Download or read book Metallophthalocyanine Thin Films written by Corneliu Nicolai Colesniuc and published by . This book was released on 2011 with total page 85 pages. Available in PDF, EPUB and Kindle. Book excerpt: Organic semiconductors represent a class of carbon-based compounds with a tremendous potential to exhibit novel physical properties, and to be used in new and important applications. They display different properties compared to their inorganic counterparts, and present many advantages such as unlimited potential to be synthesized in new molecular structures, and capability of being processed inexpensively. Metallophthalocyanines (MPc) belong to the small-molecule group of organic semiconductors, and represent a model system for the whole class of flat, organic molecules. This dissertation presents a study of the structure and the electrical and magnetic properties of thin phthalocyanine films and phthalocyanine-based devices. Chapter one gives an introduction to the general properties of organic semiconductors and the wide range of their physical properties. In particular, the metallophtalocyanines are introduced as being a model system for the small-molecule group of organic semiconductors. Metallophthalocyanines are very well suited to be grown in thin films using organic molecular beam deposition (OMBD) techniques. Chapter two discusses the fabrication of thin phthalocyanine films and devices using OMBD, and the study of their structural properties using a wide range of experimental methods. The molecular shape anisotropy, combined with the interplay between intermolecular and the molecule-substrate interactions, determine different thin film structures that can be controlled by the fabrication conditions. The structure of phthalocyanine thin films determines their electrical transport properties. Chapter three investigates the electrical transport properties of hybrid metal-organic sandwich devices. These properties are controlled not only by the organic film, but also by the metal-organic interfaces. It was found that the low-voltage regime is linear, i.e. Ohmic, for a wide range of temperatures and organic layer thicknesses. The conductance increases exponentially with the temperature and decreases exponentially with the thickness. This behavior was explained with a model that incorporates tunneling between localized states with thermally-induced overlap. Chapter 4 studies the magnetic properties of MPcs. They are controlled by the central metal ion, and the type of molecular stacking in thin films, and were studied using DC magnetometry and magneto-optical techniques. Experimental data suggest the existence of two different magnetic regimes as a function of temperature.
Download or read book Metallophthalocyanine Optical Properties Dependence on Grain Size written by Taylor D. Fry and published by . This book was released on 2018 with total page 64 pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: Vacuum sublimated thin films of metallophthalocyanines (where metal = Cu, Fe, Zn, and Mn) and metal-free phthalocyanine were prepared at different deposition temperatures. The optical properties have been studied in the wavelength range of 340 nm to 2500 nm for samples deposited at room temperature up to 250 °C. Atomic force microscopy was used to obtain images of the surface morphology. Absorption coefficient spectra obtained verify the [pi] to [pi]* transition in the region 526 nm to 735 nm for the Q band, throughout all samples studied. The independence of deposition temperature or grain size in peak positions in absorption coefficient throughout all samples has been shown. The ratio of intensity of the two absorption coefficient peaks in the Q band has been calculated, showing a change in MnPc intensity ratio with changing deposition temperature. The intensity of the highest peak in the Q band has been compared for different metallophthalocyanines and across different deposition temperatures. CuPc deposited at 250 °C has been shown to have the highest peak magnitude of absorption coefficient, with a value of 3.9×10 5 cm–1.
Download or read book Bimolecular Recombination and Complete Photocurrent Decay in Metallophthalocyanine Thin Films written by Ramsey S. Noah and published by . This book was released on 2012 with total page 242 pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: Metallophthalocyanines (MPc) are a class of planar small molecule semiconductors that are of great interest due to their applications in organic solar cells. However, a thorough understanding of many of their charge transport properties, especially those related to trap states, is lacking. In previous works the increase of grain size in MPc thin films with higher substrate temperature during the thermal evaporation process was quantified. Here, we investigate the charge transport properties of phthalocyanine with varying grain sizes in five ways: 1) intensity-varied photocurrent measurements are used to study the order of recombination in zinc phthalocyanine (ZnPc) thin films; 2) the conduction dependence on oxygen doping in copper phthalocyanine (CuPc) and ZnPc is investigated through oxygen deprivation in a closed-cycle refrigerator; 3) the complete photocurrent decay in CuPc and ZnPc is explored; 4) the bandgap of CuPc and ZnPc is derived from wide temperature range ({598} 80K - 351K) resistance measurements; 5) thermally stimulated currents (TSC) in CuPc and ZnPc are induced using a modified Reber methodology. An explanation for oxygen doping in these type of thin films is presented and in addition to bimolecular recombination a second model is also applied to measurements of intensity-varied photocurrent. Our data suggest several interesting aspects of the charge transport properties in these organic semiconductors. Recombination may not be dominated by monomolecular processes but instead bimolecular. More amorphous (low deposition temperature) samples show a greater change in conductivity due to oxygen doping. The photocurrent of more crystalline samples decays more rapidly compared to amorphous samples, suggesting that deeper trap states are present in lower deposition temperature samples. The bandgap derived from temperature-varied resistance measurements is systematically low due to slow detrapping. Unlike TSC measurements in micrometer-thick organic films using current-perpendicular-to-plane geometry which show large peaks in current vs. temperature measurements, no such peaks were observed in our nanometer-thin current-in-plane geometry ZcPc and CuPc films.
