表面修饰的Q态纳米CdS的荧光性能研究

Fluorescence Properties of CdS Q-Nanoparticles Subjected to Proper Surface Modification

以硫醇为表面修饰剂 ,通过控制硫醇与Cd2 + 的比例 ,得到性能稳定的Q CdS ,而后将Q CdS与聚合物通过共混复合成膜 .通过荧光光谱研究了硫醇和聚合物对Q CdS的表面修饰作用 ,研究发现硫醇的长碳链有效阻止了CdS粒子间的团聚 ,碳链的增加导致Q CdS稳定性的增强 ,Q CdS的激子发射峰强度增大 ,且这种表面修饰效应随硫醇加入量的增大而增强 ,在一定硫醇加入量时的激子荧光发射强度达到最大 .由于介电局域效应 ,聚合物的加入使Q CdS的表面态荧光发光强度呈数量级增大 .另一方面 ,随着聚合物加入量的增加又会导致Q CdS的表面钝化 ,缺陷减小 ,表面态荧光发射峰相对减弱 。

CdS Q-nanoparticles were obtained by using n-octylthiol or dodecyl mercaptan as surface modifier, and Q-CdS/polymer nanocomposite films were gotten by mixing US Q-nanoparticles with polymer. Surface modification of Q-CdS with mercaptan and polymer was studied by fluorescent spectra. It was found that long carbon chain of mercaptan could effectively prevent the Q-CdS from reuniting and strengthen the stability of Q-CdS. The intensity of exciton emission peak (420 nm) in Q-CdS was increased as the carbon chain of mercaptan became longer. As the ratio of mercaptan to Cd2+ was changed, the intensity of exciton emission peak was also changed and the strongest emission intensity was gotten at certain ratio of mercaptan to Cd2+. Due to the dielectric local effect the intensity of surface emission peak (550 nm) in Q-CdS became 10 times stronger with the dispersion of Q-CdS nanoparticles into polymer than that of the single CdS Q-nanoparticle solution. On the other hand, with increase of the polymer content the intensity of surface emission peak in Q-CdS became to decrease reversely. Correspondingly the exciton emission peak began to appear and was gradually strengthened. It is because the polymer passivated the surface of Q-CdS and reduced the surface defect.