Quantum confinement effects on charge-transfer between PbS quantum dots and 4-mercaptopyridine.
We obtain the surface enhanced Raman spectra of 4-mercaptopyridine on lead sulfide (PbS) quantum dots as a function of nanoparticle size and excitation wavelength. The nanoparticle radii are selected to be less than the exciton Bohr radius of PbS, enabling the observation of quantum confinement effects on the spectrum. We utilize the variation of nontotally symmetric modes of both b(1) and b(2) symmetry as compared to the totally symmetric a(1) modes to measure the degree of charge-transfer between the molecule and quantum dot. We find both size dependent and wavelength dependent resonances in the range of these measurements, and attribute them to charge-transfer resonances which are responsible for the Raman enhancement.
Department of Chemistry, The City College of New York, New York, N.Y. 10031, USA.
Xiaoqi
X
Fu
Yi
Y
Pan
Xin
X
Wang
John R
JR
Lombardi
D007854:Lead / Q000737:chemistry*; D010316:Particle Size; D033362:Powder Diffraction; D011725:Pyridines / Q000737:chemistry*; D045663:Quantum Dots; D011789:Quantum Theory; D013440:Sulfides / Q000138:chemical synthesis / Q000737:chemistry*; D013499:Surface Properties
D011725:Pyridines; D013440:Sulfides; C018391:lead sulfide; D007854:Lead; C042861:4-thiopyridine