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CAS Number 1644381-95-2

Materials, Non-Fullerene Acceptors

Product Code M2242A1-100mg
Price $388 ex. VAT

FBR molecule, NFA which reduces the tendency of crystallization

Used to achieve one of the highest open voltages for polymer organic solar cells

Specifications | Pricing and Options | MSDS | Literature and Reviews

FBR (CAS number 1644381-95-2) 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

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 the Ossila Optical Spectrometer, see more on Spectrometers and Spectroscopy Accessories.

Chemical Structure

Chemical structure of FBR, CAS 1644381-95-2


Batch Quantity Price
M2242A1 100 mg £310
M2242A1 250 mg £620
M2242A1 500 mg £1100
M2242A1 1 g £2000

MSDS Documentation


Literature and Reviews

  1. 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.
  2. 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.
  3. 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.
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