Figure 5.

PENGs based on lateral ZnO nanowires. A) Experimental setup, internal structure, and mechanism of PENG fabricated by ZnO NWs vertically grown radially around textile fibers. Reproduced with permission.36 Copyright 2008, Nature Publishing Group. B) PENG prepared by growing ZnO NW arrays on graphene substrate. Reproduced with permission.34 C) PENG based on vertical ZnO nanowire arrays that grown by low‐temperature hydrothermal decomposition, which covered in PMMA by spin coating. Reproduced with permission.28 Copyright 2010, Nature Publishing Group. D) Super‐flexible ZnO based PENG with Al foil as both the substrate and the electrode. Reproduced with permission.35