2 research outputs found
A Rapid and Facile Soft Contact Lamination Method: Evaluation of Polymer Semiconductors for Stretchable Transistors
Organic stretchable electronics have
attracted extensive scientific
and industrial interest because they can be stretched, twisted, or
compressed, enabling the next-generation of organic electronics for
human/machine interfaces. These electronic devices have already been
described for applications such as field-effect transistors, photovoltaics,
light-emitting diodes, and sensors. High-performance stretchable electronics,
however, currently still involve complicated processing steps to integrate
the substrates, semiconductors, and electrodes for effective performance.
Herein, we describe a facile method to efficiently identify suitable
semiconducting polymers for organic stretchable transistors using
soft contact lamination. In our method, the various polymers investigated
are first transferred on an elastomeric polyÂ(dimethylsiloxane) (PDMS)
slab and subsequently stretched (up to 100%) along with the PDMS.
The polymer/PDMS matrix is then laminated on source/drain electrode-deposited
Si substrates equipped with a PDMS dielectric layer. Using this device
configuration, the polymer semiconductors can be repeatedly interrogated
with laminate/delaminate cycles under different amounts of tensile
strain. From our obtained electrical characteristics, e.g., mobility,
drain current, and on/off ratio, the strain limitation of semiconductors
can be derived. With a facile soft contact lamination testing approach,
we can thus rapidly identify potential candidates of semiconducting
polymers for stretchable electronics
Stretchable Self-Healing Polymeric Dielectrics Cross-Linked Through Metal–Ligand Coordination
A self-healing dielectric elastomer
is achieved by the incorporation
of metal–ligand coordination as cross-linking sites in nonpolar
polydimethylsiloxane (PDMS) polymers. The ligand is 2,2′-bipyridine-5,5′-dicarboxylic
amide, while the metal salts investigated here are Fe<sup>2+</sup> and Zn<sup>2+</sup> with various counteranions. The kinetically
labile coordination between Zn<sup>2+</sup> and bipyridine endows
the polymer fast self-healing ability at ambient condition. When integrated
into organic field-effect transistors (OFETs) as gate dielectrics,
transistors with FeCl<sub>2</sub> and ZnCl<sub>2</sub> salts cross-linked
PDMS exhibited increased dielectric constants compared to PDMS and
demonstrated hysteresis-free transfer characteristics, owing to the
low ion conductivity in PDMS and the strong columbic interaction between
metal cations and the small Cl<sup>–</sup> anions which can
prevent mobile anions drifting under gate bias. Fully stretchable
transistors with FeCl<sub>2</sub>-PDMS dielectrics were fabricated
and exhibited ideal transfer characteristics. The gate leakage current
remained low even after 1000 cycles at 100% strain. The mechanical
robustness and stable electrical performance proved its suitability
for applications in stretchable electronics. On the other hand, transistors
with gate dielectrics containing large-sized anions (BF<sub>4</sub><sup>–</sup>, ClO<sub>4</sub><sup>–</sup>, CF<sub>3</sub>SO<sub>3</sub><sup>–</sup>) displayed prominent hysteresis
due to mobile anions drifting under gate bias voltage. This work provides
insights on future design of self-healing stretchable dielectric materials
based on metal–ligand cross-linked polymers