Hydrochromic Effect of Perovskite-Polymer Composites

Area of Science:

• Materials Science
• Chemistry

Background:

• Hydrochromic materials change color with water, offering potential for sensing and security applications.
• Perovskite materials exhibit hydrochromism via water-induced fluorescence quenching, but achieving this in composites is challenging due to water isolation.

Purpose of the Study:

• To develop a hydrochromic perovskite-polymer composite material.
• To enable commercial applications of hydrochromic perovskites.

Main Methods:

• A nonsolvent-induced phase separation method was used to create a porous composite of FA₂PbBr₄/poly(vinylidene fluoride).
• Naturally formed pores within the composite facilitate moisture diffusion and subsequent water-induced phase transition of the perovskite.

Main Results:

• A hydrochromic effect was successfully demonstrated in the perovskite-polymer porous composite.
• Water penetration induced a phase transition from nonfluorescent 2D FA₂PbBr₄ to fluorescent 3D FAPbBr₃.

Conclusions:

• The developed hydrochromic perovskite-polymer composites are suitable for commercial applications.
• Demonstrated applications include fingerprint labels, anticounterfeiting labels, encrypted documents, and water-ink printing.