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Robert J Dillon, Leila Alibabaei, Thomas J Meyer, John M Papanikolas
The hole-injection and recombination photophysics for NiO sensitized with RuP ([Ru(II)(bpy)2(4,4'-(PO3H2)2-bpy)](2+)) are explored. Ultrafast transient absorption (TA) measurements performed with an external electrochemical bias reveal the efficiency for productive hole-injection, i.e. quenching of the dye excited state that results in a detectable charge-separated electron-hole pair, is linearly dependent on the electronic occupation of intragap states in the NiO film. Population of these states via a negative applied potential increases the efficiency from 0% to 100%...
July 21, 2017: ACS Applied Materials & Interfaces
Yuqiao Fu, Siu-Pang Ng, Guangyu Qiu, Tak-Fu Hung, Chi-Man Lawrence Wu, Chun-Sing Lee
Plasmonic enhanced dye-sensitized solar cells (DSSCs) with metallic nanostructures suffer from corrosion problems, especially with the presence of the iodine/triiodide redox couple in the electrolyte. Herein, we introduce an alternative approach by compensating the corrosion with a modified liquid electrolyte. In contrast to the existing method of surface preservation for plasmonic nanostructures, the redox-controlled electrolyte (RCE) contains iodoaurate intermediates, i.e. gold(i) diiodide (AuI2(-)) and gold(iii) tetraiodide (AuI4(-)) with optimal concentrations, such that these intermediates are readily reduced to gold nanoparticles during the operation of DSSCs...
July 21, 2017: Nanoscale
Giuseppe Calogero, Ilaria Citro, Gaetano Di Marco, Stefano Caramori, Laura Casarin, Carlo Alberto Bignozzi, João Avó, A Jorge Parola, Fernando Pina
We present here a complete study on four synthetic environmentally friendly flavylium salts employed as sensitizers for dye-sensitized solar cells (DSSCs). The effect of several donor groups on the molecular structure of flavylium ions was investigated by combining electrochemical, spectroscopic and computational means. The computational investigation indicated that these molecules can interact strongly with the TiO2 surface by a single OH group of the dihydroxybenzene moiety, and can efficiently inject electrons into the TiO2 following the excitation of their lowest singlet states exhibiting charge transfer (CT) character...
July 21, 2017: Photochemical & Photobiological Sciences
Joel Thomas Kirner, Richard G Finke
A planar organic thin-film composed of a perylene diimide dye (N,N´-bis(phosphonomethyl)-3,4,9,10-perylenediimide, PMPDI) with photoelectrochemically deposited cobalt oxide (CoOx) catalyst was previously shown to photoelectrochemically oxidize water (DOI: 10.1021/am405598w). Herein, the same PMPDI dye is studied for the sensitization of different nanostructured metal oxide (nano-MOₓ) films in a dye-sensitized photoelectrochemical cell architecture. Dye adsorption kinetics and saturation decreases in the order TiO₂ > SnO₂ > WO₃...
July 20, 2017: ACS Applied Materials & Interfaces
Jin Soo Kang, Hyelim Choi, Jin Kim, Hyeji Park, Jae-Yup Kim, Jung-Woo Choi, Seung-Ho Yu, Kyung Jae Lee, Yun Sik Kang, Sun Ha Park, Yong-Hun Cho, Jun-Ho Yum, David C Dunand, Heeman Choe, Yung-Eun Sung
Mesoscopic solar cells based on nanostructured oxide semiconductors are considered as a promising candidates to replace conventional photovoltaics employing costly materials. However, their overall performances are below the sufficient level required for practical usages. Herein, this study proposes an anodized Ti foam (ATF) with multidimensional and hierarchical architecture as a highly efficient photoelectrode for the generation of a large photocurrent. ATF photoelectrodes prepared by electrochemical anodization of freeze-cast Ti foams have three favorable characteristics: (i) large surface area for enhanced light harvesting, (ii) 1D semiconductor structure for facilitated charge collection, and (iii) 3D highly conductive metallic current collector that enables exclusion of transparent conducting oxide substrate...
