Research in the use of organic polymers as the active semiconductors in light-emitting diodes has advanced rapidly, and prototype devices now meet realistic specifications for applications. These achievements have provided insight into many aspects of the background science, from design and synthesis of materials, through materials fabrication issues, to the semiconductor physics of these polymers.

Electroluminescence in conjugated polymers

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

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

When asked to explain the importance of the discovery of conducting polymers, I offer two basic answers: first they did not (could not?) exist, and second, that they offer a unique combination of properties not available from any other known materials. The first expresses an intellectual challenge; the second expresses a promise for utility in a wide variety of applications.

Semiconducting and Metallic Polymers: The Fourth Generation of Polymeric Materials (Nobel Lecture).

A brief history of the development of organic and polymeric photovoltaics

Photophysics of phenylenevinylene polymers

An overview of photophysical measurements in phenylenevinylene polymers is presented and evaluated in light of the implications for organic electroluminescent materials design. Intrinsic limitations placed on device efficiency are discussed and we show that the polymer synthesis is critical to obtaining morphologies which exhibit reduced aggregation quenching of luminescence. We also document that oxidation of the polymer caused during the synthesis, or by subsequent excited state reactions, leads to luminescence quenching defects which can dramatically reduce fluorescence efficiency. We conclude with a brief review of other considerations in engineering efficient, long-lived polymer light-emitting diodes (LED's).

M. Yan

Papers

Photophysics of phenylenevinylene polymers

Fundamental and practical issues for phenylenevinylene-based polymer light-emitting diodes