Modeling of triboelectric charge accumulation dynamics at the metal–insulator interface for variable capacitive structures: application to triboelectric nanogenerators

Abstract: This paper presents a dynamic model to study triboelectric charge accumulation in a variable capacitive structure with metal–dielectric interface. The presented model addresses a serious flaw of current published theoretical works related to modeling of triboelectric energy harvesters. Electrostatic analysis of the device in the contact and non-contact modes is performed. Based on the analysis of the non-contact mode, a novel technique is introduced to measure stable parasitic triboelectric charge density on the surface of the dielectric layer. Theoretical analysis for positive and negative charge accumulation is performed separately and key characteristic equations of both cases are extracted. A new measurement technique is developed to assess triboelectric charge build-up on the surface of the dielectric layer by employing a simple bridge rectifier as a test circuit. Based on the measured data, a time-dependent exponential model is suggested for triboelectric charge accumulation on the surface of the dielectric layer. The presented dynamic model is a vital asset in modeling dynamic output of triboelectric nanogenerators (TENG’s). The results show that failure to consider triboelectric charge dynamics in modeling of TENG’s would result in more than 50% error in the simulated output characteristics. Graphical abstract: Charge accumulation A new surface charge evaluation technique is introduced. Triboelectric charge accumulation on the surface of dielectrics is calculated and modeled using a simple half-wave rectifier. To get to the model, discrete charge-time points are measured. The dynamic charge model presents an essential asset in simulation of the output performance of TENG’s. positive and negative charge build up is measured.