title: Investigation of dye regeneration kinetics in sensitized solar cells by scanning electrochemical microscopy.
abstract: Sensitizers are responsible for the light harvesting and the charge injection in dye-sensitized solar cells (DSSCs). A fast dye-regeneration process is necessary to obtain highly efficient DSSC devices. Herein, dye-regeneration rates of two DSSC device types, that is, the reduction of immediately formed photo-oxidized sensitizers (ruthenium complex C106TBA and porphyrin LD14, k(ox)') by iodide ions (I(-)) and [Co(bpy)3](2+), and the oxidation of formed photo-reduced sensitizers (organic dye P1, k(re)') by triiodide ions (I3(-)) and the disulfide dimer (T2) are investigated by scanning electrochemical microscopy (SECM). We provide a thorough experimental verification of the feedback mode to compare the kinetics for dye-regeneration by using the above mentioned mediators. The charge recombination at the dye/semiconductor/electrolyte interface is further investigated by SECM. A theoretical model is applied to interpret the current response at the tip under short-circuit conditions, providing important information on factors that govern the dynamics of dye-regeneration onto the dye-sensitized heterojunction.
authors.affiliation: Wuhan National Laboratory for Optoelectronics, School of Optoelectronic Science and Engineering, Huazhong University of Science and Technology, Luoyu Road 1037, Wuhan, 430074 (P.R. China), Fax: (+86) 27-86692225.
authors.forename: Bingyan
authors.initials: B
authors.lastname: Zhang
authors.forename: Xiaobao
authors.initials: X
authors.lastname: Xu
authors.forename: Xiaofan
authors.initials: X
authors.lastname: Zhang
authors.forename: Dekang
authors.initials: D
authors.lastname: Huang
authors.forename: Shaohui
authors.initials: S
authors.lastname: Li
authors.forename: Yibo
authors.initials: Y
authors.lastname: Zhang
authors.forename: Fang
authors.initials: F
authors.lastname: Zhan
authors.forename: Mingzhang
authors.initials: M
authors.lastname: Deng
authors.forename: Yahui
authors.initials: Y
authors.lastname: He
authors.forename: Wei
authors.initials: W
authors.lastname: Chen
authors.forename: Yan
authors.initials: Y
authors.lastname: Shen
authors.forename: Mingkui
authors.initials: M
authors.lastname: Wang
keywords: dye-regeneration; dye-sensitized solar cells; feedback mode; redox shuttle; scanning electrochemical microscopy