Integration of biocompatible organic resistive memory and photoresistor for wearable image sensing application

The integration of multiple functional devices to achieve complex functions has become an essential requirement for future wearable biomedical electronic devices and systems. In this paper, we present a flexible multi-functional device composed of a biocompatible organic polymer resistive random-access memory (RRAM) and a photoresistor for wearable image sensing application. The resistive layer of organic polymer RRAM is composed by polychloro-para-xylylene (parylene-C), which is a flexible, transparent, biocompatibility and chemical stability polymer material. What is more, parylene-C is quite safe to be used within human body as it is a Food and Drug Administration (FDA)-approved material. This organic RRAM shows stable switching characteristics, low operation voltages (3.25 V for set voltage and −0.55 V for reset voltage), low static power consumption, high storage window and good retention properties (>10 s). A multi-functional device that can detect the light intensity of incident light and simultaneously store the information in the memory devices for wearable image sensing application was proposed and fabricated by integrating the organic resistive memory and a photoresistor. The threshold of incident light intensity can be easily adjust by changing the external voltage. This device is promising for building wearable electronic systems with various multiple functionalities.