A Supramolecular Double-Cable Structure With A 12944 Helix In A Columnar Porphyrin-C60 Dyad And Its Application In Polymer Solar Cells,
2014
The University of Akron
A Supramolecular Double-Cable Structure With A 12944 Helix In A Columnar Porphyrin-C60 Dyad And Its Application In Polymer Solar Cells, Xiong Gong
Xiong Gong
A novel porphyrin-C60 dyad (PCD1) is designed and synthesized to investigate and manipulate the supramolecular structure where geometrically isotropic [such as [60]fullerene (C60)] and anisotropic [such as porphyrin (Por)] units coexist. It is observed that PCD1 possesses an enantiomeric phase behavior. The melting temperature of the stable PCD1 thermotropic phase is 160 °C with a latent heat (ΔH) of 18.5 kJ mol−1. The phase formation is majorly driven by the cooperative intermolecular Por–Por and C60–C60 interactions. Structural analysis reveals that this stable phase possesses a supramolecular “double-cable” structure with one p-type Por core columnar channel and three helical n-type C60 …
Measurement Of Forces Across Room Temperature Ionic Liquids Between Mica Surfaces,
2014
The University of Akron
Measurement Of Forces Across Room Temperature Ionic Liquids Between Mica Surfaces, Younjin Min
Younjin Min
Ionic liquids (ILs) are liquids that consist only of cations and anions. In spite of a plethora of emerging processes involving ionic liquids, there is no experimental measurement of the structure and dynamics of ILs at the solid−liquid interface comparable to the double layers of electrolyte solutions. Here, we report the direct measurements of the interactions (force−distance functions) between two atomically smooth mica surfaces across three different types of room temperature ILs. The forces are repulsive at all measured distances in all three cases, decaying exponentially with distance. Effective Debye screening lengths are found to be around 1−4 nm, much …
Inorganic Solid State Chemistry,
2014
The University of Akron
Photoconductivity And Charge Transporting Properties Of Metal-Containing Poly ( P>-Phenylenevinylene) S,
2014
The University of Akron
Photoconductivity And Charge Transporting Properties Of Metal-Containing Poly ( P>-Phenylenevinylene) S, Xiong Gong
Xiong Gong
A novel type of poly (p- phenylenevinylene)s which contain ( bis (2,2′:6′,2′′ -terpyridine) ruthenium (II) complexes has been developed. The absorption of the polymers at 500 nm was strongly enhanced by the metal complexes due to the presence of the metal–ligand charge transfer transition. The charge transportation is dispersive with hole carrier mobilities and activation energy of ∼7×10-5 cm 2 V -1 s -1 and 0.20 eV, respectively, depending on the concentration of the metal complex. A log μ vs E1/2 plot shows that hole mobilities decrease with increasing field, which suggests the presence of off-diagonal disorder in the hopping …
Mechanomutable And Reversibly Swellable Polyelectrolyte Multilayer Thin Films Controlled By Electrochemically Induced Ph Gradients,
2014
The University of Akron
Mechanomutable And Reversibly Swellable Polyelectrolyte Multilayer Thin Films Controlled By Electrochemically Induced Ph Gradients, Younjin Min
Younjin Min
We present a new strategy to electrochemically control the swelling state and mechanical properties of a polyelectrolyte multilayer thin film. While a number of pH-responsive polymer films and hydrogels have been developed, biological systems typically will not tolerate substantial deviations in pH. Therefore, to apply such pH-responsive systems for biomedical or other sensitive applications, we developed an electrochemical approach to alter local pH, while maintaining a constant, mild, bulk pH. The polymer film investigated in this work comprises polyallylamine hydrochloride (PAH) and sulfonated polystyrene (SPS) assembled at high pH (>9.0), which is known to exhibit a large pH-induced swelling …
Methods And Devices Utilizing Soluble Conjugated Polymers,
2014
The University of Akron
Methods And Devices Utilizing Soluble Conjugated Polymers, Xiong Gong
Xiong Gong
Methods, compositions and articles of manufacture involving soluble conjugated polymers are provided. The conjugated polymers have a sufficient density of polar substituents to render them soluble in a polar medium, for example water and/or methanol. The conjugated polymers may desirably comprise monomers which alter their conductivity properties. The different solubility properties of these polymers allow their deposition in solution in multilayer formats with other conjugated polymers. Also provided are articles of manufacture comprising multiple layers of conjugated polymers having differing solubility characteristics. Embodiments of the invention are described further herein.
