title: Enhancement of recombination process using silver and graphene quantum dot embedded intermediate layer for efficient organic tandem cells.
abstract: High performance of organic tandem solar cell is largely dependent on transparent and conductive intermediate layer (IML). The current work reports the design and fabrication of an IML using a simple solution process. The efficiency of a homo-tandem device with poly(3-hexylthiophene):phenyl-C61-butyric acid methyl ester as an active layer and poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate)/poly(ethylenimine) as an IML was initially found to be 3.40%. Further enhancement of the cell efficiency was achieved using silver nanoparticles (Ag-NPs) of different sizes and graphene quantum dot embedded IML. A maximum efficiency of 4.03% was achieved using 7 nm Ag-NPs that contribute to a better recombination process. Also, the performance of the tandem cell was solely based on the electrical improvements indicated by the current - voltage measurements, external quantum efficiency and impedance analysis. The use of Ag-NPs in the IML has been shown to lengthen the life time of electron-hole pairs in the device. This study thus paves way to develop such efficient IMLs for more efficient tandem solar cells.
authors.affiliation: Department of Physics and Energy Harvest Storage Research Center, University of Ulsan, Ulsan 44610, S. Korea.
authors.forename: Nhu Thuy
authors.initials: NT
authors.lastname: Ho
authors.affiliation: Department of Chemical Engineering, University of South Carolina, Columbia, South Carolina 29208, USA.
authors.forename: Huynh Ngoc
authors.initials: HN
authors.lastname: Tien
authors.affiliation: Department of Physics and Energy Harvest Storage Research Center, University of Ulsan, Ulsan 44610, S. Korea.
authors.forename: Se-Joeng
authors.initials: SJ
authors.lastname: Jang
authors.affiliation: Department of Physics and Energy Harvest Storage Research Center, University of Ulsan, Ulsan 44610, S. Korea.
authors.forename: Velusamy
authors.initials: V
authors.lastname: Senthilkumar
authors.affiliation: Measurement and Analysis Division, National Nanofab Center, Daejeon 34141, S. Korea.
authors.forename: Yun Chang
authors.initials: YC
authors.lastname: Park
authors.affiliation: Department of Physics and Energy Harvest Storage Research Center, University of Ulsan, Ulsan 44610, S. Korea.
authors.forename: Shinuk
authors.initials: S
authors.lastname: Cho
authors.affiliation: Department of Physics and Energy Harvest Storage Research Center, University of Ulsan, Ulsan 44610, S. Korea.
authors.forename: Yong Soo
authors.initials: YS
authors.lastname: Kim