung Min Kim, Yong Il Park, Taeghwan Hyeon, Dae-Hyeong Kim
Multi-dye-sensitized upconverting nanoparticles (UCNPs), which harvest photons of wide wavelength range (450-975 nm) are designed and synthesized. The UCNPs embedded in photo-acid generating layer are integrated on destructible nonvolatile resistive memory device. Upon illumination of the light, the system permanently erases stored data, achieving enhanced information security.
October 17, 2016: Advanced Materials
Shuguang Chen, Hailang Jia, Mengxi Zheng, Kang Shen, Hegen Zheng
Herein we prepare four novel D-π-A dyes based on triphenylamine (ZHG1, ZHG2, ZHG3 and ZHG4) by modifying the π-bridges. Compared with ZHG1, the power conversion efficiency (PCE) of ZHG2 is improved to 6.1% after the introduction of ethynyl. But further extension of the conjugation of the π-bridges by introducing the chromophore 4,8-bis(n-octyloxy)-benzo[1,2-b:4,5-b']dithiophene (BDT) into ZHG3 conversely decreases the PCE to 4.6%. Improving the coplanarity by replacing cyclobenzene with thiophene in ZHG4 after introducing BDT further decreases the PCE of ZHG4 to 4...
October 17, 2016: Physical Chemistry Chemical Physics: PCCP
Maciej Zalas, Agata Wawrzyńczak, Paulina Półrolniczak, Jan Sobuś, Grzegorz Schroeder, Stefan Jurga, Elena Selli
A series of 14 mesoporous titania materials has been synthesized using the simple alcothermal template-free method and various alcohols, such as methanol, propanols and butanols, as solvents. All materials were characterized by both wide and small angle XRD, which exhibited the anatase phase with short-range ordered mesoporous structure that is still forming during post synthetic temperature treatment in most of the investigated materials. Nitrogen adsorption-desorption isotherms confirmed the mesoporous structure with surface area ranging from 241 to 383 m2g- 1 and pore volumes from 0...
2016: PloS One
Xing Qian, Hongmei Li, Li Shao, Xiancai Jiang, Linxi Hou
In this work, morphology-tuned ternary nickel cobalt selenides based on different Ni/Co molar ratios have been synthesized via a simple precursor conversion method and used as counter electrode (CE) materials for dye-sensitized solar cells (DSSCs). The experimental facts and mechanism analysis clarified the possible growth process of product. It can be found that the electrochemical performances and structures of ternary nickel cobalt selenides can be optimized by tuning the Ni/Co molar ratio. Benefiting from the unique morphology and tunable composition, among the as-prepared metal selenides, the electrochemical measurements showed that the ternary nickel cobalt selenides exhibited a more superior electrocatalytic activity in comparison with binary Ni and Co selenides...
October 14, 2016: ACS Applied Materials & Interfaces
Chang Yu, Zhiqiang Liu, Xiangtong Meng, Bing Lu, Dan Cui, Jieshan Qiu
Alternative high-performance electrocatalysts for triiodide (I3(-)) reduction of low-cost dye-sensitized solar cells (DSSCs) are urgently sought after. To address the concerned issues, we report a facile strategy for engineering the nitrogen and phosphorus dual-doped graphene (NPG) via an efficient ball-milling process, followed by a simple thermal annealing approach utilizing melamine (C3H6N6) and triphenylphosphine ((C6H5)3P) as the N and P source, respectively. When employed as the counter electrode (CE) in DSSCs, such a metal-free material exhibits excellent electrocatalytic activity towards the I3(-)/I(-) redox reaction...
October 14, 2016: Nanoscale
Poul Erik Hansen, Torben Lund, Jacob Krake, Jens Spanget-Larsen, Soren Hvidt
The complex between diisopropylethylamine (DIPEA) and formic acid has been reinvestigated. Mixing the compounds in the ratio 1:1 leads to a phase separation in which the upper phase is DIPEA, the lower phase is the "ionic liquid" named DIPEF. A combined NMR and DFT study shows that the lower phase primarily is formic acid:formate and diisopropylammonium ions in the ratio 2:1 (acid:base) plus the formic acid dimer. Addition of more acid leads to more and more of the acid dimer. The proton transfer in the system is ~ 0...
