Dye-sensitized solar cell (DSC) has been attracting much attention due to its high energy conversion efficiency and low production cost.In order to commercialize DSCs successfully,we need to further improve the efficiency.Many researches have been carried out so far.Our group has carried out systematic studies on the DSCs from fundamental to application since 2001,including modification of photoanode and development of new dyes and new catalysts,and design of new structure DSCs.In this paper,we will report the recent progress of the studies on improvement of efficiency in our group.In particular,the preparation of DSC materials with high performance and the fabrication of DSCs will be presented.And we will report that three classes (carbides,nitrides and oxides) of nano-scaled early transition metal catalysts were proposed to replace the expensive Pt catalyst as counter electrodes (CEs).The DSC based on the VC–MC CE reached high power conversion efficiency (PCE) of 7.63%,comparable to the photovoltaic performance of the DSC using Pt CE (7.50%).In addition,the carbide catalysts demonstrated catalytic activity higher than Pt for the regeneration of new organic redox couples.