Recently, the research team led by Prof. Wang Jinlan and Prof. Ju Minggang from the School of Physics, SEU, in collaboration with Prof. Peng Dengfeng from the School of Physics and Optoelectronic Engineering, Shenzhen University, has made new progress in the microscopic mechanism and rational design of self-recoverable mechanoluminescent materials. The related findings were published in the Journal of the American Chemical Society, a top-tier international journal, under the title “Understanding the Origins of Self-Recoverable Mechanoluminescence for Rational Materials Design.”
Mechanoluminescence (ML) is an energy conversion process that directly transduces mechanical stimuli into optical signals, making it highly attractive for applications in stress sensing, nondestructive testing, soft robotics, and optical communication. Despite considerable progress in experimental studies and application development, the mechanistic understanding of ML remains largely phenomenological, relying on qualitative interpretations of observed behaviors. In particular, a clear microscopic picture of how localized luminescent centers evolve electronically and how charge carriers migrate under mechanical stress is still lacking. This knowledge gap has in turn constrained the discovery of ML materials to largely empirical trial-and-error, with few theoretical guidelines or predictive tools available to accelerate screening. Thus, unraveling the underlying electronic processes and establishing broadly applicable material descriptors remain central to achieving rational design and high-throughput discovery of mechanoluminescent materials.
To tackle these challenges, the team applied the classic self-recoverable mechanoluminescent material ZnS as a model system. Through first-principles calculations combined with thermodynamic and kinetic analyses of defects and charge carriers, they elucidated a mechanical-stress-driven “defect-mediated electronic state cycling” mechanism. Specifically, during the loading process, stress alters the local potential field and defect energy levels, prompting electrons to migrate from the luminescent centers to intrinsic defects and form charged intermediate states. Upon unloading, the electrons are re-trapped by the luminescent centers into excited states, followed by radiative transitions back to the initial ground state, thereby completing a reversible electronic state cycle. On this basis, the team further discovered that stress-induced half-occupied antibonding states serve as a key electronic structural feature of self-recoverable mechanoluminescent systems, and distilled this finding into a universal descriptor for predicting mechanoluminescence activity. Using this descriptor, the team conducted theoretical screening of candidate materials and successfully predicted and experimentally verified four novel self-recoverable mechanoluminescent materials. Collectively, this work accomplishes a systematic progression—from mechanistic elucidation and descriptor development to material prediction and experimental verification.
The first author of this paper is Pan Xiaofeng, a Ph.D. student at Southeast University. Professors Wang Jinlan and Ju Minggang from the School of Physics, SEU, along with Prof. Peng Dengfeng from the School of Physics and Optoelectronic Engineering, Shenzhen University, are the co-corresponding authors. This study was supported by the National Key Research and Development Program of China, the National Natural Science Foundation of China, and other funding sources.
Paper’s link:https://doi.org/10.1021/jacs.6c07144
Source: School of Physics, SEU
Translated by: Melody Zhang
Edited by: Leah Li
