Roles of adsorption sites in electron transfer from CdS quantum dots to molecular catalyst cobaloxime studied by time-resolved spectroscopy.
Electron transfer from CdS quantum dots (QDs) to cobaloxime (Co(dmgH)2pyCl) is demonstrated by transient absorption spectroscopy (TAS), and further confirmed using photoluminescence (PL) techniques. The analysis of the PL quenching results offers a novel way to understand the roles of the surface adsorption sites of CdS QDs in the performance of charge transfer in the CdS QDs-cobaloxime hybrid system. Two types of quenching dynamics reveal that there are two different adsorption modes of cobaloxime on the CdS QD surface. When cobaloxime substitutes the surface capping ligands of CdS QDs under low cobaloxime concentrations, the transfer is nearly unfavorable for both the free and trapped electrons. When cobaloxime occupies the surface defect sites of the CdS QDs under high cobaloxime concentrations, the transfer of both the free and trapped electrons is very effective, with an extremely high quenching rate constant of ∼10(12) M(-1) s(-1). Therefore, controlling the molecular adsorption sites and adjusting the surface defect properties of semiconductor QDs provide a strategy to improve the electron transfer efficiency of the QDs-cobaloxime photocatalytic system.
State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian National Laboratory for Clean Energy, Dalian 116023, China. xiuliwang@dicp.ac.cn canli@dicp.ac.cn and University of Chinese Academy of Sciences, Beijing 100049, China.
Yun
Y
Ye
State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian National Laboratory for Clean Energy, Dalian 116023, China. xiuliwang@dicp.ac.cn canli@dicp.ac.cn and University of Chinese Academy of Sciences, Beijing 100049, China.
Yuxing
Y
Xu
State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian National Laboratory for Clean Energy, Dalian 116023, China. xiuliwang@dicp.ac.cn canli@dicp.ac.cn.
Lei
L
Huang
State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian National Laboratory for Clean Energy, Dalian 116023, China. xiuliwang@dicp.ac.cn canli@dicp.ac.cn and University of Chinese Academy of Sciences, Beijing 100049, China.
Dayong
D
Fan
State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian National Laboratory for Clean Energy, Dalian 116023, China. xiuliwang@dicp.ac.cn canli@dicp.ac.cn.
Zhaochi
Z
Feng
State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian National Laboratory for Clean Energy, Dalian 116023, China. xiuliwang@dicp.ac.cn canli@dicp.ac.cn.
Xiuli
X
Wang
State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian National Laboratory for Clean Energy, Dalian 116023, China. xiuliwang@dicp.ac.cn canli@dicp.ac.cn.
Can
C
Li