Reducing mass-transport limitations in cobalt-electrolyte-based dye-sensitized solar cells by photoanode modification.
Mass transport has been identified as a limiting problem in the photovoltaic performance of dye-sensitized solar cells based on electrolytes consisting of ionic liquids or cobalt complexes. A mixed TiO2 macroporous-mesoporous morphology employed as photoanode is demonstrated to assist the diffusion of electrolytes with higher viscosity or consisting of bulky redox mediators, such as cobalt di-tert-butyl bipyridine [Co(dtb)3](2+/3+). This morphology with large pores improves the non-linearity of photocurrent response to light intensity indicating better diffusion. The incorporated sub-micrometer pores also reduce recombination and decrease diffusion resistance, as revealed by electrochemical impedance spectroscopy.
Energy Research Institute @ NTU (ERI@N), Nanyang Technological University, 1 CleanTech Loop, 06-04 CleanTech One, Singapore 637141 (Singapore); Division of Materials Technology, School of Materials Science and Engineering, Nanyang Technological University, Block N4.1 Nanyang Avenue, Singapore 639798 (Singapore).
Thi Thu
TT
Trang Pham
Teck Ming
TM
Koh
Kazuteru
K
Nonomura
Yeng Ming
YM
Lam
Nripan
N
Mathews
Subodh
S
Mhaisalkar
TiO2; cobalt electrolyte; dye-sensitized solar cells; impedance; mesoporous materials