A pentacene field-effect transistor with light-programmable threshold voltage

We report the effect of light illumination on the electrical characteristics of pentacene field-effect transistors with a large-bandgap conjugated polymer PFO as the interfacial layer. The nanostructured PFO servers as charge-trapping centers that capture charges injected from the pentacene active layer. When the device is under light illumination, the threshold voltage (V_th) can be modulated by varying positive gate biases such that the operation mode can be switched from the enhancement mode to the depletion mode. This light-programmable feature may motivate the development of this new type of organic memory devices.