July 19, 2017: Small
Tomohiro Higashino, Yuma Kurumisawa, Ning Cai, Yamato Fujimori, Yukihiro Tsuji, Shimpei Nimura, Daniel Packwood, Jaehong Park, Hiroshi Imahori
A hydroxamic acid group has been employed for the first time as an anchoring group for cobalt-based dye-sensitized solar cells (DSSCs). The porphyrin dye YD2-o-C8HA with the hydroxamic acid anchoring group exhibited a power conversion efficiency (η) of 6.4%, which is close to that of YD2-o-C8, a representative porphyrin dye with a conventional carboxylic acid one. More importantly, YD2-o-C8HA was found to be superior to YD2-o-C8 in terms of both binding ability to TiO2 and durability of cobalt-based DSSCs...
July 18, 2017: ChemSusChem
Nicolò Canever, Fraser Hughson, Thomas J Macdonald, Thomas Nann
This work demonstrates a protocol to fabricate a fiber-based photoanode for dye-sensitized solar cells, consisting of a light-scattering layer made of electrospun titanium dioxide nanofibers (TiO2-NFs) on top of a blocking layer made of commercially available titanium dioxide nanoparticles (TiO2-NPs). This is achieved by first electrospinning a solution of titanium (IV) butoxide, polyvinylpyrrolidone (PVP), and glacial acetic acid in ethanol to obtain composite PVP/TiO2 nanofibers. These are then calcined at 500 °C to remove the PVP and to obtain pure anatase-phase titania nanofibers...
June 28, 2017: Journal of Visualized Experiments: JoVE
Patrik Schmuki, A H El-Zarka, Ning Liu, Imgon Hwang, Mustafa Kamal
In the present work we grow anodic TiO2 nanotube layer with a tube diameter > 500 nm and an open tube mouth. We use this morphology in dye-sensitized solar cells (DSSCs) and show that these tubes allow the construction of hybrid hierarchical photoanode structures of nanotubes with a defined and wall-conformal TiO2 nanoparticle decoration. At the same time, the large diameter allows the successful establishment of an additional (insulating) blocking layer of SiO2 or Al2O3 on the tube wall. We show that this combination of hierarchical structure and blocking layer significantly enhances the solar cell efficiency by suppressing recombination reactions...
July 13, 2017: Chemistry: a European Journal
Minmin Zhang, Jiantao Zai, Jie Liu, Ming Chen, Zeren Wang, Guan Li, Xuefeng Qian, Liwu Qian, Xibin Yu
Transition metal sulfides are a kind of potential candidates for efficient and stable CE materials in DSSCs due to their good electrocatalytic ability and stability towards I3(-) reduction. However, the low conductivity of sulfides is harmful for the electron collection and transfer process, and the absorption/desorption and diffusion process of I(-)/I3(-) should be optimized to achieve high electrocatalytic activity over Pt. Herein, a hierarchical CoFeS2/reduced graphene oxide (CoFeS2/rGO) composite was rationally designed and prepared via the in situ conversion of CoFe layer double hydroxide anchored on rGO...
July 12, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
Wei-Chieh Chen, Santhanamoorthi Nachimuthu, Jyh-Chiang Jiang
Determining an ideal adsorption configuration for a dye on the semiconductor surface is an important task in improving the overall efficiency of dye-sensitized solar cells. Here, we present a detailed investigation of different adsorption configurations of designed model dyes on TiO2 anatase (101) surface using first principles methods. Particularly, we aimed to investigate the influence of cyano group in the anchoring part of dye on its adsorption stability and the overall photovoltaic properties such as open circuit voltage, electron injection ability to the surface...
