Mobility-independent doping in crystalline rubrene field-effect transistors

We report doping effects in an organic semiconductor, crystalline rubrene. Oxygen-related states are introduced (removed) by annealing in oxygen (vacuum), at an elevated temperature. Room temperature stability is found in the resulting effects: (1) about two orders of magnitude increase in carrier density at equilibrium, (2) significant modification of threshold voltages, and (3) an unchanged field-effect mobility in the on-current state. Density of states data are modeled as tunneling from the valence band in the channel region into deep-level acceptors in the adjacent region. These oxygen acceptors are the likely dopant species.     

Living radical polymerization of vinyl chloride initiated with iodoform and catalyzed by nascent Cu0/tris(2‐aminoethyl)amine or polyethyleneimine in water at 25 °C proceeds by a new competing pathways mechanism

The first example of living radical polymerization of vinyl chloride carried out in water at 25 °C is reported. This polymerization was initiated by iodoform and catalyzed by nascent Cu⁰ produced by the disproportionation of Cu^I in the presence of strongly Cu^II binding ligands such as tris(2‐aminoethyl)amine or polyethyleneimine. The resulting poly(vinyl chloride) was free of structural defects, had controlled molecular weight and narrow molecular weight distribution, contained two ～CHClI active chain ends, and had a higher syndiotacticity (62%) than the one obtained by conventional free‐radical polymerization at the same temperature (56%). This novel polymerization proceeds, most probably, by a combination of competitive pathways that involves activation by single electron transfer mediated by nascent Cu⁰ and degenerative chain transfer. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 3283–3299, 2003     

Oxidative polymerization of 5 amino,1,10‐phenanthroline: A theoretical study

The molecular and electronic structures of 5‐amino‐1,10‐phenanthroline and its monoprotonated and diprotonated species were obtained from ab initio quantum mechanical calculations with unrestricted Hartree–Fock (HF) and Møller–Plesset perturbation theories. The analysis of the net atomic charges and the total spin densities show three possible sites for the monomeric coupling in the polymerization process. The minimal energy conformation for the different kinds of coupling in the formation of the dimers was obtained. The studies were extended to the HF/6‐311 + G(2d,p)//B3LYP (Becke's three‐parameter exchange functional and the gradient‐corrected functional of Lee, Yang, and Paar)/6‐31G(d) level of theory to obtain theoretical nuclear magnetic resonance spectra to study the number and kinds of species involved in the protonation mechanism. Theoretical and experimental nuclear magnetic resonance spectra are in excellent agreement. © 2004 Wiley Periodicals, Inc. Int J Quantum Chem, 2004     

Polyamide-imides from 3′,4′-dicarboxy-4″-chloroformyl terephthaloylphenone anhydride

Novel polyamide-imides were prepared from 3′,4′-dicarboxy-4″-chloroformyl terephthaloylphenone anhydride and various aromatic and aliphatic diamines. The polymers were characterized by viscosity, infrared spectra, TGA, DSC, and elemental analysis. The thermal stability of the films was comparable to that of polyamide-imides previously reported.