Acta Phys. -Chim. Sin. ›› 1997, Vol. 13 ›› Issue (05): 445-448.doi: 10.3866/PKU.WHXB19970511

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Preparation and Optical Absorption of Nanometr-sized NiO Powder

Wang Guo-Zhong,Zhang Li-De,Mou Ji-Mei   

  1. Institute of Solid State Physics,Chinese Academy of Sciences,Hefei 230031,P.R.China|Department of Science and Engineering of Material,University of Science and Technology of China,Hefei 230026,P.R.China
  • Received:1996-07-15 Revised:1996-12-25 Published:1997-05-15
  • Contact: Wang Guo-Zhong

Abstract:

Uniform nanosized NiO particles were prepared by a chemical coprecipitation using NiCl2?6H2O as the starting material. The relationship between various annealing temperatures and grain size of NiO crystallite was investigated. Optical reflectivity spectra of Nanometer-sized NiO powders at room temperature were studied. The results show that seven optical absorption bands (P1、 P2、P3、P4、P5、P6 and P7) with the peak energies of 3.30, 2.99, 2.78, 2.25,1.92, 1.72 and 1.07eV, respectively, are located on a continuous refiectivity background. P1、 P2、P3 and P4 exhibit "blue shift", but P5、P6 and P7 present "red shift" in comparison with that of single crystal NiO. The continuous reflectivity background increases rapidly with increasing the annealing temperature from 500℃ to 600℃ to 700℃. The origins of P1 to P7 and the reasons of "blue shift", "red shift" and the increase of the reflectivity background with increasing the annealing temperature have been analyzed in detail.

Key words: Nnanometer-sized powder, NiO, Coprecipitation, Optical absorption, Red shift, Blue shift