Cation-inverting-injection: a novel method for synthesis of aqueous ZnSe quantum dots with bright excitionic emission and suppressed trap emission
Cation-inverting-injection: a novel method for synthesis of aqueous ZnSe quantum dots with bright excitionic emission and suppressed trap emission
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DOI：
10.1088/0957-4484/25/29/295602
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发表时间：
2014-07
期刊：
影响因子：
3.5
通讯作者：
Yanbin Wang;Chunlei Wang;Shuhong Xu;Zhuyuan Wang;Yiping Cui
中科院分区：
文献类型：
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作者：
Yanbin Wang;Chunlei Wang;Shuhong Xu;Zhuyuan Wang;Yiping Cui
在传统的水相锌硒量子点的合成方法中，高活性的硒单体在室温下被快速注入到锌-硫醇络合物溶液中，导致所制备的锌硒量子点的激发发光较差，陷阱发射严重。在本论文中，我们发展了一种新的阳离子反相注入方法来制备具有明亮激发发光的水相锌硒量子点。在该方法中，首先在反应溶液中稀释高活性的硒单体，然后在较高的反应温度(90°C)下缓慢滴下低活性的锌硫醇络合物。阳离子反转注入法中单体注入顺序的颠倒、单体反应性的抑制以及较高的成核温度有助于低浓度但高质量的锌硒晶核的形成，从而促进大颗粒、高激子发射和弱陷阱发射的锌硒量子点的形成。所制备的ZnSe量子点表现出强烈的深蓝色激子发射，这是第一个报道的可见激子发射而不是直接在水介质中合成的ZnSe量子点产生的陷阱发射的情况。使用三种染料，通过两种测量方法，测得所制备的ZnSe量子点的精确光致发光量子产率为15%，这是在水介质中合成的巯基羧酸稳定的ZnSe量子点的新记录。
In the conventional synthesis of aqueous ZnSe quantum dots (QDs), highly reactive Se monomers are rapidly injected into a Zn-thiol complexes solution at room temperature, resulting in a poor excitionic luminescence and a serious trap emission of as-prepared ZnSe QDs. In this paper, we develop a novel cation-inverting-injection method to prepare aqueous ZnSe QDs with a bright excitionic luminescence. In this method, highly reactive Se monomers are first diluted in the reaction solution, followed by low-reaction Zn-thiol complexes slowly dropped at a high reaction temperature (90 °C). The inverting monomer injection order, the suppressed monomer reactivity and the high nucleation temperature in the cation-inverting-injection method can contribute to low-concentration but high-quality ZnSe nuclei, thereby promoting the formation of ZnSe QDs with large-sized particles, a high excitionic emission and a weak trap emission. As-prepared ZnSe QDs exhibit an intense deep-blue excitionic emission, which is the first reported case of a visible excitionic emission instead of a trap emission resulting from ZnSe QDs that are directly synthesized in an aqueous media. Using three types of dyes, via two measuring methods, the accurate photoluminescence quantum yield of the as-prepared ZnSe QDs is measured as 15%, which is a new record for mercaptocarboxylic acid stabilized ZnSe QDs synthesized in an aqueous media.