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Mahmoud A M Al-Alwani, Norasikin A Ludin, Abu Bakar Mohamad, Abd Amir H Kadhum, Kamaruzzaman Sopian
Current study employs mixture of chlorophyll-anthocyanin dye extracted from leaves of Cordyline fruticosa as new sensitizers for dye-sensitized solar cell (DSSCs), as well as betalains dye obtained from fruit of Hylocereus polyrhizus. Among ten pigments solvents, the ethanol and methanol extracts revealed higher absorption spectra of pigments extracted from C. fruticosa and H. polyrhizus respectively. A major effect of temperature increase was studied to increase the extraction yield. The results indicated that extraction temperature between 70 and 80°C exhibited a high dye concentration of each plant than other temperatures...
February 14, 2017: Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
Yuki Kimura, Kin-Ichi Oyama, Yasujiro Murata, Atsushi Wakamiya, Kumi Yoshida
Anthocyanins as natural pigments are colorful and environmentally compatible dyes for dye-sensitized solar cells (DSSCs). To increase the efficiency, we designed and synthesized unnatural O-methylflavonols and O-methylcyanidins that possess an aryl group at the 8-position. We synthesized per-O-methylquercetin from quercetin, then using selective demethylation prepared various O-methylquercetins. Using the Suzuki-Miyaura coupling reaction, 8-arylation of per-O-methylquercetin was achieved. Using a LiAlH₄ reduction or Clemmensen reduction, these flavonols were transformed to the corresponding cyanidin derivatives in satisfactory yields...
February 16, 2017: International Journal of Molecular Sciences
Özgül Birel, Said Nadeem, Hakan Duman
The current review aims to collect short information about photovoltaic performance and structure of porphyrin-based sensitizers used in dye-sensitized solar cells (DSSC). Sensitizer is the key component of the DSSC device. Structure of sensitizer is important to achieve high photovoltaic performance. Porphyrin derivatives are suitable for DSSC applications due to their thermal, electronic and photovoltaic properties. It describes some electrochemical and spectral properties as well as thestructure of porphyrin dyes used in dye based-solar cells...
February 16, 2017: Journal of Fluorescence
Dongsheng Chen, Yanyan Zhu
CH3NH3PbI3 perovskite nanofibers were synthesized by versatile electrospinning techniques. The synthetic CH3NH3PbI3 nanofibers were characterized by X-ray diffraction, scanning electron microscopy, thermogravimetric analysis, and photoluminescence. As counter electrodes, the synthesized nanofibers increased the performance of the dye-sensitized solar cells from 1.58 to 2.09%. This improvement was attributed to the enhanced smoothness and efficiency of the electron transport path. Thus, CH3NH3PbI3 perovskites nanofibers are potential alternative to platinum counter electrodes in dye-sensitized solar cells...
December 2017: Nanoscale Research Letters
Yaowarat Surakhot, Viktor Laszlo, Chirawat Chitpakdee, Vinich Promarak, Taweesak Sudyoadsuk, Nawee Kungwan, Tim Kowalczyk, Stephan Irle, Siriporn Jungsuttiwong
The search for greater efficiency in organic dye-sensitized solar cells (DSCs) and in their perovskite cousins is greatly aided by a more complete understanding of the spectral and morphological properties of the photoactive layer. This investigation resolves a discrepancy in the observed photoconversion efficiency (PCE) of two closely related DSCs based on carbazole-containing D-π-A organic sensitizers. Detailed theoretical characterization of the absorption spectra, dye adsorption on TiO2 , and electronic couplings for charge separation and recombination permit a systematic determination of the origin of the difference in PCE...
February 13, 2017: Journal of Computational Chemistry
Kyung-Ho Bae, Van-Duong Dao, Ho-Suk Choi
This study presents the synthesis of PtNi alloys with different volume ratios of Pt and Ni precursors in mixture solutions using dry plasma reduction under atmospheric pressure and low temperature. The developed materials are applied as efficient counter electrodes (CEs) in dye-sensitized solar cells (DSCs). The investigation of the Pt utility in PtNi alloys for electrocatalytic activity, and cost effective and highly efficient DSCs are also investigated. Compared with the reference electrodes (Pt and Ni CEs), the developed PtNi alloy CEs exhibit better reversibility as indicated by the peak-to-peak separation and better catalytic activity for the regeneration of iodide ions from triiodide ions...
February 3, 2017: Journal of Colloid and Interface Science
Ken Tue Ngo, Nicholas A Lee, Sashari Pinnace, Jonathan Rochford
An alternative approach towards the replacement of the isothiocyantate ligands of the N3 photosensitizer with light-harvesting bidentate ligands is investigated for application in dye-sensitized solar cells. An in depth theoretical analysis has been applied to inform on the optical and redox properties of four non-innocent ligand platforms which is corroborated with experiment. Taking advantage of the 5- and 7-positions of 8-oxyquinolate, or the carboxyaryl ring system of the N-arylcarboxy-8-amidoquinolate ligand, fluorinated aryl substituents are demonstrated as an effective means to tune complex redox potentials and light harvesting properties...
