Abstract

The luminescence properties of colloidal Ag₂S quantum dots (QDs) with ZnS or SiO₂ shells coated with thioglycolic or 2-mercaptopropionic acids are comparatively analyzed. It is demonstrated that the quantum yield of the IR recombination luminescence of colloidal Ag₂S QDs increases by a factor of up to 35 as a result of formation of ZnS or SiO₂ shells with a simultaneous increase in the average luminescence lifetime. It is shown that the radiative and nonradiative recombination constants for core/shell Ag₂S/ZnS QDs coated with thioglycolic acid decrease, which is explained by localization of electrons in the shell and localization of holes in the core. In core/shell Ag₂S/SiO₂ QDs coated with 2-mercaptopropionic acid, the radiative recombination constant increases and the nonradiative recombination constant decreases. In this case, the increase in the radiative recombination constant is caused by localization of electrons and holes in the core. The decrease in the nonradiative recombination constant is explained by passivation of interface defects of QDs upon the shell formation.

中文翻译：

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胶核/壳Ag 2 S / ZnS和Ag 2 S / SiO 2量子点的发光量子产率和复合常数

摘要

比较分析了具有巯基乙酸或2-巯基丙酸涂层的ZnS或SiO ₂壳的胶体Ag ₂ S量子点（QDs）的发光特性。结果表明，由于形成了ZnS或SiO ₂壳层，并且平均发光寿命同时增加，胶体Ag ₂ S QD的IR复合发光的量子产率提高了35倍。结果表明，涂有巯基乙酸的核/壳Ag ₂ S / ZnS量子点的辐射和非辐射复合常数降低，这可以通过壳中电子的定位和核中孔的定位来解释。在核/壳中Ag ₂ S / SiO用2-巯基丙酸包被的2_个量子点，其辐射复合常数增加而非辐射复合常数减小。在这种情况下，辐射复合常数的增加是由电子和空穴在芯中的局部化引起的。通过壳形成时量子点界面缺陷的钝化，可以解释非辐射复合常数的降低。