New Approach to Boosting Fill Factor and Voltage in OPVs

Check out the research article, developed in collaboration with our project partner FAU and featuring BOOSTER project acknowledgement, titled: “A High Throughput Platform to Minimize Voltage and Fill Factor Losses”, recently published in Advanced Energy Materials.

Organic photovoltaics (OPV) now can exceed 20% power conversion eﬃciency in single junction solar cells. To close the remaining gap to competing technologies, both ﬁll factor and open-circuit voltage must be optimized. The Langevin reduction factor is a well-known concept that measures the degree to which charge extraction is favoured over charge recombination. It is therefore ideally suited as an optimization target in high-throughput workﬂows; however, its evaluation so far requires expert interaction. An integrated high-throughput workﬂow is presented, able to obtain the Langevin reduction factor within a few seconds with high accuracy without human intervention and thus suited for autonomous experiments. This is achieved by combining evidence from UV–vis spectra, current–voltage curves, and a novel implementation of microsecond transient absorption kinetics allowing, for the ﬁrst time, the intrinsic determination of charge absorption cross-sections, which is crucial to reporting stationary charge densities. The method is demonstrated by varying the donor:acceptor ratio of the high performance OPV blend PM6:Y12. The high reproducibility of the method allows to ﬁnd a strictly exponential relationship between the PM6exciton energy and the Langevin reduction facto.

The proposed workﬂow has the potential to greatly enhance high throughput processes by providing a more comprehensive understanding of charge generation, recombination, and extraction in near real-time. It therefore oﬀers a robust tool for accelerating OPV research, targeting progress in material design and device performance.

Read the full open-access paper here: https://advanced.onlinelibrary.wiley.com/doi/epdf/10.1002/aenm.202403479