Memory-like behavior as a feature of electrical signal transmission in melanin-like bio-polymers

Abstract

The memory-like behavior of melanin biopolymer under electrical stimuli is shown through electrical transport characterization performed on melanin based metal insulator semiconductor structures on silicon. The presence of a memory window and retention behavior is verified by capacitance-voltage read outs before and after the application of voltage pulses. Interestingly, these phenomena occur without the presence of metallic nanoclusters enclosed in the melanin matrix. Charge trapping is considered the main mechanism responsible for the melanin memory-like character. The inability to erase the memory window has been ascribed to the permanent polarization effect during the application of the voltage pulse.

A Photoresponsive Red‐Hair‐Inspired Polydopamine‐Based Copolymer for Hybrid Photocapacitive Sensors

“…This because, in ambient air, water-mediated transport via charge (electrons or holes) hopping mechanisms overwhelm that of dipole one. [ 47 ] The fl at band voltage rightward shift in the pCDA-based MIS devices, with respect to pDA-based ones, also suggested the presence of a dipole on the pSi surface, as represented in the sketch of Figure 10 Figure 11 summarizes representative photo-capacitance results at 1.0 kHz (11a) and the extracted photo-yield behaviour under white light and at the different AC signal frequencies (11b) Again, the best effi ciency was inferred in structures embodying the mixed polymer although in p(DA/CDA) 50:50-based MIS devices the photo-capacitance effect starts at + 1.0 V. It is noteworthy that, with respect to pDA-based devices, the structures with pCDA and p(DA/CDA) 75:25 layers showed an increase in the photo-capacitance yield of one order of magnitude while keeping it nearly constant throughout the entire signal frequency range up to 1.0 MHz. In pDA-based devices, a reduction of photo-effi ciency was observed at low frequency.…”

Macroscale Biomolecular Electronics and Ionics

“…However, as discussed below, we now understand this electrical switching behavior in terms of protonic currents and space charge effects at non‐Ohmic and electrochemically active electrodes. That said, there are examples of more recent reports claiming resistive switching in melanin: for example Di Mauro et al and Ambrico et al The former relying on capacitive ion drift with a strong hydration dependence, but the latter invoking a semiconductor‐like argument with trapping and detrapping of electronic carriers.…”

Production of Melanin Pigment by Fungi and Its Biotechnological Applications

“…In this study, melanin films showed excellent thermal stability and adhere well to glass substrates and silicon, indicating the possibility of using this technique for the production of films from synthetic melanin. Other groups have published various device architectures with applications such as memory (metal-insulator-semiconductor geometries) [131], batteries [132], and biomimetic interfaces [133].…”