Chemical Identity and Structure

4-Methoxyphenylethylammonium Bromide (abbreviated MeO-PEABr) is an organic ammonium halide salt derived from 4-methoxyphenylethylamine by protonation with hydrobromic acid. The molecule features a para-methoxyphenyl (anisyl) group attached to an ethylammonium chain, with bromide serving as the counterion.

The electron-donating methoxy substituent on the aromatic ring modifies the electronic density of the phenyl group relative to unsubstituted phenylethylammonium salts, influencing both its supramolecular packing behavior and its interactions with perovskite lattice surfaces. This structural feature is exploited in materials science to fine-tune the properties of layered (Ruddlesden–Popper) perovskite films.

Molecular formula: C₉H₁₄NO·Br (as the protonated ammonium bromide salt). The compound is supplied by Aladdin Scientific under SKU M494110.

Key Physicochemical Properties and Storage

4-Methoxyphenylethylammonium Bromide is typically isolated as a white to off-white crystalline solid. As an ionic compound, it exhibits good solubility in polar protic solvents such as water and alcohols (e.g., ethanol, methanol), as well as in polar aprotic solvents including dimethyl sulfoxide (DMSO) and dimethylformamide (DMF). These solubility characteristics make it compatible with common perovskite precursor solution systems.

Hygroscopicity: Like most organic ammonium halide salts, MeO-PEABr is hygroscopic and should be protected from atmospheric moisture to prevent caking and compositional changes.

Recommended storage conditions:

• Store in a tightly sealed container under an inert atmosphere (nitrogen or argon) or with desiccant.
• Keep in a cool, dry location away from light and oxidizing agents.
• Refrigerated storage (2–8 °C) is advisable for long-term preservation.

Specific melting point, exact purity grade, and other lot-dependent physicochemical data should be verified against the Certificate of Analysis (CoA) provided with each batch of SKU M494110.

Research Applications

4-Methoxyphenylethylammonium Bromide has attracted significant interest in the following research domains:

1. Perovskite solar cells and LEDs: MeO-PEABr is used as a large organic cation spacer to form quasi-2D (Ruddlesden–Popper) layered perovskite structures. Incorporation of this bulky ammonium salt can passivate grain boundary defects, suppress ion migration, and improve the moisture and thermal stability of perovskite thin films. The methoxy group provides additional electronic tunability compared with the parent PEABr.
2. Surface and interface passivation: Post-treatment of three-dimensional (3D) perovskite absorber layers with MeO-PEABr solutions can form a protective 2D capping layer, reducing non-radiative recombination at film surfaces and interfaces and thus improving photovoltaic efficiency and operational stability.
3. Organic synthesis: As a stable, crystalline ammonium salt, it serves as a protected amine equivalent or a versatile intermediate in the synthesis of methoxyphenylethylamine derivatives.

Researchers should optimize reagent concentration, solvent system, and processing conditions for their specific device architecture or synthetic target.

Safe Handling and Waste Disposal

While 4-Methoxyphenylethylammonium Bromide is not classified as an acutely hazardous substance under standard reagent categories, good laboratory practice requires the following precautions:

• Personal protective equipment (PPE): Wear appropriate gloves (nitrile recommended), safety glasses, and a laboratory coat when handling the solid or its solutions. Use a dust mask or work in a fume hood when weighing fine powders to avoid inhalation of dust.
• Skin and eye contact: Avoid direct contact. In case of skin or eye exposure, rinse immediately with copious amounts of water and seek medical attention if irritation persists.
• Incompatibilities: Keep away from strong oxidizing agents and strong bases.
• Waste disposal: Dispose of all waste containing this compound in accordance with applicable local, national, and institutional environmental regulations. Do not pour solutions down the drain without verification that such disposal is compliant.

Always consult the Safety Data Sheet (SDS) for SKU M494110 before use. The SDS is available from Aladdin Scientific upon request or via the product page.

Preparation and Solution Handling Tips

The following protocol guidance is recommended for preparing stock solutions of 4-Methoxyphenylethylammonium Bromide for perovskite or synthetic applications:

1. Drying: If the reagent has been exposed to humidity, dry it under vacuum at mild temperature (e.g., 50–60 °C, 12 h) before use to remove adsorbed moisture. Monitor weight to confirm dryness.
2. Solvent selection: For perovskite applications, dissolve in anhydrous DMF, DMSO, or a DMF:DMSO mixture. For organic synthesis, ethanol or methanol is typically appropriate.
3. Inert atmosphere: Prepare and store solutions under nitrogen or argon to minimize oxidative degradation and moisture uptake, particularly for perovskite device fabrication.
4. Concentration: Prepare stock solutions at a known concentration (e.g., 1–10 mg/mL for surface treatment, or as required by the synthetic protocol) and filter through a 0.22 µm PTFE syringe filter prior to deposition.
5. Stability: Use freshly prepared solutions where possible. If storing solutions, keep refrigerated in sealed vials under inert gas and use within a short timeframe.

Exact concentrations and processing parameters should be optimized empirically for each application. Refer to the primary literature and consult Aladdin Scientific technical support for application-specific guidance.