Bio-Organic Optoelectronic Devices Using DNA

Biomolecular DNA, as a marine waste product from salmon processing, has been exploited as biodegradable polymeric material for photonics and electronics. For preparing high optical quality thin films of DNA, a method using DNA with cationic surfactants such as DNA-cetyltrimethylammonium, CTMA has been applied. This process enhances solubility and processing for thin film fabrication. These DNA-CTMA complexes resulted in the formation of self-assembled supramolecular films. Additionally, the molecular weight can be tailored to suit the application through sonication. It revealed that DNA-CTMA complexes were thermostable up to 230 degrees C. UV-VIS absorption shows that these thin films have high transparency from 350 to about 1,700 nm. Due to its nature of large band gap and large dielectric constant, thin films of DNA-CTMA has been successfully used in multiple applications such as organic light emitting diodes (OLED), a cladding and host material in nonlinear optical devices, and organic field-effect transistors (OFET). Using this DNA based biopolymers as a gate dielectric layer, OFET devices were fabricated that exhibits current-voltage characteristics with low voltages as compared with using other polymer-based dielectrics. Using a thin film of DNA-CTMA based biopolymer as the gate insulator and pentacene as the organic semiconductor, we have demonstrated a bio-organic FET or BioFET in which the current was modulated over three orders of magnitude using gate voltages less than 10 V. Given the possibility to functionalise the DNA film customised for specific purposes viz. biosensing, DNA-CTMA with its unique structural, optical and electronic properties results in many applications that are extremely interesting.