Mass transport and charge transfer rates for Co(III)/Co(II) redox couple in a thin-layer cell

Graphene Nanoplatelets Doped with N at its Edges as Metal‐Free Cathodes for Organic Dye‐Sensitized Solar Cells

“…Extrapolations of both linear components of the CA plots intersect at the so-called transition time ( t trans ), which provides the diffusion coeffi cient D according to the Equation 4 and 5 . [ 39 ] …”

“…The overall cell resistance ( R CV ) can be deduced at low current densities. [ 39 ] The voltammogram of the NGnP5 dummy cell exhibits a steeper slope than that of the Pt cell, indicating that the R CV value of the NGnP5 cell is much lower (13.0 Ω cm 2 ) than that of the Pt cell (20.9 Ω cm 2 ). The R CV value of the NGnP5 cell is also similar to the value reported for commercial graphene nanoplatelets (GnPs) with a Co(bpy) 3 2+/3+ redox couple.…”

“…Shortly after the potential step, the current follows semi-infi nite Cottrell-like decay. [ 39 ] The current drops linearly with t −1/2 (where t is time) as long as the concentration profi les in front of each electrode merge to form a single linear profi le. At this stage, the current attains a steadystate value, which is equal to the limiting current.…”

Two Redox Couples are Better Than One: Improved Current and Fill Factor from Cobalt‐Based Electrolytes in Dye‐Sensitized Solar Cells

“…Because of the larger effective size of the cobalt complexes as compared to polyiodide species, the ion mobility of the cobalt complexes are considerably lower; in particular inside the mesoporous TiO 2 fi lm. [ 9,10 ] Recently, TiO 2 fi lms with a higher degree of porosity and larger pore size was proven to reduce the mass-transport problem. [ 11,12 ] However, for non-volatile solvent electrolytes, implicitly also of higher viscosity used in DSCs, mass transport is still a serious problem.…”

“…Another signifi cant challenge for cobalt-complex redox systems is the ineffi cient charge transfer at the counter electrode. [ 10 ] Most recent studies have focused on fi nding new materials to replace the traditional catalytic Pt on the counter electrode. Graphene, [ 13,14 ] PEDOT [ 15 ] and other materials, such as TiC, [ 16 ] etc., have proven better performance than platinized fl uorine-doped tin oxide (FTO) as counter electrode materials.…”