5 research outputs found
pH Induced switching in hydrogel coated fiber bragg grating sensor
In this paper we report a novel hydrogel functionalized optical Fiber Bragg Grating (FBG) sensor based on chemo-mechanical-optical sensing, and demonstrate its specific application in pH activated process monitoring. The sensing mechanism is based on the stress due to ion diffusion and polymer phase transition which produce strain in the FBG. This results in shift in the Bragg wavelength which is detected by an interrogator system. A simple dip coating method to coat a thin layer of hydrogel on the FBG has been established. The gel consists of sodium alginate and calcium chloride. Gel formation is observed in real-time by continuously monitoring the Bragg wavelength shift. We have demonstrated pH sensing in the range of pH of 2 to 10. Another interesting phenomenon is observed by swelling and deswelling of FBG functionalized with hydrogel by a sequence of alternate dipping between acidic and base solutions. It is observed that the Bragg wavelength undergoes reversible and repeatable pH dependent switching
Direct Chemical-Vapor-Deposition-Fabricated, Large-Scale Graphene Glass with High Carrier Mobility and Uniformity for Touch Panel Applications
In
this work, we report the transfer-free measurement of carrier
dynamics and transport of direct chemical vapor deposition (CVD) grown
graphene on glass with the aid of ultrafast transient absorption microscopy
(TAM) and demonstrate the use of such graphene glass for high-performance
touch panel applications. The 4.5 in.-sized graphene glass was produced
by an optimized CVD procedure, which can readily serve as transparent
conducting electrode (TCE) without further treatment. The graphene
glass exhibited an intriguing optical transmittance and electrical
conductance concurrently, presenting a sheet resistance of 370–510
Ω·sq<sup>–1</sup> at a transmittance of 82%, much
improved from our previous achievements. Moreover, direct measurement
of graphene carrier dynamics and transport by TAM revealed the similar
biexponential decay behavior to that of CVD graphene grown on Cu,
along with a carrier mobility as high as 4820 cm<sup>2</sup>·V<sup>–1</sup>·s<sup>–1</sup>. Such large-area, highly
uniform, transparent conducting graphene glass was assembled to integrate
resistive touch panels that demonstrated a high device performance.
Briefly, this work aims to present the great feasibility of good quality
graphene glass toward scalable and practical TCE applications
Direct Chemical-Vapor-Deposition-Fabricated, Large-Scale Graphene Glass with High Carrier Mobility and Uniformity for Touch Panel Applications
In
this work, we report the transfer-free measurement of carrier
dynamics and transport of direct chemical vapor deposition (CVD) grown
graphene on glass with the aid of ultrafast transient absorption microscopy
(TAM) and demonstrate the use of such graphene glass for high-performance
touch panel applications. The 4.5 in.-sized graphene glass was produced
by an optimized CVD procedure, which can readily serve as transparent
conducting electrode (TCE) without further treatment. The graphene
glass exhibited an intriguing optical transmittance and electrical
conductance concurrently, presenting a sheet resistance of 370–510
Ω·sq<sup>–1</sup> at a transmittance of 82%, much
improved from our previous achievements. Moreover, direct measurement
of graphene carrier dynamics and transport by TAM revealed the similar
biexponential decay behavior to that of CVD graphene grown on Cu,
along with a carrier mobility as high as 4820 cm<sup>2</sup>·V<sup>–1</sup>·s<sup>–1</sup>. Such large-area, highly
uniform, transparent conducting graphene glass was assembled to integrate
resistive touch panels that demonstrated a high device performance.
Briefly, this work aims to present the great feasibility of good quality
graphene glass toward scalable and practical TCE applications