ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Optical, film surface and photovoltaic properties of PTB7-Fx-based polymer-organic solar cells prepared in ambient conditions

Georgy Grancharov, Valeria Gancheva, Petar Petrov, Rositsa Gergova, Georgi Popkirov, and Marushka Sendova-Vassileva

Bulgarian Academy of Sciences, Sofia, Bulgaria

E-mail: granchar@polymer.bas.bg

Abstract: Bulk heterojunction organic solar cells based on active layer of PTB7-Fx (x = 0–100), conjugated block copolymer incorporating benzo[1,2-b:4,5-b′]dithiophene and partly fluorinated thieno[3,4-b]thiophene units, and fullerene derivatives as phenyl C₆₁ and phenyl C₇₁ butyric acid methyl esters sandwiched between a transparent anode of indium tin oxide, a hole conducting layer of either poly(ethylene dioxythiophene) : polystyrene sulfonate or magnetron-sputtered molybdenum oxide and evaporated aluminum cathodes were fabricated. Polymer-organic thin films were prepared at 1:1.5 mass ratio of the donor:acceptor mixture and deposited from dichlorobenzene solution of different concentrations by spin coating in ambient conditions. To control the active layer morphology, the films were subjected either to post-deposition treatments (annealing) at different temperatures or incorporation of an additive such as diiodooctane. Optical transmission, film surface topography and thickness measurements were used to characterize the active layer. Test devices with the architecture described above were prepared and their current–voltage characteristics, quantum efficiency and impedance spectra were measured and used to compare the different active layers, architectures and deposition sequences.

Keywords: Polymer-organic solar cells ; Bulk heterojunction layers ; Polymer photovoltaics ; Current–voltage characteristics 

Full paper is available at www.springerlink.com.

DOI: 10.1007/s11696-018-0446-2

Chemical Papers 72 (7) 1669–1676 (2018)