title: Economical Pt-free catalysts for counter electrodes of dye-sensitized solar cells.
abstract: Three classes (carbides, nitrides and oxides) of nanoscaled early-transition-metal catalysts have been proposed to replace the expensive Pt catalyst as counter electrodes (CEs) in dye-sensitized solar cells (DSCs). Of these catalysts, Cr(3)C(2), CrN, VC(N), VN, TiC, TiC(N), TiN, and V(2)O(3) all showed excellent catalytic activity for the reduction of I(3)(-) to I(-) in the electrolyte. Further, VC embedded in mesoporous carbon (VC-MC) was prepared through in situ synthesis. The I(3)(-)/I(-) DSC based on the VC-MC CE reached a high power conversion efficiency (PCE) of 7.63%, comparable to the photovoltaic performance of the DSC using a Pt CE (7.50%). In addition, the carbide catalysts demonstrated catalytic activity higher than that of Pt for the regeneration of a new organic redox couple of T(2)/T(-). The T(2)/T(-) DSCs using TiC and VC-MC CEs showed PCEs of 4.96 and 5.15%, much higher than that of the DSC using a Pt CE (3.66%). This work expands the list of potential CE catalysts, which can help reduce the cost of DSCs and thereby encourage their fundamental research and commercial application.
authors.affiliation: State Key Laboratory of Fine Chemicals, Dalian University of Technology, No. 2 Linggong Road, Ganjingzi District, Dalian City, Liaoning Province, P. R. China 116024.
authors.forename: Mingxing
authors.initials: M
authors.lastname: Wu
authors.forename: Xiao
authors.initials: X
authors.lastname: Lin
authors.forename: Yudi
authors.initials: Y
authors.lastname: Wang
authors.forename: Liang
authors.initials: L
authors.lastname: Wang
authors.forename: Wei
authors.initials: W
authors.lastname: Guo
authors.forename: Daidi
authors.initials: D
authors.lastname: Qi
authors.forename: Xiaojun
authors.initials: X
authors.lastname: Peng
authors.forename: Anders
authors.initials: A
authors.lastname: Hagfeldt
authors.forename: Michael
authors.initials: M
authors.lastname: Grätzel
authors.forename: Tingli
authors.initials: T
authors.lastname: Ma