1,613 research outputs found
Liquid-crystal displays: Fabrication and measurement of a twisted nematic liquid-crystal cell
No full textEric R. Waclawik, Michael J. Ford, Penny S. Hale, Joe G. Shapter and Nico H. Voelcke
Enhanced molecular chaperone activity of the small heat-shock protein alpha beta-crystallin following covalent immobilization onto a solid-phase support
No full textWe report on an improved method to interpret single molecule dissociation measurements using atomic force microscopy. We describe an easy to use methodology to reject nonspecific binding events, as well as estimating the number of multiple binding events. The method takes nonlinearities in the force profiles into account that result from the deformation of the used polymeric linkers. This new method is applied to a relevant enzyme−inhibitor system, latent matrix metalloprotease 9 (ProMMP-9, a gelatinase), and its inhibitor, tissue inhibitor of metalloproteases 1 (TIMP 1), which are important players in cancer metastasis. Our method provides a measured kinetic off-rate of 0.010 ± 0.003 s−1 for the dissociation of ProMMP9 and TIMP1, which is consistent with values measured by ensemble methods.Megan Garvey, Stefani S. Griesser, Hans J. Griesser, Benjamin Thierry, Matthew R. Nussio, Joseph G. Shapter, Heath Ecroyd, Sofia Giorgetti, Vittorio Bellotti, Juliet A. Gerrard and John A. Carve
Dip Pen Nanolithography: Direct‐Patterning SWCNTs Using Dip Pen Nanolithography for SWCNT/Silicon Solar Cells (Small 16/2018)
No full textIn article number 1800247, Joseph G. Shapter and co‐workers use dip pen nanolithography, which works much like a fountain pen, to write very long lines of single‐walled carbon nanotubes within a photovoltaic device. The lines are highly conducting and hence improve the performance of solar cells by about 40%, with increases in both observed voltage and current
Nitrogen-doped CNx/CNTs heteroelectrocatalysts for highly efficient dye-sensitized solar cells
No full textData source: Supporting information, https://doi.org/10.1002/aenm.201602276
Link to a related website: https://rss.onlinelibrary.wiley.com/doi/am-pdf/10.1002/aenm.201602276, Open Access via UnpaywallThe use of polydopamine as a nitrogen containing precursor to generate catalytically active nitrogen-doped carbon (CNx) materials on carbon nanotubes (CNTs) is reported. These N-doped CNx/CNT materials display excellent electrocatalytic activity toward the reduction of triiodide electrolyte in dye-sensitized solar cells (DSSCs). Further, the influence of various synthesis parameters on the catalytic performance of CNx/CNTs is investigated in detail. The best performing device fabricated with the CNx/CNTs material delivers power conversion efficiency of 7.3%, which is comparable or slightly higher than that of Pt (7.1%) counter electrode-based DSSC. These CNx/CNTs materials show great potential to address the issues associated with the Pt electrocatalyst including the high cost and scarcity.Aabhash Shrestha, Munkhbayar Batmunkh, Cameron J. Shearer, Yanting Yin, Gunther G. Andersson, Joseph G. Shapter, Shizhang Qiao, and Sheng Da
Synthesis of ultra-long hierarchical ZnO whiskers in a hydrothermal system for dye-sensitised solar cells
No full textAccepted 7th November 2016One-dimensional (1-D) ZnO structures are of great interest for many applications but the direct hydrothermal synthesis of ultra-long ZnO whiskers (>100 μm) remains a great challenge. Herein, we demonstrate the first synthesis of three kinds of ultra-long hierarchical ZnO whiskers, which are defined as ZnO-2 (>100 μm in length), ZnO-3 (>200 μm in length with relatively smooth surface) and ZnO-4 (>200 μm in length with relatively rough surface), via a one-pot hydrothermal process. The maximum length of hierarchical ZnO-4 whiskers can reach up to about 270 μm. The formation of oval-shaped quasi-hollow structural precursors plays a key role for the correct attachment of Zn²⁺-terminated and O²⁻-terminated active surfaces, producing well-ordered Zn²⁺⋯O²⋯Zn²⁺ bonds, and finally promoting the formation of ultra-long ZnO whiskers with hierarchical structures. When the synthesized ultra-long hierarchical ZnO-4 whiskers are mixed with commercial TiO₂for dye-sensitised solar cells (DSCs), the current density increases significantly from 13.68 mA cm⁻² (commercial TiO₂) to 16.81 mA cm⁻²(TiO₂–ZnO hybrid materials). The hybrid materials show a conversion efficiency of 7.95% which is higher as compared to that of commercial TiO₂ (5.87%). This interesting performance of a hybrid material sheds light on the possibility of preparing ultra-long hierarchical ZnO whiskers (>100 μm) with tunable lengths through hydrothermal approaches and their application in DSCs.Guo Gao, Leping Yu, Ajayan Vinu, Joseph G. Shapter, Munkhbayar Batmunkh, Cameron J. Shearer, Ting Yin, Peng Huang and Daxiang Cu
Black phosphorus: synthesis and application for solar cells
