Linear dipole behavior of single quantum dots encased in metal oxide semiconductor nanoparticles films
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Understanding of charge/energy exchange processes and interfacial interactions that occur between quantum dots (QDs) and the metal oxides is of critical importance to these QD-based optoelectronic devices. This work reports on linear dipole behavior of single near-infrared emitting CdSeTe/ZnS core/shell QDs which are encased in indium tin oxide (ITO) semiconductor nanoparticles films. A strong polarization anisotropy in photoluminescence emission is observed by defocused wide-field imaging and polarization measurement techniques, and the average polarization degree is up to 0.45. A possible mechanism for the observation is presented in which the electrons, locating at single QD surface from ITO by electron transfer due to the equilibration of the Fermi levels, result in a significant Stark distortion of the QD electron/hole wavefunctions. The Stark distortion results in the linear polarization property of the single QDs. The investigation of linear dipole behavior for single QDs encased in ITO films would be helpful for further improving QD-based device performance.
Keywordssingle quantum dots linear dipole behavior electron transfer polarization property metal oxide nanoparticles
We gratefully acknowledge financial support from the National Key R&D Program of China (No. 2017YFA0304203), the National Natural Science Foundation of China (Grant Nos. 61527824, 61675119, U1510133, 11434007, 11504216, and 61605104), PCSIRT (No. IRT 17R70). Y. Peng was supported by the National Natural Science Foundation of China (No. 11404189). H. Xie was supported by the National Natural Science Foundation of China (No. 11504260).
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