Impact of carbon nanodot uptake on complex impedance charge transport and energy storage mechanism in aloe vera leaves

Nano phase uptake of nutrients, medicines and pesticides improves the efficiency and energy storage capacity of the plants. In this work, we have studied the complex impedance and charge transport mechanism of the Aloe Vera plant spiked with various doses of well characterized carbon nano dots (CND, crystallite size ~ 2 nm). The complex impedance of the samples was investigated using an equivalent circuit model consisting of parallel combination of resistance and constant phase elements (replacing capacitor because of non-ideal Debye relaxation behaviour) representing grain and grain boundary. Interestingly, for both the grain and grain boundary, the resistances increase, and the capacitance decrease with uptake of carbon nano dots. Specifically, the constant phase element resistance of the grain (grain boundary) increases from 161 (2166) Ω to 240 (3518) Ω on spiking the plant with 10 mg/L solution of while the grain (grain boundary) capacitance decreased from 1.8E-8 (1.9E-9) Farad to 2.0E-10 (4.2E-10) Farad indicating changes electric transport. The Nyquist plot for all the samples showed a small semi-circle in the high frequency region and a large semi-circle in the mid frequency regions, representing the grain and the grain boundary conduction, respectively. Jonscher power law applied to AC conductivity data in the mid frequency range revealed a reduction in hopping frequency and an increase in the frequency exponent with uptake of CND. To our knowledge, this is the first study to explore electrochemical behaviour of Aloe vera with CND enrichment, presenting insights into CND- plant interaction and their potential application.