Aggregation-regulated room-temperature phosphorescence materials with multi-mode emission, adjustable excitation-dependence and visible-light excitation

Constructing room-temperature phosphorescent materials with multiple emission and special excitation modes is fascinating and challenging for practical applications. Herein, we demonstrate a facile and general strategy to obtain ecofriendly ultralong phosphorescent materials with multi-mode emission, adjustable excitation-dependence, and visible-light excitation using a single organic component, cellulose trimellitate. Based on the regulation of the aggregation state of anionic cellulose trimellitates, such as CBtCOONa, three types of phosphorescent materials with different emission modes are fabricated, including blue, green and color-tunable phosphorescent materials with a strong excitation-dependence. The separated molecularly-dispersed CBtCOONa exhibits blue phosphorescence while the aggregated CBtCOONa emits green phosphorescence; and the CBtCOONa with a coexistence state of single molecular chains and aggregates exhibits color-tunable phosphorescence depending on the excitation wavelength. Moreover, aggregated cellulose trimellitates demonstrate unique visible-light excitation phosphorescence, which emits green or yellow phosphorescence after turning off the visible light. The aggregation-regulated phenomenon provides a simple principle for designing the proof-of-concept and on-demand phosphorescent materials by using a single organic component. Owing to their excellent processability and environmental friendliness, the aforementioned cellulose-based phosphorescent materials are demonstrated as advanced phosphorescence inks to prepare various disposable complex anticounterfeiting patterns and information codes. Room temperature phosphorescent materials have potential in a range of applications, but it is challenging to achieve multiple emission and excitation modes. Here, the authors report the development of RTP materials with different emission modes by regulating the aggregation state.