Brightening Blue Photoluminescence in Non-emission MOF-2 by Pressure Treatment Engineering.

As equally essential as the synthesis of new materials, manoeuvring new structure configurations can endow the brand-new functional properties to existing materials, which is also one of the core goals in the synthesis community. In this respect, pressure-induced emission (PIE) that triggers photoluminescence (PL) in non-emission materials is an emerging stimuli-responsive smart materials technology. In the PIE paradigms, harvesting bright PL at ambient conditions, however, has remained elusive. Herein, we report a remarkable PIE phenomenon in initially non-emission MOF-2, which shows bright blue-emission at 455 nm under pressure. Intriguingly, the bright blue PL with an excellent photoluminescence quantum yield up to 70.4% is unprecedentedly retained to ambient conditions upon decompression from 16.2 GPa. The detailed structural analyses combined with density functional theory calculations reveal that hydrogen bonding cooperativity effect elevates powerfully the rotational barrier of the linker rotor to 3.87 eV/mol from initial 0.91 eV/mol through pressure treatment. The downgrade rotational freedom turns on PL of MOF-2 after releasing pressure completely. This is the first case of harvesting PIE to ambient conditions. Our findings offer a new platform for the creation of promising alternatives to high-performance PL materials based on initially non-emission counterparts. This article is protected by copyright. All rights reserved.