What Is 4,8-Bis-n-octyloxybenzo[1,2-b:4,5-b']dithiophene and Why Is It Important?

4,8-Bis-n-octyloxybenzo[1,2-b:4,5-b']dithiophene (BDT) is a planar, fused bicyclic aromatic compound in which a central benzene ring is annulated symmetrically by two thiophene rings. The 4- and 8-positions carry n-octyloxy substituents that confer good solubility in common organic solvents (e.g., chloroform, chlorobenzene, o-dichlorobenzene) while preserving the coplanar π-conjugated backbone essential for efficient charge transport.

The BDT scaffold is one of the most broadly adopted donor units in the design of low-bandgap conjugated polymers. Its symmetric, electron-rich aromatic system facilitates strong π–π stacking in the solid state, which correlates with high hole mobility values in thin-film devices. When copolymerized with electron-deficient acceptor units, BDT-based polymers routinely achieve power conversion efficiencies (PCEs) well above 5% in bulk-heterojunction OPV cells, and high field-effect mobilities in OFET configurations.

Physical and Chemical Properties

The compound features a rigid, planar fused-ring architecture that promotes self-assembly in the solid state. The two n-octyloxy side chains improve processability from solution without significantly disrupting backbone planarity. Key physicochemical characteristics include:

• Molecular formula: C₂₄H₃₄O₂S₂
• Core structure: Benzo[1,2-b:4,5-b']dithiophene with alkoxy substitution at C-4 and C-8
• Solubility: Soluble in halogenated solvents (chloroform, chlorobenzene, o-dichlorobenzene) and tetrahydrofuran; limited solubility in polar protic solvents
• Electronic character: Electron-rich donor; relatively low ionization potential facilitating hole transport
• Appearance: Typically a pale to off-white solid

Specific melting point, exact molecular weight, and purity data for lot B153039 are provided on the product certificate of analysis (CoA). Researchers should consult the current CoA for batch-specific values.

Handling, Storage, and Safety Guidelines

Storage: Store in a tightly sealed container under an inert atmosphere (nitrogen or argon) in a cool, dry environment away from light and moisture. Prolonged exposure to air, moisture, or UV radiation may lead to oxidative degradation of the thienyl sulfur centers or hydrolysis of the ether linkages.

Handling: Use standard laboratory personal protective equipment (PPE): lab coat, nitrile gloves, and safety glasses. Work in a well-ventilated fume hood when handling powders or solutions to minimize inhalation exposure. Avoid contact with strong oxidizing agents.

Disposal: Dispose of waste in accordance with local institutional and regulatory guidelines for organic chemical waste. Do not pour solvent solutions down the drain.

Note: Always consult the current Safety Data Sheet (SDS) provided by Aladdin Scientific for lot-specific hazard information before use.

Applications in Organic Electronics

4,8-Bis-n-octyloxybenzo[1,2-b:4,5-b']dithiophene serves primarily as a donor (D) monomer in donor–acceptor (D–A) alternating conjugated copolymers synthesized via transition-metal-catalyzed cross-coupling reactions, most commonly Stille or Suzuki polycondensation.

Organic Photovoltaics (OPV): BDT-containing polymers blended with fullerene acceptors (e.g., PC₆₁BM, PC₇₁BM) or non-fullerene acceptors in bulk-heterojunction (BHJ) active layers have demonstrated competitive power conversion efficiencies. The planar backbone promotes face-on orientation relative to the substrate, which is favorable for vertical charge transport in OPV devices.

Organic Field-Effect Transistors (OFET): Thin films of BDT-based polymers exhibit p-type (hole-transport) behavior. The strong π–π stacking facilitated by the planar BDT core contributes to high hole mobility.

Other uses: BDT monomers are also explored as active components in organic electrochemical transistors (OECTs), photodetectors, and thermoelectric devices, reflecting the versatility of the fused-ring scaffold.

Ordering, Specifications, and Quality Assurance

4,8-Bis-n-octyloxybenzo[1,2-b:4,5-b']dithiophene is available from Aladdin Scientific under SKU B153039. Researchers and procurement teams can place orders directly through the Aladdin Scientific website or by contacting customer service.

Purity and Quality: Each lot is characterized by standard analytical techniques. The certificate of analysis (CoA) is available upon request and includes purity (typically by HPLC or GC), structural confirmation (NMR, MS), and physical data. Please request the CoA for your specific lot number to verify batch-to-batch consistency.

Pack sizes and pricing: Multiple pack sizes may be available to suit both exploratory research and scale-up needs. Current availability, pricing, and lead times are listed on the product page. Contact Aladdin Scientific customer support for bulk quotations or custom requirements.

Returns and quality issues: If the product does not meet the stated specifications, please contact Aladdin Scientific customer service within the applicable returns window, quoting your order number and lot number, for assistance with replacement or refund as per our returns and refunds policy.