We produce piezoelectric ZnO nanorods on flexible substrates using solution-based methods, which are then combined with the p-type semiconducting polymer PEDOT:PSS to produce a novel p-n junction device. These devices successfully demonstrate voltage output when the substrate is bent, i.e. mechanical energy harvesting.

We have developed the device structures to improve the output from a few mV up to over 1 V of output when strained via mechanical bending, and generating 10s of μW of power under continous vibration in a cantilever arrangement. We have developed and validated a model to demonstrate that reduction screening of free carriers in both the contacts and ZnO nanorods themselves is key to increase voltage and power output from the devices, and have developed a number of adaptations to achieve this.

Selected relevant publications:

• First report of p-n junction nanogenerator
• Efficiency measurements
• Measurement techniques and comparison to semiconductor-insulator-metal-type nanogenerator
• Surface passivation using CuSCN
• Surface passivation using polyelectrolytes
• Review of piezoelectric nanogenerators
• Textile-based energy harvester