Publications

Nanostructured metal mesh structures demonstrating excellent conductivity and high transparency are one of the promising transparent conducting electrode (TCE) alternatives for indium tin oxide (ITO). Often, these metal nanostructures are to be employed as hybrids along with a conducting filler layer to collect charge carriers from the network voids and to minimize current and voltage losses. The influence of filler layers on dictating the extent of such ohmic loss is complex. Here, we used a general numerical model to correlate the sheet resistance of the filler, lateral charge transport distance in network voids, metal mesh line width and ohmic losses in optoelectronic devices. To verify this correlation, we prepared gold or copper network electrodes with different line widths and different filler layers, and applied them as TCEs in perovskite solar cells. We show that the photovoltaic parameters scale with the hybrid metal network TCE properties and an Au-network or Cu-network with aluminum-doped zinc oxide (AZO) filler can replace ITO very well, validating our theoretical predictions. Thus, the proposed model could be employed to select an appropriate filler layer for a specific metal mesh electrode geometry and dimensions to overcome the possible ohmic losses in optoelectronic devices.

A well-defined main-chain conjugated photoswitchable poly(3-hexylthiophene) with homogeneous hydrogen end groups was synthesized. Opening and closing the photoswitch enables reversible modulation of P3HT emission, which is quenched by 70% when the switch is closed. The optical properties during switching cycles were quantified by irradiation/spectroscopy sequences.

A series of new heteroleptic Ru(II)(4,4′-dicarboxylic acid-2,2′-bipyridine)(bipyridyl donor-antenna ligand)(NCS)2 complexes carrying different donor-antenna moieties was designed, synthesised and characterised. A general synthetic procedure was used for the covalent attachment of the donor-antenna units 1,3-di(2-thienyl)benzo[c]-thiophene (DTBT), trans-stilbene (tS) and 4-{2-[2-(2-methoxyethoxy)ethoxy]-ethoxy}-N,N-diphenylbenzenamine (TPA-EO) to 2,2′-bipyridine. First, a Vilsmeier-Haack reaction was applied to get the respective aldehyde-functionalised donor-antenna compounds which secondly reacted with 4,4′-bis(triphenylphosphonium-methyl)-2,2′-bipyridyl chloride under Wittig conditions to give the desired bipyridyl donor-antenna molecules. To create a dimethylamino (NMe2) substituted donor-antenna compound a reaction between 4,4′-dimethyl-2,2′-bipyridine and Bredereck's reagent was carried out. The final Ru(II) complexes referred to as Ru-DTBT-NCS, Ru-tS-NCS, Ru-TPA-EO-NCS and Ru-NMe2-NCS were obtained via one-pot reactions, starting from dichloro(p-cymene)ruthenium(II) dimer. The bipyridyl donor-antenna molecules as well as the complexes were fully characterised and their optical and electrochemical properties were studied in detail. Preliminary tests of the novel Ru(II)bis(bipyridyl)(NCS)2 dyes in solid-state dye-sensitized solar cells under AM1.5G conditions (100 mW cm−2) yielded short-circuit current densities of 1.06, 2.15, 3.42 and 4.03 mA cm−2, open-circuit voltages of 625, 635, 685 and 735 mV and fill factors of about 45% corresponding to overall efficiencies of 0.31, 0.58, 0.99 and 1.37% for Ru-DTBT-NCS, Ru-NMe2-NCS, Ru-tS-NCS and Ru-TPA-EO-NCS, respectively.

The emission of millions of fluorescence photons from a chromophore is controlled by the absorption of a few tens of photons in a photochromic molecule. The parameters that determine the efficiency of this process are investigated, providing insights for the development of an all-optical gate.

Abstract The realization of a photonic logic AND gate, i.e. a logic AND gate that runs on photons rather than electrons, and where all steps are controlled by light, is demonstrated. In a proof‐of‐principle experiment, this is accomplished by exploiting photochromic molecules for monitoring the presence or absence of photons of particular wavelengths that represent the logic variables.

Proper percolation of charges in solar cells is possible with the self-assembled nanostructure of a block-copolymer film (see the TEM cross section of a solar cell). A photovoltaic device made from such a block copolymer exhibits a ten-times higher short circuit current and a considerably larger photovoltage than its polymer-blend analogue.

ADVERTISEMENT RETURN TO ISSUEPREVCommunication to the...Communication to the EditorNEXTSubsurface Mapping of Amorphous Surface Layers on Poly(3-hexylthiophene)M. Zerson*†, E.-C. Spitzner†, C. Riesch†, R. Lohwasser‡, M. Thelakkat‡, and R. Magerle*†View Author Information† Fakultät für Naturwissenschaften, Technische Universität Chemnitz, Chemnitz, Germany‡ Angewandte Funktionspolymere, Makromolekulare Chemie I, Universität Bayreuth, Bayreuth, GermanyE-mail: [email protected] (M.Z.); [email protected] (R.M.).Cite this: Macromolecules 2011, 44, 15, 5874–5877Publication Date (Web):July 8, 2011Publication History Received17 May 2011Revised23 June 2011Published online8 July 2011Published inissue 9 August 2011https://pubs.acs.org/doi/10.1021/ma2011359https://doi.org/10.1021/ma2011359rapid-communicationACS PublicationsCopyright © 2011 American Chemical SocietyRequest reuse permissionsArticle Views729Altmetric-Citations12LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access optionsGet e-Alertsclose SUBJECTS:Annealing (metallurgy),Layers,Materials,Organic polymers,Thin films Get e-Alerts

Using surface-templated electrophoretic deposition, we have created arrays of polymer beads (photonic units) incorporating photo-switchable DAE molecules, which can be reversibly and individually switched between high and low emission states by direct photo-excitation, without any energy or electron transfer processes within the molecular system. The micropatterned array of these photonic units is spectroscopically characterized in detail and optimized with respect to both signal contrast and cross-talk. The optimum optical parameters including laser intensity, wavelength and duration of irradiation are elucidated and ideal conditions for creating reversible on/off cycles in a micropatterned array are determined. 500 such cycles are demonstrated with no obvious on/off contrast attenuation. The ability to process binary information is demonstrated by selectively writing information to the given photonic unit, reading the resultant emissive signal pattern and finally erasing the information again, which in turn demonstrates the possibility of continuous recording. This basic study paves the way for building complex circuits using spatially well-arranged photonic units.

A flexible organic triad consisting of two perylene bisimide antennas covalently linked to a [60]fullerene by flexible spacers has been synthesized and studied by electrochemistry, steady-state and time-resolved spectroscopy. We found that π-π-stacking of the two antenna subunits has considerable impact on the photophysics of the system and leads to a reduction of the effective light-harvesting efficiency of the assembly. This finding is important for light harvesting in flexible materials based on the dye antenna-fullerene concept.