Optical, electro-optic and optoelectronic properties of natural and chemically modified DNAs

This article reviews recent findings on the optical, electro-optic and optoelectronic properties of natural and modified DNAs. When the sodium (Na ⁺) ions of DNA are replaced with long alkyl quaternary ammonium (Q⁺) ions, the resulting compositions (Q⁺ DNA^- ) are organic-soluble, and thin films produced using these materials reveal many interesting optical and optoelectronic properties. These films tend to form well-structured supramolecular assemblies. In contrast, natural DNAs are water-soluble and hygroscopic. DNAs are strong absorbers of UV wavelengths in the region of 260 nm. The Q⁺ DNA films are excellent dielectrics that can be utilized as insulating layers in organic thin film transistors. Chemical modification of the Q⁺ parts results in many interesting structures that can be used in a wide variety of optical and optoelectronic devices. This review specifically deals with the optical and fluorescence properties of, organic lasing composites, the nonlinear optical characteristics of, light-emitting diodes, and photovoltaic cells based on natural and modified DNAs.