Tenne Ron, Pedetti Silvia, Kazes Miri, Ithurria Sandrine, Houben Lothar, Nadal Brice, Oron Dan, Dubertret Benoit
Department of Physics of Complex Systems, Weizmann Institute of Science, 76100 Rehovot, Israel.
ESPCI ParisTech, PSL Research University, CNRS, Sorbonne Universités, UPMC Univ. Paris 6; LPEM, 10 rue Vauquelin, F-75231 Paris Cedex 5, France and Nexdot, 10 Rue Vauquelin, 75005 Paris, France.
Phys Chem Chem Phys. 2016 Jun 1;18(22):15295-303. doi: 10.1039/c6cp01177b.
Cadmium chalcogenide nanoplatelet (NPL) synthesis has recently witnessed a significant advance in the production of more elaborate structures such as core/shell and core/crown NPLs. However, controlled doping in these structures has proved difficult because of the restrictive synthetic conditions required for 2D anisotropic growth. Here, we explore the incorporation of tellurium (Te) within CdSe NPLs with Te concentrations ranging from doping to alloying. For Te concentrations higher than ∼30%, the CdSexTe(1-x) NPLs show emission properties characteristic of an alloyed material with a bowing of the band gap for increased concentrations of Te. This behavior is in line with observations in bulk samples and can be put in the context of the transition from a pure material to an alloy. In the dilute doping regime, CdSe:Te NPLs, in comparison to CdSe NPLs, show a distinct photoluminescence (PL) red shift and prolonged emission lifetimes (LTs) associated with Te hole traps which are much deeper than in bulk samples. Furthermore, single particle spectroscopy reveals dramatic modifications in PL properties. In particular, doped NPLs exhibit photon antibunching and emission dynamics significantly modified compared to undoped or alloyed NPLs.
近年来，硫族化镉纳米片（NPL）的合成在制备更精细的结构（如核壳和核冠NPL）方面取得了重大进展。然而，由于二维各向异性生长所需的合成条件受限，在这些结构中进行可控掺杂已被证明具有难度。在此，我们探索在CdSe NPL中掺入碲（Te），碲的浓度范围从掺杂到合金化。对于碲浓度高于约30%的情况，CdSexTe(1-x) NPL表现出合金材料的发射特性，随着碲浓度增加，带隙出现弯曲。这种行为与块状样品中的观察结果一致，并且可以在从纯材料到合金的转变背景下进行理解。在稀掺杂体系中，与CdSe NPL相比，CdSe:Te NPL表现出明显的光致发光（PL）红移和与碲空穴陷阱相关的延长发射寿命（LT），这些陷阱比块状样品中的要深得多。此外，单粒子光谱揭示了PL特性的显著变化。特别是，与未掺杂或合金化的NPL相比，掺杂的NPL表现出光子反聚束和发射动力学的显著改变。
