[Mn(en)_3]_2·Sn_2Se_4Te_2的结构和光吸收性能

Synthesis, structure and reflectance spectra of [Mn(en)_3]_2·Sn_2Se_4Te_2

按照K_2Se:K_2Te_2:MnCl_2·4H_2O:SnCl_2·2H_2O:Se:乙二胺(en)=3.8:1:2:2:6:270的摩尔比配料,采用溶剂热法使原料混合物在180℃反应7d,得到黑色块状晶体[Mn(en)_3]_2·Sn_2Se_4Te_2。属于三斜晶系。空间群为P1,晶胞参数a=0.91428(7)nm,b=1.02781(7)nm,c=1.15745(8)nm,α=94.632(2)°,β=100.944(2)°,γ=115.918(1)°,V=0.94382(12)nm^3,Z=1。晶体由[Mn(en)_3]^(2+)和(Sn_2Se_4Te_2)^(4-)堆积而成。具有Zintl结构的特征。半导体[Mn(en)_3]_2·Sn_2Se_4Te_2的光学能隙(E_g)为2.2eV。当温度低于190℃时,[Mn(en)_3]_2·Sn_2Se_4Te_2晶体是稳定的。详细讨论了这类化合物的组成对晶体结构和光吸收性能的影响。

The compound [Mn(en)3]2·Sn2Se4Te2 was solvothermally synthesized by reacting K2Se, K2Te2, MnCI2·4H2O, SnCI2-2H2O, Se and 1,2-Ethylenediamine (en) in a molar ratio of 3.8 : 1:2:2:6: 270 at 180 ℃ for 7 days, and characterized by semi-quantitative elemental analysis, X-ray crystallography, diffuse reflectance spectroscopy and thermogravimetric analysis. The X-ray crystal structure determination reveals a zero-dimensional structure for the crystal which consist of [Sn2Se4Te2]4- ZintI anions as electron acceptor and complex cations [Mn (en)3]2+ as electron donor in 1 : 2 molar ratio. [Mn(en)3]2-Sn2Se4Te2 belongs to triclinic space group with the unit cell parameters, α = 0.91428(7) nm, b = 1.02781(7) nm, c = 1.15745(8) nm, α = 94.632(2)°,β= 100.944(2) °,γ = 115.918(1)°, V = 0.94382(12) nm3, Z = 1. Studies of diffuse reflectance spectra for the powder sample suggest that this compound is a semiconductor with an optical band gap of 2.2 eV, showing the characteristic of ZintI structure. The result of TG analysis indicates that [Mn(en)3]2-Sn2Se4Te2 is thermally stable up to 190 ℃. The effect of composition of the compound on crystal structure and optical energy gap has been explored.