The photovoltaic conversion systems based on photosynthesis have recently attracted much attention as alternative energy technology of the future. More interests are focused on the development of eco-friendly

cost-effective and safer dye-sensitized solar cells （DSSC）based on the principles and natural pigments of photosynthesis. Purple bacteria in anoxygenic phototrophic bacteria are good model systems for elucidating molecular mechanisms of photosynthesis. In this study

the photoelectrochemical properties of seven different natural photosynthetic pigments of bacteriochlorophyll a (BChl a) and carotenoids (Car) from Rhodopseudomonas palustris CQV97

Rhodobacter azotoformans R7 and Marichromatium sp. 283-1

and three modified BChl a derivatives were investigated in DSSC. The results showed that under the condition of simulated sunlight of 100 mW·cm-2 intensity and without addition of spacer

natural BChl a of 0.48 mg·ml-1 achieved better conversion efficiency of 1.26%. Purified rhodopin Car had higher conversion efficiency than that of mixture-Car and other purified Car. The absorption spectrum of TiO2 electrode sensitized by BChl a red-shifted

and the fluorescence at 800 nm could be quenched

indicating that the electron ejected by BChl a entered TiO2 conduction band. TiO2 electrode sensitized by co-sensitization of BChl a and rhodopin exhibited wide spectrum response in visible light and near-infrared region

the photocurrent and conversion efficiency of co-sensitized solar cells increased by 12% and 7.3% compared to BChl a. The photosynthetic pigments from purple bacteria are inexpensive and environment friendly

and are promising dye sensitizers due to higher light-harvesting capacity in near-infrared region. This study provides valuable information for fabricating visible light-infrared responsive solar cells.