A spray-coating process for highly conductive silver nanowire networks as the transparent top-electrode for small molecule organic photovoltaics

We present a novel top-electrode spray-coating process for the solution-based deposition of silver nanowires (AgNWs) onto vacuum-processed small molecule organic electronic solar cells. The process is compatible with organic light emitting diodes (OLEDs) and organic light emitting thin film transistors (OLETs) as well. By modifying commonly synthesized AgNWs with a perfluorinated methacrylate, we are able to disperse these wires in a highly fluorinated solvent. This solvent does not dissolve most organic materials, enabling a top spray-coating process for sensitive small molecule and polymer-based devices. The optimized preparation of the novel AgNW dispersion and spray-coating at only 30 °C leads to high performance electrodes directly after the deposition, exhibiting a sheet resistance of 10.0 Ω □−1 at 87.4% transparency (80.0% with substrate). By spraying our novel AgNW dispersion in air onto the vacuum-processed organic p-i-n type solar cells, we obtain working solar cells with a power conversion efficiency (PCE) of 1.23%, compared to the air exposed reference devices employing thermally evaporated thin metal layers as the top-electrode

Legislative Documents

Also, variously referred to as: House bills; House documents; House legislative documents; legislative documents; General Court documents

Transparent Electrodes for Organic Solar Cells

The aim of this work was to investigate silver nanowire as well as carbon nanotube networks as transparent conducting electrodes for small molecule organic solar cells. In the framework of the nanowire investigations, a low-temperature method at less than 80 °C is developed to obtain highly conductive networks directly after the deposition and without post-processing. In detail, specific non-conductive organic materials act as a matrix where the nanowires are embedded in such that a mutual attraction based on capillary forces and hydrophobic interaction is created. This process is mediated by the ethanol contained in the nanowire dispersion and works only for sublayer materials which exhibit hydrophobic and hydrophilic groups at the same time. In contrast to high-temperature processed reference electrodes (210 °C for 90 min) without matrix, a slightly lower sheet resistance of 10.8 Ohm/sq at a transparency of 80.4 % (including substrate) is obtained by using polyvinylpyrrolidone as the sublayer material. In comparison to annealed silver nanowire networks, the novel approach yields a performance enhancement in corresponding organic solar cells which can compete with ITO-based devices. Furthermore, a novel approach for scalable, highly conductive, and transparent silver nanowire top-electrodes for organic optoelectronic devices is introduced. By utilizing a perfluorinated methacrylate as stabilizer, silver nanowires with high aspect ratio can be transferred into inert solvents which do not dissolve most organic compounds making this modified dispersion compatible with small molecule and polymer-based organic optoelectronic devices. The inert silver nanowire dispersion yields highly performing top-electrodes with a sheet resistance of 10.0 Ohm/sq at 80.0 % transparency (including substrate) directly after low-temperature deposition at 30 °C and without further post-processing. In comparison to similarly prepared reference devices comprising a thin-metal film as transparent top-electrode, reasonable power conversion efficiencies are demonstrated by spray-coating this dispersion directly on simple, air-exposed small molecule-based organic solar cells. Moreover, a deeper understanding of the percolation behavior of silver nanowire networks has been achieved. Herein, direct measurements of the basic network parameters, including the wire-to-wire junction resistance and the resistance of a single nanowire of pristine and annealed networks have been carried out for the first time. By putting the values into a simulation routine, a good accordance between measurement and simulation is achieved. Thus, an examination of the electrical limit of the nanowire system used in this work can be realized by extrapolating the junction resistance down to zero. The annealed silver nanowires are fairly close to the limit with a theoretical enhancement range of only 20 % (common absolute sheet resistance of approximately 10 Ohm/sq) such that a significant performance improvement is only expected by an enlargement of the nanowire length or by the implementation of new network geometries. In addition, carbon nanotube networks are investigated as alternative network-type, transparent bottom-electrode for organic small molecule solar cells. For that purpose, cleaning and structuring as well as planarization procedures are developed and optimized which maintain the optoelectronic performance of the carbon nanotube electrodes. Furthermore, a hybrid electrode consisting of silver nanowires covered with carbon nanotubes is fabricated yielding organic solar cells with only 0.47 % power conversion efficiency. In contrast, optimized electrodes comprising only carbon nanotubes show significantly higher efficiency. In comparison to identically prepared ITO devices, comparable or lower power conversion efficiencies of 3.96 % (in p-i-n stack), 4.83 % (in cascade cell) as well as 4.81 % (in p-n-i-p architecture) are demonstrated. For an inverted n-i-p stack design, the highest power conversion efficiency of 5.42 % is achieved

Hierarchical porous zeolite ZSM-58 derived by desilication and desilication re-assembly

