Effect of linker used in D-A-π-A metal free dyes with different π-spacers for dye sensitized solar cells

► Two organic dyes with different π-spacer based on dihioketopyrrole were synthesized. ► Dye having thiophene π-spacer have absorption band in longer wavelength region. ► Dye containing thiophene π-spacer gives power conversion efficiency of 4.81%. ► The power conversion efficiency further improved up to 6.34% with DCA as coadsorbant.