| With the continuous development of technology,there is a growing demand for micro-power devices and wearable electronic devices,which has also stimulated the research and application of piezoelectric nanogenerators.As a type of micro-energy harvesting device,a piezoelectric nanogenerator can convert mechanical energy into electrical energy,providing power for microelectronic devices.It has advantages such as low cost,simple structure,lightweight,and high energy conversion efficiency.Compared to triboelectric nanogenerators,piezoelectric nanogenerators offer better stability.However,the current output power of piezoelectric nanogenerators is still relatively low,which greatly limits their practical applications.One of the urgent problems to be solved is how to increase the output power density of piezoelectric nanogenerators.The output power density of piezoelectric nanogenerators is closely related to the polarization state of ferroelectric domains within the piezoelectric materials.Therefore,studying the dynamic evolution of ferroelectric domains inside piezoelectric nanogenerators is crucial for improving their output power.Research in this area holds significant value and significance.In this paper,the phase-field method is employed to study the evolution of ferroelectric films under electric and stress fields,using barium titanate(BTO)as the research subject.The specific research content is as follows:(1)A two-dimensional phase-field model for barium titanate is established,providing non-dimensionalization methods,numerical calculations,spatial discretization methods,and studying the effects of temperature,elastic long-range interaction energy,and gradient energy on domain structures.(2)Different external electric fields and different applied stresses are incorporated into the two-dimensional phase-field model of barium titanate,studying the output of piezoelectric nanogenerators under different polarized electric fields and the influence of different stresses on the output of piezoelectric nanogenerators.(3)A flexible barium titanate piezoelectric nanogenerator is fabricated,and its output under different polarized electric fields and different stresses is tested to validate the results obtained from the phase-field simulation. |
