| AVS 60th International Symposium and Exhibition | |
| Electronic Materials and Processing | Thursday Sessions |
| Session EM+AS+EN+TF-ThM |
| Session: | Hybrid and Organic Electronics |
| Presenter: | F. Schreiber, University of Tuebingen, Germany |
| Correspondent: | Click to Email |
Functional organic materials and devices are becoming increasingly complex. Their preparation and growth is, not surprisingly, similarly complex, and the resulting structure will be determined by a competition between kinetics and thermodynamics, which is not trivial to predict in particular for multi-component systems. We discuss general concepts [1] and recent examples [2,3] of organics-based heterostructure growth in the context of kinetic effects compared to thermodynamic (equilibrium) structure.
These include unconventional roughening and smoothing behavior at interfaces as well as unconventional structural motifs, such as a frozen-smectic structure formed in a blend of organic semiconductors which form conventional crystals as pure compounds [4].
Particular attention is paid to the case of kinetically limited phase separation of a donor-acceptor pair (DIP:C60) used in organic photovoltaics [5]. This leads to asymmetric domain sizes near bottom vs top electrode due to the time (thickness) dependent phase separation with important implications for device modeling [1,6].
We also discuss the associated optical properties and the question of coupling between donor and acceptor components [7,8]. Finally, we comment on the implications for the optical and electronic properties as well as possible device applications with focus on organic photovoltaics [1,6].
Contributions by A. Hinderhofer, C. Frank, K. Broch, F. Anger, J. Novak, R. Banerjee, A. Gerlach, and S. Kowarik, are gratefully acknowledged.
[1] A. Hinderhofer and F. Schreiber, Organic-organic heterostructures: Concepts and applications, ChemPhysChem, 13 (2012) 628
[2] A. Hinderhofer et al., Templating effect for organic heterostructure film growth: Perfluoropentacene on diindenoperylene, J. Phys. Chem. C 115 (2011) 16155
[3] A. Hinderhofer et al., Structure and morphology of co-evaporated pentacene-perfluoropentacene thin films, J. Chem. Phys. 134 (2011) 104702
[4] A. Aufderheide et al., Mixing-induced anisotropic correlations in molecular crystalline systems, Phys. Rev. Lett. 109 (2012) 156102
[5] R. Banerjee et al., Evidence for kinetically limited thickness dependent phase separation in organic thin film blends, Phys. Rev. Lett. (2013)
[6] J. Wagner et al., High fill factor and open circuit voltage in organic photovoltaic cells with diindenoperylene as donor material, Adv. Funct. Mater. 20 (2010) 4295
[7] K. Broch et al., Optical evidence for intermolecular coupling in mixed films of pentacene and perfluoropentacene, Phys. Rev. B 83 (2011) 245307
[8] F. Anger et al., Photoluminescence spectroscopy of pure pentacene, perfluoropentacene and mixed thin films, J. Chem. Phys. 136 (2012) 054701