Nanoparticle-based Organic Energy Storage with Harvesting Systems

Abstract

A new form of organic energy storage devices (organic capacitors) is presented in the first part of this dissertation. The storage devices are made out of an organic semiconductor material and charge storage elements from synthesized nanoparticles. The semiconducting polymer is obtained by blending poly (vinyl alcohol) and poly (acrylic acid) in crystal state polymers with a known plasticizer; glycerol or sorbitol. Synthesized nanoparticles namely, zinc-oxide (ZnO), erbium (Er), cadmium sulfide (CdS), palladium (Pd) and silver-platinum (AgPt) were used as charge storage elements in fabrication of metal-insulator-semiconductor (MIS) structure. The organic semiconductor and synthesized nanoparticles are tested to evaluate and characterize their electrical performance and properties. Fabrication of the organic capacitors consisted of layer-by-layer deposition and thermal evaporation of the electrode terminals. Capacitance versus voltage (C-V) measurement tests were carried out to observe hysteresis loops with a window gate that would indicate the charging, discharging and storage characteristics. Experimental investigation of various integrated energy harvesting techniques combined with these organic based novel energy storage devices are performed in the second part of this dissertation. The source of the energy is the wind and is harvested by means of miniature wind turbines and vibrations, using piezoelectric transduction. In both cases, the generated electric charge is stored in these capacitors. The performance of the organic capacitors are evaluated through their comparison with commercial capacitors. The results show that the voltage produced from the two energy harvesters was high enough to store the harvested energy in the organic capacitors. The charge and energy levels of the organic capacitors are also reported.

The third part of this dissertation focuses on harvesting energy from a self-induced flutter of a thin composite beam. The composite beam consisted of an MFC patch bonded near the clamped end and placed vertically in the center of a wind tunnel test section. The self sustaining energy harvesting from the unimorph composite beam is exploited. The effects of different operational parameters including the optimum angle of attack, wind speed and load resistance are determined.