title: Role of additional PCBM layer between ZnO and photoactive layers in inverted bulk-heterojunction solar cells.
abstract: In order to induce greater light absorption, nano-patterning is often applied to the metal-oxide buffer layer in inverted bulk-heterojunction(BHJ) solar cells. However, current homogeneity was significantly disturbed at the interface, leading to an efficiency that was not fully optimized. In this work, an additional PC61BM layer was inserted between the ZnO ripple and the photoactive layer to enhance the electron extraction. The insertion of additional PC61BM layer provided substantial advantages in the operation of inverted BHJ solar cells; specifically, it enhanced current homogeneity and lowered accumulation and trapping of photogenerated charges at the ZnO interface. Inclusion of the additional PC61BM layer led to effective quenching of electron-hole recombination by a reduction in the number of accumulated charges at the surface of ZnO ripples. This resulted in a 16% increase in the efficiency of inverted BHJ solar cells to 7.7%, compared to solar cells without the additional PC61BM layer.
authors.affiliation: Department of Physics and Energy Harvest Storage Research Center, University of Ulsan, Ulsan 680-749 (Republic of Korea).
authors.forename: Shinuk
authors.initials: S
authors.lastname: Cho
authors.affiliation: Department of Chemistry, Sungkyunkwan University, Suwon 440-746 (Republic of Korea).
authors.forename: Kwang-Dae
authors.initials: KD
authors.lastname: Kim
authors.affiliation: Surface Technology Division, Korea Institute of Materials Science, Changwon 641-010 (Republic of Korea).
authors.forename: Jinhee
authors.initials: J
authors.lastname: Heo
authors.affiliation: Surface Technology Division, Korea Institute of Materials Science, Changwon 641-010 (Republic of Korea).
authors.forename: Joo Yul
authors.initials: JY
authors.lastname: Lee
authors.affiliation: Surface Technology Division, Korea Institute of Materials Science, Changwon 641-010 (Republic of Korea).
authors.forename: Gihoon
authors.initials: G
authors.lastname: Cha
authors.affiliation: Surface Technology Division, Korea Institute of Materials Science, Changwon 641-010 (Republic of Korea).
authors.forename: Bo Yeol
authors.initials: BY
authors.lastname: Seo
authors.affiliation: Department of Chemistry, Sungkyunkwan University, Suwon 440-746 (Republic of Korea).
authors.forename: Young Dok
authors.initials: YD
authors.lastname: Kim
authors.affiliation: Department of Physics and Energy Harvest Storage Research Center, University of Ulsan, Ulsan 680-749 (Republic of Korea).
authors.forename: Yong Soo
authors.initials: YS
authors.lastname: Kim
authors.affiliation: Surface Technology Division, Korea Institute of Materials Science, Changwon 641-010 (Republic of Korea).
authors.forename: Si-young
authors.initials: SY
authors.lastname: Choi
authors.affiliation: Surface Technology Division, Korea Institute of Materials Science, Changwon 641-010 (Republic of Korea).
authors.forename: Dong Chan
authors.initials: DC
authors.lastname: Lim