A Library of Selenourea Precursors to PbSe Nanocrystals with Size Distributions near the Homogeneous Limit

• Published in: Journal of the American Chemical Society Vol. 139; no. 6; pp. 2296 - 2305
• Main Authors: Campos, Michael P, Hendricks, Mark P, Beecher, Alexander N, Walravens, Willem, Swain, Robert A, Cleveland, Gregory T, Hens, Zeger, Sfeir, Matthew Y, Owen, Jonathan S
• Format: Journal Article
• Language: English
• Published: WASHINGTON American Chemical Society 15.02.2017; Amer Chemical Soc; American Chemical Society (ACS)
• Subjects: Chemistry; Chemistry, Multidisciplinary; Lead - chemistry; MATERIALS SCIENCE; Molecular Structure; Nanoparticles - chemistry; Organoselenium Compounds - chemistry; Particle Size; Physical Sciences; Science & Technology; Selenium Compounds - chemistry; Surface Properties; Urea - analogs & derivatives; Urea - chemistry; SOLAR-CELLS; MONODISPERSE; SEMICONDUCTOR QUANTUM DOTS; STOICHIOMETRY; STRUCTURAL-CHARACTERIZATION; CDSE NANOCRYSTALS; NUCLEATION; SPECTRAL LINEWIDTHS; EXTINCTION COEFFICIENT; CADMIUM CARBOXYLATE
• ISSN: 0002-7863; 1520-5126
• DOI: 10.1021/jacs.6b11021

We report a tunable library of N,N,N′-trisubstituted selenourea precursors and their reaction with lead oleate at 60–150 °C to form carboxylate-terminated PbSe nanocrystals in quantitative yields. Single exponential conversion kinetics can be tailored over 4 orders of magnitude by adjusting the selenourea structure. The wide range of conversion reactivity allows the extent of nucleation ([nanocrystal] = 4.6–56.7 μM) and the size following complete precursor conversion (d = 1.7–6.6 nm) to be controlled. Narrow size distributions (σ = 0.5–2%) are obtained whose spectral line widths are dominated (73–83%) by the intrinsic single particle spectral broadening, as observed using spectral hole burning measurements. The intrinsic broadening decreases with increasing size (fwhm = 320–65 meV, d = 1.6–4.4 nm) that derives from exciton fine structure and exciton–phonon coupling rather than broadening caused by the size distribution.