July 10, 2017: Scientific Reports
Jacqueline Manina Cole, Martin Blood-Forsythe, Tze-Chia Lin, Philip Pattison, Yun Gong, Alvaro Vázquez-Mayagoitia, Paul G Waddell, Lei Zhang, Nagatoshi Koumura, Shogo Mori
Donor--Acceptor dyes containing thiophenyl -conjugated units and cyanoacrylate acceptor groups are among the best-performing organic chromophores used in dye-sensitized solar cell (DSC) applications. Yet, the molecular origins of their high photovoltaic output have remained unclear until now. This synchrotron-based X-ray diffraction study eluci-dates these origins for the high-performance thiophenylcy-anoacrylate-based dye, MK-2 (7.7% DSC device efficiency), and its molecular building block, MK-44. The crystal struc-tures of MK-2 and MK-44 are both determined, while a high-resolution charge-density mapping of the smaller mole-cule was also possible, enabling the nature of its bonding to be detailed...
July 10, 2017: ACS Applied Materials & Interfaces
Pongthep Prajongtat, Songwut Suramitr, Somkiat Nokbin, Koichi Nakajima, Koichiro Mitsuke, Supa Hannongbua
Structural and electronic properties of eight isolated azo dyes (ArNNAr', where Ar and Ar' denote the aryl groups containing benzene and naphthalene skeletons, respectively) were investigated by density functional theory (DFT) based on the B3LYP/6-31G(d,p) and TD-B3LYP/6-311G(d,p) methods The effect of methanol solvent on the structural and electronic properties of the azo dyes was elucidated by employing a polarizable continuum model (PCM). Then, the azo dyes adsorbed onto the anatase TiO2 (101) slab surface through a carboxyl group...
June 11, 2017: Journal of Molecular Graphics & Modelling
Qidong Tai, Feng Yan
Semitransparent solar cells can provide not only efficient power-generation but also appealing images and show promising applications in building integrated photovoltaics, wearable electronics, photovoltaic vehicles and so forth in the future. Such devices have been successfully realized by incorporating transparent electrodes in new generation low-cost solar cells, including organic solar cells (OSCs), dye-sensitized solar cells (DSCs) and organometal halide perovskite solar cells (PSCs). In this review, the advances in the preparation of semitransparent OSCs, DSCs, and PSCs are summarized, focusing on the top transparent electrode materials and device designs, which are all crucial to the performance of these devices...
July 6, 2017: Advanced Materials
Zhihui Wang, Mao Liang, Huanhuan Dong, Ping Gao, Ya Su, Peng Cai, Shijie Ding, Jing Chen, Song Xue
Asymmetric 8H-thieno[2',3':4,5]thieno[3,2-b]thieno[2,3-d]pyrrole (TTP) unit has been synthesized and used as a rigid and coplanar π-bridge to construct four new metal-free sensitizers W05-08. These dyes sensitized solar cells exhibit high photocurrent due to strong light harvesting capability. Among these dyes, the W05-based cell in conjunction with cobalt(II/III) redox shuttle exhibits the best power conversion efficiency up to 9.22%.
July 6, 2017: Organic Letters
Javid Khan, Jiuwang Gu, Shiman He, Xiaohui Li, Gulzar Ahmed, Zhongwu Liu, Muhammad Nadeem Akhtar, Wenjie Mai, Mingmei Wu
A tri-layered photoelectrode for dye-sensitized solar cells (DSSCs) is assembled using single crystal hollow TiO2 nanoparticles (HTNPs), sub-micro hollow TiO2 mesospheres (SHTMSs) and hierarchical TiO2 microspheres (HTMSs). The bottom layer composed of single crystal hollow TiO2 nanoparticles serves to absorb dye molecules, harvest light due to its hollow structure and keep a better mechanical contact with FTO conducting glass; the middle layer consisting of sub-micro hollow mesospheres works as a multifunctional layer due to its high dye adsorption ability, strong light trapping and scattering ability and slow recombination rates; and the top layer consisting of hierarchical microspheres enhances light scattering...
