Please cite this article in press as: S. Emamian, et al., Gravure printed flexible surface enhanced Raman spectroscopy (SERS) substrate for detection of 2,4-dinitrotoluene (DNT) vapor, Sens. Actuators B: Chem. (2014), http://dx. a b s t r a c tAn efficient surface enhanced Raman spectroscopy (SERS) substrate was successfully fabricated by gravure printing a thin film of silver nanoparticle (Ag NP) ink, with average particle size of 150 nm, on flexible polyethylene terephthalate (PET) sheet. The feasibility of the printed SERS substrate for detecting explosive organic compounds such as 2,4-dinitrotoluene (DNT), in vapor phase, was investigated. The SERS based response of the printed substrate demonstrated an enhancement factor of four in the intensity of the Raman signal of DNT vapor when compared to target molecules adsorbed on bare PET. An 85% decrease in the intensity of the Raman spectrum was also observed as the temperature increased from 25 • C to 65 • C. The results obtained show the efficiency of the gravure printed SERS substrate to be used in applications for the detection of explosive organic compounds.

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We report the fabrication and testing of a multilayer flexible screen-printed coil that can be used to generate low-frequency (<1 kHz) magnetic fields for applications such as electrodynamic wireless power transmission (EWPT). Compared to traditional coil-forming methods, screen printing enables rapid fabrication of thin, light weight, conformable, and flexible structures. The flexibility is demonstrated by repeated bending of a stack of up to three layers for a curvature (inverse bending radius) of 53.2 mm −1 . We also demonstrate wireless power transmission of 1 mW of power at a distance of 4 cm between the flexible receiver and transmitter. The effect of the flexibility is observed through a 32% power increase when the receiver is bent concavely and a 20% output power decrease when the stack is bent convexly. It is also seen that the insertion of a 0.2 mm-thick soft-magnetic material sheet increased the magnetic field by 41% from its original value. Mechanical cycling was also performed for the stack. After 10 000 bending cycles, a 16.4% increase in the coil resistance was measured for a 0.33 Hz frequency and 78% increase for a 1 Hz cycling frequency, respectively. Screen printed 3D flexible transmitter coils can enable the incorporation of EWPT for wireless charging in applications such as healthcare and consumer-based electronics.