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Interface Modification (interface + modification)
Selected AbstractsInterface Modification to Improve Hole-Injection Properties in Organic Electronic Devices,ADVANCED FUNCTIONAL MATERIALS, Issue 8 2006A. Choulis Abstract The performance of organic electronic devices is often limited by injection. In this paper, improvement of hole injection in organic electronic devices by conditioning of the interface between the hole-conducting layer (buffer layer) and the active organic semiconductor layer is demonstrated. The conditioning is performed by spin-coating poly(9,9-dioctyl-fluorene- co - N - (4-butylphenyl)-diphenylamine) (TFB) on top of the poly(3,4-ethylene dioxythiophene): poly(styrene sulfonate) (PEDOT:PSS) buffer layer, followed by an organic solvent wash, which results in a TFB residue on the surface of the PEDOT:PSS. Changes in the hole-injection energy barriers, bulk charge-transport properties, and current,voltage characteristics observed in a representative PFO-based (PFO: poly(9,9-dioctylfluorene)) diode suggest that conditioning of PEDOT:PSS surface with TFB creates a stepped electronic profile that dramatically improves the hole-injection properties of organic electronic devices. [source] Theoretical Evaluation of the Interface Modification for Aluminium Nitride Growth on SiPHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 1 2003P. Masri Abstract In this work, we propose a strategy for the optimization of the SiC/Si structure as a subsequent substrate to grow aluminium nitride (AlN) layers on Si. Several routes are investigated within the framework of a theoretical approach which we recently developed and which has proved itself to be very useful in many aspects of the physics of heteroepitaxy. In this paper, we investigate one useful task of using Si as substrate with SiC buffer layer which may be grown by carbonization (C) of the Si surface. Germanium (Ge) incorporation is also modelled. The AlN/SiC/Si structure is theoretically optimized by determining the composition out of C and Ge of the buffer layer. [source] Anode Interfacial Tuning via Electron-Blocking/Hole-Transport Layers and Indium Tin Oxide Surface Treatment in Bulk-Heterojunction Organic Photovoltaic CellsADVANCED FUNCTIONAL MATERIALS, Issue 4 2010Alexander W. Hains Abstract The effects of anode/active layer interface modification in bulk-heterojunction organic photovoltaic (OPV) cells is investigated using poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) and/or a hole-transporting/electron-blocking blend of 4,4,-bis[(p -trichlorosilylpropylphenyl)-phenylamino]biphenyl (TPDSi2) and poly[9,9-dioctylfluorene- co - N -[4-(3-methylpropyl)]-diphenylamine] (TFB) as interfacial layers (IFLs). Current,voltage data in the dark and AM1.5G light show that the TPDSi2:TFB IFL yields MDMO-PPV:PCBM OPVs with substantially increased open-circuit voltage (Voc), power conversion efficiency, and thermal stability versus devices having no IFL or PEDOT:PSS. Using PEDOT:PSS and TPDSi2:TFB together in the same cell greatly reduces dark current and produces the highest Voc (0.91,V) by combining the electron-blocking effects of both layers. ITO anode pre-treatment was investigated by X-ray photoelectron spectroscopy to understand why oxygen plasma, UV ozone, and solvent cleaning markedly affect cell response in combination with each IFL. O2 plasma and UV ozone treatment most effectively clean the ITO surface and are found most effective in preparing the surface for PEDOT:PSS deposition; UV ozone produces optimum solar cells with the TPDSi2:TFB IFL. Solvent cleaning leaves significant residual carbon contamination on the ITO and is best followed by O2 plasma or UV ozone treatment. [source] Online light scattering measurements: A method to assess morphology development of polymer blends in a twin-screw extruderPOLYMER ENGINEERING & SCIENCE, Issue 10 2002G. Schlatter Light scattering has proved itself an efficient technique to determine particle diameters in heterogeneous dilute dispersions in the micrometer range. Extrusion of polymer blends is expected to give rise to very small particles, typically in the range from hundreds of nanometers to tens of micrometers. A light scattering device developed in our laboratory has been used to study the morphology of polymer blends obtained in a twin-screw extruder. The main advantage of this technique is the immediate response obtained without any surface or interface modification that can occur during the sample preparation by using more conventional techniques like electron microscopy. To show the possible applications of this light scattering device, preliminary tests have been carried out. First, we present a comparison between experimental measurements and theoretical results for dilute systems. Second, we have investigated the effect of shear flow on the droplet deformation. Finally, we have studied the variations of the light scattering pattern for a reactive blend. [source] A review on interface modification and characterization of natural fiber reinforced plastic compositesPOLYMER ENGINEERING & SCIENCE, Issue 9 2001Jayamol George An Important aspect with respect to optimal mechanical performance of fiber reinforced composites in general and durability in particular is the optimization of the interfacial bond between fiber and polymer matrix. The quality of the fiber-matrix interface is significant for the application of natural fibers as reinforcement for plastics. Since the fibers and matrices are chemically different, strong adhesion at their interfaces is needed for an effective transfer of stress and bond distribution throughout an Interface. A good compatibilization between cellulose fibers and non-polar matrices is achieved from polymeric chains that will favor entanglements and interdiffiusion with the matrix. This article gives a critical review on the physical and chemical treatment methods that improve the fiber-matrix adhesion and their characterization methods. [source] | ||||||||||