Colloidal Chromium-Doped In<sub>2</sub>O<sub>3</sub> Nanocrystals as Building Blocks for High-<i>T</i><sub>C</sub> Ferromagnetic Transparent Conducting Oxide Structures Shokouh S. Farvid Ling Ju Matthew Worden Pavle V. Radovanovic 10.1021/jp807841k.s001 https://acs.figshare.com/articles/journal_contribution/Colloidal_Chromium_Doped_In_sub_2_sub_O_sub_3_sub_Nanocrystals_as_Building_Blocks_for_High_i_T_i_sub_C_sub_Ferromagnetic_Transparent_Conducting_Oxide_Structures/2898646 Colloidal free-standing Cr<sup>3+</sup>-doped In<sub>2</sub>O<sub>3</sub> nanocrystals were synthesized in oleylamine from indium (III) and chromium (III) acetylacetonate precursors. The nanocrystals were treated with trioctylphosphine oxide to remove surface-bound dopant ions and ensure internal doping. The lattice resolved transmission electron microscopy images reveal that nanocrystals are faceted and highly crystalline, with no evidence of a secondary phase formation. The average doping concentration estimated with energy dispersive X-ray spectroscopy at the single nanocrystal level agrees with the average doping concentration from the analogous nanocrystal ensemble measurement. Ligand-field electronic absorption spectroscopy suggests that Cr<sup>3+</sup> dopants are preferentially substituted for In<sup>3+</sup> ions in their trigonally distorted octahedral (<i>b</i>) sites in In<sub>2</sub>O<sub>3</sub> nanocrystals. Nanocrystalline films, prepared under mild conditions using colloidal Cr<sup>3+</sup>-doped In<sub>2</sub>O<sub>3</sub> nanocrystals as building blocks, exhibit robust room temperature ferromagnetism. Structural and compositional analyses combined with the ligand-field spectroscopy indicate intrinsic ferromagnetism in this material. The ability to rationally synthesize and manipulate a new form of transition-metal-doped In<sub>2</sub>O<sub>3</sub> nanocrystals opens up new opportunities for spintronics applications and may provide a framework for understanding the origin of ferromagnetism in transparent conducting oxides. 2008-11-20 00:00:00 doping concentration 2O nanocrystals transmission electron microscopy images Conducting Oxide StructuresColloidal room temperature ferromagnetism spectroscopy Cr III nanocrystal ensemble measurement