Influence of dilution with organic solvents on emission spectra of CdSe/ZnS quantum dots

The emission spectra of CdSe/ZnS core-shell dots have been monitored after the dilution of their toluene solution with organic solvents (toluene, n-hexane, diethyl ether, acetone, ethanol, and methanol). In addition to the well-known difference of the emission efficiency according to the solvent, we found their time variation depending on the solvent. From the discussion based on the solubility of the capping organic ligand, hexadecylamine (HDA), to each solvent it is suggested that the observed time variation is caused by the liquation of the capping molecules form the dot surface and the resulting change of the number of the trap site for charges in the quantum dot.

[1]  K. H. Ibnaouf,et al.  Photoluminescence spectra of CdSe/ZnS quantum dots in solution. , 2014, Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy.

[2]  K. H. Ibnaouf,et al.  Influence of the solvent environments on the spectral features of CdSe quantum dots with and without ZnS shell , 2014 .

[3]  Tadashi Itoh,et al.  Optical manipulation of CuCl nanoparticles under an excitonic resonance condition in superfluid helium , 2006 .

[4]  S. Ramakrishna,et al.  Dependence of luminescence efficiency of cdse quantum dots on chemical environments. , 2008, Journal of Nanoscience and Nanotechnology.

[5]  Emission of double core infrared (CdSeTe)/ZnS quantum dots conjugated to antibodies , 2013 .

[6]  Y. Baba,et al.  White-light-emitting CdSe quantum dots synthesized at room temperature , 2006 .

[7]  Yosuke Minowa,et al.  Optical levitation of a microdroplet containing a single quantum dot. , 2014, Optics letters.

[8]  Shuming Nie,et al.  Semiconductor nanocrystals: structure, properties, and band gap engineering. , 2010, Accounts of chemical research.

[9]  M. Bawendi,et al.  (CdSe)ZnS Core-Shell Quantum Dots - Synthesis and Characterization of a Size Series of Highly Luminescent Nanocrystallites , 1997 .

[10]  Myriam Protière,et al.  Optical transitions in polarized CdSe, CdSe∕ZnSe, and CdSe∕CdS∕ZnS quantum dots dispersed in various polar solvents , 2007 .

[11]  C. W. Hoerr,et al.  SOLUBILITIES OF HIGH MOLECULAR WEIGHT NORMAL ALIPHATIC PRIMARY AMINES , 1944 .

[12]  Norris,et al.  Measurement and assignment of the size-dependent optical spectrum in CdSe quantum dots. , 1996, Physical review. B, Condensed matter.

[13]  H. J. Harwood,et al.  SOLUBILITIES OF HIGH MOLECULAR WEIGHT ALIPHATIC COMPOUNDS IN n-HEXANE , 1951 .