(ZnX)_3(X=S、Se和Te)量子点配体效应的密度泛函理论研究

Density functional theoretical study for ligands effects on (ZnX)_3( X = S,Se,Te) quantum dots

采用密度泛函理论研究了一系列含磷配体(OPH_3、OPH_2Me、OPHMe_2和OPMe_3)对量子点(ZnX)_3(X=S、Se、Te)结构和性质的影响.Zn原子与配体中的O原子生成新的Zn-O配位键,使量子点的结构、吸附能、电荷分布、吸收光谱和HOMO-LUMO轨道等性质随着配体中甲基数目逐渐增多发生规律性的改变.计算结果表明:有机配体三甲基氧膦(OPMe_3)是阻止小尺寸(ZnX)_3量子点聚集,保护此类量子点的较为有效的配体.

The structures and properties of the ligands-capped and bare （ZnX）3 quantum dots（QDs） were investigated by density functional theory（DFT） calculations. A new Zn–O coordination bond are formed between and Zn atom and O atoms in the ligands （OPH3、OPH2Me、OPHMe2 and OPMe3）. The geometrical structures, absorption energy, electron distribution, electronic absorption spectra and HOMO-LUMO orbital of the ligands-capped （ZnX）3 QDs are gradually different from those of bare （ZnX）3 QDs with increasing of CH3. OPMe3 has proven to be the effective ligands to prevent the small （ZnX）3 QDs from coalescence.