This document summarizes research on using nanoimprint lithography to shape poly(3-hexylthiophene-2,5-diyl) (P3HT) into nanogratings. Field effect transistors and organic photovoltaic devices were fabricated using these P3HT nanogratings. Device measurements found that the nanoimprint-induced three-dimensional polymer chain alignment in the nanogratings enhanced hole mobility in the transistors by about 60 times compared to non-optimized thin film transistors. The organic photovoltaic devices using the P3HT nanogratings also showed improved performance compared to similar bilayer and bulk heterojunction devices, due to the higher charge carrier mobility enabled by the favorable chain configuration.
1) Researchers developed a double nanoimprinting process to fabricate photovoltaic devices with precisely defined interpenetrating nanoscale columnar features of polymer blends.
2) The process involves first imprinting the electron donor polymer P3HT, then using the patterned P3HT film as a stamp to imprint the electron acceptor polymer F8TBT, forming interdigitated polymer bilayers down to feature sizes of 25 nm.
3) Photovoltaic devices based on films with smaller nanoscale features showed higher power conversion efficiencies, with the 25 nm feature size device achieving 1.9% efficiency, among the best reported for polymer-polymer blend devices.
The document investigates the physical aging of carbon nanotube/PEDOT:PSS nanocomposite thin films with different multi-walled carbon nanotube (MWCNT) concentrations using electrochemical impedance spectroscopy. The key findings are:
1) The aging rate and change in electrical resistance decreases with increasing MWCNT concentration, from 21.2% change for pure PEDOT:PSS to 6.8% change at 0.1 wt.% MWCNT.
2) MWCNTs restrict the mobility of polymer chains near the MWCNT/PEDOT:PSS interface, reducing the aging rate.
3) An equivalent circuit model with tunneling resistance and capacitance components fits the imped
Boron nitride nanotubes (BNNTs) are structurally similar to carbon nanotubes but are electrically insulating. When added to polymer matrices as nanocomposites, BNNTs can improve the mechanical, thermal, and dielectric properties of polymers. BNNTs enhance stiffness, thermal conductivity, and breakdown voltage while maintaining the electrical insulation of polymers. They disperse well due to strong interfacial interactions and do not negatively impact polymer properties. BNNTs show promise as nanofillers for high performance polymer composites.
20180323 electrospinning and polymer nanofibersTianyu Liu
Electrospinning uses electric fields to produce polymer nanofibers. It works by applying a high voltage to a polymer solution, forming a Taylor cone and whipping jet that dries into nanofibers collected on a grounded target. Key parameters that affect fiber diameter are polymer concentration and viscosity, applied voltage, injection rate, and collector pattern. Electrospun nanofibers have various applications including tissue engineering scaffolds, filtration membranes, sensors, and energy storage devices like batteries.
This document discusses polymer nanocomposites, which combine a polymer matrix with nanoscale inorganic fillers. Polymer nanocomposites can overcome limitations of conventional composites and monolithic polymers by exhibiting improved mechanical, thermal, and optical properties due to the high surface area of nanoparticles. Properties of nanocomposites depend on the matrix polymer, nanoparticle fillers, and their dispersion within the polymer. Potential applications of nanocomposites include use in automobiles, electronics, packaging, and military equipment by exploiting their enhanced strength, thermal and chemical resistance.
This document discusses using inkjet printing to pattern carbon nanotubes (CNTs) for multifunctional composite applications. It explores how to functionalize CNTs through oxidation to improve compatibility with polymer matrices. The objectives are to examine how the electrical conductivity of printed CNT networks is influenced by printing parameters and surface functionalization. An inkjet printing process is used to deposit CNT solutions onto fiber substrates with high precision. The conductivity is characterized for different printing configurations and levels of CNT sheet oxidation. The results show that printing direction, droplet spacing, and repeated overwriting influence conductivity, and that surface functionalization through ozone oxidation can both increase and decrease conductivity depending on exposure time.
This document provides an overview of electrospinning functional materials for biomedical applications and tissue engineering. It discusses how electrospinning can be used to create ultrathin polymer fibers with properties that mimic the extracellular matrix, including large surface area to volume ratio and control over mechanical properties. The document also describes how electrospinning parameters can be modified to control fiber properties, and how fiber surfaces can be modified through treatments like plasma treatment, chemical modification, and immobilization of bioactive molecules to enhance cell interactions.
1) Researchers developed a double nanoimprinting process to fabricate photovoltaic devices with precisely defined interpenetrating nanoscale columnar features of polymer blends.
2) The process involves first imprinting the electron donor polymer P3HT, then using the patterned P3HT film as a stamp to imprint the electron acceptor polymer F8TBT, forming interdigitated polymer bilayers down to feature sizes of 25 nm.
3) Photovoltaic devices based on films with smaller nanoscale features showed higher power conversion efficiencies, with the 25 nm feature size device achieving 1.9% efficiency, among the best reported for polymer-polymer blend devices.
The document investigates the physical aging of carbon nanotube/PEDOT:PSS nanocomposite thin films with different multi-walled carbon nanotube (MWCNT) concentrations using electrochemical impedance spectroscopy. The key findings are:
1) The aging rate and change in electrical resistance decreases with increasing MWCNT concentration, from 21.2% change for pure PEDOT:PSS to 6.8% change at 0.1 wt.% MWCNT.
2) MWCNTs restrict the mobility of polymer chains near the MWCNT/PEDOT:PSS interface, reducing the aging rate.
3) An equivalent circuit model with tunneling resistance and capacitance components fits the imped
Boron nitride nanotubes (BNNTs) are structurally similar to carbon nanotubes but are electrically insulating. When added to polymer matrices as nanocomposites, BNNTs can improve the mechanical, thermal, and dielectric properties of polymers. BNNTs enhance stiffness, thermal conductivity, and breakdown voltage while maintaining the electrical insulation of polymers. They disperse well due to strong interfacial interactions and do not negatively impact polymer properties. BNNTs show promise as nanofillers for high performance polymer composites.
20180323 electrospinning and polymer nanofibersTianyu Liu
Electrospinning uses electric fields to produce polymer nanofibers. It works by applying a high voltage to a polymer solution, forming a Taylor cone and whipping jet that dries into nanofibers collected on a grounded target. Key parameters that affect fiber diameter are polymer concentration and viscosity, applied voltage, injection rate, and collector pattern. Electrospun nanofibers have various applications including tissue engineering scaffolds, filtration membranes, sensors, and energy storage devices like batteries.
This document discusses polymer nanocomposites, which combine a polymer matrix with nanoscale inorganic fillers. Polymer nanocomposites can overcome limitations of conventional composites and monolithic polymers by exhibiting improved mechanical, thermal, and optical properties due to the high surface area of nanoparticles. Properties of nanocomposites depend on the matrix polymer, nanoparticle fillers, and their dispersion within the polymer. Potential applications of nanocomposites include use in automobiles, electronics, packaging, and military equipment by exploiting their enhanced strength, thermal and chemical resistance.
This document discusses using inkjet printing to pattern carbon nanotubes (CNTs) for multifunctional composite applications. It explores how to functionalize CNTs through oxidation to improve compatibility with polymer matrices. The objectives are to examine how the electrical conductivity of printed CNT networks is influenced by printing parameters and surface functionalization. An inkjet printing process is used to deposit CNT solutions onto fiber substrates with high precision. The conductivity is characterized for different printing configurations and levels of CNT sheet oxidation. The results show that printing direction, droplet spacing, and repeated overwriting influence conductivity, and that surface functionalization through ozone oxidation can both increase and decrease conductivity depending on exposure time.
This document provides an overview of electrospinning functional materials for biomedical applications and tissue engineering. It discusses how electrospinning can be used to create ultrathin polymer fibers with properties that mimic the extracellular matrix, including large surface area to volume ratio and control over mechanical properties. The document also describes how electrospinning parameters can be modified to control fiber properties, and how fiber surfaces can be modified through treatments like plasma treatment, chemical modification, and immobilization of bioactive molecules to enhance cell interactions.
