  In the last decade, an explosive attention has been paid to piezoelectric
harvesters due to their flexility in design and increasing need to small-scale
energy generation. As a result, many review papers have been presented by many
researchers to cover different aspects of piezo-based energy harvesting,
including piezomaterials, modeling approaches, and design points in various
applications. Most of such papers tried to shed light on recent progresses in
related interdisciplinary fields, and to pave the road for future prospects of
development of this technology. However, several parts of the field have been
missed in existing review papers, and many similar overlaps or even some
contradictions exist. In the present review of review article, all
recommendations for future research directions suggested by the review papers
have been systematically summed up nuder one umbrella. At the final section,
our recommendations for missing review papers and concluding remarks on
outlooks and possible research topics have been presented.
