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Biomimetic Approach to Inhibition of Photooxidation in Organic Solar Cells Using Beta-Carotene as an Additive



Sebastian Engmann, Vida Turkovic, Michela Prete, Mikkel Bregnhoj, Liana Inasaridze, Dmytro Volyniuk, Filipp Obrezkov, Juozas V. Grazulevicius, Horst G. Rubahn, Pavel Troshin, Peter R. Ogilby, M. Madsen


Recent improvements in the power conversion efficiencies of organic photovoltaic (OPV) cells have highlighted the fact that OPV device lifetimes are now the main bottleneck for further advances of this technology. As such, understanding and controlling events that result in OPV device degradation must now take center stage. The incorporation of stabilizers to a given OPV system is a desirable approach to attenuate degradation; in the least, it is inexpensive and readily scaled-up for mass production. However, to date, the incorporation of such additives has only resulted in limited accumulated power generation (APG) enhancement factors. In this work, we demonstrate that beta-carotene (BC) is a green, natural-occurring stabilizer for OPV systems, leading to record-high APG enhancement factors. Specifically, upon the addition of BC, the well-known P3HT:[60]PCBM system can reach APG enhancement factors of 100 due to extraordinarily stabilized long-term performance (tlifetime). For PTB7:[70]PCBM systems, equally remarkable APG enhancement factors of 10 were reached, due to BC dependent changes in both the burn-in (tburn-in) and the long-term performance (tlifetime). We used electron spin resonance and time-resolved near-infrared emission spectroscopies, respectively, to probe the concentration of radicals and singlet oxygen production in these systems. For experiments performed on OPV cells with different polymer and fullerene ratios, we demonstrate, for the first time that singlet oxygen sensitized by [70]PCBM is the main relevant contributor to the burn-in behavior in PTB7:[70]PCBM solar cells, and that singlet oxygen quenching from BC is the main relevant stabilizing mechanism leading to the large APG values observed. The results and methods presented herein point to a desirable route for mitigating degradation in the active layer of OPV systems.
ACS Applied Materials and Interfaces


Organic solar cells, stabilization, organic electronics


Engmann, S. , Turkovic, V. , Prete, M. , Bregnhoj, M. , Inasaridze, L. , Volyniuk, D. , Obrezkov, F. , Grazulevicius, J. , Rubahn, H. , Troshin, P. , Ogilby, P. and Madsen, M. (2019), Biomimetic Approach to Inhibition of Photooxidation in Organic Solar Cells Using Beta-Carotene as an Additive, ACS Applied Materials and Interfaces, [online], (Accessed May 27, 2024)


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Created October 13, 2019, Updated September 11, 2020