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Photoluminescence Enhancement of CdSe and CdSe–ZnS Nanocrystals by On‐Surface Ligand Modification
Author(s) -
Oszajca Marek,
Lincheneau Christophe,
Amelia Matteo,
Schäfer Christian,
Szaciłowski Konrad,
Credi Alberto
Publication year - 2013
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/ejic.201300331
Subject(s) - nanocrystal , chemistry , luminescence , quantum dot , photoluminescence , photochemistry , quenching (fluorescence) , ligand (biochemistry) , electron acceptor , electron transfer , molecule , fluorescence , nanotechnology , optoelectronics , materials science , organic chemistry , physics , receptor , quantum mechanics , biochemistry
We have investigated the spectroscopic properties of CdSe and CdSe–ZnS nanocrystal quantum dots (QDs) in the presence of the electron acceptor tetracyanoethene (TCNE) in organic solution. Our results indicate that TCNE reacts with the n ‐alkylamine capping ligands at the surfaces of nanocrystals to generate (cyanovinyl)amine products that remain bound to the surfaces of the QDs, substantially increasing their emission efficiency. Further addition of an excess of TCNE caused a decrease in the luminescence intensity, most likely because of an electron‐transfer quenching process from the photoexcited nanocrystals to the electron‐accepting TCNE molecules. TCNE‐induced emission enhancement was also observed for the strongly luminescent CdSe–ZnS core–shell QDs. This approach enables a post‐synthetic adjustment of the luminescence efficiency of amine‐capped QDs. We have also shown that the threshold‐dependent response of the QD emission on the TCNE concentration can be used to encode NAND and XOR Boolean logic operations.