Controlled Growth of ZnSe Nanocrystals by Tuning Reactivity and Amount of Zinc Precursor

Lai-Jun Zhang,Ji-Zao Tong,Hai-Jin Huang,Fa-Yun Chen,Guang-Da Chen,Xing-Can Shen

doi:10.1155/2013/791437

Lai-Jun Zhang, Ji-Zao Tong + Show 4 more

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https://doi.org/10.1155/2013/791437

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Abstract

Zinc selenide (ZnSe) nanocrystals were synthesized via a phosphine-free route using the highly reactive alkylamine-H2Se complex as selenium precursor and zinc precursors with different reactivity. The reactivity of zinc precursor was tuned by using three kinds of zinc carboxylates with different alkyl chain lengths, including zinc acetate, zinc nonanoate, and zinc stearate. The effect of the reactivity and the amount of zinc precursor on nucleation and growth of ZnSe nanocrystals were investigated by ultraviolet-visible absorption and photoluminescence spectra. Result indicates that the growth and optical property of the resulting ZnSe nanocrystals are strongly dependent on the alkyl chain length and the amount of the zinc carboxylates and both shorter alkyl chain length, and more amount of zinc carboxylate will lead to faster growth of ZnSe nanocrystals. This allows that the controlled growth and excellent optical property of high-quality ZnSe nanocrystals can be achieved by combining the different reactivity and the used amount of zinc precursor, such as by using stoichiometric and reactive Zn precursor and Se precursor or by using larger amount of more unreactive Zn precursor relative to the highly reactive alkylamine-H2Se complex precursor.

Highlights

Relative to cadmium chalcogenide, zinc chalcogenide is regarded as a “greener” luminescent semiconductor due to the absence of cadmium element, a very toxic heavy metal to human body and natural environment
High-quality Zinc selenide (ZnSe) NCs were usually synthesized at high temperatures by using the stable tri-n-octylphosphine selenide (TOP-Se) or selenium dispersed/dissolved in 1octadecene (ODE-Se) as selenium (Se) precursors to react with various kinds of zinc (Zn) precursors with the proper reactivity, such as the relatively inactive zinc stearate (ZnSt2 )
ZnSe NCs indicate that the growth and optical property of the resulting ZnSe nanocrystals are strongly dependent on both the different alkyl chain length and the used amount of the zinc carboxylates

Summary

Introduction

Zinc chalcogenide is regarded as a “greener” luminescent semiconductor due to the absence of cadmium element, a very toxic heavy metal to human body and natural environment. High-quality ZnSe NCs were usually synthesized at high temperatures by using the stable tri-n-octylphosphine selenide (TOP-Se) or selenium dispersed/dissolved in 1octadecene (ODE-Se) as selenium (Se) precursors to react with various kinds of zinc (Zn) precursors with the proper reactivity, such as the relatively inactive zinc stearate (ZnSt2 ). We made our effort to synthesize highquality metal selenide NCs by appropriately increasing the reactivity of Se precursor [11, 12]. The alkylamine-H2 Se complex, which was generated by adsorbing H2 Se gas with long-chain alkylamine and used as a more active Se precursor than the traditional TOP-Se and ODE-Se, showed rather high reactivity to zinc nonanoate (Zn(NA)2 ), which results in the formation of magic-sized and even regular ZnSe NCs at relatively low temperatures [12]. A new problem occurs, that is, whether the Zn precursor species used will affect the synthesis and optical properties of the resulting ZnSe NCs when using the alkylamine-H2 Se complex as Se precursor, as can be found in those reaction systems using traditional TOP-Se or ODE-Se precursors [2,3,4]

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