Printable, Transparent, and Flexible Touch Panels Working in Sunlight and Moist Environments

Abstract

The ongoing revolution of touch‐based user interfaces sets new requirements for touch panel technologies, including the need to operate in a wide range of environments. Such touch panels need to endure moisture and sunlight. Moreover, they often need to be curved or flexible. Thus, there is a need for new technologies suitable, for example, for home appliances used in the kitchen or the bathroom, automotive applications, and e‐paper. In this work, the development of transparent and flexible touch panels for moist environments is reported. A piezoelectric polymer, poly(vinylidene difluoride) (PVDF), is used as a functional substrate material. Transparent electrodes are fabricated on both sides of a PVDF film using a graphene‐based ink and spray coating. The excellent performance of the touch panels is demonstrated in moist and underwater conditions. Also, the transparent device shows very small pyroelectric response to radiative heating in comparison to a non‐transparent device. Solution processable electrode materials in combination with functional substrates allow the low‐cost and high‐throughput manufacturing of touch panels using printing technologies.

Flexible Piezoelectric Touch Sensor by Alignment of Lead‐Free Alkaline Niobate Microcubes in PDMS

“…To that end a piezoelectric polymer is required. [7,8,9] We note that high values of the voltage coefficient have been reported for ferroelectret polymers, i.e. soft electroactive films, [10][11][12] but applications are hampered by discharging at elevated temperature.…”

Inkjet-Printed Graphene/PEDOT:PSS Temperature Sensors on a Skin-Conformable Polyurethane Substrate

“…The choice of the graphene/PEDOT:PSS composite was done based on previous case studies that were performed in our lab that shed light on the electrical properties of the ink and the potential for stretchable applications3031. The compatibility of the ink composite (Innophene Phene plus I3015) for inkjet printing was also studied independently by other groups, providing further rationale for the ink’s suitability for our needs32.…”

Cellulose Nanofibril Film as a Piezoelectric Sensor Material

“…Processing in aqueous media ensures low cost and high throughput manufacturing of functional devices for electronics 2,3 , sensing 4 and optics 5 . Furthermore, the combination of nanocelluloses with water-processable carbon-based nanomaterials, such as carbon nanotubes or graphene, is beneficial towards flexible and disposable devices, including supercapacitors 6-8 among many others.…”