FBR
FBR molecule, NFA which reduces the tendency of crystallization
Used to achieve one of the highest open voltages for polymer organic solar cells
FBR, having a similar AA-D-AA type structure to IDFBR, contains electron-donating alkylated fluorene as the core, flanked by electron withdrawing benzothiadiazole (BT) and 3-ethylrhodanine units on the periphery terminals.
FBR reduces the tendency of crystallization and helps to prevent the formation of large crystalline domains in the BHJ donor/acceptor blend composition leading to better device performance efficiency and longer life-times.
Comparing to PC71BM, FBR has a relatively high lowest unoccupied molecular orbital (LUMO) which in theory should give a higher open voltage (Voc). This is indeed the case for polymer organic solar cells with PffBT4T-2DT as the polymer donor and FBR as the electron acceptor, yielding a device performance efficiency over 7.8% with an open voltage of 1.12 eV. This is one of the highest achieved open voltages for polymer organic solar cells.
Device structure: ITO/ZnO/PffBT4T-2DT:FBR/MoOx/Ag [1]
Thickness (nm) | VOC (V) | JSC (mA cm-2) | FF (%) | PCE (%) |
120 | 1.12 | 11.5 | 61 | 7.8 |
Chemical Structure

Literature and Reviews
- Reduced voltage losses yield 10% efficient fullerene free organic solar cells with >1 V open circuit voltages, D. Baran et al., Energy Environ. Sci., 9, 3783--3793 (2016); DOI: 10.1039/c6ee02598f.
- A Rhodanine Flanked Nonfullerene Acceptor for Solution-Processed Organic Photovoltaics, S. Holliday et al., J. Am. Chem. Soc., 137, 2, 898–904 (2015); doi: 10.1021/ja5110602.
- Critical review of the molecular design progress in non-fullerene electron acceptors towards commercially viable organic solar cells, A. Wadsworth et al., Chem. Soc. Rev., 48, 1596 (2019); DOI: 10.1039/c7cs00892a.
- Influence of Blend Morphology and Energetics on Charge Separation and Recombination Dynamics in Organic Solar Cells Incorporating a Nonfullerene Acceptor, H. Cha et al., Adv. Funct. Mater., 1704389 (2017); doi: 10.1002/adfm.201704389.
General Information
CAS Number | 1644381-95-2 |
Chemical Formula | C53H56N6O2S6 |
Purity | >98% (1H NMR) |
Full Name | 5,5′-[(9,9-Dioctyl-9H-fluorene-2,7-diyl)bis(2,1,3-benzothiadiazole-7,4-diylmethylidyne)]bis[3-ethyl-2-thioxo-4-thiazolidinone] |
Molecular Weight | 1001.44 g/mol |
Absorption* | λmax 510 nm (Film) |
HOMO / LUMO | HOMO = -5.83 eV, LUMO = -3.75 eV [1] |
Solubility | Chloroform, chlorobenzene |
Form | Red powder/crystals |
Synonyms | (5Z,5'Z)-5,5'-((7,7'-(9,9-dioctyl-9H-fluorene-2,7-diyl)bis(benzo[c][1,2,5]thiadiazole-7,4-diyl))bis(methanylylidene))bis(3-ethyl-2-thioxothiazolidin-4-one) |
Classification / Family | NFAs, n-type non-fullerene electron acceptors, Organic semiconducting materials, Low band-gap small molecule, Small molecular acceptor, Organic photovoltaics, Polymer solar cells, NF-PSCs. |
*Measurable with an optical spectrometer, see our spectrometer application notes.
MSDS Documentation

Pricing
Batch | Quantity | Price |
M2242A1 | 100 mg | £280 |
M2242A1 | 250 mg | £560 |
M2242A1 | 500 mg | £1000 |
M2242A1 | 1 g | £1800 |
To the best of our knowledge the information provided here is accurate. However, Ossila assume no liability for the accuracy of this page. The values provided are typical at the time of manufacture and may vary over time and from batch to batch. All products are for laboratory and research and development use only, and may not be used for any other purpose including health care, pharmaceuticals, cosmetics, food or commercial applications.