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, Cr3C2, CrN, VC(N), VN, TiC, TiC(N), TiN, and V2O3 all showed excellent catalytic activity for the reduction of I3– to I– in the electrolyte. Further, VC embedded in mesoporous carbon (VC–MC) was prepared through in situ synthesis. The I3–/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 T2/T–. The T2/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.

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, Cr3C2, CrN, VC(N), VN, TiC, TiC(N), TiN, and V2O3 all showed excellent catalytic activity for the reduction of I3– to I– in the electrolyte. Further, VC embedded in mesoporous carbon (VC–MC) was prepared through in situ synthesis. The I3–/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 T2/T–. The T2/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.

Herein, an organic redox couple 1-methy-1H-tetrazole-5-thiolate (T−) and its disulfide dimer (T2) redox shuttle, as an electrolyte, is introduced in a p-type dye-sensitized solar cell (DSC) on the basis of an organic dye (P1) sensitizer and nanocrystal CuCrO2 electrode. Using this iodide-free transparent redox electrolyte in conjunction with the sensitized heterojunction, we achieve a high open-circuit voltage of over 300 mV. An optimal efficiency of 0.23% is obtained using a CoS counter electrode and an optimized electrolyte composition under AM 1.5 G 100 mW cm−2 light illumination which, to the best of our knowledge, represents the highest efficiency that has so far been reported for p-type DSCs using organic redox couples.

Herein, an organic redox couple 1-methy-1H-tetrazole-5-thiolate (T−) and its disulfide dimer (T2) redox shuttle, as an electrolyte, is introduced in a p-type dye-sensitized solar cell (DSC) on the basis of an organic dye (P1) sensitizer and nanocrystal CuCrO2 electrode. Using this iodide-free transparent redox electrolyte in conjunction with the sensitized heterojunction, we achieve a high open-circuit voltage of over 300 mV. An optimal efficiency of 0.23% is obtained using a CoS counter electrode and an optimized electrolyte composition under AM 1.5 G 100 mW cm−2 light illumination which, to the best of our knowledge, represents the highest efficiency that has so far been reported for p-type DSCs using organic redox couples.