In this paper, we have developed a low temperature process to make two type of paste by using $TiO_2$ nanoparticles(P25). The interconnections between substrate and $TiO_2$ films or link between particles of free-binder paste(FP1, FP2, FP3) is very poor. Therefore, the Titanium(IV) isopropoxide was added to the TP paste to improve the interconnection. Electron transport time (${ au}_t$) and recombination time (${ au}_r$) are analyzed by IMPS (intensity-modulated photocurrent spectroscopy) and IMVS(Intensity-modulated photovoltage spectroscopy). In the results, ${ au}_t$ of TP paste based DSSCs (about $4.3{ imes}10^{-3}$) is faster than other samples. ${ au}_r$ is longer from $2.7{ imes}10^{-2}$ s of FP2 to $3.0{ imes}10^{-2}$ s of TP. A solar conversion efficiency (DSSCs) of TP is 3.54% for an incident solar energy of 100 mW $cm^{-2}$(meanwhile, 2.70% for DSSCs with FP2). The conversion efficiency is increased by 1.3 times.