Ag-In-Zn-S四元半导体纳米晶的可控制备及其在电致发光二极管中的应用

Controllable Synthesis of Ag-In-Zn-S Quaternary Nanocrystals and Their Applications in Electroluminescent Light-emitting Diodes

Ag-In-Zn-S四元半导体纳米晶(以下简称AIZS NCs)不仅具有传统半导体纳米晶带隙可调、发光效率高等优异的发光特性,同时凭借其低毒和合成工艺简单等优点,在发光二极管、生物医学和光电转换等领域得到了广泛应用,成为传统镉基半导体纳米材料的有力竞争者之一。本文通过一步反应法制备出发光性能良好的AIZS NCs,并通过组分调控扩大其发光范围,使其发光颜色从绿光调至红光。在此基础上,采用注射法研究了AIZS NCs的形成过程,证明AIZS纳米晶的形成是阳离子交换反应发生的结果。为了进一步提高其发光性能,采用种子生长法继续在AIZS纳米晶中引入Zn源形成合金型AIZS-ZnS NCs,使其光致发光量子产率达到47%。最后,采用全溶液处理方法以AIZS-ZnS NCs作为发光层构筑了绿、黄和红三色电致发光二极管,其中黄光电致发光二极管的电流效率达到了1.07 cd·A^(-1)。

Ag-In-Zn-S quaternary semiconductor nanocrystals(AIZS NCs)not only have the excellent luminescent proeprties including the tunable optical band gap and high photoluminescence quantum yield and so on,but also possess low toxicity and simple synthesis technique.These NCs were widely used in the fields of light-emitting diodes,biomedicine,photoelectric conversion devices and so on,which was regarded as one of the substitutes for cadmium-based nanomaterials.In this paper,highly luminescent Ag-In-Zn-S NCs were synthesized by one-step reaction method,and the emission region was tuned effectively by varying the element ratios,which led to the emission color from green to red.On the basis of the reaction,the formation mechanism of AIZS NCs was studied through a hot-injection method,indicating that the partial cation exchange dominated the formation of AIZS NCs.In order to further optimize the luminescence performance,the alloyed AIZS-ZnS NCs were obtained by further incorporation of Zn source into AIZS NCs through a seeded-mediated growth method,which exhibited a high photoluminescent quantum yield of 47%.Finally,red,yellow and green electroluminescent light-emitting diodes were fabricated by using AIZS-ZnS NCs as the emissive layer,and the yellow device exhibited a current efficiency of 1.07 cd·A^(-1).