Measurement And Characterization Of Resonance Friction At High Sliding Speeds In A Model Automotive Wet Clutch,
2014
The University of Akron
Measurement And Characterization Of Resonance Friction At High Sliding Speeds In A Model Automotive Wet Clutch, Younjin Min
Younjin Min
The friction forces between various lubricated “friction materials” and sapphire disks were measured using a new “high-speed” rotating disk attachment to the surface forces apparatus (SFA). Two different clutch lubricants and two different friction materials were tested at sliding speeds and normal loads from 5 to 25 m/s, and 0.2 to 1 N (nominal pressures ~1 MPa), respectively. The results show that “resonance friction”—characterized by large amplitude oscillatory (i.e., sinusoidal) vibrations, also known as shudder or chatter—dominates dynamical considerations at high sliding speed, replacing the smooth sliding or low-amplitude stick–slip that is characteristic of low speed/low load sliding. The characteristic …
Fine-Tuning Of Fluorinated Thieno[3,4-B]Thiophene Copolymer For Efficient Polymer Solar Cells Adv. Mater.,
2014
The University Of Akron
Fine-Tuning Of Fluorinated Thieno[3,4-B]Thiophene Copolymer For Efficient Polymer Solar Cells Adv. Mater., Hangxing Wang, Xinfei Yu, Chao Yi, He Ren, Chang Liu, Yali Yang, Steven Xiao, Jie Zheng, Alamgir Karim, Stephen Cheng, Xiong Gong
Xiong Gong
Novel low band gap fluorinated copolymers have been synthesized and characterized. The performance of inverted polymer solar cells made by these fluorinated copolymers blended with fullerene derivatives was also investigated. The studies of the effect of fluorine units on the electronic properties and the thin film morphologies of fluorinated copolymers demonstrated that an optimal window of 20–40% fluorine units coupled with thieno[3,4-b]thiopehene exists for a maximum hole mobility that correlated well with a dispersed interconnected morphology of the fluorinated copolymer, thus enhancing the performance of polymer solar cells. More fluorine units coupled with thieno[3,4-b]thiopehene adversely affected the phase morphology to …
The Stability Of Electro-Opto-Active Organics,
2014
The University of Akron
The Stability Of Electro-Opto-Active Organics, Xiong Gong
Xiong Gong
No abstract provided.
Semiconducting Polymers And Its Applications,
2014
The University of Akron
Semiconducting Polymers And Its Applications, Xiong Gong
Xiong Gong
No abstract provided.
Formation Of Supported Bilayers On Silica Substrates,
2014
The University of Akron
Formation Of Supported Bilayers On Silica Substrates, Younjin Min
Younjin Min
We have investigated the formation of phospholipid bilayers of the neutral (zwitterionic) lipid dimyristoyl-phosphatidylcholine (DMPC) on various glass surfaces from vesicles in various aqueous solutions and temperatures using a number of complementary techniques: the surface forces apparatus (SFA), quartz crystal microbalance (QCM), fluorescence recovery after photobleaching (FRAP), fluorescence microscopy, and streaming potential (SP) measurements. The process involves five stages: vesicle adhesion to the substrate surfaces via electrostatic and van der Waals forces, steric interactions with neighboring vesicles, rupture, spreading via hydrophobic fusion of bilayer edges, and ejection of excess lipid, trapped water, and ions into the solution. The forces between …
High Sensitivity Solution-Processed Near-Infrared Polymer Photodetectors With An Inverted Device Structure,
2014
The University of Akron
High Sensitivity Solution-Processed Near-Infrared Polymer Photodetectors With An Inverted Device Structure, Xiong Gong
Xiong Gong
No abstract provided.
