title: Bismuth-Based Coordination Polymers with Efficient Aggregation-Induced Phosphorescence and Reversible Mechanochromic Luminescence.
abstract: Two bismuth coordination polymers (CPs), (TBA)[BiBr4 (bp4mo)] (TBA=tetrabutylammonium) and [BiBr3 (bp4mo)2 ], which are based on the rarely used simple ditopic ligand N-oxide-4,4'-bipyridine (bp4mo), show mechanochromic luminescence (MCL). High solid-state phosphorescence quantum yields of up to 85 % were determined for (TBA)[BiBr4 (bp4mo)] (λem =540 nm). Thorough investigations of the luminescence properties combined with DFT and TDDFT calculations revealed that the emission is due to aggregation-induced phosphorescence (AIP). Upon grinding, both samples became amorphous, and their luminescence changed from yellow to orange and red, respectively. Heating or exposure to water vapor led to the recovery of the initial luminescence. These materials are the first examples of mechanochromic phosphors based on bismuth(III).
authors.affiliation: MOLTECH-Anjou, UMR-CNRS 6200, University of Angers, 2 Bd Lavoisier, 49045, Angers, France.
authors.forename: Oksana
authors.initials: O
authors.lastname: Toma
authors.affiliation: MOLTECH-Anjou, UMR-CNRS 6200, University of Angers, 2 Bd Lavoisier, 49045, Angers, France.
authors.forename: Magali
authors.initials: M
authors.lastname: Allain
authors.affiliation: Dipartimento di Scienza dei Materiali, Università degli Studi di Milano Bicocca, via Cozzi 55, 20125, Milano, Italy.
authors.forename: Francesco
authors.initials: F
authors.lastname: Meinardi
authors.affiliation: Istituto di Scienze e Tecnologie Molecolari, Università degli Studi di Milano, via C. Golgi 19, 20133, Milano, Italy. a.forni@istm.cnr.it.
authors.forename: Alessandra
authors.identifier: 0000-0002-5020-5544
authors.initials: A
authors.lastname: Forni
authors.affiliation: Istituto per lo Studio delle Macromolecole (ISMAC), CNR, Via Corti 12, 20133, Milano, Italy. c.botta@ismac.cnr.it.
authors.forename: Chiara
authors.identifier: 0000-0001-8722-0417
authors.initials: C
authors.lastname: Botta
authors.affiliation: MOLTECH-Anjou, UMR-CNRS 6200, University of Angers, 2 Bd Lavoisier, 49045, Angers, France. nicolas.mercier@univ-angers.fr.
authors.forename: Nicolas
authors.identifier: 0000-0003-0458-0789
authors.initials: N
authors.lastname: Mercier
keywords: N,O ligands; bismuth; coordination polymers; luminescence; mechanochromic materials