本文使用稳态及时间分辨发光光谱研究CdS量子点钴肟(CoⅢ(dmgH)2(3-(OH)py)Cl)分子耦合光催化产氢体系中CdS量子点粒径大小在CdS-钴肟分子间电荷转移中的作用。粒径为3.9,4.4 和5.0 nm的CdS量子点都表现出带边发光及长波处的橙色缺陷发光。随CdS量子点粒径的减小,带边发光减弱,缺陷发光增强,且小粒径量子点表现出了更长的发光寿命。钴肟分子的引入迅速猝灭CdS量子点的带边发光和缺陷发光,且缺陷发光的猝灭常数比带边发光更大。CdS量子点的粒径越小,发光猝灭的效率越高。这些结果证明,CdS量子点的自由载流子和束缚载流子都可以转移到钴肟分子上,且束缚载流子的转移效率更高。CdS量子点粒径越小,CdS向钴肟分子的光生电荷转移效率越高。

In this work,steady-state and time-resolved photoluminescence(PL)spectroscopy were applied to study the effects of CdS particle size on the charge transfer between CdS quantum dots(QDs)and cobaloxime(CoⅢ(dmgH)2(3-(OH)py)Cl)in CdS QDs-cobaloxime hybrid photocatalytic hydrogen production system.All three kinds of CdS QDs with different particle size(3.9,4.4 and 5.0 nm)show a band-edge emission and a broad trap-related emission.When the particle size of CdS QDs is smaller,the band-edge emissionintensity is reduced while the trap-related emission enhanced,and CdS QDs with smaller particle size exhibit longer emission lifetime.Upon mixing with cobaloxime,the band-edge emission and trap-related emission of CdS QDs are quenched quickly,and the quenching constant of the trap-related emission is bigger than that of the band-edge emission.The emission intensity of CdS QDs is quenched more efficiently with the particle size decreasing.These results demonstrate that,both the free and trapped charge carriers of CdS QDs could transfer to cobaloxime,and the trapped ones transfer to cobaloxime more efficiently; CdS QDs with smaller particle size exhibit higher charge transfer efficiency.