Efficient color manipulation of zinc sulfide-based mechanoluminescent elastomers for visualized sensing and anti-counterfeiting

Abstract

Elastomeric mechanoluminescence (EML) materials capable of generating luminescence during elastic deformation are promising for many practical applications in modern technologies. Among them, copper- or manganese-doped zinc sulfide (ZnS) in a polydimethylsiloxane (PDMS) matrix has emerged as the most efficient EML material by virtue of its intense EML intensity. However, it is insufficient to trigger abundant electron entrapments and activate high energy blue emission under weak mechanical stimuli (<1k Hz) due to the softness of the composite. The limited range of available emission spectra has greatly constrained its applications. In this case, an efficient approach is developed for expanding EML emission through incorporation of long afterglow phosphors. The as-fabricated composites show efficient and tunable EML emissions covering three primary colors of red-green-blue (RGB) even under extremely weak mechanical stimuli (1 Hz; ε = 10%). Furthermore, various application prospects of a series of proof-of-concept optical devices such as handwriting input, gesture sensing, and encrypted anti-counterfeiting are successively demonstrated. This feasible technique provides a general platform to broaden color expression under weak mechanical stimuli, which could inspire the fabrication of various novel applications.