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北大王中林主任报道“压电纳米发电机”的SCIENCE论文遭德马普所研究人员质疑

  作者:Science

  由美国Georgia Tech材料科学与工程学院,北京大学纳米技术系及国家纳米
中心发表的报道“压电纳米发电机”的SCIENCE论文“Piezoelectric 
Nanogenerators Based on Zinc Oxide Nanowire Arrays”(Zhong Lin Wang 
and Jinhui Song,Science, 312 (2006): 242-246)遭德国马普所研究人员质
疑。 德马普所研究人员认为,其电信号来自仪器而非压电纳米材料,因为用此
方法从非压电材料硅纳米线也可以得到同样的信号。详情请见November 3, 2008
出版的Advanced Materials(Volume 20 Issue 21)。
  德马普所论文共涉及到5篇在国际著名学术期刊发表的有关“压电纳米发电
机”的论文:

  [2] Z. L. Wang, J. Song, Science 2006, 312, 242. 
  [3] X. Wang, J. Song, J. Liu, Z. L. Wang, Science 2007, 316, 102.
  [5] J. Song, J. Zhou, Z. L. Wang, Nano Lett. 2006, 6, 1656.
  [6] P. X. Gao, J. Song, J. Liu, Z. L. Wang, Adv. Mater. 2007, 19, 
67.
  [7] X. Wang, J. Liu, J. Song, Z. L. Wang, Nano Lett. 2007, 7, 2475.

  德马普所论文:

  Energy Harvesting Using Nanowires? (p 4021-4026)
  Marin Alexe, Stephan Senz, Markus Andreas Schubert, Dietrich Hesse, 
Ulrich G?sele
  Max Planck Institute of Microstructure Physics Weinberg 2, 06120 
Halle (Germany)
  Advanced Materials, Volume 20 Issue 21, Pages 4021-4026 (November 3, 
2008)
  The present paper focuses on the basic science of the energy 
harvesting mechanism proposed in the literature to explain how ZnO 
nanowire-based generators operate. It tries to unveil the signal 
sources which - based on experiments and theoretical considerations - 
are different than commonly suggested.
  …………
  In summary, we have observed similar voltage signals and similar 
‘‘energy harvesting’’ from piezoelectric ZnO and nonpiezoelectric 
silicon nanowire arrays. We have analyzed the signal generation 
mechanism based on a Schottky diode in detail and we have demonstrated 
that the suggested mechanism has major problems. Firstly, it does not 
take into account that the piezoelectric effect generates charge and 
not potentials. Secondly, it ignores that the charge generated in ZnO 
by the piezoelectric effect will be cancelled by internal free charges 
in a very short time, which is directly related to the effective 
resistivity and dielectric constant. Finally, the Schottky barrier 
formed at the Pt-ZnO interface can not effectively rectify signals of 
a few mV as observed in the original measurements of Wang and Song.[2] 
We have demonstrated that the measured signals might have different 
sources than the piezoelectric effect, most of them being features of 
the measuring instruments and set-up, and the energy is rather 
harvested from the instruments than from the nanowires.

(XYS20081108)

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