title: Electrical and Plasmonic Properties of Ligand-Free Sn(4+) -Doped In2 O3 (ITO) Nanocrystals.
abstract: Sn(4+) -doped In2 O3 (ITO) is a benchmark transparent conducting oxide material. We prepared ligand-free but colloidal ITO (8 nm, 10 % Sn(4+) ) nanocrystals (NCs) by using a post-synthesis surface-modification reaction. (CH3 )3 OBF4 removes the native oleylamine ligand from NC surfaces to give ligand-free, positively charged NCs that form a colloidal dispersion in polar solvents. Both oleylamine-capped and ligand-free ITO NCs exhibit intense absorption peaks, due to localized surface plasmon resonance (LSPR) at around λ=1950 nm. Compared with oleylamine-capped NCs, the electrical resistivity of ligand-free ITO NCs is lower by an order of magnitude (≈35 mΩ cm(-1) ). Resistivity over a wide range of temperatures can be consistently described as a composite of metallic ITO grains embedded in an insulating matrix by using a simple equivalent circuit, which provides an insight into the conduction mechanism in these systems.
authors.affiliation: Department of Chemistry, Indian Institute of Science Education and Research (IISER), Pune, 411008, India.
authors.forename: Metikoti
authors.initials: M
authors.lastname: Jagadeeswararao
authors.affiliation: Solid State and Structural Chemistry Unit, Indian Institute of Science, Bangalore, 560012, India.
authors.forename: Somnath
authors.initials: S
authors.lastname: Pal
authors.affiliation: Department of Chemistry, Indian Institute of Science Education and Research (IISER), Pune, 411008, India. angshuman@iiserpune.ac.in.
authors.forename: Angshuman
authors.initials: A
authors.lastname: Nag
authors.affiliation: Solid State and Structural Chemistry Unit, Indian Institute of Science, Bangalore, 560012, India. sarma@sscu.iisc.ernet.in.|Department of Physics and Astronomy, Uppsala University, Box 516, 75120, Uppsala, Sweden. sarma@sscu.iisc.ernet.in.|Council of Scientific and Industrial Research-Network of Institutes for Solar Energy (CSIR-NISE), New Delhi, 110001, India. sarma@sscu.iisc.ernet.in.
authors.forename: D D
authors.initials: DD
authors.lastname: Sarma
keywords: ITO nanocrystals; conducting materials; doping; surface modification; surface plasmon resonance