The project fits into the economic development strategy for alternative and sustainable sources of energy. The energy that we want to harvest in this project are ‘truly free’ mechanical sources like fluid flows (like wind or river), parasitic vibration (in engines or rotating machines, for example) or human movements (voluntary motion like walking or hand movements). The main applications are low consumption nomad electronics and remote wireless sensors. The heart of the project is to develop a prototype that integrates, on the same flexible chip, a microgenerator that converts this ambient mechanical energy into electrical energy that can recharge a lithium battery, through a specific electrical converter. Since the efficiency of such a mechanical harvesting device strongly depends on the matching between: a piezoelectric microgenerator, the power management block, the electrical load block (a Li battery), we propose in this project to have an integrative approach: studying and designing the whole energy conversion chain.
The piezoelectric microgenerator is a ZnO – polymer composite device that will be optimized in order to fulfill the requirements of the other sub-systems, power management block and Li battery. ZnO is a promising wide band gap semiconductor exhibiting valuable properties such as high exciton binding energy, thermal stability as well as excellent piezoelectric and pyroelectric properties. Recently, extensive research efforts have been carried out to investigate synthesis of high quality zinc oxide (ZnO) nanostructures.