October 12, 2016: Journal of Physical Chemistry. B
Oliver Langmar, Carolina R Ganivet, Gema de la Torre, Tomás Torres, Rubén D Costa, Dirk M Guldi
We introduce a novel and comprehensive approach for the evaluation and interpretation of electrochemical impedance spectroscopy (EIS) measurements in p-type DSSCs. In detail, we correlate both the device performance and EIS figures-of-merit of a series of devices in which, the calcination temperature, film thickness, and electrolyte concentration have been systematically modified. This new approach enables the separation of the different processes across the dye/semiconductor/electrolyte interface, namely the unfavorable charge recombination and the favorable electron injection/regeneration processes...
October 12, 2016: Nanoscale
Norman Lu, Yun-Peng Yeh, Guan-Bo Wang, Tsung-Yao Feng, Yang-Hsin Shih, Dong Chen
Visible light-induced photocatalysis is potentially advantageous and could be an efficient approach to degrade contaminants because it can be used to selectively target specific wavelength for decomposition of organic contaminants in water and wastewater. This study demonstrates the photodegradation of sulfamethoxazole (SMX) using [Pt(3,3'-dicarboxy-2,2'-bpy)(1,2-benzenedithiolate)] (Complex 1)-sensitized and [Pt(4,4'-dicarboxy-2,2'-bpy)(1,2-benzenedithiolate)] (Complex 2)-sensitized titanium dioxide (TiO2) under blue or yellow light (420 or 580 nm, respectively) irradiation in water...
October 12, 2016: Environmental Science and Pollution Research International
Lu Zhang, Zhong-Sheng Wang
To improve the electron collection, electron lifetime and light harvesting efficiency of dye-sensitized solar cells simultaneously, Au nanoflowers are prepared and used to wrap around the whole TiO2 film. Deposition of Au nanoflowers around the TiO2 film forms a light scattering box covering the whole TiO2 film. As compared to the top light scattering layer just covering the top surface of TiO2, the Au nanoflowers box exhibits better light harvesting efficiency, due to the omnidirectional light scattering, faster electron transport, attributed to the formation of electron channel between metallic Au nanoflowers and the electron collection electrode, and slower charge recombination...
October 11, 2016: Chemistry, An Asian Journal
Satoshi Yamamoto, Angel Zhang, Martin J Stillman, Nagao Kobayashi, Mutsumi Kimura
Two low-symmetry phthalocyanines (Pcs) substituted with thiophene units at the non-peripheral (α) and peripheral (β) positions were synthesized and their optical, electronic-structure, and electrochemical properties were investigated. The substitution of thiophene units at the α positions of the phthalocyanine skeleton resulted in a red shift of the Q band and significantly modified the molecular-orbital electronic distributions just below the HOMO and just above the LUMO, with distortion of the typical Gouterman four-orbital arrangement of MOs...
October 10, 2016: Chemistry: a European Journal
Dae-Kue Hwang, Shi-Joon Sung
To meet the nanofabrication requirements, such as control of structure and scalability, we investigated an electrospray-based method to manufacture scattering layers (SLs) for dye-sensitized solar cells (DSSCs). TiO2 spherical and disk-shaped particles with a large surface area, high crystallinity, uniform nanostructure and good light scattering properties were fabricated via a simple electrospray method. We showed how the morphology and structure of the resulting films can be controlled by varying the droplet evaporation rates before impact on the substrate...
October 10, 2016: Physical Chemistry Chemical Physics: PCCP
Yan Hao, Erik Gabrielsson, Peter William Lohse, Wenxing Yang, Erik M J Johansson, Anders Hagfeldt, Licheng Sun, Gerrit Boschloo
Investigation of charge transfer dynamics in dye-sensitized solar cells is of fundamental interest and the control of these dynamics is a key factor for developing more efficient solar cell devices. One possibility for attenuating losses through recombination between injected electrons and oxidized dye molecules is to move the positive charge further away from the metal oxide surface. For this purpose, a metal-free dye named E6 is developed, in which the chromophore core is tethered to two external triphenylamine (TPA) units...
