title: Correlating excited state and charge carrier dynamics with photovoltaic parameters of perylene dye sensitized solar cells: influences of an alkylated carbazole ancillary electron-donor.
abstract: Two perylene dyes characteristic of electron-donors phenanthrocarbazole (PC) and carbazyl functionalized PC are selected to study the complicated dynamics of excited states and charge carriers, which underlie the photovoltaic parameters of dye-sensitized solar cells (DSCs). We have combined femtosecond fluorescence up-conversion and time-resolved single-photon counting techniques to probe the wavelength-dependent photoluminescence dynamics of dye molecules not only dissolved in THF but also grafted on the surface of oxide nanoparticles. Excited state relaxation and electron injection both occur on a similar timescale, resulting in a very distributive kinetics of electron injection. It is also found that the carbazyl ancillary electron-donor causes a faster electron injection, which over-compensates the adverse impact of a slightly shorter lifetime of the equilibrium excited state. Nanosecond transient absorption and transient photovoltage decay measurements have shown that conjugating carbazyl to PC can effectively slow down the kinetics of charge recombination of electrons in titania with both photo-oxidized dye molecules and triiodide anions, improving the cell photovoltage.
authors.affiliation: Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, China. min.zhang@ciac.ac.cn and University of Chinese Academy of Sciences, Beijing 100049, China.
authors.forename: Yang
authors.initials: Y
authors.lastname: Li
authors.affiliation: Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, China. min.zhang@ciac.ac.cn and University of Chinese Academy of Sciences, Beijing 100049, China.
authors.forename: Junting
authors.initials: J
authors.lastname: Wang
authors.affiliation: Department of Chemistry, Zhejiang University, Hangzhou 310028, China. pw2015@zju.edu.cn.
authors.forename: Yi
authors.initials: Y
authors.lastname: Yuan
authors.affiliation: Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, China. min.zhang@ciac.ac.cn.
authors.forename: Min
authors.initials: M
authors.lastname: Zhang
authors.affiliation: Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, China. min.zhang@ciac.ac.cn.
authors.forename: Xiandui
authors.initials: X
authors.lastname: Dong
authors.affiliation: Department of Chemistry, Zhejiang University, Hangzhou 310028, China. pw2015@zju.edu.cn.
authors.forename: Peng
authors.initials: P
authors.lastname: Wang