title: Small molecule based N-phenyl carbazole substituted diketopyrrolopyrroles as donors for solution-processed bulk heterojunction organic solar cells.
abstract: We report two acetylene-bridged small molecules DPP5 and DPP6 with low HOMO-LUMO gaps as donors along with PC71BM as an acceptor for the fabrication of solution-processed bulk heterojunction solar cells. After the optimization, i.e. weight ratio of donor to acceptor and surface treatment of the active layer, we achieved overall power conversion efficiencies up to 4.65% (Jsc = 8.19 mA cm(-2), Voc = 0.98 V and FF = 0.58) and 5.73% (Jsc = 9.58 mA cm(-2), Voc = 0.98 V and FF = 0.61), for DPP5:PC71BM and DPP6:PC71BM respectively, which are superior to those for the devices based on as-cast active layers. The significant change in the power conversion efficiency is attributed to the improvement in nanoscale morphology, balanced charge transport and charge collection efficiency, induced through the surface treatment.
authors.affiliation: Department of Chemistry, Indian Institute of Technology, Indore (MP) 452020, India.
authors.forename: Yuvraj
authors.initials: Y
authors.lastname: Patil
authors.affiliation: Department of Chemistry, Indian Institute of Technology, Indore (MP) 452020, India.
authors.forename: Rajneesh
authors.initials: R
authors.lastname: Misra
authors.affiliation: Department of Photonics, National Chiao Tung University, Hsinchu, Taiwan 300, Taiwan, Republic of China.
authors.forename: F C
authors.initials: FC
authors.lastname: Chen
authors.affiliation: Department of Physics, The LNM Institute of Information Technology (Deemed University), Jamdoli, Jaipur (Raj.), 302031, India. gdsharma273@gmail.com.
authors.forename: Ganesh D
authors.initials: GD
authors.lastname: Sharma