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Hexagonal Boron Nitride-Enhanced Optically Transparent Polymer Dielectric Inks for Printable Electronics.

Accepted version
Peer-reviewed

Type

Article

Change log

Authors

Zhu, Xiaoxi 
Ng, Leonard WT 
Hu, Guohua 
Wu, Tien-Chun 
Um, Doo-Seung 

Abstract

Solution-processable thin-film dielectrics represent an important material family for large-area, fully-printed electronics. Yet, in recent years, it has seen only limited development, and has mostly remained confined to pure polymers. Although it is possible to achieve excellent printability, these polymers have low (≈2-5) dielectric constants (ε r ). There have been recent attempts to use solution-processed 2D hexagonal boron nitride (h-BN) as an alternative. However, the deposited h-BN flakes create porous thin-films, compromising their mechanical integrity, substrate adhesion, and susceptibility to moisture. These challenges are addressed by developing a "one-pot" formulation of polyurethane (PU)-based inks with h-BN nano-fillers. The approach enables coating of pinhole-free, flexible PU+h-BN dielectric thin-films. The h-BN dispersion concentration is optimized with respect to exfoliation yield, optical transparency, and thin-film uniformity. A maximum ε r ≈ 7.57 is achieved, a two-fold increase over pure PU, with only 0.7 vol% h-BN in the dielectric thin-film. A high optical transparency of ≈78.0% (≈0.65% variation) is measured across a 25 cm2 area for a 10 μm thick dielectric. The dielectric property of the composite is also consistent, with a measured areal capacitance variation of <8% across 64 printed capacitors. The formulation represents an optically transparent, flexible thin-film, with enhanced dielectric constant for printed electronics.

Description

Keywords

2D materials, K‐bar coatings, dielectrics, functional inks, hexagonal boron nitride, printed electronics

Journal Title

Adv Funct Mater

Conference Name

Journal ISSN

1616-301X
1616-3028

Volume Title

30

Publisher

Wiley

Rights

All rights reserved
Sponsorship
Engineering and Physical Sciences Research Council (EP/L016087/1)
EPSRC funding acknowledged (EP/L016087/1)