Effect of the Side Chains and Anode Material on Thermal Stability and Performance of Bulk-Heterojunction Solar Cells Using DPP(TBFu) 2 Derivatives as Donor Materials

Abstract

An optimized fabrication of bulk-heterojunction solar cells (BHJ SCs) based on previously reported diketopyrrolopyrrole donor,ethyl-hexylated DPP(TBFu)2,aswellastwonewDPP(TBFu)2derivatives with ethyl-hexyl acetate and diethyl acetal solubilizingside-chains and PC60BM as an acceptor is demonstrated. Slow gradual annealing of the solar cell causing the effective donor-acceptor reorganization, and as a result higher power conversion efficiency (PCE), is described. By replacing a hole transportinglayer PEDOT:PSS with MoO3we obtained higher PCE values as well as higher thermal stability of the anode contact interface.DPP(TBFu)2derivative containing ethyl-hexyl acetate solubilizing side-chains possessed the best as-cast self-assembly and highcrystallinity. However, the presence of ethyl-hexyl acetate and diethyl acetal electrophilic side-chains stabilizes HOMO energy ofisolated DPP(TBFu)2donors with respect to the ethyl-hexylated one, according to cyclic voltammetry. Effect of the Side Chains and Anode Material on Thermal Stability and Performance of Bulk-Heterojunction Solar Cells Using DPP(TBFu) 2 Derivatives as Donor Materials.An optimized fabrication of bulk-heterojunction solar cells (BHJ SCs) based on previously reported diketopyrrolopyrrole donor,ethyl-hexylated DPP(TBFu)2,aswellastwonewDPP(TBFu)2derivatives with ethyl-hexyl acetate and diethyl acetal solubilizingside-chains and PC60BM as an acceptor is demonstrated. Slow gradual annealing of the solar cell causing the effective donor-acceptor reorganization, and as a result higher power conversion efficiency (PCE), is described. By replacing a hole transportinglayer PEDOT:PSS with MoO3we obtained higher PCE values as well as higher thermal stability of the anode contact interface.DPP(TBFu)2derivative containing ethyl-hexyl acetate solubilizing side-chains possessed the best as-cast self-assembly and highcrystallinity. However, the presence of ethyl-hexyl acetate and diethyl acetal electrophilic side-chains stabilizes HOMO energy ofisolated DPP(TBFu)2donors with respect to the ethyl-hexylated one, according to cyclic voltammetry. Effect of the Side Chains and Anode Material on Thermal Stability and Performance of Bulk-Heterojunction Solar Cells Using DPP(TBFu) 2 Derivatives as Donor Materials.