Surface passivation is the most significant step to keep the recombination loss at a tolerable minimum and avoid an unacceptably large efficiency loss when moving towards thinner silicon material. In this study, the modification and photosensitization on back surface field (BSF) of bifacial solar cell was investigated by using dye molecules nanostructure namely DiO. The DiO dye molecules nanostructure was passivated on SiNW and BSF layers using spin-coating method. The energy gaps of DiO dye are 2.14 eV (DiO in chloroform), 2.13 eV (DiO on silicon nanowire (SiNW)) and 2.12 eV (DiO on BSF). The time resolved photoluminescence increased with the DiO dye coated on SiNW ( 14Ï„"> = 1.24 nm) and BSF layers ( 14Ï„"> = 0.93 nm) compared to DiO dye in chloroform ( 14Ï„"> = 0.54 nm). The light trapping inside the interface layers of DiO dye/silicon indicating a slow process of charge recombination before its reach equilibrium states, it is due to interface interaction bonding within boundary layers and dye molecules nanostructure. The short circuit current density also increased about 25% from 4.44 to 5.56 mA/cm2 when applying the dye molecules nanostructure on BSF of the cell. Collection of photo carrier lead of internal and external quantum efficiency improved about 19% and 25%, respectively, is mainly due to energy transported to the junction. The photo-generated electron on DiO dye lead to improvement in the exciton dissociation efficiency leading to increase in the electrical properties.