In
comparison with the traditional silicon-based solar cells,1
dye-sensitized solar cells (DSSCs) are one of the most promising
next-generation photovoltaic cells due to their versatile,
energy-saving, and environmentally friendly nature.
Therefore, DSSCs have attracted much attention since the
breakthrough made by Gr€atzel et al. in 1991.2 Several
ruthenium-based sensitizers, such as N3,3 N719,4 and black
dye,5 have achieved remarkable power conversion efficiency
of 10-11% under standard global air mass 1.5 (AM 1.5G)
illumination.