title: Enhanced charge separation in ternary P3HT/PCBM/CuInS2 nanocrystals hybrid solar cells.
abstract: Geminate recombination of bound polaron pairs at the donor/acceptor interface is one of the major loss mechanisms in organic bulk heterojunction solar cells. One way to overcome Coulomb attraction between opposite charge carriers and to achieve their full dissociation is the introduction of high dielectric permittivity materials such as nanoparticles of narrow band gap semiconductors. We selected CuInS2 nanocrystals of 7.4 nm size, which present intermediate energy levels with respect to poly(3-hexylthiophene) (P3HT) and Phenyl-C61-butyric acid methyl ester (PCBM). Efficient charge transfer from P3HT to nanocrystals takes place as evidenced by light-induced electron spin resonance. Charge transfer between nanocrystals and PCBM only occurs after replacing bulky dodecanethiol (DDT) surface ligands with shorter 1,2-ethylhexanethiol (EHT) ligands. Solar cells containing in the active layer a ternary blend of P3HT:PCBM:CuInS2-EHT nanocrystals in 1:1:0.5 mass ratio show strongly improved short circuit current density and a higher fill factor with respect to the P3HT:PCBM reference device. Complementary measurements of the absorption properties, external quantum efficiency and charge carrier mobility indicate that enhanced charge separation in the ternary blend is at the origin of the observed behavior. The same trend is observed for blends using the glassy polymer poly(triarylamine) (PTAA).
authors.affiliation: 1] Univ. Grenoble Alpes, F-38000 Grenoble, France [2] CEA-INAC-SPrAM-LEMOH, F-38000 Grenoble, France [3] CNRS UMR5819 SPrAM, F-38000 Grenoble, France.
authors.forename: Aurélie
authors.initials: A
authors.lastname: Lefrançois
authors.affiliation: 1] Univ. Grenoble Alpes, F-38000 Grenoble, France [2] CEA-INAC-SPrAM-LEMOH, F-38000 Grenoble, France [3] CNRS UMR5819 SPrAM, F-38000 Grenoble, France [4] CEA-Liten-DTNM, 17 rue des Martyrs, F-38000 Grenoble, France.
authors.forename: Beata
authors.initials: B
authors.lastname: Luszczynska
authors.affiliation: 1] Univ. Grenoble Alpes, F-38000 Grenoble, France [2] CEA-INAC-SPrAM-LEMOH, F-38000 Grenoble, France [3] CNRS UMR5819 SPrAM, F-38000 Grenoble, France.
authors.forename: Brigitte
authors.initials: B
authors.lastname: Pepin-Donat
authors.affiliation: 1] Univ. Grenoble Alpes, F-38000 Grenoble, France [2] CEA-INAC-SPrAM-LEMOH, F-38000 Grenoble, France [3] CNRS UMR5819 SPrAM, F-38000 Grenoble, France.
authors.forename: Christian
authors.initials: C
authors.lastname: Lombard
authors.affiliation: CEA-Liten-DTNM, 17 rue des Martyrs, F-38000 Grenoble, France.
authors.forename: Benjamin
authors.initials: B
authors.lastname: Bouthinon
authors.affiliation: CEA-Liten-DTNM, 17 rue des Martyrs, F-38000 Grenoble, France.
authors.forename: Jean-Marie
authors.initials: JM
authors.lastname: Verilhac
authors.affiliation: 1] Univ. Grenoble Alpes, F-38000 Grenoble, France [2] CEA-INAC-SCIB-RICC, F-38000 Grenoble, France.
authors.forename: Marina
authors.initials: M
authors.lastname: Gromova
authors.affiliation: 1] Univ. Grenoble Alpes, F-38000 Grenoble, France [2] CEA-INAC-SPrAM-LEMOH, F-38000 Grenoble, France [3] CNRS UMR5819 SPrAM, F-38000 Grenoble, France.
authors.forename: Jérôme
authors.initials: J
authors.lastname: Faure-Vincent
authors.affiliation: 1] Univ. Grenoble Alpes, F-38000 Grenoble, France [2] CEA-SP2M-SGX, F-38000 Grenoble, France.
authors.forename: Stéphanie
authors.initials: S
authors.lastname: Pouget
authors.affiliation: 1] Univ. Grenoble Alpes, F-38000 Grenoble, France [2] CEA-INAC-SPrAM-LEMOH, F-38000 Grenoble, France [3] CNRS UMR5819 SPrAM, F-38000 Grenoble, France.
authors.forename: Frédéric
authors.initials: F
authors.lastname: Chandezon
authors.affiliation: 1] Univ. Grenoble Alpes, F-38000 Grenoble, France [2] CEA-INAC-SPrAM-LEMOH, F-38000 Grenoble, France [3] CNRS UMR5819 SPrAM, F-38000 Grenoble, France.
authors.forename: Saïd
authors.initials: S
authors.lastname: Sadki
authors.affiliation: 1] Univ. Grenoble Alpes, F-38000 Grenoble, France [2] CEA-INAC-SPrAM-LEMOH, F-38000 Grenoble, France [3] CNRS UMR5819 SPrAM, F-38000 Grenoble, France.
authors.forename: Peter
authors.initials: P
authors.lastname: Reiss