Ternary Eu3+ crystalline complexes with photoluminescence and triboluminescence for dynamic stress visualization.

[Display omitted] • Eu(DBM) 3 DETA is a newly synthesized, unreported lanthanide crystal complex. • Eu(DBM) 3 DETA has both excellent photoluminescence and triboluminescence properties. • Eu(DBM) 3 DETA can recover to its original PL and TL properties after recrystallization. • Piezoelectric effect on crystals during breakage provide excellent TL properties. • Eu(DBM) 3 DETA can display stress visualization differences of handwriting signatures. Investigation of photoluminescence (PL) and fracture-induced triboluminescence (TL) is necessary for the development of both fundamental theories and practical applications in mechanical energy conversion; however, most known PL/TL-emitting materials are confined to inorganic systems. In this study, a novel lanthanide-based crystalline complex (LnCC), Eu(DBM) 3 DETA was synthesized via the synergistic coordination of Eu3+ with DBM (Dibenzoylmethane) and DETA (Diethylenetriamine) units, leading to the formation of brighter LnCC with bright red emission, high PL quantum yields (57.19 %) and unique TL characteristics. The key to success in obtaining Eu(DBM) 3 DETA is the utilization of DETA molecule as synergistic ligand, presenting block crystals with higher coordination number of Eu3+ ions via recrystallization. Due to the dense accumulation of cross-linked three-dimensional frameworks through van der Waals interactions, the fracture-induced piezoelectric effect results in charge separation and excitation through the resultant electric field and discharge, triggering a fast TL response of Eu(DBM) 3 DETA and expanding the possibilities of the quantitative stress sensing. Importantly, amorphous powders can still recover to their original PL and TL emission intensities after recrystallization in cyclic crystal-to-amorphous phase transitions. The unique PL and TL characteristics of Eu(DBM) 3 DETA provide promising opportunities to display stress visualization differences of electronic signatures under different forces. [ABSTRACT FROM AUTHOR]