Carbonaceous materials as substitutes for conventional dye-sensitized solar cell counter electrodes

Abstract

Carbon structures present high surface area as well as low impedance, which lead to efficient solar cells.

Ruthenium nanofibers as efficient counter electrodes for dye-sensitized solar cells

“…The PVDF in the counter electrode could innovatively increase the adhesion between the Ru nanofibers and the FTO glass, leading to the improved physical stability of the counter electrode in DSSCs. [6,9,10]. The pastes were then squeeze-printed onto fluorine-doped SnO 2 glass (FTO, 8 Ω/square, Pilkington) and then dried at 100°C for 12 h. For comparison, the commercial Pt counter electrode was prepared from a solution containing chloroplatinic acid hydrate (H 2 PtCl·xH 2 O, Aldrich) and 2-propanol via spin coating and then annealed at 450°C for 0.5 h. For fabrication of a working electrode, the TiO 2 paste was formed by mixing TiO 2 (P25, Degussa AG), hydroxypropyl cellulose (HPC, Mw~80,000 g mol −1 , Aldrich), and acetyl acetone (Aldrich) in DI water.…”

“…Currently, Pt is typically used as the counter electrode because of its excellent electrocatalytic activity and high electrical conductivity [9]. However, Pt is very expensive and has limited availability [10]. Therefore, there is a desperate need to find an efficient alternative for Pt as the counter electrode material in DSSCs.…”

“…In recent years, the carbonaceous materials (activated carbon, carbon black, carbon nanotube, carbon nanofiber, and graphene), conducting polymers (PEDOT, PEDOT:PSS, PANI, and Ppy), transition metals (Co and Ni), metal and metalloid oxides (Al 2 O 3 , SnO 2 , SiO 2 , and Ga 2 O 3 ), metal sulfides (Co 9 S 8 , FeS 2 , SnS 2 , and NiS 2 ), metal carbides (TiC, Cr 3 C 2 , and VC) and metal nitrides (TiN, VN, and ZrN) have been used as counter electrodes in DSSCs [9][10][11][12][13][14]. Among them, the transition metals are the most promising choice for the use as the counter electrode due to their rapid redox reactions which owe to their high electrical conductivity [15][16][17].…”

“…Among these improvements, the counter electrode performs as the catalyst by reducing the redox species after electron injection and thereby regenerates the dye molecules [9,10]. Therefore, the ideal counter electrode in DSSCs should have a large number of electrochemical active sites, a low charge transfer resistance, and electrochemical stability [9][10][11][12]. Currently, Pt is typically used as the counter electrode because of its excellent electrocatalytic activity and high electrical conductivity [9].…”

“…The recent research and development of DSSCs has mainly focused on the improvement of their solar conversion efficiency. Among these improvements, the counter electrode performs as the catalyst by reducing the redox species after electron injection and thereby regenerates the dye molecules [9,10]. Therefore, the ideal counter electrode in DSSCs should have a large number of electrochemical active sites, a low charge transfer resistance, and electrochemical stability [9][10][11][12].…”