Proceedings of 6th International Conference on Hybrid and Organic Photovoltaics (HOPV14)
Publication date: 1st March 2014
Many diketopyrrolopyrrole based polymers feature an additional low energy shoulder next to the main absorption peak in the UV/vis absorption spectra. We show that this additional shoulder is due to homo-coupling defects originating from a side reaction of the DPP2TBr2 monomers used in the palladium catalyzed polymerization reaction. PDPPTPT has been used as a model system to investigate the influence of these homo-coupling defects on the photovoltaic performance. We have compared polymers that were synthesized with optimal and suboptimal reaction conditions, yielding polymers with and without defects. Additionally, polymers were synthesized where a fixed amount of homo-coupled (DPP2T)2Br2 monomer was introduced to the reaction mixture, whilst using optimal conditions. The resulting defects effectively decrease the LUMO and increase the HOMO energy levels of the material, and can act as low lying energy trap sites, inhibiting exciton dissociation. This reduces the photocurrent that can be obtained from solar cells when combined with [70]PCBM and leads to a significant reduction of the PCE from 7.5% all the way down to 2.9%, depending on the amount of defects present. It is very likely that other DPP based polymers published in literature which display the long wavelength shoulder suffer from the same type of defects and resulting performance loss. It shows that a relative small amount of defects can have a detrimental effect on the photovoltaic performance and the importance of carefully optimizing reaction conditions in order to obtain high performing, defect free, polymers.
Formation of homo-coupling defects in PDPPTPT
Bijleveld, J. C.; Gevaerts, V. S.; Di Nuzzo, D.; Turbiez, M.; Mathijssen, S. G. J.; de Leeuw, D. M.; Wienk, M. M.; Janssen, R. A. J. Efficient Solar Cells Based on an Easily Accessible Diketopyrrolopyrrole Polymer. Adv. Mater. 2010, 22, E242–E246. Hendriks, K. H.; Heintges, G. H. L.; Gevaerts, V. S.; Wienk, M. M.; Janssen, R. A. J. High-Molecular-Weight Regular Alternating Diketopyrrolopyrrole-based Terpolymers for Efficient Organic Solar Cells. Angew. Chem. Int. Ed. 2013, 52, 8341−8344.
nanoGe is a prestigious brand of successful science conferences that are developed along the year in different areas of the world since 2009. Our worldwide conferences cover cutting-edge materials topics like perovskite solar cells, photovoltaics, optoelectronics, solar fuel conversion, surface science, catalysis and two-dimensional materials, among many others.
Previously nanoGe Spring Meeting (NSM) and nanoGe Fall Meeting (NFM), MATSUS is a multiple symposia conference focused on a broad set of topics of advanced materials preparation, their fundamental properties, and their applications, in fields such as renewable energy, photovoltaics, lighting, semiconductor quantum dots, 2-D materials synthesis, charge carriers dynamics, microscopy and spectroscopy semiconductors fundamentals, etc.
International Conference on Hybrid and Organic Photovoltaics
International Conference on Hybrid and Organic Photovoltaics (HOPV) is celebrated yearly in May. The main topics are the development, function and modeling of materials and devices for hybrid and organic solar cells. The field is now dominated by perovskite solar cells but also other hybrid technologies, as organic solar cells, quantum dot solar cells, and dye-sensitized solar cells and their integration into devices for photoelectrochemical solar fuel production.
Asia-Pacific International Conference on Perovskite, Organic Photovoltaics and Optoelectronics
The main topics of the Asia-Pacific International Conference on Perovskite, Organic Photovoltaics and Optoelectronics (IPEROP) are discussed every year in Asia-Pacific for gathering the recent advances in the fields of material preparation, modeling and fabrication of perovskite and hybrid and organic materials. Photovoltaic devices are analyzed from fundamental physics and materials properties to a broad set of applications. The conference also covers the developments of perovskite optoelectronics, including light-emitting diodes, lasers, optical devices, nanophotonics, nonlinear optical properties, colloidal nanostructures, photophysics and light-matter coupling.
The International Conference on Perovskite Thin Film Photovoltaics Perovskite Photonics and Optoelectronics (NIPHO) is the best place to hear the latest developments in perovskite solar cells as well as on recent advances in the fields of perovskite light-emitting diodes, lasers, optical devices, nanophotonics, nonlinear optical properties, colloidal nanostructures, photophysics and light-matter coupling.