Polyfluorene Conjugated Polyelectrolytes-Covalently Modified Black Phosphorus Nanosheets for Bioinspired Electronics

As some of the most promising candidates for constituting bioinspired electronics, polymer memristors with analog-type switching behavior exhibit great potential for synaptic mimicking and neuromorphic computing systems. By using highly soluble conjugated polyelectrolyte poly[9,9-bis(6-(3-methyl-1-imidazolium-yl)hexyl)fluorene]-covalently modified black phosphorus (BP) nanomaterial (BP-PF-NMI+Br-) as the active layer, an electronic device with the BP-PF-NMI+Br- film sandwiched between the aluminum and indium tin oxide electrodes is successfully fabricated. This device exhibits an excellent amount of electricity-dependent memristive performance at a small sweep voltage range of +/- 1 V. With increasing amount of electricity flowing through the device, the device resistance gradually decreased in a linear pattern. The changes in frequency, amplitude, and duration of voltage pulses do not affect the linear relationship between the amount of electricity passing through the device and the resistance value achieved after each state reached equilibrium at different numbers of the same voltage pulse stimulations. Both the synaptic potentiation/depression and learning/memorizing/forgetting functions of biological systems have been emulated. In contrast to BP-PF-NMI+Br-, the pure PF-NMI+Br--based device shows a write-once-read-many-times effect at the same scanning voltage range, while the BP:PF-NMI+Br- blends exhibit very unstable memristive performances.