Tracking, Diagnosing and Arresting Dielectric Breakdown Using Multiscale Characterization and Simulations.
Abstract
The objectives of this project are to develop a unified understanding of polymer dielectric breakdown, and to use this understanding" to design ~breakdown resistant~ dielectrics. The hypotheses on which our proposed program is based on are: (i) breakdown is a ~loca"l~, ~weak link~ phenomenon; (ii) engineering breakdown is the result of high field aging, involvingpositive feedback mechanisms tha"t promote the development of a breakdown (or conduction)path through progressive polymer degradation; (iii) the feedback mechanisms are most likely initiated by field-induced charge carrier injection at metal-polymer interfaces and charge transport through the complex polymer morphology; and (iv) the feedback loop is closed by bond scission and defect creation (due to exciton formation and ca"rrier recombination) in criticallocations leading to ~defect states~, which in turn increase carrier populations and open up additi"onal charge transport pathways. These hypotheses suggest routes for developing ~breakdown resistant~ dielectrics by controlling carrier transport/recombination and defectformation. In order to reveal (and impede) positive feedback dielectric breakdown mechanisms", amulti-disciplinary team of theoreticians and experimentalists are brought together in thisprogram. Creation of model polymers c"overing a diversity of defect populations and morphology and stressing these at electric fields up to breakdown at timescales ranging from DC to optical regimes will require development of new techniques. Tracking rapid processes such as carrier creation/recombina"tion and the resulting chemical changes requires ultrafast experimental techniques such as in-situ luminescence, laser induced press"ure/thermal pulse and 2D infraredspectroscopy systems. Diagnosing the actual mechanism of defect formation will require computation"al techniques of varying scale and accuracy, e.g., quantum, classical and coarsegrainedmolecular dynamics simulations, to see the e""ffect of interfaces and morphology on these phenomena. Finally, mining the information meticulously accumulated from the planned exp"erimental and simulation work to reveal correlations and non-linear coupling betweenbreakdown behavior and key features of the material will require advanced statistical or ~machine learning~ techniques. These efforts are expected to lead to strategies for impedi"ng dielectric breakdown in polymers.As DOD moves to a more electric military, capacitors are required at nearly every level of fiel""d activity, from power electronics in hybrid electric vehicles to rail guns on navy vessels, to the harsh temperature and electric f""ield environments of avionics in a jet fighter.Fundamentally increasing the long-term reliability (and, consequently, the energy de"nsity) of capacitors under harsh conditions will require understanding and controlling the electrical breakdown strength of dielectrics. Our program is directed towards addressing these issues that account for recent emphasis on capacitor technology within DOD.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Jul 07, 2017
- Source ID
- N000141712656
Entities
People
- Ramamurthy Ramprasad
Organizations
- Office of Naval Research
- United States Navy
- University of Connecticut