Proceedings of International Conference on Hybrid and Organic Photovoltaics (HOPV23)
DOI: https://doi.org/10.29363/nanoge.hopv.2023.116
Publication date: 30th March 2023
Organic solar cells have made large strides with power conversion efficiencies exceeding 18% and the milestone of 20% well within sight1. The emergence of non-fullerene acceptors (NFAs) has played a vital role in these advancements2. Particularly, there have been extensive studies focusing on the process of free charge generation in organic blends comprising of NFAs with polymeric donors having low energy offset3,4. Adding to this discussion, we systematically explore the role of offset on charge transfer dynamics at bulk heterojunction interfaces between polymeric donor PM6 and two structurally similar NFAs from the Y-series acceptor family, namely Y5 and Y6. Herein, Y5 is found to have a relatively lower offset between the highest occupied molecular orbitals (HOMO) in PM6:Y5 as compared to PM6:Y6. The low offset in case of PM6:Y5 leads to enhancement in open circuit voltage as compared to the optimized blends of PM6:Y6, however this enhancement comes at cost of reduced short circuit current densities and poor fill factors. Here, PM6:Y5 blends are found to show strong voltage dependence of free charge generation as seen through time delayed collection field (TDCF) measurements along with its complete anticorrelation with the bias-dependence of steady state photoluminescence quenching of the blend. Using transient absorption spectroscopy (TAS), we show that the poor free charge generation in optimized PM6:Y5 (1:1.2) blend as compared to PM6:Y6 originates due to the differences in interfacial kinetics which contributes towards poor exciton dissociation yields. We verify the role of interfacial energetics using blends with low acceptor (Y5/Y6) content to avoid contributions from morphology-dependent exciton diffusion. This work underlines the importance of energetic offset on charge generation and in contrast to the earlier reports, indicates that vanishing HOMO-
Liu, F., Zhou, L., Liu, W., Zhou, Z., Yue, Q., Zheng, W., Sun, R., Liu, W. Y., Xu, S., Fan, H., Feng, L., Yi, Y., Zhang, W., Zhu, X., Organic Solar Cells with 18% Efficiency Enabled by an Alloy Acceptor: A Two-in-One Strategy. Adv. Mater. 2021, 33, 2100830
Armin, A., Li, W., Sandberg, O. J., Xiao, Z., Ding, L., Nelson, J., Neher, D., Vandewal, K., Shoaee, S., Wang, T., Ade, H., Heumüller, T., Brabec, C., Meredith, P., A History and Perspective of Non-Fullerene Electron Acceptors for Organic Solar Cells. Adv. Energy Mater. 2021, 11, 2003570.
Bertrandie, J., Han, J., De, C. S. P., Yengel, E., Gorenflot, J., Anthopoulos, T., Laquai, F., Sharma, A., Baran, D., The Energy Level Conundrum of Organic Semiconductors in Solar Cells. Adv. Mater. 2022, 34, 2202575
Zhong, Y., Causa’, M., Moore, G.J. et al. Sub-picosecond charge-transfer at near-zero driving force in polymer:non-fullerene acceptor blends and bilayers. Nat Commun. 2020, 11, 833.
HOMO offset can be detrimental to overall device performance.
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.