Polyelectrolyte interlayer for ultra-sensitive organic transistor humidity sensors.
We demonstrate low-voltage, flexible, transparent pentacene humidity sensors with ultrahigh sensitivity, good reliability, and fast response/recovery behavior. The excellent performances of these devices are derived from an inserted polyelectrolyte (poly[2-(methacryloyloxy)ethyltrimethylammonium chloride-co-3-(trimethoxysilyl)propyl methacrylate] (poly(METAC-co-TSPM)) interlayer, which releases free Cl- ions in the electrolyte dielectric layer under humid conditions and boosts the electrical current in the transistor channel. This has led to extreme device sensitivity, such that electrical signal variations exceeding 7 orders of magnitude have been achieved in response to a 15% change in the relative humidity level. The new sensors exhibit a fast responsivity and a stable performance toward changes in humidity levels. Furthermore, the humidity sensors, mounted on flexible substrates, provided low voltage (<5 V) operation while preserving the unique ultrasensitivity and fast responsivity of these devices. We believe that the strategy of utilizing the enhanced ion motion in an inserted polyelectrolyte layer of an OFET structure can potentially improve sensor technologies beyond humidity-responsive systems.
Department of Energy and Chemical Engineering, Incheon National University , Incheon, 406-772, Korea.
Yeong Don
YD
Park
Boseok
B
Kang
Ho Sun
HS
Lim
Kilwon
K
Cho
Moon Sung
MS
Kang
Jeong Ho
JH
Cho
D004573:Electrolytes / Q000737:chemistry*; D006813:Humidity; D011108:Polymers / Q000737:chemistry; D012822:Silicon Dioxide / Q000737:chemistry; D014173:Transistors, Electronic
D004573:Electrolytes; D011108:Polymers; D012822:Silicon Dioxide