Metallophthalocyanines as High-Dielectric Constant Materials

Synthesis, Characterization, and Dielectric Properties of Phthalocyanines with Ester and Carboxylic Acid Functionalities

“…The search for organic compounds exhibiting high dielectric constants (ε > 1 ×10 3 ) has gained considerable attention because of their applicability in electric devices such as actuators, random access memories based on capacitive elements, and gate dielectrics for organic field effect transistors . Since the discovery of the semiconducting property of phthalocyanines (Pc) in 1948 by Eley, these compounds have become one of the most studied organic semiconductors and have found applications in solar cells, , organic field effect transistors, photovoltaic and fuel cells, − electroactive polymers, , and sensors. , Oligophthalocyanines (o-Pc), where at least one benzene ring is shared by two Pcs, have an extended π-conjugation and show a high ϵ and intrinsic electric conductivity (Scheme ). − They became attractive components for actuator technology. , Often these o-Pcs have a transition metal like Cu, Fe, Co, or Zn as central atom. They are usually synthesized from pyromellitic anhydride ( A ) or 1,2,4,5-tetracyanobenzene ( B ) either in solution or in melt (Scheme ). − In addition to the desired oligomers ( C ) consisting of fused Pcs only, the formation of byproduct was reported which contain units of both, Pc and isoindolenine, or triazine (structures not shown).…”

“…Because of this unfortunate complexity of products, measured properties could not unequivocally be correlated with a concrete molecular structure. For example, it is not clear which of the factors, extended conjugation, aggregation due to hydrogen bonding, or an unintentional doping by some impurities contributes to the attractively high dielectric constants of ε > 1 × 10 3 reported. − In addition, there is scarce information about the reproducibility of the reported ε-values. Impurities capable of doping Pcs may dramatically alter results from one batch to another.…”

Core-shell like structured barium zirconium titanate-barium calcium titanate–poly(methyl methacrylate) nanocomposites for dielectric energy storage capacitors

“…Polymeric dielectric materials on the other hand, have some advantages over the traditional electroactive ceramics, e.g., low cost, high mechanical elasticity, high electrical breakdown strength, ease of processing in large areas/volumes, and self-healing ability 3 . However, most dielectric polymers possess relatively low dielectric constants ranging from 2 to 12 4 .…”

Indium(III) phthalocyanine eka-conjugated polymer as high-performance optical limiter upon nanosecond laser irradiation

“…3 Pc polymers are classified as covalently bonded eka-conjugated polymers because they are highly conjugated planar aromatic systems. 4,5 Generally, a molecule is said to be ekaconjugated if the number of alternate single and multiple bonds is so large that the molecule exists in electronically excited states to an appreciable degree (greater than 10 À12 mol fraction) at room temperature. The extent of potential eka-conjugation is proportional to the number of consecutive -electron orbitals in the structure.…”

“…Analytical and spectroscopic data of polymer(4). DMF, 10 mM) ( excitation / max emission ) (nm): 710/718.…”