A novel TiO2 film photoanode decorated with spirulina-derived residual groups for enhanced photocurrent in dye-sensitized solar cells

•Spirulina extract fragments anchor on the surface of TiO2 by thermal treatment.•Spirulina-derived residual groups help anchor dye to enhance light adsorption.•TiO2 films are decorated with spirulina for improving photocurrent.

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 TiOCH2OH 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 Voc and Jsc 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.