Energy harvesting performance of piezoelectric ceramic and polymer nanowires

• Published in: Nanotechnology 2015-08, Vol.26 (34), p.344001-344001
• Main Authors: Crossley, Sam, Kar-Narayan, Sohini
• Format: Article
• Language: English
• Subjects: Ceramics; Devices; Energy harvesting; figures of merit; nanogenerator; Nanostructure; Nanotechnology; Nanowires; piezoelectric; Piezoelectricity; Vibration
• ISSN: 0957-4484; 1361-6528
• DOI: 10.1088/0957-4484/26/34/344001

Energy harvesting from ubiquitous ambient vibrations is attractive for autonomous small-power applications and thus considerable research is focused on piezoelectric materials as they permit direct inter-conversion of mechanical and electrical energy. Nanogenerators (NGs) based on piezoelectric nanowires are particularly attractive due to their sensitivity to small-scale vibrations and may possess superior mechanical-to-electrical conversion efficiency when compared to bulk or thin-film devices of the same material. However, candidate piezoelectric nanowires have hitherto been predominantly analyzed in terms of NG output (i.e. output voltage, output current and output power density). Surprisingly, the corresponding dynamical properties of the NG, including details of how the nanowires are mechanically driven and its impact on performance, have been largely neglected. Here we investigate all realizable NG driving contexts separately involving inertial displacement, applied stress T and applied strain S, highlighting the effect of driving mechanism and frequency on NG performance in each case. We argue that, in the majority of cases, the intrinsic high resonance frequencies of piezoelectric nanowires (∼tens of MHz) present no barrier to high levels of NG performance even at frequencies far below resonance (