Freestanding ZnO nanorod/graphene/ZnO nanorod epitaxial double heterostructure for improved piezoelectric nanogenerators

Dong Myeong Shin, Ermias Libnedengel Tsege, Seok Hee Kang, Wanchul Seung, Sang Woo Kim, Hyung Kook Kim, Suck Won Hong, Yoon Hwae Hwang

Research output: Contribution to journalArticlepeer-review


It has been intensively studied that vertically aligned ZnO nanorods over the last decade due to their remarkable piezoelectric properties and a potential for various applications. Here, we present a simple strategy for fabricating the freestanding ZnO nanorods/graphene/ZnO nanorods double sided heterostructures. The characterization of the double sided heterostructures by using SEM, and Raman scattering spectroscopy reveals the key process and working mechanism of a formation of the heterostructure. The mechanism is discussed in detail in term of the decomposed seed layer and the vacancy defect of graphene. The approach consists of a facile one-step fabrication process and could achieve ZnO coverage with a higher number density than that of the epitaxial single heterostructure. The resulting improvement in the number density of nanorods has a direct beneficial effect on the double side heterostructured nanogenerator performance. The total output voltage and current density are improved up to~2 times compared to those of a single heterostructure due to the coupling of the piezoelectric effects from both upward and downward grown nanorods. The facile one-step fabrication process suggests that double sided heterostructures would improve the performance of electrical and optoelectrical device, such as touch pad, pressure sensor, biosensor and dye-sensitized solar cells.

Original languageEnglish
Pages (from-to)268-277
Number of pages10
JournalNano Energy
Publication statusPublished - 2015 Mar 1

Bibliographical note

Funding Information:
We thank Dr. Seunghun Lee and Prof. Se-Young Jeong for their helpful discussions about the instrument set-up and for providing the instruments for the piezoelectric output voltage and current measurements. This work was supported by the National Research Foundation of Korea(NRF) grant funded by the Korea government(MSIP) (No. 2014R1A2A1A11051146 ). This research was also supported by the Civil & Military Technology Cooperation Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Science, ICT & Future Planning (No. 2013M3C1A9055407 ).

Publisher Copyright:
© 2015 Elsevier Ltd.

All Science Journal Classification (ASJC) codes

  • Renewable Energy, Sustainability and the Environment
  • Materials Science(all)
  • Electrical and Electronic Engineering


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