BIO MEDICAL APPLICATIONS OF NANOCELLULOSEArjun K Gopi
Nanocellulose is a lightweight, high-strength material produced from cellulose sources like wood pulp through mechanical and chemical processes. It has properties making it suitable for applications like reinforced polymers, optical films, and biomedical uses. Nanocellulose can be used as tissue scaffolds, drug delivery systems, blood vessel replacements, and other medical biomaterials due to its biocompatibility, renewability, and impressive mechanical properties. The document discusses the production, properties, and medical applications of different types of nanocellulose like microfibrillated cellulose and nanocrystalline cellulose.
Cellulose nanofiber is made from wood fibers that have been micro-refined to the nano scale and are several hundredths of a micron in size. It is the world's most advanced biomass material due to its light weight, strength, and low environmental impact. Cellulose nanofiber has properties including high strength, stiffness, barrier properties, and renewability that make it suitable for a wide range of applications like paper products, composites, and electronics.
MECHANICAL & THERMAL PROPERTIES OF NANO COMPOSITESArjun K Gopi
This document discusses the mechanical and thermal properties of polymer nanocomposites. It explains that polymer nanocomposites consist of a polymer matrix reinforced with nanoparticles, which have high surface area. This results in enhanced bonding between the polymer and nanoparticles. As a result, polymer nanocomposites often demonstrate improved mechanical properties over micro-composites, such as increased elastic modulus. A key factor influencing the mechanical properties is the interphase layer that forms between the polymer matrix and nanoparticles. The properties of this interphase region, which can differ from the bulk materials, largely determine how stress is transferred between phases. Several experimental techniques for characterizing the structure and properties of polymer nanocomposites are described, including tensile testing,
CNT in nanocomposites and structural compositeslmezzo
The document discusses the development of carbon nano tubes (CNTs) in nanocomposites and structural composites. It describes three generations of CNT composites with CNTs arranged randomly, confined, or oriented. The first generation provided benefits like higher cleanliness and dimensional stability. Subsequent generations improved CNT-matrix interactions, dispersion, and the final targeted properties. The highest challenge is achieving the desired CNT dispersion and orientation cost-effectively to supply the market.
It is described about polymer/clay nanocomposites which can be abbreviated to PCNC, their preparation methods, properties and relevances, important types of polymers employed in the preparation of PCNC, montmorillonite crystal structures,
The document presents a study of ballistic transport in carbon nanotube field effect transistors (CNTFETs) using numerical modeling and simulation. It compares the performance of Schottky-barrier CNTFETs and MOSFET-like CNTFETs. Key findings include that thinner oxides and higher dielectric constant materials provide better electrostatic gate control and higher on-off current ratios, and that doped contact CNTFETs generally exhibit better performance than Schottky-barrier CNTFETs. The study provides insights into scaling effects and quantum phenomena in CNTFET devices.
Basic description of nanofibers, their propeties. The type of marterials used for the preparation of nanofibers and the techniques involves into it. Also the recent technologies emerging fot the prodcution of nanofibers.
This seminar presentation summarizes polymer nanocomposites. It defines nanocomposites as multiphase solid materials with one phase having dimensions less than 100 nm. The major constituent is the polymer matrix and the minor constituent is nanoscale reinforcement materials like nanotubes, nanoplates, or nanoparticles. The advantages of nanoscale fillers over conventional fillers include low percolation thresholds, large interfacial areas, and short particle distances. Surface modification of nanofillers is important to prevent agglomeration and improve interfacial interactions. Common synthesis methods for polymer nanocomposites include melt compounding, solvent processing, and in situ polymerization. Polymer nanocomposites provide enhanced properties compared to
Nanocomposite biomaterials are multiphase solid materials where one phase has dimensions less than 100 nm. This nano-scale structure gives nanocomposites improved mechanical, electrical, thermal and other properties compared to their components. There are several types of nanocomposite biomaterials including ceramic-matrix nanocomposites, polymer-matrix nanocomposites, polymer-silicate nanocomposites, elastomeric nanocomposites, and bionanocomposites. Bionanocomposites are of particular interest for biomedical applications like tissue engineering due to their biocompatibility and ability to be biodegraded in the body.
POLYMER MODIFICATION WITH CARBON NANOTUBESArjun K Gopi
This document discusses the modification of polymers with carbon nanotubes to produce polymer-carbon nanotube composites. It first introduces different types of carbon nanotubes and discusses challenges in dispersing carbon nanotubes in polymer matrices due to their low compatibility. It then covers various methods used to functionalize carbon nanotubes and polymers to improve their interaction and dispersion, including covalent and non-covalent attachment of polymers to carbon nanotube surfaces. The document also discusses applications of these composites, particularly for reinforcing polymers like polyethylene, and their potential use in radiation shielding and resistant materials.
POLYMER NANOCOMPOSITE ARE THE FUTURE for packaging industriesPrajwal Ghadekar
Flexible packaging consumption’s rapid growth represents a $38 billion market in the global Community. As the demand in the industry continues to rise at an average of 3.5% each year, flexible materials need to meet and exceed the high expectations of consumers And the stressors of the supply chain. Increased competition between suppliers Along with government regulations translates into innovations in films that enhance product and Package performance as well as address worldwide concerns with packaging waste.
One such innovation is polymer nanocomposite technology which holds the key to future Advances in flexible packaging. According to Aaron Brody in a December, 2003 Food Technology article, “…Nano composites appear capable of approaching the elusive goal of converting plastic into a superbarrier—the equivalent of glass or metal—without upsetting regulators” (Brody, 2003). This paper will discuss how nanocomposites are made and the growth of nanocomposite materials as a function of their numerous advantages in the packaging industry today and in the future.
Nanofiber Technology & different techniques. Eliminating the use of solvent MEK. Suitable solvents with different Techniques to produce nanofiber coatings. Applications of nanofiber technology. Market analysis and startup project team build up for the same.
Karthik S.K. presented on nanocomposites and their applications in food packaging. The presentation covered the history of nanocomposites, definitions of composites and nanocomposites, methods for preparing polymer nanocomposites, various types of nanocomposites including clay, polymer, biobased, starch, cellulose, and protein nanocomposites. The presentation discussed characterization techniques for nanocomposites and concluded that nanocomposites can improve mechanical, barrier and antimicrobial properties of food packaging materials.
Fiber is a component of composite materials used to make products like paper. Fibers are categorized as either natural or manufactured. Nanofibers are manufactured fibers with diameters less than 100 nm produced via electrospinning. The electrospinning process involves injecting a polymer solution through a charged needle towards a collector. Process parameters like collector distance and flow rate affect fiber diameter. Many polymers can be used including PGA, PLA, and PCL. Electrospinning was first observed in 1914 and patented in 1934. Nanofibers have a variety of uses like cosmetics, military clothing, filters, sensors, and life science applications due to their small scale.
Patent Landscape Report on “Dielectric Polymer Nanocomposites” by DexPatentCaroline Charumathy
The Dielectric Property of Polymer Nanocomposite is an emerging and fast moving concept in electrical insulation. It is used in wide range of applications including Energy storage devices, Thin films, Semiconductor devices and Electromagnetic shielding or as radar- absorbent materials (RAMs). This landscape report will help in understanding the developments relating to preparation and use of Dielectric Polymer Nanocomposites
To get in-depth analysis of specific technology areas and the competitive patent landscape similar to this, contact us.
This document discusses nanocomposites for solar energy storage. It defines nanocomposites as composite materials with at least one nanoscale component that produces different properties than the individual components. For solar energy storage, electron donor and acceptor materials are blended into a nanocomposite rather than using semiconductor p-n junctions. Popular donor and acceptor materials discussed are P3HT polymer and PCBM fullerene. Nanocomposites can be fabricated with organic donors paired with either inorganic oxide acceptors like ZnO or organic acceptors like PCBM. Poly(3-butylthiophene) nanowires are mentioned as an example donor material.
