Organic Persistent RTP Crystals: From Brittle to Flexible by Tunable Self-Partitioned Molecular Packing.

Aiming to solve trade-off of "RTP-flexibility" in principle, organic room temperature phosphorescence (RTP) crystals with elastic/plastic deformation have been realized. These properties are mainly due to the divisional aggregation structures of aromatics and alkoxy chains, and can be modulated by the controllable molecular configurations. The longest RTP lifetime of 972.3 ms has been achieved as the highest record for organic flexible crystals. The plastic crystals with persistent RTP were realized for the first time, which can be applied into biomedical optical technologies by afterglow delivery. Moreover, relationship among elastic/plastic deformation, RTP property and aggregated structures have been established. Elastic/plastic deformation is mainly determined by difference of interaction energies from aromatics and alkoxy chains. For BP-OR series with twisted configurations, the alkoxy chain with the middle length is favorable for RTP property, while the strength of π-π coupling is the cruical factor to RTP property of Xan-OR series with planar skeletons. It explored a new way to promote the development of flexible RTP crystals, by modulation of aggregated structures as well as rational distribution of intermolecular interactions. This article is protected by copyright. All rights reserved.