Evolution of lateral structures during the functional stack build-up of P3HT:PCBM-based bulk heterojunction solar cells.
Bulk heterojunction (BHJ) solar cells from 1,2-dichlorobenzene solution processed regioregular poly(3-hexylthiophene-2,5-diyl) (P3HT): phenyl-C61-butyric acid methyl ester (PCBM) are prepared and investigated at different steps of the multilayer stack build-up of the device. The inner structure is probed from the molecular to the mesoscale with grazing incidence small/wide-angle X-ray scattering (GISAXS/GIWAXS) and X-ray reflectivity (XRR). The surface morphology is detected with atomic force microscopy (AFM). Therefore, an in-depth knowledge of the three-dimensional morphology of the bulk heterojunction solar cell, starting from the cleaned ITO substrate up to the final post-treated solar cell, is generated. The active layer structure is influenced by the annealing as well as by the top contact deposition. Structures coarsen during the evaporation of the metal contacts. The P3HT crystal structure strongly depends on the device processing as well. These morphological changes together with the diffusion of aluminum atoms to the active layer are of importance for the device efficiency.
Lehrstuhl für Funktionelle Materialien, Physik-Department, Technische Universität München , James-Franck-Strasse 1, 85748 Garching, Germany.
Shuai
S
Guo
Matthias A
MA
Ruderer
Monika
M
Rawolle
Volker
V
Körstgens
Christopher
C
Birkenstock
Jan
J
Perlich
Peter
P
Müller-Buschbaum
D037741:Fullerenes / Q000737:chemistry; D018625:Microscopy, Atomic Force; D053838:Scattering, Small Angle; D012993:Solar Energy; D013876:Thiophenes / Q000737:chemistry*; D017971:Tin Compounds / Q000737:chemistry; D014961:X-Ray Diffraction
D037741:Fullerenes; D013876:Thiophenes; D017971:Tin Compounds; C507295:poly(3-hexylthiophene); C109984:indium tin oxide