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 [ Time:2013/5/30 ]
Developing a general strategy for synthesis of doped hematite based on LAL technology
Author :YE Yixing

The doping of foreign atoms is critical in tailoring the propertiesand potential applications of semiconductor nanocrystals. A general strategy forsuccessfully incorporating various impurities (e.g., Ge, Si, Mn, Sn, Ti) inside theregular crystal lattice of hematite (¦Á-Fe2O3), a promising candidate for watersplitting and environmental protection, is developed. Liquid-phase laser ablation-derived colloidal clusters are used as doping precursors for the metastable growthof doped hematite nanocrystals, thereby avoiding surfactants and hazardous liquidbyproducts. The doping percentage, morphology, and structure of the hematitenanocrystals are greatly affected by the type and amount of the colloidalprecursors used. High-resolution transmission electron microscopy and thecorresponding component analysis reveal that the dopant atoms either formsuperlattice structures (Ge and Si) or distribute as disordered solid solutions (Mn,Sn, Ti) inside the crystal lattice of hematite. The optical absorption spectra andthe resulting band gaps of the doped-hematite nanocrystals are investigated.Typical electronic transitions consisting of ligand to metal charge transitions, Fe3+d−d transitions, and pair excitations distinctlyoccur in the optical spectra. The simultaneous incorporation of impurities and preferential growth mechanism of hematitenanocrystals are also further elaborated.Thedeveloped doping strategy is completely different from othermethods, and may provide new insights into establishing adoping model by colloidal chemistry.
1. Jun Liu,Changhao Liang*,Hemin Zhang,Shuyuan Zhangand Zhenfei Tian, ¡°Silicon-doped hematite nanosheets with superlattice structure¡±, Chem. Commun., 2011, 47, 8040-8042.
2. Jun Liu,Changhao Liang*, Hemin Zhang,Zhenfei Tian,and Shuyuan Zhang, ¡°General Strategy for Doping Impurities (Ge, Si, Mn, Sn, Ti) inHematite Nanocrystals¡±, J. Phys. Chem. C2012, 116, 4986-4992.
3. Jun Liu, Changhao Liang*, Guoping Xu, Zhenfei Tian,Guosheng Shao, Lide Zhang, ¡°Ge-doped hematite nanosheets with tunabledoping level, structure and improvedphotoelectrochemical performance¡±, Nano Energy, 2013, 2, 328-336.

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