What is the reason behind unequal current/voltage signal (upper and lower part) in a transient output from a piezoelectric nanogenerator when measured through oscilloscope?
The reason behind this unequal voltage/current signal could be the screening of piezoelectric charges developed in the strained sample during the bi-directional flow of electrons through the external circuit. Various kinds of surface states present in the sample affect the concentration of piezo-charges which can partially hinder the electron flow.
unequal means the bipolar signal or the dissimilar values of voltage/current?
@sayan-bayangmail-com Usually, piezoelectric or triboelectric nanogenerators developed charge separation due to mechano-stimuli application. And it is a momentarily charge transportation process with a stress-induced/released sequential process. This charge generation completely depends on the frequency and amplitude of the applied forces. It will be very difficult to control the applied amplitude and hence the current/voltage generation shows dissimilar values.
