Low-Temperature Processed Ga-Doped ZnO Coatings from Colloidal Inks
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- 作者：Enrico Della Gaspera ; Marco Bersani ; Michela Cittadini ; Massimo Guglielmi ; Diego Pagani ; Rodrigo Noriega ; Saahil Mehra ; Alberto Salleo ; Alessandro Martucci
- 刊名：The Journal of the American Chemical Society
- 出版年：2013
- 出版时间：March 6, 2013
- 年：2013
- 卷：135
- 期：9
- 页码：3439-3448
- 全文大小：591K
- 年卷期：v.135,no.9(March 6, 2013)
- ISSN：1520-5126
文摘
We present a new colloidal synthesis of gallium-doped zinc oxide nanocrystals that are transparent in the visible and absorb in the near-infrared. Thermal decomposition of zinc stearate and gallium nitrate after hot injection of the precursors in a mixture of organic amines leads to nanocrystals with tunable properties according to gallium amount. Substitutional Ga3+ ions trigger a plasmonic resonance in the infrared region resulting from an increase in the free electrons concentration. These nanocrystals can be deposited by spin coating, drop casting, and spray coating resulting in homogeneous and high-quality thin films. The optical transmission of the Ga鈥揨nO nanoparticle assemblies in the visible is greater than 90%, and at the same time, the near-infrared absorption of the nanocrystals is maintained in the films as well. Several strategies to improve the films electrical and optical properties have been presented, such as UV treatments to remove the organic compounds responsible for the observed interparticle resistance and reducing atmosphere treatments on both colloidal solutions and thin films to increase the free carriers concentration, enhancing electrical conductivity and infrared absorption. The electrical resistance of the nanoparticle assemblies is about 30 k惟/sq for the as-deposited, UV-exposed films, and it drops down to 300 惟/sq after annealing in forming gas at 450 掳C, comparable with state of the art tin-doped indium oxide coatings deposited from nanocrystal inks.