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采用化学腐蚀法制备碳化硅(SiC)量子点荧光材料,对其进行Fourier变换红外光谱分析及X射线粉末衍射结构解析,研究了SiC量子点的晶体结构,而后基于密度泛函理论的CASTEP平面波模守恒赝势对SiC量子点表面不同功能团的吸附机制进行计算模拟。结果表明:SiC量子点属于面心立方晶系,修正后的点阵参数为:a=b=c=0.434 8 nm,α=β=γ=90°,空间群为F-43m,晶型为3C-SiC,每单胞含化学式Z=4。Rietveld精修的2个主要可靠因子分别为:R_p=10.82%,R_(wp)=14.72%。–COOH、–OH功能团能够在SiC量子点表面形成稳定的化学键结合,键能分别为2.65、5.09 eV,并对吸附后构型的态密度、电子密度分布及其成键机理进行了分析探讨。
The silicon carbide (SiC) quantum dot fluorescent material was prepared by chemical etching method, Fourier transform infrared spectroscopy analysis and X-ray powder diffraction structure analysis were carried out, the crystal structure of SiC quantum dots was studied, and then the CASTEP plane mode based on density functional theory Convergent pseudopotential is used to simulate the adsorption mechanism of different functional groups on the surface of SiC quantum dots. The results show that the SiC quantum dots belong to the face-centered cubic system. The modified lattice parameters are: a = b = c = 0.434 8 nm, α = β = γ = 90 °, space group F- 3C-SiC, per unit cell with chemical formula Z = 4. Rietveld refined the two main reliability factors are: R_p = 10.82%, R_ (wp) = 14.72%. The -COOH and -OH functional groups can form stable chemical bonds on the surface of SiC quantum dots with bond energies of 2.65 and 5.09 eV, respectively. And the state density, electron density distribution and bond formation mechanism of the adsorbed structures are discussed .