Proceedings of Materials for Sustainable Development Conference (MAT-SUS) (NFM22)
Publication date: 11th July 2022
Understanding morphology control plays a crucial role in realizing high performance polymer solar cells (PSCs). In all-polymer solar cells (all-PSCs), blend films usually suffer from large-scaled phase separation due to either poor miscibility between donor and acceptor or small contribution from entropy mixing between two components [1]. To address these issues, random copolymer strategy has been introduced with aims to finely control the aggregation and crystallinity of semiconducting polymers for tuning the blend morphology then improving the photovoltaic performance of all-PSCs. In this work, a series of three copolymers acceptors were synthesized with different amounts of 3-octylthiophene (OT) replacing bithiophene (T2) to give PNDI-OTx copolymers where x = 5%, 10%, or 15%. Another polymer, namely PNDI2OD-C8T2, consisting of naphthalene diimide (NDI) polymerized with 3-octyl-2,2’-bithiophene (C8T2) is also synthesized for comparison.
In comparison with the reference PNDI2OD-T2, the solution aggregation and thin film crystallinity of PNDI-OTx are systematically decreased with increasing OT amount, evidenced by temperature-dependent UV-Vis and grazing incidence wide angle X-ray scattering (GIWAXS) measurements. PNDI2OD-C8T2 is also found to have reduced solution aggregation and thin film crystallinity relative to PNDI2OD-T2. However, the photovoltaic performance of all-PSCs based on J71:PNDI-OTx and J71:PNDI2OD-C8T2 blends are poorer than that of the reference J71:PNDI2OD-T2 system. The morphological studies demonstrate that reduced aggregation and crystallinity do not improve the blend morphology, with coarser phase separation found in J71:PNDI-OTx and J71:PNDI2OD-C8T2 blends which could be due to poor miscibility between J71 and polymer acceptors. Alternatively, unaggregated polymer acceptor chains could cause earlier phase separation onset during spin coating method. Furthermore, the OT-modified copolymers are found to have reduced electron mobilities relative to PNDI2OD-T2. The results here suggest that reduced aggregation and less crystallinity of random copolymer acceptors do not always produce favorable morphology in polymer:polymer blends and do not guarantee for improvement in photovoltaic performance [2]. Instead, an effective copolymer acceptor is likely required to exhibit enhanced miscibility with the donor polymer while maintaining good electron mobility for efficient solar cell devices [2].
This work was performed in part at the Soft X-ray and SAXS/WAXS beamlines at the Australian Synchrotron, part of ANSTO. AFM was performed at Monash Centre for Nanofabrication (MCN) in the Victorian node of Australian National Fabrication Facility (ANFF). This research used the Spectroscopy Soft and Tender (SST-1) beamline of the National Synchrotron Light Source II, a U.S. Department of Energy (DOE) Office of Science User Facility operated for the DOE Office of Science by Brookhaven National Laboratory under Contract DE-SC0012704. This activity received funding from ARENA as part of ARENA’s Research and Development Program—Solar PV Research. The views expressed herein are not necessarily the views of the Australian Government, and the Australian Government does not accept responsibility for any information or advice contained herein. This work was also supported by the Australian Research Council (DP190102100).
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.