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Computable Bulk and Interfacial Electronic Structure Features as Proxies for Dielectric Breakdown of Polymers
journal contribution
posted on 2020-08-07, 16:03 authored by Deepak Kamal, Yifei Wang, Huan Doan Tran, Lihua Chen, Zongze Li, Chao Wu, Shamima Nasreen, Yang Cao, Rampi RamprasadBreakdown
strength, the maximum electric field that can be applied
on a dielectric polymer without destroying its insulating characteristics,
sets an upper limit on the maximum energy that can be stored in this
material. Despite its significance, the breakdown strength remains
poorly understood and impractical to compute. This is a major challenge
in the development of high-energy dielectric polymers for which a
large number of candidates must be screened for identifying those
with high breakdown strength. In this work, we develop a multistep
strategy for accessing the breakdown strength through two proxies
that can be computationally estimated in a high-throughput manner,
i.e., the polymer band gap and electron injection barrier at electrode–polymer
interfaces. First, these properties are experimentally proven (established)
to be correlated strongly with the breakdown strength of a number
of benchmark polymers. Then, we develop a simple model, which relies
on the chain structure of polymers, to estimate their band gap and
electron injection barrier at the level of density functional theory.
After validation, this model was finally used for 990 polymers, identifying
53 candidates that have preferable proxies, and thus, potentially
having high breakdown strength. Because of the past synthesizability
evidence of these polymers, we hope that they may be considered to
be synthesized and tested in the near future. Moreover, some empirical
rules that were extracted from our computed data could be useful for
polymer selection and design in general. We note that the strategy
used here is generic and can be used to design materials with other
attractive, but complex, properties as well.