Hierarchical porosity in zeolite ZSM-58 was achieved by desilication with pure solutions of NaOH and mixtures of NaOH and cetyltrimethylammonium bromide (CTAB) in a desilication and desilication re-assembly process. The resulting ZSM-58 samples were investigated concerning their chemical and textural structure by means of transmission and scanning electron microscopy, X-ray diffraction, nitrogen and argon physisorption, elemental analyses, 27Al and 29Si solid-state magic angle spinning nuclear magnetic resonance spectroscopy, and temperature programmed desorption of ammonia. In the case of applying pure NaOH solutions on Si/Al ratios of Si/Al = 50 rather macroporous zeolite ZSM-58 with broad pore size distribution was obtained and pore volume depended on the sodium hydroxide concentration. Higher Si/Al ratios did not result in any additional porosity. Adding CTAB to the desilication solution lead to hierarchical ZSM-58 materials with narrow additional pores in the range of 3-4 nm resulting from an amorphous layer on the surface of the ZSM-58 crystals that was long range ordered for intermediate NaOH concentrations independent from the initially deployed Si/Al ratio. The total specific surface area of such materials was as high as 868 m2 g-1 with high values of external specific surface area and simultaneously the desilication yield could be increased due to the re-assembly of dissolved silica species. Therefore, high values for the hierarchy factor and desilication efficiency could be achieved. The amount of strong acid sites of the desilicated samples decreased with increasing NaOH concentration because of the generation of silanol groups, pentahedral, and octahedral coordinated extra framework aluminum

Status quo der Umsetzung von Naturschutz im Wald gegen Entgelt in Deutschland. Ergebnisse einer Befragung von Forstbetrieben

Contract-based nature conservation or payments for nature conservation measures are de facto sporadically implemented in forests. Against this background, the joint research project “Nature Conservation Contracts in Forests (WaVerNa Project)” aims to analyze the current implementation status as well as opportunities and constraints of nature conservation contracts in the field of forest ecology, economics and law. In this context representatives of forest enterprises were asked in a nationwide online survey referring to their engagement in forest nature conservation for a consideration. The answers of 195 representatives of forest enterprises which either have already experiences in forest nature conservation contracts or intend its implementation in near future were assessed. Although the online survey was carried out as an open questionnaire, mainly middle-sized and large forest enterprises have participated. Thus, they build a non-representative sample for a nationwide assessment of the implementation practice, referring to payments for nature conservation in forest. As the answers indicate, a large scale of forest nature conservation measures is principally implemented by different funding instruments and programs. These areas cover up to 5 % of the forestal income in most of the consulted forest enterprises. More than half of the enterprises stated, that payments for nature conservation measures contribute up to 5 % of the whole turnover related to forestry. In a few cases these payments for nature conservation in forests significantly exceed the remaining forest income. Three-quarter of the forest enterprises stated positive experiences regarding nature conservation contracts, one third plans to raise its engagement. Less than one third of those forest enterprises, which have already experiences in forest nature conservation, plans to implement nature conservation measures in the future. A possible explanation for this apparent contradiction is that the potential for nature conservation measures is currently exhausted in the forest enterprises. But in summary, the results of the online survey suggest that a scarce demand referring to nature conservation measures in forests does not seem to be the only constraint for limiting the interest on side of forest enterprises. Based up on the results of the online survey, it can be stated further, that a significant increase of forest enterprises’ engagement in nature conservation cannot be expected under the current framework

Status quo der Umsetzung von Naturschutz im Wald gegen Entgelt in Deutschland. Ergebnisse einer Befragung von Stiftungen

Contract-based nature conservation or payments for nature conservation measures are de facto sporadically implemented in forests. Against this background the joint research project “Nature Conservation Contracts in Forests (WaVerNa Project)” aims to analyze the current implementation status as well as opportunities and constraints of nature conservation contracts in the field of forest ecology, economics, and law. In this context foundations were asked in a nationwide online survey referring to their financial involvement in forest nature conservation. The answers of 38 foundations which financially sponsor or intend to sponsor measures of forest nature conservation were assessed. When asked, foundations stated to sponsor or intend to sponsor a broad range of measures of forest nature conservation. Most of the foundations are actively supporting almost small areas outside of nature reserves. Consequently, most of the foundations deal with an annual funding budget for nature conservation measures in forests of less than 50,000 €. The number of foundations which sponsor nature conservation measures in third-party forest areas in Germany is unknown. Based on assumptions referring to the response rate, the basic population of foundations could roughly be estimated by an approximate dimension of 90 to 170 foundations. Based on this dimension the annually funded forest area of all German foundations involved in forest nature conservation is estimated between approximately 14,000 and 17,000 hectares, while the corresponding estimate of annual funding budget ranges between 2.7 and 3.7 million € at mean. Due to an almost positive assessment of their experiences of nature conservation contracts in forests, two third of the participating foundations are planning for the future to continue their engagement in the same manner