A Dual-Scale Porous Architecture with Anisotropic Mechanoluminescence for Flexible Sensing

Abstract Mechanoluminescence (ML) materials, which convert mechanical stimuli into optical signals, hold great promise for applications in flexible sensing and human–machine interfaces. However, conventional dense or randomly porous composite structures often suffer from uniform stress distribution, limited emission intensity, and a lack of directional selectivity. In this work, we propose and fabricate a dual-scale porous copper-doped zinc sulfide/polydimethylsiloxane (ZnS:Cu/PDMS) composite architecture featuring both micron-sized pores and aligned through-holes. Finite element analysis, mechanical characterization, and force–light synchronized measurements reveal that the dual-scale architecture promotes stress redistribution and strengthens the ML response, particularly under radial compression. Compared with dense and single-scale porous counterparts, the dual-scale porous composite exhibits enhanced ML intensity and sensitivity, together with a distinct direction-dependent luminescent response under axial and radial loading. Leveraging this anisotropic emission, its potential in various application scenarios is demonstrated, including bimodal flexible sensing, programmable pattern display, and direction-dependent information encoding. This study provides an effective structural design strategy for developing advanced ML materials and devices with high performance and directional recognition capabilities.