# Polymer-constrained excimer enables flexible and self-healable optoelectronic elastomer for mechanical sensor

## TL;DR

This paper introduces a self-healing, flexible optoelectronic material with high photoluminescence for use in wearable sensors.

## Contribution

A polymer-constrained excimer strategy is introduced to achieve ultra-high photoluminescence and self-healing properties in a flexible elastomer.

## Key findings

- Naphthyl-naphthyl microphase separation in polyisoprene enhances mechanical and self-healing properties.
- The material achieves a photoluminescence quantum yield of over 98% through excimer formation.
- The copolymer shows superior electret performance suitable for opto-electro-mechanical sensors.

## Abstract

The development of high-performance, flexible, and self-healable optoelectronic materials is pivotal for advancing next-generation wearable technologies. In this study, we introduce nanoscale naphthyl-naphthyl microphase separation into a polyisoprene matrix, endowing olefin copolymers with exceptional mechanical properties, high flexibility, and intrinsic self-healing capabilities at room temperature without external stimuli. Notably, by employing a “polymer-constrained excimer” strategy, these copolymers exhibit remarkable photoluminescent properties, achieving an ultra-high photoluminescence quantum yield (PLQY > 98%) through the formation of naphthyl-naphthyl excimers. Experimental and theoretical analyses reveal that under the encapsulation of flexible cis-1,4-polyisoprene segments, nanoscale naphthyl aggregates form stable excimers upon UV stimulation, resulting in extraordinary fluorescence quantum efficiency. Additionally, the nanoscale aggregation of naphthyls imparts superior electret performance to these copolymers, making them ideal for opto-electro-mechanical sensors for the robotic hand and other devices.

Flexible optoelectronic materials are promising for wearable technology, though it is challenging to optimize the mechanical properties. Here the authors design a copolymer taking advantage of microphase separation to optimize mechanical and photophysical properties.