Maintaining the configuration of a light-responsive metal–organic framework: LiYGeO4:Bi3+-incorporation-induced long-term bending through short-time light irradiation

Abstract

Light-responsive adsorbents have attractive application prospects owing to their adjustable performance under light irradiation. Introducing light-responsive azobenzene moieties to a metal–organic framework (MOF) as the backbone of the organic linkers is a significant method to construct light-responsive adsorbents. The modulation of this kind of adsorbent via light irradiation requires maintaining exposure to the illumination with a specific wavelength. Herein, we report a series of light-responsive composites which realize the long-term suppressed bending of light-responsive ligands in the frameworks through short-time light irradiation. An inorganic persistent luminescent material, LiYGeO₄:Bi³⁺, was incorporated into a light-responsive MOF, PCN-250, to fabricate the composites. After ultraviolet irradiation at 254 nm for 10 min, the LiYGeO₄:Bi³⁺ in the composites can provide continuous illumination at 365 nm for at least 6 h. Driven by this illumination, the composites can regulate CO₂ adsorption capacity without continuous light irradiation, and the best change amount of the adsorption capacity is up to 14.6%, while that on PCN-250 can be negligible. This work provides a new route to develop light-responsive materials for real-world applications.