Investigation of regeneration kinetics in quantum-dots-sensitized solar cells with scanning electrochemical microscopy.
A fast quantum dots (QDs) regeneration process is necessary for highly efficient QDs-sensitized solar cells. Herein, CdSe and CdS QDs regeneration rates (kQD') in three redox electrolytes, which are triiodide and iodide ions (I3(-)/I(-)), Co(bpy)3(PF6)2 and Co(bpy)3(PF6)3 (Co(3+)/Co(2+)), and 1-methy-1-H-tetrazole-5-thiolate and its dimer (T2/T(-)), have been first investigated with scanning electrochemical microscopy (SECM). The results reveal that the kinetics of QDs regeneration depends on the nature of the QDs and the redox shuttles presented in QDSSCs. For QDs of CdSe and CdS, the regeneration rate (kQD') in the case of a T2/T(-)-based electrolyte is about two times larger than that of Co(3+)/Co(2+) and I3(-)/I(-). Additionally, the kQD' for CdSe is about two times larger than that of CdS in the same redox shuttle electrolyte, which could be due to a large driving force for the reaction between the exited state quantum dots (QD(+)) and redox electrolytes.
Wuhan National Laboratory for Optoelectronics, School of Optoelectronic Science and Engineering, Huazhong University of Science and Technology , Wuhan 430074, P. R. China.
Bingyan
B
Zhang
Huailiang
H
Yuan
Xiaofan
X
Zhang
Dekang
D
Huang
Shaohui
S
Li
Mingkui
M
Wang
Yan
Y
Shen
interfacial charge transfer; quantum dots; regeneration kinetics; scanning electrochemical microscopy; solar cell