1.  By bending single nanowires voltages are induced.  The electrical energy can be harnessed by contacting both ends of the nanowires. Thai Tran, Applied Science & Technology Group

2. Strain leads to piezolelectric voltage drop  ZnO nanowires are grown by Physical Vapor Deposition (PVD) Length: 100-500 μm Diameter: 0.1-0.8 μm  The two ends of the nanowires were firmly fixed onto 50 μm thick Kapton polymide  Material of the nanowires exhibit piezoelectric effect.  Potential drop is determined by orientation of c-axis and deformation condition (stretching/ compressing) Yang et al., Nat. Nanotechnol. 2009, 4, 34

3. Proposed mechanism for current generation Yang et al., Nat. Nanotechnol. 2009, 4, 34 a) Band diagram of device with relaxed nanowire b) Strain in wire induces voltage drop c) Electrons flow from right contact to left contact. d) After relaxation of wire electrons flow back to right electrode Nanowire acts “capacitor” and “charge pump” Presence of at least one Schottky barrier is essential in order to prevent current flow through wire

4. Biomechanical Energy Conversion… OC-VoltageShort circuit current  Peak height of current and Voltage depend on stress and strain rate.

5. Hamster

6. In conclusion:  The authors demonstrated durable and robust nanowire based generators that can convert mechanical energy into electricity. PLEASE NOTE: Authors also demonstrated devices with up to 4 nanogenerators in series: voltages of ~0.1-0.15 V have been achieved.

7. Thank You for your Attention