Photovoltaic properties of new cyanine–naphthalimide dyads synthesized by ‘Click’ chemistry

Two novel cyanine dyads, in which a naphthalimide unit is attached to benzoindole ring of unsymmetric trimethine cyanine, have been synthesized via ‘Click’ reaction and characterized by 1H NMR, 13C NMR, and MS-ESI. Under the illumination of AM 1.5 (75 mW cm−2), the power conversion efficiency of cyanine I reached 4.8% (Jsc = 14.5 mA cm−2, Voc = 0.50, FF = 0.49). The results show that the two cyanine dyes are promising sensitizers for nanocrystalline dye-sensitized solar cell.