November 2015: Advanced Science (Weinheim, Baden-Wurttemberg, Germany)
Xiao-Xin Gao, Qian-Qing Ge, Ding-Jiang Xue, Jie Ding, Jing-Yuan Ma, Yao-Xuan Chen, Bao Zhang, Yaqing Feng, Li-Jun Wan, Jin-Song Hu
Tuning the band alignment is proved to be an effective way to facilitate carrier transportation and thus enhance the power conversion efficiency (PCE) of solar cells. Doping the compact layer with metal ions or modifying the interfaces among functional layers in perovskite solar cells (PSCs) can appreciably improve the PCE of PSCs. Inspired by the rare earth elemental doping of TiO2, which has witnessed the success in photocatalysis and dye-sensitized solar cells, we firstly demonstrated here that La(3+) doping in the mesoporous TiO2 layer of a mesostructured PSC can tune its Fermi level and thus significantly enhance the device PCE...
September 29, 2016: Nanoscale
Krishna K Barakoti, Suman Parajuli, Pushpa Chhetri, Ganesh R Rana, Rezvan Kazemi, Ryan Malkiewich, Mario A Alpuche-Aviles
We report the stochastic interactions between dye sensitized anatase nanoparticles, suspended in a colloid, and a Pt ultramicroelectrode (UME) that result in step-wise behavior in the current vs. time response. The stochastic currents are observed in the dark and under illumination. In the dark, the currents are anodic, consistent with the oxidation of the dye N719 at the Pt surface. The electrochemical behavior of the dye was investigated in MeOH and MeCN with a quasireversible cyclic voltammogram (CV) observed at 1 V s(-1)...
September 21, 2016: Faraday Discussions
Jun-Xiang Zhang, Yu Wu, Jia-Cheng Liu, Ren-Zhi Li
An acylhydrazone zinc porphyrin P1 and its coordination polymers (CPs, denoted as P1M, M = Mn, Co, Ni, Cu, Zn) with different metal ions (Mn(2+), Co(2+), Ni(2+), Cu(2+) and Zn(2+)) were synthesized. Then these coordination polymers were assembled into bilayer structured supramolecular chromophores through axially coordinating with anchoring porphyrin AP, and their performance in dye sensitized solar cells was investigated. Our results reveal that the bilayer structured supramolecular chromophore based solar cells show significantly improved photocurrent conversion efficiency...
October 18, 2016: Dalton Transactions: An International Journal of Inorganic Chemistry
Yanxia Jiang, Yulin Yang, Junjiang Zhu, Liangsheng Qiang, Tengling Ye, Liang Li, Ting Su, Ruiqing Fan
A new type of polyoxometalate material, K6SiW11O39Ni(H2O)·xH2O (denoted as SiW11Ni), was successfully synthesized and introduced to a dye-sensitized solar cell (DSSC) with modified traditional Pt as a novel composite counter electrode. The new counter electrode showed superior electrochemical catalytic activity for the reduction of I3(-) to I(-) in analysis utilizing a Tafel-polarization curve, cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS). The DSSC assembled with the SiW11Ni/Pt photocathode exhibited an enhanced performance (7...
September 28, 2016: Dalton Transactions: An International Journal of Inorganic Chemistry
Raúl Mera-Adasme, Wen-Hua Xu, Dage Sundholm, Fernando Mendizabal
Solar power is a strong alternative to the currently used fossil fuels in order to satisfy the world's energy needs. Among them, dye-sensitized solar cells (DSSC) represent a low-cost option. Efficient and cheap dyes are currently needed to make DSSCs competitive. Computational chemistry can be used to guide the design of new light-absorbing chromophores. Here, we have computationally studied the lowest excited states of ZnPBAT, which is a recently synthesized porphyrinoid chromophore with high light-absorption efficiency...
October 12, 2016: Physical Chemistry Chemical Physics: PCCP
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