Solar-Blind UV Organic Mechanoluminescent Materials

Area of Science:

• Materials Science
• Organic Chemistry
• Photophysics

Background:

• Organic mechanoluminescent (ML) materials are promising for stress sensing and damage monitoring.
• Current ML sensors are limited to dark environments due to interference from ambient light.

Purpose of the Study:

• To develop organic ML materials that operate in the solar-blind ultraviolet (UV) region.
• To enable ML-based sensing in bright-field conditions.

Main Methods:

• Strategic design of diphenylphosphine oxide derivatives to alter molecular conjugation and packing.
• Photophysical studies, single crystal analysis, and theoretical calculations.
• Testing ML response to mechanical stimuli (stretching, folding, impact) in daylight.

Main Results:

• Achieved the shortest ML emission (ca. 293 nm) in the solar-blind UV region among organic ML materials.
• Demonstrated wide-range color-tunable ML emissions from 293 nm to 741 nm.
• Successfully recorded ML signals under various mechanical stresses in daylight, showing quantitative relationships.

Conclusions:

• A feasible strategy for creating solar-blind UV ML materials was established.
• This work paves the way for practical ML sensors that function in bright-field environments.
• The developed materials offer new possibilities for real-time structural health monitoring.