Single-Source Precursors for Lanthanide Diselenide Nanosheets
Single-Source Precursors for Lanthanide Diselenide Nanosheets
复制标题
DOI：
10.1021/acs.chemmater.9b03067
复制
发表时间：
2019-09-24
影响因子：
8.6
通讯作者：
Stoll, Sarah L.
中科院分区：
文献类型：
--
作者：
Atif, Rida;Zarkov, Aleksej;Stoll, Sarah L.
合成了一系列类型为[Ln(Se2P-（苯基）(2))(3)(CH3CN)(x)] （x = 1或2）的配合物，并对Ln = La-Lu（不包括Pm）进行了结构表征。该配合物易于制备和结晶，并且可溶于纳米颗粒合成中通常使用的溶剂中。这些配合物的固相热裂解形成镧系二硒化物或LnSe（2-x）纳米片，对于Ln = La-Ho，除了Eu形成EuSe。相比之下，最小的镧系元素Ln = Er-Lu形成了Ln(2)Se(3)纳米材料。镧系二硫族化合物是过渡金属二硫族化合物的稀土类似物，具有类似的性质，包括小带隙、电荷密度波、反铁磁性和超导性。镧系二硒化物纳米材料表现出高度的各向异性生长，除CeSe2（也形成氧化铈和超磷酸铈）外，其余均为相纯。基于透射电子显微镜（TEM）的横向纳米片尺寸在50到500 nm之间，原子力显微镜发现最薄的纳米片的厚度接近4 nm。通过粉末x射线衍射、扫描电镜和拉曼光谱对纳米片进行了进一步的表征。通过Sm和Gd配合物的联合溶液热裂解生成Sm1-xGdxSe1.8。通过粉末x射线衍射和透射电镜分析，发现合金成分均匀。
A series of complexes of the type [Ln(Se2P-(phenyl)(2))(3)(CH3CN)(x)] (x = 1 or 2) have been synthesized and structurally characterized for Ln = La-Lu (excluding Pm). The complexes are straightforward to prepare and crystallize and are soluble in solvents typically used in nanoparticle synthesis. Solution-phase thermolysis of these complexes formed lanthanide diselenide or LnSe(2-x) nanosheets, for Ln = La-Ho, except Eu, which formed EuSe. By contrast, the smallest lanthanides Ln = Er-Lu formed Ln(2)Se(3) nanomaterials. The lanthanide dichalcogenides are rare-earth analogues of the transition metal dichalcogenides and exhibit similar properties, including small band gaps, charge density waves, antiferromagnetism, and superconductivity. The lanthanide diselenide nanomaterials exhibited highly anisotropic growth and were phase pure with the exception of CeSe2 (which also formed a cerium oxide and cerium ultraphosphate). The lateral nanosheet dimensions, based on transmission electron microscopy (TEM), range from similar to 50 to 500 nm, and the thickness was found to be similar to 4 nm for the thinnest sheets by atomic force microscopy. The nanosheets were further characterized by powder X-ray diffraction, scanning electron microscopy, and Raman spectroscopy. Alloy formation was also demonstrated with the combined solution thermolysis of Sm and Gd complexes to form Sm1-xGdxSe1.8. The alloy was found to have homogeneous composition on the basis of powder X-ray diffraction and TEM.