New polymer synthesis by nitroxide mediated living radical polymerizations.

Metal-catalyzed living radical polymerization.

A review was presented to demonstrate a historical description of the synthesis of light-emitting conjugated polymers for applications in electroluminescent devices. Electroluminescence (EL) was first reported in poly(para-phenylene vinylene) (PPV) in 1990 and researchers continued to make significant efforts to develop conjugated materials as the active units in light-emitting devices (LED) to be used in display applications. Conjugated oligomers were used as luminescent materials and as models for conjugated polymers in the review. Oligomers were used to demonstrate a structure and property relationship to determine a key polymer property or to demonstrate a technique that was to be applied to polymers. The review focused on demonstrating the way polymer structures were made and the way their properties were controlled by intelligent and rational and synthetic design.

Synthesis of Light-Emitting Conjugated Polymers for Applications in Electroluminescent Devices

Hyperbranched polymers: from synthesis to applications

This article provides a review about electroluminescence from organic materials and deals in detail with organic light-emitting diodes (OLEDs), light-emitting electro-chemical cells (LECs) and electrogenerated chemilumi-nescence (ECL) reflecting different electrooptical appli-cations of conjugated materials. It is written from an organic chemist's point of view and pays particular attention to the development of organic materials involved in corresponding devices. In recent years a substantial amount of both academic and industrial research has been directed to organic electroluminescence in an effort to improve the processability and tunability of organic materials and the longevity of OLEDs and LECs. On the eve of the commercialization of organic electrolumi-nescence this review provides an overview of lifetimes and efficiencies attained and reflects materials and device concepts developed over the last decade. In this context electrogenerated chemiluminescence is discussed with respect to its importance as a versatile tool to simulate the fundamental electrochemical processes in OLEDs.

The electroluminescence of organic materials

The thermal stability of the electric field induced poled order in a new class of second-order optically nonlinear polymers, "donor-imbedded" side-chain polyimides containing no flexible connectors or tethers to the nonlinear optical (NLO) chromophore, is investigated. In these polymers, the electron-donor part of the chromophore is a diaryl-substituted amine that is incorporated as a part of the polymer backbone. The donorimbedded systems used in this study have exceptional chemical stabilities at elevated temperatures (350°C) and impressive poled order stability at extremely high temperatures (300°C). In both respects, they were significantly more stable than a true side-chain polyimide with a similar NLO-active chromophore covalently linked to the polymer backbone by a flexible tether group.

https://science.sciencemag.org/content/sci/268/5217/1604.full.pdf

Exceptionally Thermally Stable Polyimides for Second-Order Nonlinear Optical Applications

A Novel Approach to Functionalized Nanoparticles: Self‐Crosslinking of Macromolecules in Ultradilute Solution

The orientational decay of chemically and thermally stable high‐temperature chromophores doped into thin films made from polyimides and a variety of other polymeric hosts has been investigated. The chromophores are aligned using electric field poling and second‐harmonic generation (SHG) is used to probe the decay of the electric field poling induced alignment. The decay rate of the SHG signal from films poled using both a corona discharge and side‐by‐side in‐plane electrodes was measured. When electrodes are chosen so that the effects of charge injection are minimized, little difference has been observed between the orientational decays from films poled using the two methods for either an amorphous preimidized polyimide host or a highly anisotropic film poled during imidization. The films imidized during poling showed significant orientational stability at 250 °C for over 15 h after a fast initial partial decay. In addition, the decay of the SHG signal was measured as a function of temperature below the glass transition in a wide variety of different polymer host systems. The temperature dependence of the decay was found to be non‐Arrhenius, but could be strongly correlated with the glass transition temperature of the guest‐host system using an empirical relationship similar to the Williams–Landel–Ferry or Vogel–Tamann–Fulcher equation.

Orientational decay in poled second‐order nonlinear optical guest‐host polymers: Temperature dependence and effects of poling geometry

Optical third‐harmonic generation was used to measure third‐order nonlinear susceptibilities χ(3) for thin films of planar zigzag polysilanes and polygermanes. A χ(3) of 11.3×10−12 esu was measured, the largest value ever reported for a polymer with transparency throughout the visible. The value of χ(3) was found to vary substantially with thermally induced reversible changes in polymer backbone conformation and also with film thickness.

R. D. Miller

Papers

Exceptionally Thermally Stable Polyimides for Second-Order Nonlinear Optical Applications

A Novel Approach to Functionalized Nanoparticles: Self‐Crosslinking of Macromolecules in Ultradilute Solution

Orientational decay in poled second‐order nonlinear optical guest‐host polymers: Temperature dependence and effects of poling geometry

Temperature dependence of the third‐order nonlinear optical susceptibilities in polysilanes and polygermanes

Efficient, blue light-emitting diodes using cross-linked layers of polymeric arylamine and fluorene