Berlin 2015 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 60: Organic Electronics and Photovoltaics: OPV II (jointly with CPP, HL)
TT 60.7: Talk
Wednesday, March 18, 2015, 11:00–11:15, C 130
Effect of solvent vapor annealing on perylene-based solar cells — •Stefan Grob1, Mark Gruber1, Andrew Bartynski2, Theresa Linderl1, Mark Thompson2, and Wolfgang Brütting1 — 1University of Augsburg, Augsburg, Germany — 2University of Southern California, Los Angeles, USA
Diindenoperylene (DIP) and Tetraphenyldibenzoperiflanthene (DBP) are two common materials used in organic solar cell devices. While DIP is growing crystalline, showing good charge and exciton transport but only weak absorption, DBP exhibits an amorphous character, leading to lower carrier mobility and a short exciton diffusion length, however, DBP reveals a distinctly higher absorption. For both materials we investigate the influence of solvent vapor annealing (SVA) on solar cell performance. In general, SVA leads to a reorganization of the treated materials due to a partial re-solubilization of the layers, allowing the molecules to rearrange into structures characterized by a higher degree of order [1]. Though, for DBP, extended annealing times lead to a strong aggregation of the molecules, resulting in inhomogeneous layers unfavorable for solar cells. For DIP cells however, SVA leads to an increase in fill factor (FF) and also a slight increase in short-circuit current density (Jsc) due to interface roughening. Nevertheless, the best results are obtained by combining annealed DIP layers with strongly absorbing DBP and C70 on top. Thereby, we obtain the same increase in FF but a higher gain in Jsc, elevating the power conversion efficiency by almost 20 % up to more than 4 %.
[1] G. De Luca et al., J. Mater. Chem., 2010, 20, 2493-2498