Tuning Perovskite Nanocrystal Synthesis via Amphiphilic Block Copolymer Templates and Solvent Interactions

Area of Science:

• Materials Science
• Nanotechnology
• Chemical Engineering

Background:

• Amphiphilic block copolymers (a-BCP) form micelles with tunable morphology for perovskite nanocrystal fabrication.
• Precise control over perovskite nanocrystal nucleation and growth using a-BCP templates is not well understood.

Purpose of the Study:

• To investigate the influence of solvents (toluene, methanol) and a specific a-BCP (polystyrene-block-poly(2-vinylpyridine), PS-b-P2VP) on cesium lead bromide (CsPbBr3) nanocrystal formation.
• To elucidate the stages involved in CsPbBr3 nanocrystal synthesis within a-BCP micelles.

Main Methods:

• Micellization of PS-b-P2VP in toluene.
• Complexation of lead bromide (PbBr2) and cesium bromide (CsBr) within the micelles.
• Controlled addition of methanol to induce nucleation and growth.
• Analysis of solvent effects on micelle stability and crystal phase.

Main Results:

• Toluene promotes spherical micelle formation and PbBr2 encapsulation.
• Methanol addition triggers CsPbBr3 nucleation, but excess methanol leads to irregular shapes and CsPb2Br5 formation via Ostwald ripening.
• High methanol concentrations destabilize micelles, causing precipitation of larger CsPb2Br5 microcrystals.

Conclusions:

• Solvent composition critically dictates CsPbBr3 nanocrystal morphology and phase purity.
• Careful control of toluene-methanol ratios and a-BCP concentration is essential for targeted perovskite nanocrystal synthesis.
• Understanding these solvent-micelle interactions enables tailored fabrication of perovskite nanocrystals.