TY - JOUR
T1 - Synthesis and characterization of CdSe nanocrystals capped with TOPO and pyridine
AU - Luo, Xiang Dong
AU - Farva, Umme
AU - Truong, Nguyen Tam Nguyen
AU - Son, Kyung Soo
AU - Liu, Pei Sheng
AU - Adachi, Chihaya
AU - Park, Chinho
N1 - Funding Information:
This research was supported by Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Korean Ministry of Education, Science and Technology ( 2011-0026189 ), and the Human Resources Development Program of Korea Institute of Energy Technology Evaluation and Planning (KETEP) Grant (no. 20104010100580 ) funded by the Korea Ministry of Knowledge Economy. Authors would like to thank Major Fundamental Research Program of University of Jiangsu Province (Grant no. 08KJA510002 ), Applied Science Foundation of Nantong (Grant no. K2008024 ), and Jiangsu government scholarship for overseas studies ( JS-2007-057 ). Authors would like to also thank Dr. Ryan Smith at the Department of Physics, Yeungnam University, Korea for his valuable suggestions and comments.
PY - 2012/1/15
Y1 - 2012/1/15
N2 - TOPO-capped CdSe nanocrystals with different sizes were synthesized by a slightly modified Peng and Pengs method, and pyridine-capped CdSe nanocrystals were obtained from TOPO-capped CdSe by exchange of TOPO with pyridine. By applying X-ray powder diffraction, X-ray photoelectron spectroscopy (XPS), transmission electron microscopy, photoluminescence (PL) and time-resolved PL (TRPL) spectroscopy, structural and optical characteristics of TOPO-capped and pyridine-capped CdSe are studied in detail. Analysis results show that, by exchanging the surface ligand from TOPO to pyridine, the crystalline quality and optical properties of CdSe nanocrystals are improved. During surface ligand exchange, the diameter of CdSe is decreased, which is caused by the loss of surface Cd and Se atoms with leaving TOPO molecules. The TRPL results suggest that the localized optical transitions of pyridine-capped CdSe, which result from defects and impurities existing in the nanocrystals, are suppressed, compared with those from the original TOPO-capped CdSe. The PL blue-shifts of pyridine-capped CdSe are also observed, and the PL and XPS results indicate that, when TOPO is substituted by pyridine, the surface electronic density of CdSe is re-distributed.
AB - TOPO-capped CdSe nanocrystals with different sizes were synthesized by a slightly modified Peng and Pengs method, and pyridine-capped CdSe nanocrystals were obtained from TOPO-capped CdSe by exchange of TOPO with pyridine. By applying X-ray powder diffraction, X-ray photoelectron spectroscopy (XPS), transmission electron microscopy, photoluminescence (PL) and time-resolved PL (TRPL) spectroscopy, structural and optical characteristics of TOPO-capped and pyridine-capped CdSe are studied in detail. Analysis results show that, by exchanging the surface ligand from TOPO to pyridine, the crystalline quality and optical properties of CdSe nanocrystals are improved. During surface ligand exchange, the diameter of CdSe is decreased, which is caused by the loss of surface Cd and Se atoms with leaving TOPO molecules. The TRPL results suggest that the localized optical transitions of pyridine-capped CdSe, which result from defects and impurities existing in the nanocrystals, are suppressed, compared with those from the original TOPO-capped CdSe. The PL blue-shifts of pyridine-capped CdSe are also observed, and the PL and XPS results indicate that, when TOPO is substituted by pyridine, the surface electronic density of CdSe is re-distributed.
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U2 - 10.1016/j.jcrysgro.2011.11.048
DO - 10.1016/j.jcrysgro.2011.11.048
M3 - Article
AN - SCOPUS:84855202893
SN - 0022-0248
VL - 339
SP - 22
EP - 30
JO - Journal of Crystal Growth
JF - Journal of Crystal Growth
IS - 1
ER -