Water Soluble Etl Polymers,
2014
The University of Akron
Polyhedral Oligomeric Silsesquioxane-Fullerene Dyads And Its Application As The Interfacial Layer In Inverted Polymer Solar Cells,
2014
The University of Akron
Polyhedral Oligomeric Silsesquioxane-Fullerene Dyads And Its Application As The Interfacial Layer In Inverted Polymer Solar Cells, Xiong Gong
Xiong Gong
No abstract provided.
Infrared Polymer Photodetector,
2014
The University of Akron
Methods For Improving The Qualities Of Polymer Light-Emitting Electrochemical Cells,
2014
The University of Akron
Methods For Improving The Qualities Of Polymer Light-Emitting Electrochemical Cells, Xiong Gong
Xiong Gong
No abstract provided.
Use Of Catechol Modified Polymers In Layer By Layer Assembly To Enhance Its Stability And Sustained Release Of Biomolecules: A Bio Inspired Approach,
2014
The University of Akron
Use Of Catechol Modified Polymers In Layer By Layer Assembly To Enhance Its Stability And Sustained Release Of Biomolecules: A Bio Inspired Approach, Younjin Min
Younjin Min
Although Layer-by-Layer (LbL) assembly technique has been successfully used in various areas of nanotechnology and biotechnology, some LbL-assembled nanostructures have suffered from lack of stability when they are exposed to any changes in aqueous environments (e.g., pH and ionic strength). In addition, this technique has been limited because of the diffusion of polyelectrolytes throughout the film during the deposition process, resulting in poorly organized architectures, thus limiting the control of release characteristics. To improve the stability of LbL-assembled nanostructures, and to control interlayer diffusion, we have developed a strategy to conjugate catechol groups, which are largely present in mussel adhesive …
Effect Of Y-Ray Irradiation On Structures And Luminescent Properties Of Nanocrystallines Mso4: Xeu3+ (M= Ca, Sr, Ba; X= 0.001-0.005),
2014
The University of Akron
Effect Of Y-Ray Irradiation On Structures And Luminescent Properties Of Nanocrystallines Mso4: Xeu3+ (M= Ca, Sr, Ba; X= 0.001-0.005), Xiong Gong
Xiong Gong
A series of nanocrystalline rare earth doped alkaline earth sulphates, MSO4:xEu3+ (M=Ca,Sr,Ba; x=0.001–0.005), have been prepared by co-precipitation method. Their crystal structures and luminescent properties with and without γ-ray irradiation are compared. It was found that their crystal structures have not changed, but their lattice parameters with irradiation become smaller than those without irradiation. On the other hand, the characteristic emissions of both Eu3+ and Eu2+ are observed in the same nanocrystals with γ-irradiation. The differences in their crystal structures and luminescent properties are also discussed.
Multilayer White Lighting Polymer Light-Emitting Diodes,
2014
The University of Akron
Multilayer White Lighting Polymer Light-Emitting Diodes, Xiong Gong
Xiong Gong
No abstract provided.
White Electrophosphorescence From Semiconducting Polymer Blends,
2014
The University of Akron
White Electrophosphorescence From Semiconducting Polymer Blends, Xiong Gong
Xiong Gong
White emission from polymer light-emitting diodes (PLEDs) is demonstrated using semiconducting polymers blended with organometallic emitters and spin-cast from solution. Because a single semiconducting polymer was used as the common host for red, green, and blue emission, the color coordinates, color temperatures, and color rendering indices of the white emission are insensitive to the brightness, applied voltage, and applied current density. The PLEDs have luminous efficiency of 4.3 cd A–1 and luminance of 223 cd m–2 at current density of 5.2 mA cm–2 (V = 14 V); at 17 V, L = 1.2 × 104 cd m–2.