Download or read book Fabrication and Characterization of Metallophthalocyanine based Organic Thin film Transistors written by Xiaojiang Yu and published by . This book was released on 2008 with total page 196 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Nanocomposites of Metallophthalocyanines and Conjugated Polymers written by Shujian Yi and published by . This book was released on 1998 with total page 8 pages. Available in PDF, EPUB and Kindle. Book excerpt: Nanocomposites of phenoxy-substituted vanadyl phthalocyanine with a pi- conjugated polymer, poly(benzimidazobenzophenanthroline ladder), have been prepared from their Lewis acid complexes in organic solvents. The resulting composite thin films obtained by spin-coating have excellent optical transparency and interesting composition-dependent morphology and photoelectronic properties. Enhanced photoconductivity, compared to the components, was observed in some composites with discrete nanoscale metallophthalocyanine aggregates.
Download or read book Temperature dependent Structures of Heteroepitaxial Metallo phthalocyanine Mpc M written by Kedar Manandhar and published by . This book was released on 2007 with total page 95 pages. Available in PDF, EPUB and Kindle. Book excerpt: Metallo-phthalocyanines (MPcs, M = Cu, Fe) thin films were formed on Ag(111) surface by vapor deposition in ultra high vacuum (UHV). The morphology and structure of the MPcs were studied by scanning tunneling microscope (STM). Submonolayer (sub-ML) MPcs deposited at room temperature (RT) without subsequent annealing did not form ordered film regions. After annealing the sub-ML films to 500 K for 30 minutes, ordered regions as well as individual molecules therein were observed. By successive annealing MPc, the symmetry of the overlayer increased from oblique to the square lattice. This is understood by a delicate balance between intermolecular van der Waals (vdW) interaction and molecule-substrate diffusion potential. Furthermore, the number of molecular vacancies within the ordered regions was reduced. Annealing the thin films well beyond the sublimation temperature, much of the CuPc molecules were desorbed. However, the remaining molecules reacted and formed dendrite-like chains, in which each CuPc molecule was linked through its isoindole rings. A possible model for the formation of dendritic chains through dehydrogenation and subsequent polymerization is discussed. Another system of FePc adsorbed on Ag(111) was also studied. The ordered region shows an oblique lattice of FePc. Within the unit cell, the molecules at the opposite corners align their isoindole rings such that the nearest and the next nearest neighbor distances are increased substantially compared to those in the close-packed, square lattice observed in CuPc/Ag(111). In addition to the unit cell, which is about 38 % larger than that of CuPc, the oblique lattice of FePc is commensurate to the substrate, and the molecular axes align along the high-symmetry azimuths of the substrate. The overlayer lattice structure and the distinct molecular orientation are attributed to the dxz, yz orbital interaction between the central Fe2+ and Ag(111).
Download or read book Phthalocyanine Research and Applications written by Arthur L. Thomas and published by CRC Press. This book was released on 2024-11-01 with total page 302 pages. Available in PDF, EPUB and Kindle. Book excerpt: The purpose of this monograph is to provide a summary for those who are active in the field of phthalocyanine research. This volume allows the reader to quickly-and at a reasonable cost-determine what is being accomplished so that he may plan his own research programs. It covers such topics as synthesis, reactions, inks, energy systems, coatings, toners, and electrophotographic plates and developers, just to name a few. Packed with over 40 structural drawings of phthalocyanine molecules, this one-of-a-kind reference provides the necessary description and visualization to stimulate further research. This work is an indispensable resource for researchers and practitioners, both novice and experienced, in the field of phthalocyanine science and technology.