The document discusses polymer-matrix nanocomposites, which consist of a polymeric matrix with nanoscale particles dispersed within. Nanoparticles can control the fundamental properties of materials without changing their chemical composition. Polymer nanocomposites are classified based on the type of polymer matrix used, and can be prepared through various methods like solution casting or melt blending. They exhibit improved properties like electrical conductivity, optical transparency, and mechanical strength compared to conventional composites. Potential applications of polymer nanocomposites include in the automobile, energy storage, and coatings industries.
Novel electrospun funtionalized nanofibers based on biopolymersSergio Torres-Giner
Electrospinning is a novel method for producing nanofibers from polymers through the application of a strong electrostatic field. It can produce fibers less than 100 nm in diameter from natural polymers like proteins and polysaccharides by optimizing process parameters. These electrospun nanofiber mats have high surface area and porosity, and exhibit improved thermal and mechanical properties compared to conventional films. They show potential for applications in food packaging, drug delivery, tissue engineering, and other industrial sectors by incorporating biological, mineral, or therapeutic compounds within the nanofibers.
This document discusses several papers on modeling different transistor devices using finite element analysis software. It includes figures from papers on modeling carbon nanotube field-effect transistors (CNTFETs) using wrapped gates, modeling the effects of temperature on silicon carbide metal-semiconductor field-effect transistors (SiC MESFETs), and modeling the on-resistance of fin field-effect transistors (FinFETs) accounting for quantum mechanical effects. The papers used finite element modeling to simulate device performance and capacitances under varying conditions.
This document provides an overview of nanocomposite materials. It defines nanocomposites as materials with at least one component that has dimensions between 1-100 nm. Nanocomposites consist of inorganic or organic nanoparticles embedded in a matrix. They exhibit enhanced and unique properties compared to bulk materials due to quantum effects and high surface area. The document discusses various synthesis methods for nanomaterials and nanocomposites, as well as their advantages and limitations.
- The document contains lesson plans and reflections from a student teacher on their teaching experience.
- When planning lessons, the student teacher considered the methodology used by their guide teacher, the goals and activities in the English course program, and how to motivate students.
- Creating lesson plans that followed the textbook more closely while also including fun, challenging activities was difficult but the student teacher worked with their guide teacher to find a balance.
- Not being able to fully apply what was learned at university about lesson planning due to the school context was also challenging.
- The student teacher was satisfied that they could include some of their own ideas while still meeting the requirements of their guide teacher and school program.
Michael Fox has over 20 years of experience in system testing, software development and support. He has worked on several projects for the City of Edmonton, including FINES, PETS, and MMSX. He is proficient in languages such as C#, SQL, and VB, and tools like Visual Studio, Team Foundation Server, and Microsoft Testing Center. He holds a Computer Systems Technology Diploma and certification in software testing from ISTQB.
BIO MEDICAL APPLICATIONS OF NANOCELLULOSEArjun K Gopi
Nanocellulose is a lightweight, high-strength material produced from cellulose sources like wood pulp through mechanical and chemical processes. It has properties making it suitable for applications like reinforced polymers, optical films, and biomedical uses. Nanocellulose can be used as tissue scaffolds, drug delivery systems, blood vessel replacements, and other medical biomaterials due to its biocompatibility, renewability, and impressive mechanical properties. The document discusses the production, properties, and medical applications of different types of nanocellulose like microfibrillated cellulose and nanocrystalline cellulose.
Cellulose nanofiber is made from wood fibers that have been micro-refined to the nano scale and are several hundredths of a micron in size. It is the world's most advanced biomass material due to its light weight, strength, and low environmental impact. Cellulose nanofiber has properties including high strength, stiffness, barrier properties, and renewability that make it suitable for a wide range of applications like paper products, composites, and electronics.
MECHANICAL & THERMAL PROPERTIES OF NANO COMPOSITESArjun K Gopi
This document discusses the mechanical and thermal properties of polymer nanocomposites. It explains that polymer nanocomposites consist of a polymer matrix reinforced with nanoparticles, which have high surface area. This results in enhanced bonding between the polymer and nanoparticles. As a result, polymer nanocomposites often demonstrate improved mechanical properties over micro-composites, such as increased elastic modulus. A key factor influencing the mechanical properties is the interphase layer that forms between the polymer matrix and nanoparticles. The properties of this interphase region, which can differ from the bulk materials, largely determine how stress is transferred between phases. Several experimental techniques for characterizing the structure and properties of polymer nanocomposites are described, including tensile testing,
CNT in nanocomposites and structural compositeslmezzo
The document discusses the development of carbon nano tubes (CNTs) in nanocomposites and structural composites. It describes three generations of CNT composites with CNTs arranged randomly, confined, or oriented. The first generation provided benefits like higher cleanliness and dimensional stability. Subsequent generations improved CNT-matrix interactions, dispersion, and the final targeted properties. The highest challenge is achieving the desired CNT dispersion and orientation cost-effectively to supply the market.
It is described about polymer/clay nanocomposites which can be abbreviated to PCNC, their preparation methods, properties and relevances, important types of polymers employed in the preparation of PCNC, montmorillonite crystal structures,
The document presents a study of ballistic transport in carbon nanotube field effect transistors (CNTFETs) using numerical modeling and simulation. It compares the performance of Schottky-barrier CNTFETs and MOSFET-like CNTFETs. Key findings include that thinner oxides and higher dielectric constant materials provide better electrostatic gate control and higher on-off current ratios, and that doped contact CNTFETs generally exhibit better performance than Schottky-barrier CNTFETs. The study provides insights into scaling effects and quantum phenomena in CNTFET devices.
Basic description of nanofibers, their propeties. The type of marterials used for the preparation of nanofibers and the techniques involves into it. Also the recent technologies emerging fot the prodcution of nanofibers.
This seminar presentation summarizes polymer nanocomposites. It defines nanocomposites as multiphase solid materials with one phase having dimensions less than 100 nm. The major constituent is the polymer matrix and the minor constituent is nanoscale reinforcement materials like nanotubes, nanoplates, or nanoparticles. The advantages of nanoscale fillers over conventional fillers include low percolation thresholds, large interfacial areas, and short particle distances. Surface modification of nanofillers is important to prevent agglomeration and improve interfacial interactions. Common synthesis methods for polymer nanocomposites include melt compounding, solvent processing, and in situ polymerization. Polymer nanocomposites provide enhanced properties compared to
Nanocomposite biomaterials are multiphase solid materials where one phase has dimensions less than 100 nm. This nano-scale structure gives nanocomposites improved mechanical, electrical, thermal and other properties compared to their components. There are several types of nanocomposite biomaterials including ceramic-matrix nanocomposites, polymer-matrix nanocomposites, polymer-silicate nanocomposites, elastomeric nanocomposites, and bionanocomposites. Bionanocomposites are of particular interest for biomedical applications like tissue engineering due to their biocompatibility and ability to be biodegraded in the body.
POLYMER MODIFICATION WITH CARBON NANOTUBESArjun K Gopi
This document discusses the modification of polymers with carbon nanotubes to produce polymer-carbon nanotube composites. It first introduces different types of carbon nanotubes and discusses challenges in dispersing carbon nanotubes in polymer matrices due to their low compatibility. It then covers various methods used to functionalize carbon nanotubes and polymers to improve their interaction and dispersion, including covalent and non-covalent attachment of polymers to carbon nanotube surfaces. The document also discusses applications of these composites, particularly for reinforcing polymers like polyethylene, and their potential use in radiation shielding and resistant materials.