No full textFew-layer ultrathin nanosheets and ultrasmall quantum dots of black phosphorus (BP) have attracted increasing research interest due to their fascinating properties including a tunable bandgap, high carrier mobility, and ambipolar conduction ability. These excellent properties together with their unique structures make BP derivatives promising candidates for a wide range of device applications. In this research news, the latest advancements in the synthesis, properties, and applications of BP and its derivatives are highlighted. In particular, the focus is on the use of these rising star materials for emerging solar cells, in terms of both theoretical predictions and experimental investigations. Finally, the authors' personal perspectives on potential future research directions are provided
1D‐2D Synergistic MXene‐Nanotubes Hybrids for Efficient Perovskite Solar Cells
No full textIncorporation of 2D MXenes into the electron transporting layer (ETL) of perovskite solar cells (PSCs) has been shown to deliver high-efficiency photovoltaic (PV) devices. However, the ambient fabrication of the ETLs leads to unavoidable deterioration in the electrical properties of MXene due to oxidation. Herein, sorted metallic single-walled carbon nanotubes (m-SWCNTs) are employed to prepare MXene/SWCNTs composites to improve the PV performance of PSCs. With the optimized composition, a power conversion efficiency of over 21% is achieved. The improved photoluminescence and reduced charge transfer resistance revealed by electrochemical impedance spectroscopy demonstrated low trap density and improved charge extraction and transport characteristics due to the improved conductivity originating from the presence of nanotubes as well as the reduced defects associated with oxygen vacancies on the surface of the SnO2 . The MXene/SWCNTs strategy reported here provides a new avenue for realizing high-performance PSCs.No Full Tex
Phosphorene and phosphorene-based materials – prospects for future applications
No full textPhosphorene, a single- or few-layered semiconductor material obtained from black phosphorus, has recently been introduced as a new member of the family of two-dimensional (2D) layered materials. Since its discovery, phosphorene has attracted significant attention, and due to its unique properties, is a promising material for many applications including transistors, batteries and photovoltaics (PV). However, based on the current progress in phosphorene production, it is clear that a lot remains to be explored before this material can be used for these applications. After providing a comprehensive overview of recent advancements in phosphorene synthesis, advantages and challenges of the currently available methods for phosphorene production are discussed. An overview of the research progress in the use of phosphorene for a wide range of applications is presented, with a focus on enabling important roles that phosphorene would play in next-generation PV cells. Roadmaps that have the potential to address some of the challenges in phosphorene research are examined because it is clear that the unprecedented chemical, physical and electronic properties of phosphorene and phosphorene-based materials are suitable for various applications, including photovoltaics
Invariant tori and Lagrange stability of pendulum-type equations
No full textAbstractIn this paper we prove that the pendulum-type equation x″ + g(t, x) = 0 possesses infinitely many invariant tori whenever g(t, x) has zero mean value on the torus T2, where g(t, x) belongs to C∞(T2). This yields the boundedness for solutions of the considered pendulum-type equation and thus leads to an answer to J. Moser's boundedness problem (1973, Ann. of Math. Stud. 77)
Synthesis, purification, properties and characterization of sorted single-walled carbon nanotubes
No full textSingle-walled carbon nanotubes (SWCNTs) have attracted significant attention due to their outstanding mechanical, chemical and optoelectronic properties, which makes them promising candidates for use in a wide range of applications. However, as-produced SWCNTs have a wide distribution of various chiral species with different properties (i.e. electronic structures). In order to take full advantage of SWCNT properties, highly purified and well-separated SWCNTs are of great importance. Recent advances have focused on developing new strategies to effectively separate nanotubes into single-chirality and/or semiconducting/metallic species and integrating them into different applications. This review highlights recent progress in this cutting-edge research area alongside the enormous development of their identification and structural characterization techniques. A comprehensive review of advances in both controlled synthesis and post-synthesis separation methods of SWCNTs are presented. The relationship between the unique structure of SWCNTs and their intrinsic properties is also discussed. Finally, important future directions for the development of sorting and purification protocols for SWCNTs are provided
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