Mechanism of Label-Free DNA Detection Using the Floating Electrode on Pentacene Thin Film Transistor

The analysis of DNA in the posthuman genome project era has become an ever-expanding branch of research and is thus routinely employed in the majority of biochemical laboratories. This work discusses the mechanism and label-free detection of DNA using a pentacene thin film transistor with a gold floating electrode on the active layer. Thiolated polynucleotide probes were used, which form self-aligned monolayers on the floating electrode over the pentacene active layer. The immobilization of the DNA on floating electrode increased the work function and raised the Schottky barrier of the device, resulting in a charge screening effect. Hence, the negative charge of the DNA caused a positive shift in the threshold voltage of the transistor. Based on the change in the electrical output, synthesized DNA and the viral DNA were detected.