POLYMER NANOCOMPOSITE ARE THE FUTURE for packaging industriesPrajwal Ghadekar
Flexible packaging consumption’s rapid growth represents a $38 billion market in the global Community. As the demand in the industry continues to rise at an average of 3.5% each year, flexible materials need to meet and exceed the high expectations of consumers And the stressors of the supply chain. Increased competition between suppliers Along with government regulations translates into innovations in films that enhance product and Package performance as well as address worldwide concerns with packaging waste.
One such innovation is polymer nanocomposite technology which holds the key to future Advances in flexible packaging. According to Aaron Brody in a December, 2003 Food Technology article, “…Nano composites appear capable of approaching the elusive goal of converting plastic into a superbarrier—the equivalent of glass or metal—without upsetting regulators” (Brody, 2003). This paper will discuss how nanocomposites are made and the growth of nanocomposite materials as a function of their numerous advantages in the packaging industry today and in the future.
Nanofiber Technology & different techniques. Eliminating the use of solvent MEK. Suitable solvents with different Techniques to produce nanofiber coatings. Applications of nanofiber technology. Market analysis and startup project team build up for the same.
Karthik S.K. presented on nanocomposites and their applications in food packaging. The presentation covered the history of nanocomposites, definitions of composites and nanocomposites, methods for preparing polymer nanocomposites, various types of nanocomposites including clay, polymer, biobased, starch, cellulose, and protein nanocomposites. The presentation discussed characterization techniques for nanocomposites and concluded that nanocomposites can improve mechanical, barrier and antimicrobial properties of food packaging materials.
Fiber is a component of composite materials used to make products like paper. Fibers are categorized as either natural or manufactured. Nanofibers are manufactured fibers with diameters less than 100 nm produced via electrospinning. The electrospinning process involves injecting a polymer solution through a charged needle towards a collector. Process parameters like collector distance and flow rate affect fiber diameter. Many polymers can be used including PGA, PLA, and PCL. Electrospinning was first observed in 1914 and patented in 1934. Nanofibers have a variety of uses like cosmetics, military clothing, filters, sensors, and life science applications due to their small scale.
Patent Landscape Report on “Dielectric Polymer Nanocomposites” by DexPatentCaroline Charumathy
The Dielectric Property of Polymer Nanocomposite is an emerging and fast moving concept in electrical insulation. It is used in wide range of applications including Energy storage devices, Thin films, Semiconductor devices and Electromagnetic shielding or as radar- absorbent materials (RAMs). This landscape report will help in understanding the developments relating to preparation and use of Dielectric Polymer Nanocomposites
To get in-depth analysis of specific technology areas and the competitive patent landscape similar to this, contact us.
This document discusses nanocomposites for solar energy storage. It defines nanocomposites as composite materials with at least one nanoscale component that produces different properties than the individual components. For solar energy storage, electron donor and acceptor materials are blended into a nanocomposite rather than using semiconductor p-n junctions. Popular donor and acceptor materials discussed are P3HT polymer and PCBM fullerene. Nanocomposites can be fabricated with organic donors paired with either inorganic oxide acceptors like ZnO or organic acceptors like PCBM. Poly(3-butylthiophene) nanowires are mentioned as an example donor material.
The document discusses polymer-matrix nanocomposites, which consist of a polymeric matrix with nanoscale particles dispersed within. Nanoparticles can control the fundamental properties of materials without changing their chemical composition. Polymer nanocomposites are classified based on the type of polymer matrix used, and can be prepared through various methods like solution casting or melt blending. They exhibit improved properties like electrical conductivity, optical transparency, and mechanical strength compared to conventional composites. Potential applications of polymer nanocomposites include in the automobile, energy storage, and coatings industries.
Novel electrospun funtionalized nanofibers based on biopolymersSergio Torres-Giner
Electrospinning is a novel method for producing nanofibers from polymers through the application of a strong electrostatic field. It can produce fibers less than 100 nm in diameter from natural polymers like proteins and polysaccharides by optimizing process parameters. These electrospun nanofiber mats have high surface area and porosity, and exhibit improved thermal and mechanical properties compared to conventional films. They show potential for applications in food packaging, drug delivery, tissue engineering, and other industrial sectors by incorporating biological, mineral, or therapeutic compounds within the nanofibers.
This document discusses several papers on modeling different transistor devices using finite element analysis software. It includes figures from papers on modeling carbon nanotube field-effect transistors (CNTFETs) using wrapped gates, modeling the effects of temperature on silicon carbide metal-semiconductor field-effect transistors (SiC MESFETs), and modeling the on-resistance of fin field-effect transistors (FinFETs) accounting for quantum mechanical effects. The papers used finite element modeling to simulate device performance and capacitances under varying conditions.
This document provides an overview of nanocomposite materials. It defines nanocomposites as materials with at least one component that has dimensions between 1-100 nm. Nanocomposites consist of inorganic or organic nanoparticles embedded in a matrix. They exhibit enhanced and unique properties compared to bulk materials due to quantum effects and high surface area. The document discusses various synthesis methods for nanomaterials and nanocomposites, as well as their advantages and limitations.
- The document contains lesson plans and reflections from a student teacher on their teaching experience.
- When planning lessons, the student teacher considered the methodology used by their guide teacher, the goals and activities in the English course program, and how to motivate students.
- Creating lesson plans that followed the textbook more closely while also including fun, challenging activities was difficult but the student teacher worked with their guide teacher to find a balance.
- Not being able to fully apply what was learned at university about lesson planning due to the school context was also challenging.
- The student teacher was satisfied that they could include some of their own ideas while still meeting the requirements of their guide teacher and school program.
Michael Fox has over 20 years of experience in system testing, software development and support. He has worked on several projects for the City of Edmonton, including FINES, PETS, and MMSX. He is proficient in languages such as C#, SQL, and VB, and tools like Visual Studio, Team Foundation Server, and Microsoft Testing Center. He holds a Computer Systems Technology Diploma and certification in software testing from ISTQB.
This document provides context about the student teacher's practice teaching placement. It describes the institution as a private Catholic school that was founded in 1878 and now includes kindergarten through high school. It has a religious mission and offers extracurricular activities. The classroom where the student teacher will teach has about 33-39 students between ages 16-19 who are generally at an equal English level. While most students seem engaged, some have behavioral or attention issues. The student teacher analyzed how the institutional context and student characteristics, like enjoying conversation practice, will influence lesson planning to create meaningful learning experiences.
The document discusses the benefits of exercise for mental health. Regular physical activity can help reduce anxiety and depression and improve mood and cognitive function. Exercise causes chemical changes in the brain that may help protect against mental illness and improve symptoms.
Open Orchestra - Meetup Symfony - SfPot Juin 2015OpenOrchestra
Open Orchestra is an open source, highly extensible CMS with a RESTful API that allows for multi-site, multi-device, and multilingual capabilities. It was created to avoid tight coupling through abstraction rather than implementation. The CMS has over 1337 PHPUnit tests and follows Symfony quality standards. It is currently powering corporate and e-commerce websites, mobile apps, and internal applications with over 250 million hits per month and 2,000 users.
This document contains a list of 10 photo credits attributed to various photographers. It concludes by encouraging the reader to get inspired and create their own Haiku Deck presentation on SlideShare.
Cracking the Whip Against Sexual Harassment at Workplacesfemme LIBERA
The Indian government is strictly enforcing the Sexual Harassment of Women at Workplace Act from 2013. Employers who do not properly implement the law, including establishing internal committees to handle complaints, face fines up to 50,000 rupees. The law aims to create safe and harassment-free work environments for women, who make up about a quarter of India's workforce. Proper implementation requires clear anti-harassment policies, unbiased internal complaint committees that handle issues sensitively and ensure no retaliation against complainants, as well as regular employee training on respect and unacceptable conduct.
Crash Records commissioned a consultancy report to analyze its market and competitive set through secondary and primary research. Key findings were that while digital music is growing, the market for physical music such as vinyl records is experiencing a revival. A comparison of Crash Records to its main competitor Jumbo Records found that neither offered differentiation and Crash's website and store atmosphere needed improvement. The report recommends that Crash add used vinyl, develop its website for online purchases, improve its store atmosphere, and advertise at local music events.
