Reduced voltage losses yield 10% efficient fullerene free organic solar cells with >1 V open circuit voltages

Baran D, Kirchartz T, Wheeler S, Dimitrov S, Abdelsamie M, Gorman J, Ashraf RS, Holliday S, Wadsworth A, Gasparini N, Kaienburg P, Yan H, Amassian A, Brabec C, Durrant JR, McCulloch I (2016)

Publication Language: English

Publication Status: Published

Publication Type: Journal article, Original article

Publication year: 2016

Journal

Energy and Environmental Science Royal Society of Chemistry

Publisher: Royal Society of Chemistry

Book Volume: 9

Pages Range: 3783-3793

Journal Issue: 12

DOI: 10.1039/c6ee02598f

Abstract

Optimization of the energy levels at the donor-acceptor interface of organic solar cells has driven their efficiencies to above 10%. However, further improvements towards efficiencies comparable with inorganic solar cells remain challenging because of high recombination losses, which empirically limit the open-circuit voltage (V) to typically less than 1 V. Here we show that this empirical limit can be overcome using non-fullerene acceptors blended with the low band gap polymer PffBT4T-2DT leading to efficiencies approaching 10% (9.95%). We achieve V up to 1.12 V, which corresponds to a loss of only E/q - V = 0.5 ± 0.01 V between the optical bandgap E of the polymer and V. This high V is shown to be associated with the achievement of remarkably low non-geminate and non-radiative recombination losses in these devices. Suppression of non-radiative recombination implies high external electroluminescence quantum efficiencies which are orders of magnitude higher than those of equivalent devices employing fullerene acceptors. Using the balance between reduced recombination losses and good photocurrent generation efficiencies achieved experimentally as a baseline for simulations of the efficiency potential of organic solar cells, we estimate that efficiencies of up to 20% are achievable if band gaps and fill factors are further optimized.

Authors with CRIS profile

Nicola Gasparini Institute Materials for Electronics and Energy Technology (i-MEET) Christoph Brabec Institute Materials for Electronics and Energy Technology (i-MEET)

Involved external institutions

Imperial College London / The Imperial College of Science, Technology and Medicine GB United Kingdom (GB) King Abdullah University of Science and Technology (KAUST) / جامعة الملك عبد الله للعلوم و التقنية SA Saudi Arabia (SA) Hong Kong University of Science and Technology (HKUST) / 香港科技大學 CN China (CN) Forschungszentrum Jülich / Research Centre Jülich (FZJ) DE Germany (DE)

How to cite

APA:

Baran, D., Kirchartz, T., Wheeler, S., Dimitrov, S., Abdelsamie, M., Gorman, J.,... McCulloch, I. (2016). Reduced voltage losses yield 10% efficient fullerene free organic solar cells with >1 V open circuit voltages. Energy and Environmental Science, 9(12), 3783-3793. https://dx.doi.org/10.1039/c6ee02598f

MLA:

Baran, D., et al. "Reduced voltage losses yield 10% efficient fullerene free organic solar cells with >1 V open circuit voltages." Energy and Environmental Science 9.12 (2016): 3783-3793.

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