Synthesis and photophysics of colloidal ZnS/PbS/ZnS nanocomposites—An analysis of dynamics of charge carriers

Kumar, Anil; Jakhmola, Anshuman; Chaudhary, Vidhi

doi:10.1016/j.jphotochem.2009.09.015

Cited by 7 publications

(3 citation statements)

References 37 publications

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“…In contrast, while depositing ZnS(3) first and then PbS(5), the absorption of ZnS(3)/PbS(5) drastically increases, showing much higher intensity than PbS(5) alone and also PbS(5)/ZnS(3). This is attributed to the cation exchange process, where the solubility product of PbS is much smaller than ZnS (Ksp, 3.4×10 −28 vs. 1.2×10 −23 for PbS vs. ZnS) [38]. The SILAR deposition consists of four important steps: 1) dipping in cation precursor, 2) rinsing and drying, 3) dipping in anion precursor, 4) rinsing and drying.…”

Section: Resultsmentioning

confidence: 99%

Employing ZnS as a capping material for PbS quantum dots and bulk heterojunction solar cells

Sun

2016

Sci. China Mater.

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Formation of bulk heterojunctions by incorporating colloidal quantum dots into a mesoporous substrate is anticipated to yield efficient charge collection and complete light absorption. However, it is still challenging in view of the bulky nature of the colloidal quantum dots and the ex situ deposition route. In this study, the feasibility of employing ZnS as a capping material for PbS quantum dots is dissected by carefully designed control experiments, with reference to the formation of bulk heterojunctions by successive ionic layer adsorption and reaction (SILAR) at ambient conditions. The results reveal that the underlying ZnS layer facilitates the PbS deposition by an ion exchange process, while the overlaying ZnS layer tends to cover the PbS in a manner similar to a physical stacking process. Therefore, PbS quantum dots capped with amorphous ZnS are developed with the SILAR technique, which could be used to fill up the mesoporous substrates and thus construct bulk heterojunctions. The hole collection is the limiting factor of such bulk heterojunction solar cells, as demonstrated by inserting a conductive polymer layer in the control devices. Further development of the quantum dot system is discussed in consideration of the fundamental issues presented in this study.

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Section: Resultsmentioning

confidence: 99%

Employing ZnS as a capping material for PbS quantum dots and bulk heterojunction solar cells

Sun

2016

Sci. China Mater.

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“…The enhancement in the emission is due to the fact that high band gap ZnS shell material suppresses the tunneling of the charge carriers from the MnS core to the surface atoms of the shell, resulting in more photogenerated electrons and holes confined inside the MnS cores. Consequently, passivated nonradiative recombination sites that exist on the core surfaces lead to high PL efficiency [16,20]. The emission of peak around ≈360nm can be ascribed to the hole traps originating from the unsaturated 3 sp orbital of the surface S atoms.…”

Section: Photoluminescence Studiesmentioning

confidence: 99%

“…The technique of successive ion layer adsorption and reaction (SILAR) has been adapted to the growth of high-quality core-shell nanocrystals and the photoluminescence efficiency of the surfaceengineered core-shell nanoparticles was substantially higher than that of the plain core structures undergoing the same surface processing. Anil Kumar et al [20] reported the deposition of ZnS layer as shell at the interface of ZnS/PbS produces ZnS/PbS/ZnS nanocomposite. The electronic properties of the nanocomposite have been examined as a function of thickness of ZnS shell and in the presence of excess [Zn 2+ ] .…”

Section: Introductionmentioning

confidence: 99%