February 11, 2017: Chemistry: a European Journal
Arshad Khan, Yu-Ting Huang, Tsutomu Miyasaka, Masashi Ikegami, Shien-Ping Feng, Wen-Di Li
A new type of embedded metal-mesh transparent electrode (EMTE) with in-situ electrodeposited catalytic platinum nanoparticles (PtNPs) is developed as a high-performance counter electrode (CE) for light-weight flexible bifacial dye-sensitized solar cells (DSSCs). The thick but narrow nickel micro-mesh fully embedded in a plastic film provides superior electrical conductivity, optical transmittance, and mechanical stability to the novel electrode. PtNPs decorated selectively on the nickel micro-mesh surface provide catalytic function with minimum material cost and without interfering with optical transparency...
February 7, 2017: ACS Applied Materials & Interfaces
Liang Zhou, Zechao Zhuang, Huihui Zhao, Mengting Lin, Dongyuan Zhao, Liqiang Mai
Intricate hollow structures garner tremendous interest due to their aesthetic beauty, unique structural features, fascinating physicochemical properties, and widespread applications. Here, the recent advances in the controlled synthesis are discussed, as well as applications of intricate hollow structures with regard to energy storage and conversion. The synthetic strategies toward complex multishelled hollow structures are classified into six categories, including well-established hard- and soft-templating methods, as well as newly emerging approaches based on selective etching of "soft@hard" particles, Ostwald ripening, ion exchange, and thermally induced mass relocation...
February 7, 2017: Advanced Materials
Ettore Fazio, Javier Jaramillo-García, María Medel, Maxence Urbani, Michael Grätzel, Mohammad K Nazeerudin, Gema de la Torre, Tomas Torres
Unique donor-π-acceptor phthalocyanines have been synthesized through the asymmetric functionalization of an ABAB phthalocyanine, crosswise functionalized with two iodine atoms through Pd-catalyzed cross-coupling reactions with adequate electron-donor and electron-acceptor moieties. These push-pull molecules have been optically and electrochemically characterized, and their ability to perform as chromophores for dye-sensitized solar cells has been tested.
February 2017: ChemistryOpen
Valerie A Chiykowski, Brian Lam, Chuan Du, Curtis P Berlinguette
A homologous set of dyes that differ only in the donor fragments, namely phenothiazine (PTZ) and triarylamine (TPA) units, were evaluated in dye-sensitized solar cells (DSSCs). The novel PTZ-based dye differs from the TPA-based dye in that it contains a sulfur bridge that planarizes two aromatic rings and enables higher dye loading and higher stability in the oxidized form. These positive features notwithstanding, the superior absorptivity of devices sensitized by TPA-based dyes resulted in significantly higher power conversion efficiencies (PCEs) than those sensitized by PTZ-based dyes...
February 6, 2017: Chemical Communications: Chem Comm
Jiawei Sun, Xiao Xie, Hengchang Bi, Haiyang Jia, Chongyang Zhu, Neng Wan, Jianqiu Huang, Meng Nie, Dan Li, Litao Sun
Vacuum filtration enables large-area graphene-based membranes (GBMs) fabrication, possessing smoother surface than that by spray, spin coating or drop casting. However, due to the strong interaction with substrates, separation of thin GBMs from the filter is problematic. Conventional stamping separation/transfer graphene oxide (GO) films requires another substrate and pressing for >10 h, which may hurt delicate structure of transfer substrates. Others require GO to be reduced on filters before separation thus limits the reduction methods...
February 6, 2017: Nanotechnology
David R Parks, Faysal El Khettabi, Eric Chase, Robert A Hoffman, Stephen P Perfetto, Josef Spidlen, James C S Wood, Wayne A Moore, Ryan R Brinkman
We developed a fully automated procedure for analyzing data from LED pulses and multilevel bead sets to evaluate backgrounds and photoelectron scales of cytometer fluorescence channels. The method improves on previous formulations by fitting a full quadratic model with appropriate weighting and by providing standard errors and peak residuals as well as the fitted parameters themselves. Here we describe the details of the methods and procedures involved and present a set of illustrations and test cases that demonstrate the consistency and reliability of the results...
February 3, 2017: Cytometry. Part A: the Journal of the International Society for Analytical Cytology
Valerie A Chiykowski, Brian Lam, Chuan Du, Curtis P Berlinguette
The stabilities of three organic dyes that differ only by two substituents (-OMe, -H and -Br) about the phenothiazine donor unit were evaluated when immobilized on a semiconductor surface. All three dyes delivered modest power conversion efficiencies (PCEs) in the dye-sensitized solar cell (DSSC), but maintained 75% of their initial PCE over 300 h of sustained simulated sunlight. Electron-donating substituents increased the stability of the phenothiazine radical unit created after light-induced charge injection into the semiconductor; however, this did not translate to higher DSSC stability, which appears to be more sensitive to the basicity of the anchoring group for this series...
