Fluorene-based host-guest phosphorescence materials for information encryption

• A new RTP system based on fluorene derivative has been developed. • A host-guest synergy effect based on different electronic structures is revealed. • The longest lifetime of RTP can reach up to 847 ms. • Novel application in information encryption on the basis of RGB values is explored. Metal-free organic phosphorescence materials are commonly utilized in the area of optoelectronics and bioelectronics. However, the development of materials with simultaneous efficiency and lifetime enhancement under ambient conditions remains a challenge. In this study, we design and synthesize a new class of highly efficient organic room-temperature phosphorescence (RTP) materials through the host-guest doping strategy. The host molecules not only act as a bridge to promote the intersystem crossing, but also build a rigid environment to limit nonradiative decay of triplet excitons. An optimal host-guest material is thus achieved which possesses an ultralong lifetime of up to 847 ms and phosphorescence quantum efficiency of 4.7% under ambient conditions. Furthermore, the RTP materials can be successfully applied to information encryption and decryption. Our developed method not only paves the way forward for RTP materials but also expands their applications.