Dual polarity open circuit voltage in triboelectric nanogenerators originated from two states series impedance

Experimental and simulation studies demonstrated that the initial voltage setting significantly influences the open-circuit voltage (V_OC) in triboelectric nanogenerators (TENGs). Utilizing diode configurations, we consistently observed two distinct V_OCs independent of the initial settings. A lower V_OC corresponded to the surface voltage (V_Surface), while a higher V_OC was amplified by the product of the V_Surface and the TENG's characteristic impedance ratio. Notably, a lower measurement system capacitance provided a more precise representation of the inherent characteristics of the TENG. Conversely, an increase in system impedance led to a convergence of the two V_OCs and a reduction in their magnitudes relative to V_Surface. These findings suggest that optimizing the initial/repeated charge balancing and minimizing capacitive loads are crucial for maximizing TENG output power in practical applications.