Spirulina-derived residual groups as a special additive to modify the dyed-TiO2/electrolyte interface are introduced to enhance the photovoltaic performance. The interaction between the spirulina residual groups and surface of TiO2 films is investigated. It is found that spirulina extracts molecule split into several small fragments as Ti-O-CH2-OH anchoring on the surface of TiO2 by thermal treatment. Spirulina residual groups modified TiO2 photoanodes have a higher light-harvesting capacity and efficient electron transport. As a result, both the V-oc and J(sc) are improved by TiO2 photoanodes decorated with spirulina derived residual groups, with the short-circuit current of 10.17 mA cm(-2) corresponding to the photoelectric conversion efficiency of 4.26%, which is 33.1% higher than the blank DSSC. (C) 2016 Elsevier Ltd. All rights reserved.