表面修饰的Q态纳米CdS的荧光性能研究

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,而激子发射峰却增强.

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

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 CdS 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 Cd 2+ was changed, the intensity of exciton emission peak was also changed and the strongest emission intensity was gotten at certain ratio of mercaptan to Cd 2+. 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.