Organic electronic devices have great potential for applications such as foldable and bendable displays and conformable sensor arrays due to their printability, low-cost, mechanical flexibility and the low processing temperatures that allow flexible plastic and paper substrates.
This work is motivated by the objective to induce additional functionality into organic transistors for multi-level memory and neuromorphic applications. One possibility is the employment of molecular switches. As a result, the devices not only can be switched on/off by the applied voltages, they can also be programmed by alternate triggers, such as light.
I will introduce our work on functionalizing polymer transistors with novel photo/thermo-responsive molecules, which undergo reversible isomerization under UV irradiation and thermal stimuli, enabling reversible switching. Irradiating the devices with different doses of UV light shows that the induced switching depends directly on the respective dose, hence enabling multi-level electronic systems.
Different photochromic systems as well as different approaches of functionalization (e.g. blending into the dielectric or into the semiconductor) will be discussed: For some strategies, we observe reversible, tunable shifts of the threshold voltage, while others result in a reversable tunable change of the on- and off-current.
The versatility of the functionalization, the cycling stability and the tunability of multiple reversible states will open up a variety of possibilities for light-gated devices such as photo memories and photo-programmable multivalued logic.