This digital marketing plan aims to help Bagel Nash grow its digital presence in the UK over the next six months. Research found that Bagel Nash currently has high SEO visibility but a website with a high bounce rate and low social media engagement. The plan proposes three objectives: creating a mobile app to achieve 500 downloads, decreasing the website bounce rate, and increasing social media followers. Tactics include improving the website design, using more engaging social content, and developing a mobile app. The plan segments the target audience as 20-24 year olds and will measure objectives using tools like app downloads, bounce rate, and social media analytics.
D.B. Satellite Engineering is a communications solutions provider in Ghana that offers services including fiber cable installation, computer networking, PABX systems, CCTV surveillance, telephone and intercom systems, cabling, and satellite networking. It aims to expand its reach and offerings of state-of-the-art satellite connectivity solutions while prioritizing customer needs. The proposal discusses D.B. Satellite Engineering's vision, mission, objectives, products/services, strategy for customer focus and relationship building, and provides examples of networking solutions.
OFET Preparation by Lithography and Thin Film Depositions ProcessTELKOMNIKA JOURNAL
This document summarizes research on preparing an organic field-effect transistor (OFET) using lithography and thin film deposition processes. The key points are:
1. An OFET was prepared with a bottom contact structure using copper phthalocyanine as the active layer deposited via vacuum evaporation on a silicon substrate.
2. Lithography was used to pattern gold source and drain electrodes, followed by deposition of the copper phthalocyanine thin film.
3. Electrical characterization of the completed OFET showed current increasing with drain voltage and gate voltage, indicating p-type accumulation mode operation, though saturation was not observed possibly due to a high threshold voltage.
The effect of ZnO Nanoparticles filler on the Attenuation of ZNO/PCL Nanocomp...Abubakar Yakubu
This paper describes an experiment that measured the attenuation of nanocomposites made from polycaprolactone (PCL) polymer and varying amounts of zinc oxide (ZnO) nanoparticles, using a modified microstrip line technique. The transmission coefficient was measured for nanocomposites with 25%, 35%, 45%, 50%, and 70% ZnO content. Attenuation, which is the absorption of electromagnetic waves, increased with higher ZnO content. The highest attenuation of 14.92 dB was found for the 70% ZnO sample, while the lowest of 6.72 dB was found for the 25% ZnO sample. This shows that increasing the ZnO nanoparticle filler content leads to greater attenuation of electromagnetic waves in
Sub Ten Micron Channel Devices Achieved by Vertical Organic Thin Film Transis...VLSICS Design
This document discusses the fabrication and characterization of vertical organic thin film transistors (OTFTs) with sub-ten micron channel lengths. Conventional OTFTs have channel lengths defined by lithography or shadow masking, limiting minimum size. Vertically oriented channels can achieve shorter lengths by deposition at an angle. The document reports successful fabrication of a vertical channel OTFT on a trenched silicon substrate with a channel length less than 10 microns. Output and transfer characteristics are presented, demonstrating the transistor action of the vertical device.
SUB TEN MICRON CHANNEL DEVICES ACHIEVED BY VERTICAL ORGANIC THIN FILM TRANSI...VLSICS Design
The channel lengths of the top contact organic thin film transistors are usually defined during their fabrication by optical lithography or by shadow masking during the metal deposition process. Realizing short channel (sub-ten micron channel length) transistors by lithography will require costly lithography equipment. On the other hand, it is extremely challenging to achieve short channel transistors using the low cost shadow mask process. One low cost method of achieving short channel devices is to build vertical transistors with the transistor, where the channel gets defined in the vertical part of the device. This paper shows that vertical channel top contact organic thin film transistor has been successfullyrealized on the vertical edge of trench. This helped in creating the device with channel lengths less than ten microns, much smaller than what could be typically achieved with the use of shadow masks.
Resonant-tunneling-diode effect in Si-based double-barrier structure sputtere...IJRES Journal
This paper presents the resonant-tunneling-diode (RTD) effect in a SiO2/n-Si/SiO2/p-Si double-barrier structural thin films fabricated using radio frequency (RF) magnetron sputtering at room temperature (300 K). The implementation of a circuit prototype is first accomplished by modulating a Si-based RTD with a solar-cell bias voltage. The important electrical properties of the peak current density and peak-to-valley current ratio (PVCR) are 184 nA/cm2 and 1.67, respectively. The connection between the two RTDs in series is biased by a solar cell. The value of the switching transition time is 24.37 μs; oscillation occurs with an operating frequency of 41.6 KHz. In semiconductor applications, the developed RTD is characterized by stability, enduring environmentally elevated temperature and relative humidity.
A Study On Double Gate Field Effect Transistor For Area And Cost Efficiencypaperpublications3
Abstract: Proposal for a field effect transistor had been presented, with numerical device simulations to verify the title in every manner possible. The two transitional field effect transistors like pMOS and nMOS functions are simultaneously performed, working as one or as the other according to the voltage applied to the gate terminal. Increase in the circuit speed is observed when this technology is implemented on the device suggested with respect to the standard CMOS technology, presented a drastic reduction of number devices and associated parasitic capacitances. In addition to it IC obtained with the proposed device are fully compatible with the standard CMOS technology and the fabrication processes. Fabrication of Static Ram cells with three transistors only with minimum dimensions and a single bit line by saving silicon area and increasing the memory performance with respect to standard CMOS technologies. It is also presented that the fully compatible CMOS process can be used to successfully manufacture the new FET structure.
IOSR Journal of Applied Physics (IOSR-JAP) is an open access international journal that provides rapid publication (within a month) of articles in all areas of physics and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications in applied physics. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
Field Effect Transistors Based on Composite Films of poly (4 vinyl phenol) wi...theijes
In order to adjust the characteristic of pentacene thin film transistor we modified the dielectric properties of the gate insulator: the poly(4-vinylphenol) (PVP). PVP is an organic polymer with a low dielectric constant, limiting the performance of organic thin film transistor. To increase the dielectric constant of PVP controlled amount of ZnO nanoparticles have been homogeneously dispersed in the dielectric layer. The effect of the concentration of ZnO on the relative permittivity of PVP is measured using impedance spectroscopy it has been demonstrated that the permittivity increase (from 3.6 to 5.5), with no percolation phenomenon even at concentration of 50 vol%. The performance of the OTFT in terms of charge carrier mobility, threshold voltage and linkage current is evaluated. It results in a dramatic increase in both the field effect mobility and the linkage current by a factor of 10. It has been demonstrated that the threshold voltage can be adjusted it shifts from 8 to 0 when the volume concentration of ZnO varied from 0 to 50 vol%.
STM Observation of the Si(111) - (7×7) Reconstructed Surface Modified by Exce...IJECEIAES
The electronic properties of semiconductor surfaces change readily upon changing the carrier densities by controlling the dopant concentration. Additionally, excess dopant atoms can exert electric field which would affect the molecular adsorption process and could be used to manipulate the dynamic movement of confined molecules. A mechanism can be developed to control the molecular dynamic movement on modified semiconductor surface by dopants thus changing the effect of the electric field on the active molecules. In this study, the Si(111) surface was doped with phosphorus excessively using thermal diffusion process. The surface was then reconstructed to the 7×7 configuration via heating under UHV conditions and then studied through STM and STS techniques. The protrusions due to surface and subsurface P atoms appear brighter due to the lone electron pair. The 7×7 reconstruction would be destabilized after a critical P substitution of Si-adatom concentration due to high surface strain result in P-terminated (6√3×6√3)R30º reconstruction.
