Regrowth of CdTe Quantum Dots Induced by Circular Polarized Light and Its Effect on the Photoluminescence

doi:10.15541/jim20170124

Abstract

Abstract:

The water soluble CdTe quantum dots were synthesized in aqueous solution using 3-mercaptopropionic acid as stabilizer reagent. Effects of non-polarized and circular polarized light modification on structural and optical properties of quantum dots were investigated by photoluminescence spectroscope, ultraviolet visible absorption spectroscope, transmission electron microscope, and X-ray diffraction. It is revealed that the non-polarized light tends to oxidize the quantum dots, which brings about photo degradation of quantum dots and blue shift of photoluminescence. By contrast, the circular polarized light oxidizes the stabilizer reagent at the surface of CdTe quantum dots, which leads to regrowth of quantum dots and red shift of photoluminescence. Moreover, the photochemical reaction mechanism together with the bonding effect between stabilizer reagent and CdTe quantum dot were studied. The photoluminescence of CdTe quantum dot is associated with its surface states.

Key words: CdTe, quantum dots, photoluminescence, polarized-light modification

CLC Number:

O613

YAN Bo, PENG Ze-Yang, LV Bin, LIU Wei. Regrowth of CdTe Quantum Dots Induced by Circular Polarized Light and Its Effect on the Photoluminescence[J]. Journal of Inorganic Materials, 2017, 32(12): 1321-1326.

Figures/Tables 4

Fig. 1 U-Vis absorption spectra (a) and PL spectra (b) of CdTe QDs-524, QDs-598 and QDs-618; XRD pattern (c) and TEM image (d) of CdTe QDs-618 with inset displaying HRTEM image of the sample

Fig. 2 (a) Experimental configuration of CPL and UnPL irradiation on the QDs; (b) PL spectra of QDs-524, QDs-598 and QDs-618 before and after CPL illumination; (c) PL spectra of QDs-618 with different time of duration in dark after CPL illumination; (d) Peak position change of PL spectra of QDs-618 with different time of duration in dark after CPL illumination

Fig. 3 XRD pattern (a) and TEM image (b) of CdTe QDs-618 after CPL irradiation with inset displaying HRTEM image of the sample; XRD pattern (c) and TEM image (d) of CdTe QDs-618 after UnPL irradiation with inset displaying HRTEM image of the sample

Fig. 4 (a) EDS patterns of QDs-618 before and after CPL as well as UnPL irradiation; (b) Schematic diagram of the oxidation process of QDs under CPL and UnPL irradiation

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