Electrostatic mechanophores in tuneable light-emitting piezo-polymer nanowires

TL;DR

This paper demonstrates that electromechanical coupling in piezoelectric polymer nanowires can reversibly tune light emission, with potential applications in sensing and soft robotics, through a combination of experiments and theoretical calculations.

Contribution

It introduces a new class of electrostatic, stress-sensitive nanostructures that enable tunable light emission in piezo-polymer nanowires, combining experimental and computational insights.

Findings

Reversible redshift of dye emission under mechanical stress.

Electrostatic interactions govern photophysical properties.

Potential for applications in sensors and soft robotics.

Abstract

Electromechanical coupling through piezoelectric polymer chains allows the emission of organic molecules in active nanowires to be tuned. This effect is evidenced by highly bendable arrays of counter-ion dye-doped nanowires made of a poly(vinylidenefluoride) copolymer. A reversible redshift of the dye emission is found upon the application of dynamic stress during highly accurate bending experiments. By density functional theory calculations it is found that these photophysical properties are associated with mechanical stresses applied to electrostatically interacting molecular systems, namely to counterion-mediated states that involve light-emitting molecules as well as charged regions of piezoelectric polymer chains. These systems are an electrostatic class of supramolecular functional stress-sensitive units, which might impart new functionalities in hybrid molecular nanosystems and anisotropic nanostructures for sensing devices and soft robotics.