title: Solution-Processed p-Dopant as Interlayer in Polymer Solar Cells.
abstract: We report here an original approach to dope the semiconducting polymer-metal interface in an inverted bulk-heterojunction (BHJ) organic solar cell. Solution-processed 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane (F4-TCNQ), is deposited on top of a P3HT:PC61BM layer before deposition of the top electrode. Doping of P3HT by F4-TCNQ occurs after thermally induced diffusion at 100 °C of the latter into the BHJ. Diffusion and doping are evidenced by XPS and UV-vis-NIR absorption. XPS highlights the decrease in Fluorine concentration on top of the BHJ after annealing. In the same time, a charge transfer band attributed to doping is observed in the UV-vis-NIR absorption spectrum. Inverted polymer solar cells using solution-processed F4-TCNQ exhibit power conversion efficiency of nearly 3.5% after annealing. This simple and efficient approach, together with the low annealing temperature required to allow diffusion and doping, leads to standard efficiency P3HT:PC61BM polymer solar cells, which are suitable for printing on plastic flexible substrate.
authors.affiliation: Bordeaux INP, IMS, CNRS, UMR 5218, F-33400, Talence, France.|Université de Bordeaux, IMS, UMR 5218, F-33400, Talence, France.
authors.forename: F
authors.initials: F
authors.lastname: Guillain
authors.affiliation: Department of Electrical Engineering, Princeton University , Princeton, New Jersey 08544, United States.
authors.forename: J
authors.initials: J
authors.lastname: Endres
authors.affiliation: Université Bordeaux, ISM , Groupe de Spectroscopie Moléculaire, 33405 Talence, France.|Bordeaux INP, ISM, CNRS, UMR 5255, F-33405, Talence, France.
authors.forename: L
authors.initials: L
authors.lastname: Bourgeois
authors.affiliation: Department of Electrical Engineering, Princeton University , Princeton, New Jersey 08544, United States.
authors.forename: A
authors.initials: A
authors.lastname: Kahn
authors.affiliation: Bordeaux INP, IMS, CNRS, UMR 5218, F-33400, Talence, France.|Université de Bordeaux, IMS, UMR 5218, F-33400, Talence, France.
authors.forename: L
authors.initials: L
authors.lastname: Vignau
authors.affiliation: Bordeaux INP, IMS, CNRS, UMR 5218, F-33400, Talence, France.|Université de Bordeaux, IMS, UMR 5218, F-33400, Talence, France.
authors.forename: G
authors.initials: G
authors.lastname: Wantz
keywords: F4-TCNQ; doping; hole transport layer; polymer solar cells; solution-processing