The effects of dye aggregation on the performance of organic dyes in dye-sensitized solar cells: From static model to molecular dynamics simulation.

Abstract The properties of three D1-π-D2-A dyes with dithiafulvenyl as donor (D1), phenothiazine as ancillary donor (D2), cyanoacrylic acid as acceptor along with different π groups, diphenyl for 1 , dithienyl for 2 , and thiopheneyl-benzothiadiazole for 3 , are studied. Besides the isolated dyes, the monomeric and dimeric adsorptions are also studied by combination of first principle and molecular dynamic simulations. There is no distinct difference among three dyes on the basis of only isolated dyes. When the dye-TiO 2 adsorption is considered, 3 is excluded because of its inferior items. However, it is still a difficult task to differentiate 1 and 2 even if the aggregation effect is included. The fluctuation of 1 is larger than that of 2 during the dynamic simulation resulting in the larger electronic coupling. The aggregation, especially for the aggregation during the dynamic simulation, is necessary to evaluate the performance of organic dye. Additionally, a new D-π-A dye 4 with the identical donor, π-bridge and acceptor is designed to compare with 2. 2 is totally superior to 4 indicating that suitable groups and appropriate configuration are both important to enhance the performance of organic dye. Graphical abstract fx1 [ABSTRACT FROM AUTHOR]