Heterovalent doping represents an effective method to control the optical and electronic properties of semiconductor nanocrystals(NCs), such as the luminescence and electronic impurities(p-, n-type doping). Considerin...Heterovalent doping represents an effective method to control the optical and electronic properties of semiconductor nanocrystals(NCs), such as the luminescence and electronic impurities(p-, n-type doping). Considering the phase structure diversity, coordination varieties of Cu atoms in Cu2 S NCs, and complexity of Cu doping in II-VI NCs, monodisperse Cu2 S NCs with pure hexagonal phase were synthesized firstly. Then through cation exchange reaction between Cd ions and well-defined Cu2 S NCs, dominant Cu(I) doped CdS NCs were produced successfully. The substitutional Cu(I) dopants with controllable concentrations were confirmed by local atom-specific fine structure from X-ray absorption near edge structure(XANES), extended X-ray absorption fine structure(EXAFS) spectroscopy, elemental analysis characterizations from X-ray photoelectron spectroscopy(XPS) and the electron spin resonance(ESR) measurement. The dominant and strong Cu(I) dopant fluorescence was verified by their absorption and photoluminescence(PL) spectra, and PL lifetime. Finally, the band positions and the p-type conductivities of the as-prepared Cu2 S and Cu(I) doped CdS NCs were identified by ultraviolet photoelectron spectroscopy(UPS) measurements. The high monodispersity of NCs enables their strong film-scale self-assembly and will hasten their subsequent applications in devices.展开更多
基金supported by the National Natural Science Foundation of China(NSFC)(51372025,21322105,91323301,51431009,and 51272015)the Research Fund for the Doctoral Program of Higher Education of China(2011101120016)the Program for New Century Excellent Talents in University(NCET-11-0793)
文摘Heterovalent doping represents an effective method to control the optical and electronic properties of semiconductor nanocrystals(NCs), such as the luminescence and electronic impurities(p-, n-type doping). Considering the phase structure diversity, coordination varieties of Cu atoms in Cu2 S NCs, and complexity of Cu doping in II-VI NCs, monodisperse Cu2 S NCs with pure hexagonal phase were synthesized firstly. Then through cation exchange reaction between Cd ions and well-defined Cu2 S NCs, dominant Cu(I) doped CdS NCs were produced successfully. The substitutional Cu(I) dopants with controllable concentrations were confirmed by local atom-specific fine structure from X-ray absorption near edge structure(XANES), extended X-ray absorption fine structure(EXAFS) spectroscopy, elemental analysis characterizations from X-ray photoelectron spectroscopy(XPS) and the electron spin resonance(ESR) measurement. The dominant and strong Cu(I) dopant fluorescence was verified by their absorption and photoluminescence(PL) spectra, and PL lifetime. Finally, the band positions and the p-type conductivities of the as-prepared Cu2 S and Cu(I) doped CdS NCs were identified by ultraviolet photoelectron spectroscopy(UPS) measurements. The high monodispersity of NCs enables their strong film-scale self-assembly and will hasten their subsequent applications in devices.
