title: Efficiency improvement using bis(trifluoromethane) sulfonamide lithium salt as a chemical additive in porphyrin based organic solar cells.
abstract: Two new conjugated acceptor-π-donor-π-acceptor (A-π-D-π-A) porphyrins have been synthesised using 3-ethylrhodanine (1a) or dicyanovinylene (1b) groups as acceptor units. Their optical and electrochemical properties made these materials excellent electron donors along with PC71BM as the acceptor for solution-processed bulk heterojunction organic solar cells. The devices based on 1a:PC71BM (1 : 2) and 1b:PC71BM (1 : 2) processed with CB showed low power conversion efficiencies (PCE) of 2.30% and 2.80%, respectively. Nonetheless, after processing the active layer using a mixture of 3 vol% of a pyridine additive in THF, the PCE was enhanced up to 5.14% and 6.06% for 1a:PC71BM and 1b:PC71BM, respectively. Moreover, when we used LiTFSI as the chemical additive in pyridine/CB-processed 1b:PC71BM an excellent PCE of 7.63% was recorded. The effects over the film morphology and the device characteristics (Jsc, Vocand FF) due to the introduction of LiTFSI are discussed.
authors.affiliation: Universidad de Castilla-La Mancha, Institute of Nanoscience, Nanotechnology and Molecular Materials (INAMOL), Campus de la Fábrica de Armas, 45071-Toledo, Spain. Fernando.Langa@uclm.es and Escuela de Ingeniería Química, Facultad de Ingeniería, Universidad de San Carlos de Guatemala, Guatemala.
authors.forename: Susana
authors.initials: S
authors.lastname: Arrechea
authors.affiliation: Universidad de Castilla-La Mancha, Institute of Nanoscience, Nanotechnology and Molecular Materials (INAMOL), Campus de la Fábrica de Armas, 45071-Toledo, Spain. Fernando.Langa@uclm.es.
authors.forename: Ana
authors.initials: A
authors.lastname: Aljarilla
authors.affiliation: Universidad de Castilla-La Mancha, Institute of Nanoscience, Nanotechnology and Molecular Materials (INAMOL), Campus de la Fábrica de Armas, 45071-Toledo, Spain. Fernando.Langa@uclm.es.
authors.forename: Pilar
authors.initials: P
authors.lastname: de la Cruz
authors.affiliation: Institute of Chemical Research of Catalonia (ICIQ), The Barcelona Institute of Science and Technology, Avda. Països Catalans, 14, Tarragona, E-43007, Spain. epalomares@ICIQ.ES and ICREA, Passeig Lluis Companys, 23, Barcelona, E-08010, Spain.
authors.forename: Emilio
authors.initials: E
authors.lastname: Palomares
authors.affiliation: Department of Physics, The LNM Institute of Information Technology (Deemed University), Rupa ki Nagal, Jamdoli, Jaipur (Raj.) 302031, India. gdsharma273@gmail.com.
authors.forename: Ganesh D
authors.initials: GD
authors.lastname: Sharma
authors.affiliation: Universidad de Castilla-La Mancha, Institute of Nanoscience, Nanotechnology and Molecular Materials (INAMOL), Campus de la Fábrica de Armas, 45071-Toledo, Spain. Fernando.Langa@uclm.es.
authors.forename: Fernando
authors.initials: F
authors.lastname: Langa