Click Functionalization of Aromatic Polymers for Organic Electronic Device Applications

Abstract

The [2 + 2] cycloaddition-retroelectrocyclization between electron-rich alkynes and tetracyanoethylene (TCNE)/7,7,8,8-tetracyanoquinodimethane (TCNQ), yielding the tetracyanated donor-acceptor (D-A) chromophores, is a new class of click chemistry reactions, due to the high efficiencies, no byproducts, and applicability to polymer syntheses. As compared to the conventional click reactions represented by the Cu(I)-catalyzed azide-alkyne cycloaddition (CuAAC), these new click reactions provide fascinating optoelectronic properties originating from the D-A chromophore structures formed. A series of π-conjugated aromatic polymers containing electron-rich alkynes were successfully functionalized by these click reactions, producing novel organic or organometallic materials featuring conducting and photovoltaic properties in thin film electronic devices. This review article describes the recent results of the author's research group. The power of click chemistry is highlighted by the polymer synthesis using CuAAC. This is followed by the alkyne-TCNE/TCNQ postfunctionalization to produce high-performance aromatic polymers for use as active components in organic electronic devices, such as thin film transistors, organic solar cells and polymer memory devices. Optical and electrochemical properties of aromatic polymers are tuned by the novel click reactions using cyano-acceptor reagents. The resulting polymers contain donor-acceptor chromophores and accordingly can be applied to organic electronic devices including thin film transistors, organic solar cells, and polymer memory devices. A series of device studies reveal the characteristic electronic features of the formed donor-acceptor chromophores.