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.

Rational screening low-cost counter electrodes for dye-sensitized solar cells

“…Thus, several Pt-free alternative materials have been explored as CEs in DSCs, such as carbon materials 8,10 , conductive organic polymers 6,11 and inorganic semiconductor materials including metal sulfides 12,13 , metal nitrides 14,15 , metal carbides 16,17 , metal oxides 18 and copper zinc tin sulfide 19 and so on. Recently, Wu et al 20 synthesized three classes (carbides, nitrides and oxides) of nanoscaled earlytransition metal catalysts and applied them in DSC systems as CE catalysts to replace the expensive Pt. However, the rational screening for Pt-free alternative CE materials has not been explored, and the catalytic mechanism of electrocatalysis for triiodide reduction on the electrode surface has also not been fully understood so far.…”

Recent Advances in Optimization of Photoanodes and Counter Electrodes of Dye-Sensitized Solar Cells

“…Besides carbonaceous materials, certain other alternatives to Pt for fabrication of DSSC CEs have also been explored. Wu et al 21 studied the application of compounds of early transition metal (Ti, V, Mo, etc.) such as transition metal carbides (TMCs), transition metal nitrides (TMNs) and transition metal oxides (TMOs) in DSSC CEs.…”

“…TMCs, TMNs and TMOs displayed good catalytic activity closely resembling that of Pt and superior to the respective pure metals, a property attributed to the alteration of the electronic structure of the metal due to the alien C or N atoms. The photovoltaic parameters of the so-formed DSSCs as noted by Wu et al 21 are given in Table 1. It can be seen from the table that an appreciable PCE of 7.63% was achieved by a CE fabricated with VC-MC compared to the 7.5% PCE of a similar Pt-based CE.…”

Facile fabrication of novel silver-polypyrrole-multiwall carbon nanotubes nanocomposite for replacement of platinum in dye-sensitized solar cell

“…[1][2][3][4][5] The standard DSSC employ platinum as a counter electrode performing a key role to shift the electron from external circuit back to redox electrolyte that regenerates the excited dye. [6][7][8][9] Platinum is a precious metal often obtained by sputtering and thermal decomposition Although platinum exhibit high conductivity and excellent catalytic activity, however, its high cost and usage of complex vacuum system offer several limitations in a large scale production of DSSCs. [10][11][12] To bring down the production cost of DSSCs it is highly desirable to develop other low cost catalytic materials.…”