ZnO Coatings with Controlled Pore Size, Crystallinity and Electrical Conductivity

  • Roman SCHMACK Technical University Berlin
  • Björn ECKHARDT Technical University Berlin
  • Gregor KOCH Technical University Berlin
  • Erik ORTEL Federal Institute for Materials Research and Testing
  • Ralph KRAEHNERT Technical University Berlin
Keywords: EISA, pore templating, pore size control, ligands, zinc oxide, conductivity

Abstract

Zinc oxide is a wide bandgap semiconductor with unique optical, electrical and catalytic properties. Many of its practical applications rely on the materials pore structure, crystallinity and electrical conductivity. We report a synthesis method for ZnO films with ordered mesopore structure and tuneable crystallinity and electrical conductivity. The synthesis relies on dip-coating of solutions containing micelles of an amphiphilic block copolymer and complexes of Zn2+ ions with aliphatic ligands. A subsequent calcination at 400°C removes the template and induces crystallization of the pore walls. The pore structure is controlled by the template polymer, whereas the aliphatic ligands control the crystallinity of the pore walls. Complexes with a higher thermal stability result in ZnO films with a higher content of residual carbon, smaller ZnO crystals and therefore lower electrical conductivity. The paper discusses the ability of different types of ligands to assist in the synthesis of mesoporous ZnO and relates the structure and thermal stability of the precursor complexes to the crystallinity and electrical conductivity of the zinc oxide.

DOI: http://dx.doi.org/10.5755/j01.ms.22.1.8634

Author Biographies

Roman SCHMACK, Technical University Berlin
Department of Chemistry
Björn ECKHARDT, Technical University Berlin
Department of Chemistry
Gregor KOCH, Technical University Berlin
Department of Chemistry
Erik ORTEL, Federal Institute for Materials Research and Testing
Division 6.8 Surface Analysis and Interfacial Chemistry
Ralph KRAEHNERT, Technical University Berlin
Department of Chemistry
Published
2016-01-21
Section
CERAMICS AND GLASSES