This document summarizes a research paper on controlling the threshold voltage in a dual gate organic field effect transistor (DGOFET) biosensor. It describes how a DGOFET can be used as a biosensor by detecting changes in the threshold voltage when biomolecules are exposed to the top dielectric layer. The threshold voltage can be tuned by applying biases to the top and bottom gates. When biomolecules are introduced, they change the capacitance of the top dielectric layer, shifting the threshold voltage in a way that depends on whether the biomolecules are positively or negatively charged. This allows the DGOFET to function as a transducer and detect the nature and polarity of biomolecules. The document concludes that a
Please read the following IEEE Spectrum articles and answer the quest.pdffasttrackcomputersol
Please read the following IEEE Spectrum articles and answer the questions given. You may
want to use illustrations in your answer to the questions, and mark them up accordingly as part of
answering the questions. If you take illustrations from some source (including the IEEE
Spectrum articles) please make sure this is properly cited.
http://spectrum.ieee.org/semiconductors/nanotechnology/the-next-highperformance-transistor-
could-be-made-from-lateral-nanowires Describe a FINFET and how it works. How is it different
than the planar MOSFET described in the first 5 slides of the TFET lecture? Is the FINFET a
quantum device? Give reasons why or why not. How is the nanowire device described here
different than the FINFET? Why is this difference an advantage for the nanowire device? They
one problem with the nanowire device is capacitive coupling. What is this and explain why it is a
problem with the nanowire device?
Solution
1)
The FinFET technology promises to provide the deliver superior levels of scalability needed to
ensure that the current progress with increased levels of integration within integrated circuits can
be maintained.
The FinFET offers many advantages in terms of IC processing that mean that it has been adopted
as a major way forwards for incorporation within IC technology.
FinFET technology has been born as a result of the relentless increase in the levels of
integration. The basic tenet of Moore\'s law has held true for many years from the earliest years
of integrated circuit technology. Essentially it states that the number of transistors on a given
area of silicon doubles every two years.
Some of the landmark chips of the relatively early integrated circuit era had a low transistor
count even though they were advanced for the time. The 6800 microprocessor for example had
just 5000 transistors. Todays have many orders of magnitude more.
basically what is finfet??
FinFET technology takes its name from the fact that the FET structure used looks like a set of
fins when viewed.
The main characteristic of the FinFET is that it has a conducting channel wrapped by a thin
silicon \"fin\" from which it gains its name. The thickness of the fin determines the effective
channel length of the device.
In terms of its structure, it typically has a vertical fin on a substrate which runs between a larger
drain and source area. This protrudes vertically above the substrate as a fin.
The gate orientation is at right angles to the vertical fin. And to traverse from one side of the fin
to the other it wraps over the fin, enabling it to interface with three side of the fin or channel.
This form of gate structure provides improved electrical control over the channel conduction and
it helps reduce leakage current levels and overcomes some other short-channel effects..
The term FinFET is used somewhat generically. Sometimes it is used to describe any fin-based,
multigate transistor architecture regardless of number of gates.
Due to the increased emphas.
The International Journal of Engineering and Sciencetheijes
This document summarizes a study on enhancing the properties of porous gallium nitride (GaN) using different intensities of ultraviolet (UV) electrochemical etching. GaN samples were etched at various current densities of UV illumination and characterized using scanning electron microscopy, photoluminescence spectroscopy, and Raman spectroscopy. The results showed that increasing the current density led to larger pore sizes, higher photoluminescence intensity, and small blue shifts and peak broadening in the Raman spectra, indicating relaxation of stress in the porous GaN layers.
1) Carbon nanotube tissues were coated with a polymer electrolyte via electrodeposition to improve their performance as anodes in flexible lithium-ion microbatteries.
2) Cyclic voltammetry was used to deposit p-sulfonated poly(allyl phenyl ether) polymer electrolyte into the carbon nanotube tissues.
3) The polymer-coated carbon nanotube tissue delivered a higher reversible capacity of 750 mAh/g compared to 450 mAh/g for the uncoated tissue, maintaining higher capacity even at fast charge/discharge rates, demonstrating its potential for flexible lithium-ion microbatteries.
Performance Enhancement of Wideband Reflectarray Antennas Embedded on Paper S...TELKOMNIKA JOURNAL
This research presents an innovative solution to address the bandwidth limitation of microstrip
reflectarray antennas. Organic substrate materials with controlled compositions have been characterized
to be employed as substrate materials for microstrip reflectarrays. The three proposed materials show low
dielectric permittivity values of 1.81, 1.64 and 1.84 along with loss tangents of 0.053, 0.047 and 0.057
respectively. The proposed substrate materials have been verified by modelling reflectarray unit elements
in CST MWS and measured using a waveguide simulator technique. The comparison between measured
and simulated results show a good agreement with promising broadband performance of 312, 340 and
207 MHz for S1, S2 and S3 substrate materials respectively.
This document discusses simulations of carbon nanotube, graphene, and silicon nanowire field effect transistors. It outlines objectives to review nanodevices, simulate different nanodevice structures to study characteristics, and compare results. Sections describe the structures, parameters varied in simulation like dielectric constant and channel length, and results showing the impact on performance metrics like on/off ratio. Future work and conclusions note limitations and potential for further simulation to better optimize device design.
Membrane Electrode Assembly based on Sulfonated Polystyrene as Proton Exchang...AnuragSingh1049
A novel membrane electrode assembly(MEA) basedonsulfonated polystyrene was synthesized and applied to a microbial fuel cell (MFCs). In this study, membrane electrode assembly made of sulfonated polystyrene (SPS) and nafion membrane were fabricated by combining 20% AgNO3/C catalystink. The performance of membrane electrode assemblybased sulfonated polystyrene (SPS) and nafion were evaluated by measuring proton conductivity and power density.This sulfonated polystyrene of membrane electrode assembly(SPS-MEA) revealed power density was higher than that nafion non activated membrane, this is considered for membrane application of proton exchange membrane (PEM). The presence of sulfonation groups of polystyrene was characterized by Fouriertransform infrared (FTIR) and nuclearmagnetic resonance (NMR) spectroscopy. The membranetopographybefore and after the fuel cell process treatment was investigatedby atomicforce microscopy (AFM).
Fabrication and characterization of nickelijoejournal
This paper shows that nickel nanowires of length 11μm and diameters 800 and 15nm were grown within
the pores of nuclear track polycarbonate membrane by electrodepositing nickel. Surface morphology and
crystallographic structure of the deposited nanowires was investigated using SEM, TEM and XRD
respectively. It is found that low current density gives good result, while high current density leads to the
formation of curled nanowires. Fabricated nanowires were further investigated for electrical properties
and found that nanowires obey ohm’s law. Through structural characterization it has been observed that
the fabricated nanowires posses FCC lattice structure.
This document describes an investigation of the LaAlO3-SrTiO3 (LAO-STO) heterointerface using transmission electron microscopy (TEM). The sample was prepared using pulsed laser deposition to grow a thin film of LAO on a STO substrate, followed by ion slicing to produce a wedge-shaped cross-section for TEM analysis. The TEM results revealed a high-density two-dimensional electron gas formed at the LAO-STO interface, which has potential applications in next-generation electronic devices and holds promise for novel electronic properties.
The document summarizes research on the effect of the speed of the support material on the structure of electrospun polyamide 6.6 (PA6.6) nanofiber webs. Nanofiber webs were produced at three different speeds and analyzed. It was found that decreasing the speed, and thus increasing the covering time, resulted in thicker nanofibers being formed. While the average fiber diameter did not significantly change, the distribution of fiber diameters shifted to include more larger fibers. The document proposes using parameters like the percentage of fibers in the first distribution peak and the average diameter of the two main peaks as better ways to characterize nanofiber web structure compared to just the average diameter.
Similar to Zhou Hole mobility enhancement 2010 (20)
2. OPV devices using these nanogratings in comparison to bi-
layer and bulk heterojunction or blend devices. The high
mobility enabled by the favorable 3D chain configuration
contributes to the improved current density, fill factor, and
efficiency of the nanoimprinted OPV.
