  Ionic current rectification (ICR) of charged conical nanopores has various
applications in fields including nanofluidics, bio-sensing, and energy
conversion, whose function is closely related to the dynamic response of
nanopores. The occurrence of ICR originates from the ion enrichment and
depletion in conical pores, whose formation is found to be affected by the
scanning rate of voltages. Here, through time-dependent simulations, we
investigate the variation of ion current under electric fields and the dynamic
formation of ion enrichment and depletion, which can reflect the response time
of conical nanopores. The response time of nanopores when ion enrichment forms
i.e. at the on state is significantly longer than that with the formation of
ion depletion i.e. at the off state. Our simulation results reveal the
regulation of response time by different nanopore parameters including the
surface charge density, pore length, tip, and base radius, as well as the
applied conditions such as the voltage and bulk concentration. The response
time of nanopores is closely related to the surface charge density, pore
length, voltage, and bulk concentration. Our uncovered dynamic response
mechanism of the ionic current can guide the design of nanofluidic devices with
conical nanopores, including memristors, ionic switches, and rectifiers.
