Heteroaryl functionalized tetraphenylethylene for AIE and mechanochromism.

Abstract

Organic luminophores exhibiting efficient emission and external-stimuli responsiveness are crucial for the development of advanced optoelectronic and sensing technologies. Aggregation-induced emission (AIE) represents a transformative design paradigm that enables strong luminescence through restriction of intramolecular motions upon aggregation. Tetraphenylethene (TPE) has emerged as a versatile AIE-active building block, owing to its twisted molecular geometry, effective suppression of intramolecular rotation and resistance to detrimental π-π stacking interactions. This perspective article provides recent advances in TPE-based luminogens with emphasis on structure-property relationships governing solid-state emission, mechanochromism and multi-stimuli responsiveness. The effects of donor-acceptor engineering and substitution topology on charge-transfer processes and structure-dependent photophysical properties are systematically discussed. Particular attention is devoted to mechanochromic systems where mechanical perturbations induce reversible emission changes via phase transitions and packing reorganization. The relevance of TPE-based AIE luminogens in optoelectronic applications, especially nondoped OLEDs and multifunctional emissive devices is highlighted along with current challenges and future perspectives. This perspective article establishes tetraphenylethene as a versatile molecular platform for the rational development of high-performance, stimuli-responsive organic materials.