II. DEVICE FABRICATIONS
Figure 1 shows the schematic of the fabrication process of
nanograting FETs and OPV devices side by side. These two
fabrication processes share some steps, such as spin coating
and nanoimprinting of P3HT. Nanoimprinting creates poly-
mer chain alignment, which is favorable to both devices as
shown. FETs were fabricated using nanoimprinted P3HT
gratings as channels to measure the hole mobility in com-
parison to nonimprinted TFT. All FETs have top contacts
deposited by evaporation through a shadow mask and use a
back gate configuration. FETs were fabricated on heavily
doped n-type ͑100͒ Si wafer ͑0.002 ⍀ cm͒ substrates with
200 nm thick thermally grown silicon oxide as gate dielec-
tric. 200 nm thick Al was deposited by an electron-beam
evaporator on the backside of the Si substrates as a back gate
electrode. Regio-regular P3HT ͑Sigma-Aldrich, Mn
=25 000–35 000 Da͒ in dichlorobenzene was spin coated
on oxidized Si, followed by annealing at 150 °C for 5 min to
obtain ϳ80 nm thick P3HT films. P3HT nanogratings were
fabricated by nanoimprinting at 170 °C for 10 min at 50 bars
and demolded at 70 °C. As shown in Fig. 2͑a͒, the nanoim-
printed gratings covering 200 mm2
areas are about 150 nm
in height, 65 nm in width, and 200 nm in pitch, with 20 nm
thick residual layer. Cr/Au ͑20 nm/200 nm͒ pads as source
and drain contacts were deposited sequentially by electron-
beam evaporation and defined by a shadow mask with a
channel length of 30 m and channel widths of 100 m on
top of the P3HT nanogratings. The source/drain metal pads
have two different orientations, e.g., along the grating direc-
tion for parallel devices and perpendicular to the grating di-
rection for perpendicular devices ͓Fig. 2͑b͔͒. For perpendicu-
lar devices, the 20 nm thick residual layer connects the
nanogratings. A set of TFT devices were also fabricated us-
ing nonimprinted P3HT films with three different thicknesses
͑20, 80, and 140 nm͒ for comparison. Among these three
thicknesses of P3HT film, 20 and 80 nm are chosen to be
equal to the residual layer thickness and starting film thick-
ness of nanoimprinted FETs, respectively. Finally, the de-
vices were annealed at 100 °C for 6–8 h in nitrogen envi-
ronment to dedope oxygen before measurements.18
The
electrical characterizations were performed using a Cascade
Microtech probing station and a Keithley 4200 semiconduc-
tor characterization system at room temperature and ambient
condition.
Figure 1͑b͒ shows the fabrication process to make the
nanograting P3HT/PCBM OPV devices using imprinted
P3HT nanogratings on patterned indium tin oxide ͑ITO͒ ͑re-
sistance 15–30 ⍀/Luminescence Technology, Taiwan͒
coated glass. The device area ͑ϳ0.1 cm2
͒ was defined by the
FIG. 1. ͑Color online͒ Schematic of the fabrication process of ͑a͒ nanograting field effect transistor and ͑b͒ nanograting solar cells. The cartoon of polymer
chain orientation shows -stacking in the lateral direction and backbone orientation in the vertical direction in P3HT nanogratings.
FIG. 2. ͑Color online͒ ͑a͒ Schematic of the nanograting field effect transistor
with source and drain parallel and perpendicular to the nanogratings, and
thin film transistor; ͑b͒ SEM image of P3HT nanogratings. The grating has
20 nm residual layer and 150–170 nm grating height.
C6M64 Zhou et al.: Hole mobility enhancement by chain alignment C6M64
J. Vac. Sci. Technol. B, Vol. 28, No. 6, Nov/Dec 2010
3. intersection of ITO and Al cathodes. First, a PEDOT:PSS
layer or poly-3,4-ethylenedioxythiophene-polystyrene sul-
phonic acid ͑H. C. Starck, Inc.͒ mixed with d-sorbitol ͑Ald-
rich͒ was spin coated on the ITO substrates and dried in N2
at 180 °C for 20 min. Then, an 85 nm thick P3HT film was
spin casted on top of the PEDOT:PSS layer. Nanoimprinting
was performed using a Si mold ͑gratings of 100 nm width,
100 nm depth, and 200 nm pitch͒ to form nanograting struc-
tures using similar NIL conditions as described for FETs.
The resulting nanogratings have the same dimensions as the
mold and a 30 nm thick residual layer. PCBM of 0.8 wt %
in dichloromethane was spin casted as electron transfer ma-
terial onto the imprinted P3HT nanogratings. Figure 3͑b͒
shows scanning electron microscopy ͑SEM͒ images of P3HT
nanogratings before and after infiltration of PCBM. We
found that dichloromethane is an orthogonal solvent that dis-
solves PCBM well but not the P3HT, allowing the stacking
of PCBM on top of the P3HT layer without distortion of the
nanostructures.14,19
A thin LiF ͑3 nm͒ layer and 100 nm thick
aluminum were thermally evaporated on the PCBM coated
sample as the top electrode. The devices are characterized
after annealing at 120 °C for 3 min. As a control study, a
similar process was used to fabricate bilayer and blended
nonpatterned solar cells without the imprint process. Figure
3͑a͒ shows the schematic designs of bilayer, blended, and
nanoimprinted OPV devices. The bilayer devices contain a
50 nm PCBM layer on top of an 85 nm thick P3HT layer,
while the blend devices were made by spin coating an
ϳ135 nm thick film of P3HT/PCBM blend ͑1:0.9͒ on a sub-
strate. The devices were measured using Air Mass 1.5 global
filtered solar simulated light ͑AM 1.5͒ calibrated using a Na-
tional Renewable Energy Laboratory certified silicon diode
with a KG-5 color filter ͑Hamamatsu͒ at an intensity of
100 mW/cm2
.
III. RESULTS AND DISCUSSIONS
Figure 4 shows drain current versus drain voltage ͑Id-Vd͒
curves demonstrating typical FETs behavior with linear and
saturation regions. Field effective mobilities are extracted ac-
cording to
ץId
ץVg
=
FEWCiVd
L
, ͑1͒
where W, L, and Ci are the channel width, channel length,
and gate capacitance, respectively.20
In our devices, the chan-
nel length and width were 100 and 30 m, respectively. We
intend to use the linear low-voltage region to calculate hole
mobility, which is close to the biasing conditions of solar
cells. The operation of solar cells can never be in the satura-
tion or high-voltage region. From Fig. 4, the linear regions of
the Id-Vd curves stay below Vd=−10 V, thereby we fixed Vd
at Ϫ5 V during Id-Vg measurements. The mobility values
were extracted using Eq. ͑1͒, where the value of GM, i.e.,
ץId/ץVg was obtained from KEITHLY software.21
The calcu-
lated mobility values are shown in Tables I and II.
As expected, nanograting FETs show mobility values
͑3.04ϫ10−2
cm2
/V s͒ 60 times higher than that of the TFT
devices of 80 nm P3HT film ͑5.62ϫ10−4
cm2
/V s͒. The
TABLE I. Hole mobility extracted from I-V curves of back-gated FETs for nanograting parallel, perpendicular,
and thin film transistors, showing strong anisotropic conductivity in P3HT nanogratings.
Device Parallel Perpendicular Thin film
Mobility ͑cm2
/V s͒ 3.04ϫ10−2
Ϯ3ϫ10−3
5.48ϫ10−5
Ϯ5ϫ10−6
5.62ϫ10−4
Ϯ5ϫ10−5
FIG. 3. ͑Color online͒ ͑a͒ Schematics of bilayer, blend, and nanograting
solar cells; SEM images of P3HT nanogratings ͑b͒ before and ͑c͒ after
infiltration of PCBM.
