High Performance and Circularly Polarized Mechanoluminescence From Noncentrosymmetric Crystals With Pronounced Macroscopic Polarity.

Abstract

Organic mechanoluminescent (ML) materials convert mechanical stimuli into light emission without photon excitation, offering opportunities for sustainable optoelectronics and flexible sensing. Yet, ambiguous mechanistic understanding limits structure to property relationships and hinders the rational design of high-performance ML materials that combine durability, sensitivity, thermal tolerance, and polarization control. Herein, a general design strategy is presented based on chiral and supramolecular synergy, in which chirality enables symmetry breaking while directional supramolecular interactions amplify macroscopic polarity in noncentrosymmetric crystals. In such crystals, ML-activity is governed by the net macroscopic rather than the molecular polarity. By constructing a zipper-like supramolecular hydrogen-bonding network, the resulting crystals show bright ML visible under ambient light, persistent emission after 90 min of friction, a low force threshold of 0.05 N, and thermal robustness up to 162°C. Modulating supramolecular interaction strength further enables tribochromic ML. Moreover, the chiral and polar crystal architecture affords circularly polarized ML (CPML), providing a mechanically driven route to polarized emission. To the best of our knowledge, this is the first example of purely organic CPML. This study establishes a general chiral-polar supramolecular design strategy for high-performance organic ML and supports their potential in advanced luminescent applications.