A non-platinum counter electrode, MnN sub(x)/C, for dye-sensitized solar cell applications

Abstract

A non-platinum metal catalyst, MnN sub(x)/C was synthesized via the high-pressure pyrolysis route. The combination of X-ray photoelectron spectroscopy (XPS) and X-ray absorption fine structure (XAFS) studies indicated the presence of Mn in +2 oxidation state surrounded by four N atoms. The peak-to-peak separation (Delta E sub(p)) of the more negative peak pair observed for I sub(3)sup(-)/I sup(-) redox couple over MnN sub(x)/C catalyst was 20 mV lower than that of the Pt catalyst, indicating high reversibility of the redox couple over MnN sub(x)/C catalyst. The charge transfer resistance of the MnN sub(x)/C electrode, as measured by the impedance spectroscopy, is approx. 2 Omega higher than that of Pt, which resulted slightly lower short circuit current (Jsc) value for MnN sub(x)/C over Pt, however the fill factor (FF) and power conversion efficiency (PCE) values of MnN sub(x)/C was slightly higher and comparable to that of Pt respectively. Hence; replacing Pt with MnN sub(x)/C would decrease the cost of DSSCs.