February 3, 2017: Chemical Communications: Chem Comm
Zhiqiang Xie, Wangwang Xu, Xiaodan Cui, Ying Wang
Metal-organic frameworks (MOFs), as a very promising category of porous materials, have attracted more and more interest in research communities due to their extremely high surface areas, diverse nanostructures and unique properties. In recent years, there is a growing body of evidence indicating that MOFs can function as ideal templates to prepare various nanostructured materials for energy and environmental cleaning applications. This work reviews the recent progresses in design and synthesis of MOFs and MOF-derived nanomaterials for particular applications in lithium-ion batteries, sodium-ion batteries, supercapacitors, dye-sensitized solar cells and heavy metal ions detection and removal...
February 2, 2017: ChemSusChem
Sunting Xuan, Ning Zhao, Xiangyi Ke, Zehua Zhou, Frank R Fronczek, Karl M Kadish, Kevin Malcolm Smith, M Graca Henriques Vicente
A series of push-pull BODIPYs bearing multiple electron-donating and electron-acceptor groups were synthesized regioselectively from 2,3,5,6,8-pentachloro-BODIPY, and characterized by NMR spectroscopy, HRMS and X-ray crystallography. The influence of the push-pull substituents on the spectroscopic and electrochemical properties of BODIPYs was investigated. Bathochromic shifts were observed for both absorbance (up to 37 nm) and emission (up to 60 nm) in different solvents upon introduction of the push-pull moieties...
February 2, 2017: Journal of Organic Chemistry
Ragu Sasikumar, Palraj Ranganathan, Shen-Ming Chen, Pedaballi Sireesha, Tse-Wei Chen, Pitchaimani Veerakumar, Syang-Peng Rwei, Thavuduraj Kavitha
In this present study, we focus on economically applicable polymeric material as photo-anode for dye-sensitized solar cells (DSSCs). Water droplets on grass like Ti2O3 decorated m-aminophenol-formaldehyde resin microspheres (mAPFR@Ti2O3) synthesized by surfactant-free and template-free hydrothermal method. The synthesized mAPFR@Ti2O3 material morphology was characterized by field emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM). From that results, it was found in uniform arrangements with excellent thermal stability...
January 19, 2017: Journal of Colloid and Interface Science
Wilbert Mtangi, Francesco Tassinari, Kiran Vankayala, Andreas Vargas Jentzsch, Beatrice Adelizzi, Anja R A Palmans, Claudio Fontanesi, Egbert Willem Meijer, Ron Naaman
The production of hydrogen through water splitting in a photoelectrochemical cell suffers from an overpotential that limits the efficiencies. In addition, hydrogen-peroxide formation is identified as a competing process affecting the oxidative stability of photoelectrodes. We impose spin-selectivity by coating the anode with chiral organic semiconductors from helically-aggregated dyes as sensitizers; Zn-porphyrins and triarylamines. Hydrogen peroxide formation is dramatically suppressed, while the overall current through the cell, correlating with the water splitting process, is enhanced...
January 30, 2017: Journal of the American Chemical Society
William Ghann, Hyeonggon Kang, Tajbik Sheikh, Sunil Yadav, Tulio Chavez-Gil, Fred Nesbitt, Jamal Uddin
The dyes extracted from pomegranate and berry fruits were successfully used in the fabrication of natural dye sensitized solar cells (NDSSC). The morphology, porosity, surface roughness, thickness, absorption and emission characteristics of the pomegranate dye sensitized photo-anode were studied using various analytical techniques including FESEM, EDS, TEM, AFM, FTIR, Raman, Fluorescence and Absorption Spectroscopy. Pomegranate dye extract has been shown to contain anthocyanin which is an excellent light harvesting pigment needed for the generation of charge carriers for the production of electricity...
January 27, 2017: Scientific Reports
Rajesh Bisht, Munavvar Fairoos M K, Ambarish Kumar Singh, Jayaraj Nithyanandhan
Metal-free near-infrared (NIR) active unsymmetrical squaraine dyes, RSQ1 and RSQ2, with benzodithiophene (BDT) π-spacer and cyanoacrylic acid acceptor were synthesized by utilizing palladium catalyzed direct (hetero)arylation reaction. Methyl and 2-ethylhexyl groups were strategically placed at the BDT unit for RSQ1 and RSQ2, respectively, to investigate the effect of alkylated π-spacer on dye aggregation on the TiO2 surface and recombination reactions at TiO2/dye/electrolyte interface. These dyes have strong absorption (ε > 10(5) M(-1) cm(-1)) in near-infrared (NIR) region and exhibit similar optical and electrochemical properties as they have same conjugated framework...
February 8, 2017: Journal of Organic Chemistry
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