July 20, 2017: Nanoscale
Nicolas Queyriaux, Ruri A Wahyuono, Jennifer Fize, Corinne Gablin, Maria Wächtler, Eugénie Martinez, Didier Léonard, Benjamin Dietzek, Vincent Artero, Murielle Chavarot-Kerlidou
Understanding the structural and electronic factors governing the efficiency of dye-sensitized NiO photocathodes is essential to optimize solar fuel production in photoelectrochemical cells (PECs). For these purpose, three different ruthenium dyes, bearing either two or four methylphosphonate anchoring groups and either a bipyridine or a dipyridophenazine ancillary ligand, were synthesized and grafted onto NiO films. These photoelectrodes were fully characterized by XPS, ToF-SIMS, UV-vis absorption, time-resolved emission and femtosecond transient absorption spectroscopies...
March 23, 2017: Journal of Physical Chemistry. C, Nanomaterials and Interfaces
Andreas J Bircher, Rita Sigg, Kathrin Scherer Hofmeier, Urs Schlegel, Urs Hauri
BACKGROUND: Temporary tattoos made with an extract of the jagua fruit (Genipa americana L.) are becoming increasingly popular. It is claimed that it is 'dermatologically tested' and does not contain p-phenylenediamine. Extracts of jagua and gardenia fruits have been used by indigenous people in South America, as well as in traditional Chinese medicine, for centuries. Genipin is currently used for its cross-linking effect in the manufacture of polysaccharides, and is being investigated for its anti-inflammatory and other properties...
July 4, 2017: Contact Dermatitis
Jun Li, Li Yang, Guozhen Zhang, Jun Jiang
Platinum(II) terpyridyl complexes with a donor-acceptor (D-A) framework have long been considered as a promising component of dye-sensitized solar cells (DSSCs). To revealing the structure-property relationship of these highly modular systems, we have conducted a first-principle study at the time-dependent density functional theory (TDDFT) level on the [Pt((t)Bu3tpy)(-C≡C-Ph)n](+) ((t)Bu3tpy is 4,4',4″-tri-tert-butyl-2,2':6',2″-terpyridine) complexes. It was found that their visible absorbance could be improved by elongating the donor chain with n (-C≡C-Ph) units, reaching a maximum at n = 16...
July 14, 2017: Journal of Physical Chemistry. A
Kevin Chia-Wen Wu, Jeffrey E Chen, Miao-Syuan Fan, Yan-Lin Chen, Yu-Heng Deng, Jung Ho Kim, Yusuke Yamauchi, Kuo-Chuan Ho
Iron pyrite has long been an attractive material for environmental and energy applications, but lack control over morphology and purity. We synthesize hollow porous iron pyrite nanoparticles by a direct sulfurization of iron oxide derived from Prussian blue. A high yielding synthesis with short reaction duration and minimal required sulphur precursor was achieved and characterized by SEM, TEM, XRD, and XPS. We hereby demonstrate the high efficiencies of our hollow porous iron pyrite nanoparticles as effective dye-sensitized solar cell counter electrodes with an efficiency of 7...
July 1, 2017: Chemistry: a European Journal
Tengfei Jiang, Baptiste Polteau, Yoann Farré, Laurent Cario, Camille Latouche, Yann Pellegrin, Mohammed Boujtita, Fabrice Odobel, Franck Tessier, François Cheviré, Stéphane Jobic
Nickel carbodiimide (NiCN2) was synthesized using a two-step precipitation-decomposition route leading to a brown powder with gypsum-flower-like morphology and a large specific surface area (75 m(2)/g). This layered material crystallizes in the 2H structure type of delafossite (space group P63/mmc), which is built upon infinite (2)/∞[NiN2] layers connected by linear carbodiimide ([N═C═N](2-)) bridges. An X-ray diffraction Rietveld refinement and thermal analyses pointed out some nickel deficiencies in the material, and band structure calculations carried out on the defect compound predicted p-type conductivity in relation to a slight amount of N(2-)...
July 17, 2017: Inorganic Chemistry
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