Small conjugated molecules (SM) are gaining momentum as an alternative to semiconducting polymers for the production of solution-processed bulk heterojunction (BHJ) solar cells. The major issue with SM-BHJs is the low carrier mobility due to the scarce control on the phase-segregation process and consequent lack of preferential percolative pathways for electrons and holes to the extraction electrodes. Here, a new paradigm for fine tuning the phase-segregation in SM-BHJs, based on the post-deposition exploitation of latent hydrogen bonding in binary mixtures of PCBM with suitably functionalized electron donor molecules, is demonstrated. The strategy consist in the chemical protection of the H-bond forming sites of the donor species with a thermo-labile functionality whose controlled thermal cleavage leads to the formation of stable, crystalline, phase-separated molecular aggregates. This approach allows the fine tuning of the nanoscale film connectivity and thereby to simultaneously optimize the generation of geminate carriers at the donor-acceptor interfaces and the extraction of free charges via ordered phase-separated domains. As a result, the PV efficiency undergoes an over twenty-fold increase with respect to control devices. This strategy, demonstrated here with mixtures of diketopyrrolopyrrole derivatives with PCBM can be extended to other molecular systems for achieving highly efficient SM-BHJ solar cells
Bruni, F., Sassi, M., Campione, M., Giovanella, U., Ruffo, R., Luzzati, S., et al. (2014). Post-deposition Activation of Latent Hydrogen-Bonding: A New Paradigm for Enhancing the Performances of Bulk Heterojunction Solar Cells. ADVANCED FUNCTIONAL MATERIALS, 24(47), 7410-7419 [10.1002/adfm.201400896].
Citazione: | Bruni, F., Sassi, M., Campione, M., Giovanella, U., Ruffo, R., Luzzati, S., et al. (2014). Post-deposition Activation of Latent Hydrogen-Bonding: A New Paradigm for Enhancing the Performances of Bulk Heterojunction Solar Cells. ADVANCED FUNCTIONAL MATERIALS, 24(47), 7410-7419 [10.1002/adfm.201400896]. | |
Tipo: | Articolo in rivista - Articolo scientifico | |
Carattere della pubblicazione: | Scientifica | |
Presenza di un coautore afferente ad Istituzioni straniere: | No | |
Titolo: | Post-deposition Activation of Latent Hydrogen-Bonding: A New Paradigm for Enhancing the Performances of Bulk Heterojunction Solar Cells | |
Autori: | Bruni, F; Sassi, M; Campione, M; Giovanella, U; Ruffo, R; Luzzati, S; Meinardi, F; Beverina, L; Brovelli, S | |
Autori: | ||
Data di pubblicazione: | 2014 | |
Lingua: | English | |
Rivista: | ADVANCED FUNCTIONAL MATERIALS | |
Digital Object Identifier (DOI): | http://dx.doi.org/10.1002/adfm.201400896 | |
Appare nelle tipologie: | 01 - Articolo su rivista |