Nuclear magnetic relaxation studies of semiconductor nanocrystals and solids

Thesis/Dissertation · Wed Sep 01 00:00:00 EDT 1993

DOI:https://doi.org/10.2172/10120364· OSTI ID:10120364

Sachleben, Joseph Robert ^[1]

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1. Lawrence Berkeley Lab., CA (United States); California Univ., Berkeley, CA (United States). Dept. of Chemistry

Semiconductor nanocrystals, small biomolecules, and ¹³C enriched solids were studied through the relaxation in NMR spectra. Surface structure of semiconductor nanocrystals (CdS) was deduced from high resolution ¹H and ¹³C liquid state spectra of thiophenol ligands on the nanocrystal surfaces. The surface coverage by thiophenol was found to be low, being 5.6 and 26% for nanocrystal radii of 11.8 and 19.2 Å. Internal motion is estimated to be slow with a correlation time > 10^-8 s^-1. The surface thiophenol ligands react to form a dithiophenol when the nanocrystals were subjected to O₂ and ultraviolet. A method for measuring ¹⁴N-¹H J-couplings is demonstrated on pyridine and the peptide oxytocin; selective 2D T₁ and T₂ experiments are presented for measuring relaxation times in crowded spectra with overlapping peaks in 1D, but relaxation effects interfere. Possibility of carbon-carbon cross relaxation in ¹³C enriched solids is demonstrated by experiments on zinc acetate and L-alanine.

• Research Organization: Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC03-76SF00098
• OSTI ID: 10120364
• Report Number(s): LBL-34884; ON: DE94006301
• Resource Relation: Related Information: Thesis (Ph.D.)
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
36 MATERIALS SCIENCE
37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
59 BASIC BIOLOGICAL SCIENCES
ORGANIC SULFUR COMPOUNDS
ADSORPTION
CADMIUM SULFIDES
SURFACE PROPERTIES
NUCLEAR MAGNETIC RESONANCE
PYRIDINE
OXYTOCIN
ACETATES
ZINC COMPOUNDS
ALANINES
NMR SPECTRA
RELAXATION
CARBON 13
LIGANDS
PEPTIDES
NITROGEN 14
665100
360606
400201
550200
NUCLEAR TECHNIQUES IN CONDENSED MATTER PHYSICS
PHYSICAL PROPERTIES
CHEMICAL AND PHYSICOCHEMICAL PROPERTIES
BIOCHEMISTRY