- MSc, (2017-2020): Design and fabrication of a triboelectric Nanogenerator based on modified polymer film
In recent years, the usage of graphene oxide (GO) super capacitors with high energy densities in storage devices have attracted a tremendous attention. The transfer of graphene onto flexible polydimethylsiloxane (PDMS) substrates has been achieved by a simple, etching- free method. This transfer is due to the very low surface energy of PDMS. In this research,in order to enhance the triboelectric performance for a single- friction triboelectric nanogenerator (S-TENG) the polymer composites consisting of various concentrations of GO nanosheets (0, 0.02, 0.05, 0.5, 1, and 1.5 wt%) were fabricated, and then PDMS surface was patterned using a nanoporous anodic titanium oxid template. In addition, GO despersion was coated on PDMS patterned surface in different concentrations(1, 2, 3 and 4 mg/ml), and it was seen that the performance of the TENG is better than the composite case. Because of the two dimensional nanostructure and excellent surface properties, the GO- based TENG shows a sensitive force detection and an antimicrobial activity. This device, which has a simple structure, was fabricated in a low- cost method and a simple manufacturing process. TENG is used to convert mechanical energy into electricity by a conjunction of triboelectriﬁcation and electrostatic induction. The output voltage of up to 60 V and current density of 11 µA/cm2 has been achieved when the TENG was pressed by a human bare hand, with the size of 2×2 cm2, which can be obtainedunder different frequency and pressure from the TENG. As the TENG is pressed by a human hand within latex glove, the output voltage has reached to 100 V, and the generated electric energy could supply the power required for 5 commercial green light emitting diodes (LEDs) without any energy storage process. This higher performance was attributed to the formation of nanopores and strengthened negative charges on PDMS from the fibrous structure and oxygen functional groups of GO, respectively. Performance of the devices are also systematically investigated under various motion types and pressure forces. Moreover, the maximum power density of the device can reach up to 4.97W/m2 (1.99 mW, 3 Hz), on palm tapping the device, 8 green LEDs can be lit up. The TENG shows a great promise for applications in systems such as wearable electronic devices, self- powered touch panels, artificial skins and smart wireless sensor networks.