K_2CuIn_3Se_6的固相合成、晶体结构和性能

Solid-state synthesis of K_2CuIn_3Se_6 and its crystal structure and characterization

采用反应性熔盐法以n(K2 Se3 )∶n(Cu)∶n(In)∶n(Se) =2∶2∶1∶6的摩尔比 ,在 773K下反应 5d ,得到四元金属硒化物K2 CuIn3 Se6。该晶体属于单斜晶系 ,空间群为C2 /c ,晶胞参数a =1 1 4 84 (2 )nm ,b =1 1 4 5 8(2 )nm ,c =2 1 32 7(4 )nm ,β =97 81 (3)° ,V =2 780 2 (1 )nm3 ,Z =8。K2 CuIn3 Se6具有层状结构 ,含有二维共价结构的负离子 ,2 ∞ [CuIn3 Se6]2 -。2 ∞ [CuIn3 Se6]2 -由配位四面体 [CuSe4]和 [InSe4]共顶点连接而成。2 ∞ [CuIn3 Se6]2 -和K+ 以静电力堆积成晶体。漫反射光谱研究表明 ,该晶体具有 1 6eV的光学能隙 ,属于半导体 ,对太阳能有选择吸收的特性。

K 2CuIn 3Se 6 was synthesized in a mole ratio of n (K 2Se 3)∶ n (Cu)∶ n (In)∶ n (Se)=2∶2∶1∶6 by a molten salt (alkali metal polyselenide flux) reaction at 700?K for five days. The orange red granular crystal crystallized in the monoclinic space group C2/c with cell parameters, a =1 148?4(2)?nm, b =1 145?8(2)?nm, c =2 132?7(4)?nm, β =97 81(3)°, V =2 780?2(1)?nm 3 and Z =8. K 2CuIn 3Se 6 has a new two dimensional layered structure containing 2∞[CuIn 3Se 6] 2- anionic layers separated by K + cations. The 2∞[CuIn 3Se 6] 2- layer is constructed with corner shared and tetrahedra. The optical band gap of K 2CuIn 3Se 6 was determined by UV/vis/NIR diffuse reflectance spectra approximately to be 1 6?eV. It is a kind of semiconductor which possesses selective absorptivity to solar radiation.