Piezoelectric Energy Harvesting Nanofibers - Hierarchical Nanostructures for Energy Devices - page 153

In the area of energy harvesting using PZT nanowires, Wang et al. have
successfully demonstrated a series of nanogenerators using epitaxially
grown PZT nanowires with outstanding performances. 1,73-75 These PZT
nanowires have limitations in length as constrained by the fabrication
method, similar to the ZnO nanowire-based nanogenerators. PZT micro-
fibers have also been machined either by using a computer controlled dicing
saw to cut fabricated PZT thin films by using mixed oxide powders with
extrusion/suspension spinning, or by a wet-chemical sol-gel process via
viscous plastic processing (VPP). 76 These fibers can be rectangular or circular
with diameters from 50-500 mm as shown in Figure 7.5(a). A nanogenerator
has been constructed in a similar fashion by using a lithography process to
define PZT ribbons (5 mm in width and 500 nm in thickness) and a dry
transfer process using a polydimethylsiloxane (PDMS) substrate as illus-
trated in Figure 7.5(b). 77 In two recent reports, on the other hand, by Chen
et al. 14

d n 3 r 4 n g | 2

and Zhang et al., 16

the researchers have applied far-field

.

(a) Rectangular or circular PZT microfibers with different diameters. 78
Reprinted with permission from ref. 78. (b) A transfer process using a
lithography process to define PZT ribbons and a PDMS substrate to
transfer the PZT fibers. 77 Copyright (2010) American Chemical Society.
(c) PZT nanofibers on two platinum comb-shaped electrodes. 14 The
generator is completed with a PDMS cover.
Reprinted with permission from ref. 14. Copyright (2010) American
Chemical Society.

Figure 7.5