FIG. 4. IDS vs VDS characteristics of nanograting FET and TFT with effective
channel length of 30 m, showing the accumulation mode operation when
gate biases were applied from Ϫ5 to Ϫ35 V with an interval of Ϫ5 V.
C6M65 Zhou et al.: Hole mobility enhancement by chain alignment C6M65
JVST B - Microelectronics and Nanometer Structures
4. P3HT thin film did not have any special treatment, such as
surface treatment8
and electrospinning;7
therefore, the crys-
tallinity of the film is low. The degree of crystallinity is
significantly proportional to mobility values,15
so the TFT
devices have much lower mobility compared to ordered nan-
ograting FETs. The measured results also show a highly an-
isotropic conductance behavior in nanogratings: mobility
along the grating direction is 3.04ϫ10−2
cm2
/V s, while
mobility perpendicular to the grating direction is 5.11
ϫ10−5
cm2
/V s. Moreover, mobility along the perpendicu-
lar direction is one order of magnitude lower than the thin
film. Table II shows the TFT mobility values for three dif-
ferent thicknesses ͑20, 80, and 140 nm͒, and as we can see,
the values are very close. It proves that the thin residual layer
in perpendicular devices was not the reason for the low value
of charge mobility of nanograting FETs in the perpendicular
direction. P3HT conducts holes by a hopping mechanism and
hopping rate decreases exponentially with increasing hop-
ping distance,16
hence mobility parallel to the grating is ex-
pected to be significantly higher than in the perpendicular
direction, as we observed experimentally. The mobility of
P3HT depends on a number of other factors, such as polymer
purity and high polydispersity, processing conditions, and
measurement conditions.22–25
With specific film optimization
and treatment, the reported mobility of P3HT can be as high
as ϳ0.1 cm2
/V s, which is higher than our results. How-
ever, they were measured under much higher drain voltage
and in the saturation region, while our mobility is measured
in the linear region under low voltages, which are the condi-
tions for solar cell applications.26
Hole mobility enhancement in P3HT nanogratings is due
to nanoconfinement induced chain alignment in P3HT nan-
ogratings defined by nanoimprint lithography, as shown in
our previous work.17
In this highly ordered 3D grating struc-
ture, hopping distances of - stacking in the parallel direc-
tion and along the vertically aligned polymer backbones are
about 3.8 Å, while a hopping distance over the side chains is
about 16.8 Å in the perpendicular direction.17
This nanocon-
finement induced ordering polymer chain is due to the com-
bined effect of polymer flow at nearly molten state during the
nanoimprinting and - interchain interaction and side chain
hydrophobic interactions with hydrophobic mold walls. It
has been shown that this directed organization goes up to
tens of nanometers ͑ϳ50 nm͒ for thin film P3HT contacting
a substrate.9
Since the P3HT is confined in the mold cavity
between two walls, this range would double. Such directed
organization is likely incomplete when the channel width
and/or the period of the nanograting mold is higher than the
range of 100 nm. The nanograting size also affects polymer
flow behavior to the nanochannels during nanoimprinting.
Therefore, such kind of chain alignment cannot be expected
when large feature size nanogratings are used. Previously,
Cui et al. used a 700 nm period grating mold with 50% duty
cycle to improve the hole mobility of P3HT by NIL. They
found a 12-fold increase in mobility from P3HT nanograt-
ings compared to thin film. They observed that the carrier
mobility in the perpendicular direction is two times that of
the parallel direction, which is contradictory to our results.15
Their results are more likely due to pressure-induced crystal-
lization for large period gratings rather than nanoconfine-
ment induced polymer chain alignment and polymer flow
behavior.27,28
As described earlier, P3HT nanogratings exhibit a highly
anisotropic conductance behavior: the mobility parallel to the
grating direction is about 600 times as much as the perpen-
dicular direction. This is due to highly ordered chain orien-
tation in the grating structure: - stacking in the parallel
direction with vertically aligned backbones.17
Since the hop-
ping distance along - stacking and along the backbone is
equal ͑3.8 Å͒, the mobility along the vertical direction
would be very close to the values parallel to the grating
direction. So the field effective mobility calculated for the
parallel direction can be a good estimate of the mobility in
the vertical direction, which is the hole transport direction in
solar cells. These results suggest that nanoimprinted solar
cells would have higher hole carrier mobility than bulk het-
erojunction solar cells. The high mobility enabled by the
favorable 3D chain configuration can contribute to the im-
proved Isc, FF, and efficiency of the nanoimprinted OPV so-
lar cells. To prove this, nanograting OPV devices were fab-
ricated and characterized.
I-V curves of bilayer, blended, and nanoimprinted OPV
devices are plotted in Fig. 5, showing our preliminary results
of using high density and ordered nanowires to make P3HT/
TABLE II. Hole mobility extracted from I-V curves of back-gated thin film transistors with different thicknesses,
showing no dependence of hole mobility on the film thickness.
Thickness 20 nm 80 nm 140 nm
Mobility ͑cm2
/V s͒ 4.67ϫ10−4
Ϯ9.43ϫ10−5
4.30ϫ10−4
Ϯ1.25ϫ10−4
5.24ϫ10−4
Ϯ1.73ϫ10−4
FIG. 5. I-V curves of bilayer, blend, and nanograting OPV devices.
C6M66 Zhou et al.: Hole mobility enhancement by chain alignment C6M66
J. Vac. Sci. Technol. B, Vol. 28, No. 6, Nov/Dec 2010
5. PCBM solar cells, and their device parameters are shown in
Table III. The efficiency of nanoimprinted OPV is higher
than bilayer and blend solar cells. Both FF and Isc are higher
in P3HT nanograting solar cells than the bilayer and blended
counterparts. There can be two factors for this improved per-
formance: increase in interface area and increase in charge
mobility. The interface area of blend solar cells is the high-
est, but its Isc is smaller than the nanograting devices, indi-
cating that the hole mobility is enhanced in nanograting solar
cells due to 3D chain alignment. On the other hand, the
polymer crystallinity of bilayer solar cells can be better than
in the nanostructures and blend devices, but it has the least
interface area. Therefore, we believe that the improved per-
formance in nanograting devices is partially due to the better
chain alignment in P3HT nanogratings because high carrier
mobility improves FF, external quantum efficiency, and
Isc.5,22,23
A significant increase in nanoimprinted solar cell
performance can be expected by increasing the density and
aspect ratio of nanogratings to increase the area of interface
in addition to the enhancement of charge carrier mobility.
IV. CONCLUSIONS
We have shown that nanoimprint lithography is an effec-
tive way to enhance the charge carrier mobility of P3HT in
field effect transistor and solar cells by inducing favorable
3D chain alignments in nanogratings. Nanoimprint also pro-
vides a precise nanostructuring method to shape heterojunc-
tions so as to decrease the exciton travel length for charge
dissociation, enhance charge transport and charge collection,
and improve power conversion efficiency in OPV. In addi-
tion, polymer chain orientation in lithographically defined
polymer nanogratings provides a unique platform to study
correlations between morphology and transport mechanism
for organic devices.
ACKNOWLEDGMENTS
This work is supported by the National Science Founda-
tion ͑Grant No. ECCS-0901759͒, Welch Foundation Grant
No. AT-1617, and CONTACT/AF consortium of Texas. M.Z.
would like to thank UT Dallas for the get-doc fellowship.
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TABLE III. Device characteristics for bilayer, blend, and nanograting solar
cells, indicating improved power conversion efficiency by the nanograting
device morphology.
Devices Gratings Blend Bilayer
Voc ͑V͒ 0.55 0.56 0.46
Isc ͑mA/cm2
͒ 11.2 10.3 10.4
FF 0.45 0.43 0.41
͑%͒ 2.76 2.50 1.96
C6M67 Zhou et al.: Hole mobility enhancement by chain alignment C6M67
JVST B - Microelectronics and Nanometer Structures