Composition control and localization of S2- in CdSSe quantum dots grown from Li4[Cd10Se4(SPh)16].
The development of ternary nanoscale materials with controlled cross-sectional doping is an important step for the use of chemically prepared quantum dots for nanoscale engineering applications. We report cross-sectional, elemental doping with the formation of an alloyed CdSSe nanocrystal from the thermal decomposition of Li(4)[Cd(10)Se(4)(SPh)(16)]. The sulfur incorporation arises from surface-mediated phenylthiolate degradation on the growing quantum dot surface. In the alloy, we identify a pure CdSe nucleus of approximately 1.5 nm, consistent with the predictions of nucleation theory. As the particle grows, S(2-) incorporation increases until the CdSSe reaches approximately 4 nm, where a marked reduction in phenylthiolate content on the nanocrystal is observed by CP-MAS NMR spectroscopy, implying that rapid decomposition of the phenylthiolate arises with subsequent enhanced S(2-) incorporation at the level of the stoichiometry of the reaction (namely approximately 60%). The use of molecular clusters to allow controlled defect ion incorporation can open new pathways to more complex nanomaterials.
Lovingood
Derek D
DD
Department of Chemistry and Biochemistry, Florida State University, Tallahassee, Florida 32306-4390, USA.
Oyler
Ryan E
RE
Strouse
Geoffrey F
GF
D019187:Cadmium Compounds / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D046529:Microscopy, Electron, Transmission; D009942:Organometallic Compounds / Q000737:chemistry*; D045663:Quantum Dots; D018036:Selenium Compounds / Q000737:chemistry*; D013457:Sulfur Compounds / Q000737:chemistry*
D019187:Cadmium Compounds; D009942:Organometallic Compounds; D018036:Selenium Compounds; D013457:Sulfur Compounds