Researchers develop adaptive organic transistors that can respond to light stimuli.
There is a huge demand for adaptive devices that adjust their behaviors and adapt to the changes in their environment. A research group from Beijing National Laboratory for Molecular Sciences and the University of the Chinese Academy of Sciences have developed an organic adaptive transistor (OAT) to mimic sensory adaptation. According to the researchers, this unique device can serve as a promising candidate for encoding dynamic stimuli and achieving multifunctional biomimetic sensing elements.
Researchers say that an ideal adaptive element should be based on a single device, in order to pursue the simplest geometry and minimized power consumption, for the goal of ‘Less is more’. To satisfy this requirement, their aim was to develop a device that can exhibit a fine-tuned transient response and dynamic adaptation according to the intensity of light stimuli.Zihan He, PhD student at the Institute of Chemistry, Chinese Academy of Sciences, says, “This seems impossible owing to the paradoxical demands of photoexcitation and inhibition of charge transport in the same channel. These questions puzzled us for a long time until we returned to the biological systems to seek inspiration. Interestingly, a similar conundrum has been overcome ingeniously in biological visual systems by using coupled physiological mechanisms. The related transmembrane transport of two different ions (Na+ and Ca2+) together with the associated gating dynamics, leading to biological active adaptation. This unique mechanism offers inspiration for the coupled manipulation of charge carriers on an organic thin-film transistor (OTFT) toward photo adaptive transistors.”
They developed an organic active adaptation transistor (OAAT) that exhibited light intensity-dependent photoadaptation by introducing two functionally complementary bulk-heterojunctions into an OTFT. Upon exposure to light, the device couples the photovoltaic effect with field-effect modulation to allow photo-triggered active adaptation for luminance intensities ranging over six orders of magnitude. Moreover, the dynamic behavior varied with light intensities in an autonomic manner, indicating the smart feature of the OAAT.
The work is published in the journal Nature Electronics.