Cu Doping in Ligand Free CdS Nanocrystals: Conductivity and Electronic Structure Study.
Ligand-free Cu-doped CdS nanocrystals (NCs) have been synthesized to elucidate their surface electronic structure. The Cu-doped ligand-free NCs unlike their undoped counterparts are shown to be luminescent. We used this Cu-related emission as a probe to study the nature of the surface trap states that results in negligible luminescence in the undoped NCs. The concentration of the sulfide ligands is shown to play a crucial role in the surface passivation of the NCs. Electrical conductivity of these NCs was also studied, and they were shown to exhibit significant conductivity of ∼10(-4) S cm(-1). Further we have shown that the electrical conductivity is closely correlated to the surface charge and hence the trap states of the individual NCs have far-reaching consequences in the device optimization.
†New Chemistry Unit, §Chemistry and Physics of Materials Unit, and ‡International Centre for Materials Science, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore 560064, India.
G Krishnamurthy
GK
Grandhi
†New Chemistry Unit, §Chemistry and Physics of Materials Unit, and ‡International Centre for Materials Science, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore 560064, India.
K
K
Swathi
†New Chemistry Unit, §Chemistry and Physics of Materials Unit, and ‡International Centre for Materials Science, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore 560064, India.
K S
KS
Narayan
†New Chemistry Unit, §Chemistry and Physics of Materials Unit, and ‡International Centre for Materials Science, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore 560064, India.
Ranjani
R
Viswanatha
Cu doped ligand free NCs; Cu-related emission; conductivity; inorganic ligands; sulfide ligands; surface