Download or read book Low Threshold Organic Thin Film Laser Devices written by Christian Karnutsch and published by Cuvillier Verlag. This book was released on 2007 with total page 155 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Characterization of Phthalocyanine Thin Films written by Latha Krishnaswamy and published by . This book was released on 1994 with total page 226 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Nanostructured Thin Films written by Maria Benelmekki and published by Elsevier. This book was released on 2019-08-25 with total page 334 pages. Available in PDF, EPUB and Kindle. Book excerpt: Nanostructured Thin Films: Fundamentals and Applications presents an overview of the synthesis and characterization of thin films and their nanocomposites. Both vapor phase and liquid phase approaches are discussed, along with the methods that are sufficiently attractive for large-scale production. Examples of applications in clean energy, sensors, biomedicine, anticorrosion and surface modification are also included. As the applications of thin films in nanomedicine, cell phones, solar cell-powered devices, and in the protection of structural materials continues to grow, this book presents an important research reference for anyone seeking an informed overview on their structure and applications. Shows how thin films are being used to create more efficient devices in the fields of medicine and energy harvesting Discusses how to alter the design of nanostructured thin films by vapor phase and liquid phase methods Explores how modifying the structure of thin films for specific applications enhances their performance
Download or read book Nonlinear Optical Materials Principles and Applications written by Società italiana di fisica and published by IOS Press. This book was released on 1995 with total page 512 pages. Available in PDF, EPUB and Kindle. Book excerpt: Nonlinear optical materials play a pivotal role in the future evolution of nonlinear optics in general and its impact in technology and industrial applications in particular. The progress in nonlinear optics has been tremendous since the first demonstration of an all-optical nonlinear effect in the early sixties, but until recently the main visible emphasis was on the physical aspects of the nonlinear radiation matter interaction. In the last decade, however, this effort has also brought its fruits in applied aspects of nonlinear optics. This can be essentially traced to the improvement of the performances of the nonlinear optical materials. Our understanding of the nonlinear polarization mechanisms and their relation to the structural characteristics of the materials has been considerably improved. In addition, the new development of techniques for the fabrication and growth of artificial materials has dramatically contributed to this evolution. The goal is to find and develop materials presenting large nonlinearities and satisfying at the same time all the technological requirements for applications such as wide transparency range, fast response, high damage threshold but also processability, adaptability and interfacing with other materials. Improvements, besides rendering possible the implementation of nonlinear effects in devices, open the way to the study of new nonlinear optical effects and the introduction of new concepts. This book describes new concepts which are emerging in the field of nonlinear optical materials, concentrating the attention on materials which seem more promising for applications in the technology of information transmission and processing.
Download or read book Phthalocyanine Materials written by Neil B. McKeown and published by Cambridge University Press. This book was released on 1998-07-13 with total page 222 pages. Available in PDF, EPUB and Kindle. Book excerpt: This monograph describes the preparation, fabrication and structure of phthalocyanine-based materials.
Download or read book Investigation of the Morphology of Phthalocyanine Thin Films written by David A. Miles and published by . This book was released on 1993 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Trends in Optical Materials Research written by Owen G. Gardens and published by Nova Publishers. This book was released on 2007 with total page 280 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is the newest research on the physical properties of optical materials used in all types of lasers and optical systems. The scope includes the most important optical materials, including crystals, glasses, polymers, metals, liquids, and gases. The properties detailed include both linear and non-linear optical properties, mechanical properties, thermal properties together with many additional special properties, such as electro-, magneto-, and elasto-optic properties.
Download or read book Nonlinear Optics of Organic Molecules and Polymers written by Hari Singh Nalwa and published by CRC Press. This book was released on 2020-07-09 with total page 896 pages. Available in PDF, EPUB and Kindle. Book excerpt: The field of nonlinear optics emerged three decades ago with the development of the first operating laser and the demonstration of frequency doubling phenomena. These milestone discoveries not only generated much interest in laser science, but also set the stage for future work on nonlinear optics. This book presents an excellent overview of the exciting new advances in nonlinear optical (NLO) materials and their applications in emerging photonics technologies. It is the first reference source available to cover every NLO material published through 1995. All theoretical approaches, measurement techniques, materials, technologies, and applications are covered. With more than 1,800 bibliographic citations, 324 figures, 218 tables, and 812 equations, this book is an invaluable reference source for graduate and undergraduate students, researchers, scientists and engineers working in academia and industries in chemistry, solid-state physics, materials science, optical and polymer engineering, and computational science.
Download or read book Intelligent Materials Second International Conference Proceedings written by Craig A. Rogers and published by CRC Press. This book was released on 1994-01-01 with total page 1416 pages. Available in PDF, EPUB and Kindle. Book excerpt: The key science and technology challenges which will facilitate the transition from a "make do and mend" philosophy inevitably restricting the degree of intelligence which can be engineered and the "designer materials systems" philosophy which is the ultimate goal are considered. The longer term vision will need to accord much more closely with nature's design paradigms, with control at the molecular, nano, micro and macro level of synthesis and assembly, of active self repair materials systems in function shapes.
Download or read book Phthalocyanines and Some Current Applications written by Yusuf Yilmaz and published by BoD – Books on Demand. This book was released on 2017-06-21 with total page 255 pages. Available in PDF, EPUB and Kindle. Book excerpt: Since their initial accidental synthesis and characterization in Scotland in the late 1920s, there has been a strong research focus on the use of phthalocyanines (Pcs) as dyes and pigments. In recent years, active research fields have included their use in electrophotography, photovoltaic and solar cells, molecular electronics, Langmuir-Blodgett films, photosensitizers, electrochromic display devices, gas sensors, liquid crystals, low-dimensional conductors, and optical disks. Phthalocyanines possess interesting biological, electronic, optical, catalytic, and structural properties. The main disadvantage is their insolubility in common solvents due to strong intermolecular - interactions. The solubility of phthalocyanines can be increased by various methods such as the formation of anionic and cationic species and both axial and peripheral substitution. Substitution at the nonperipheral and peripheral positions of the benzo moieties usually enhances their solubility in organic solvents. The most important advantage of phthalocyanines compared to porphyrins is that their Q bands lie at longer wavelengths and are considerably more intense. In this book, you will find synthesis and some applications of various phthalocyanine derivatives.
