Acta Phys. -Chim. Sin. ›› 2018, Vol. 34 ›› Issue (4): 424-436.doi: 10.3866/PKU.WHXB201709082

• ARTICLE • Previous Articles     Next Articles

Ultrafast Photoluminescence Dynamics of Organic Photosensitizers with Conjugated Linkers Containing Different Heteroatoms

Jiao LIU1,3,Jicun HUO1,3,Min ZHANG2,*(),Xiandui DONG1,*()   

  1. 1 Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, P. R. China
    2 Institute of New Energy Materials & Low-Carbon Technologies, Tianjin University of Technology, Tianjin 300384, P. R. China
    3 University of Chinese Academy of Sciences, Beijing 100049, P. R. China
  • Received:2017-08-15 Published:2018-01-02
  • Contact: Min ZHANG,Xiandui DONG E-mail:zm2016@email.tjut.edu.cn;dxd@ciac.ac.cn
  • Supported by:
    the National Science Foundation of China(51473158);the National Science Foundation of China(91233206)

Abstract:

The ultrafast photoluminescence dynamics of three organic dyes—C210, C214, and C216—with different conjugated linkers containing various heteroatoms, such as bifuran, bithiophene and biselenophene, in combination with dihexyloxy-substituted triphenylamine (TPA) as the electron donor and cyanoacrylic acid (CA) as the electron acceptor have been studied systematically. The excited-state dynamics of the three dyes were investigated in detail in different media: tetrahydrofuran (THF) and toluene (PhMe) solutions, polymethyl methacrylate (PMMA) and polystyrene (PS) polymer films, and the surfaces of alumina and titania films in contact with an ionic liquid composite electrolyte. These dyes were found to feature dynamic Stokes shifts in all the aforementioned media, indicating stepwise intramolecular relaxations of the non-equilibrium excited state. The electron injection yield was distinctly lower for the non-equilibrium excited state than the equilibrium excited states, which can be ascribed to the competition between torsional relaxation and electron injection. A broad time scale over one magnitude of order was presented for electron injection due to the great energy losses originating from the multiple torsional relaxations, which should be controlled for future dye design and device development. Moreover, despite the shorter lifetimes of the equilibrium excited states for C210 and C216 than C214, the electron injection yields of equilibrium excited states for all the dyes are comparable due to the accelerated electron injection rate.

Key words: Solar cells, Excited-state dynamics, Organic dyes, Ultrafast spectroscopy, Femtosecond fluorescence up-conversion

MSC2000: 

  • O644