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The development of flexible, room‐temperature phosphorescence (RTP) materials remains challenging owing to the quenching of their unstable triplet excitons via molecular motion. Therefore, a polymer matrix with Tg higher than room temperature is required to prevent polymer segment movement. In this study, a RTP material was developed by incorporating a 4‐biphenylboronic acid (BPBA) phosphor into a poly(vinylidene fluoride) (PVDF) matrix (Tg=−27.1 °C), which exhibits a remarkable UV‐light‐dependent oxygen consumption phosphorescence with a lifetime of 1275.7 ms. The adjustable RTP performance is influenced by the crystallinity and polymorph (α, β, and γ phases) fraction of PVDF, therefore, the low Tg of the PVDF matrix enables the polymeric segmental motion upon microwave irradiation. Consequently, a reduction in the crystallinity and an increase in the α phase fraction in PVDF film induces RTP after 2.45 GHz microwave irradiation. These findings open up new avenues for constructing crystalline and phase‐dependent RTP materials while demonstrating a promising approach toward microwave detection. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: Organic room‐temperature phosphorescence (RTP) materials have attracted immense attention in bioimaging due to their long emission lifetime and large Stokes shift. RTP materials with long emission wavelength can improve the penetration depth for bioimaging. However, the design of red persistent RTP materials is still challenging. In this study, a fused‐ring structure has been proposed to effectively decrease the triplet energy level, thus extending the emission wavelength of phosphorescence. In addition, the fused‐ring structure exhibits a high molar extinction coefficient (ɛ) and high luminescence efficiency due to the rigid structure. A new class of crystalline hosts (iminodibenzyl, IDB) are developed to stabilize the triplet excitons that are generated from the fused‐ring molecules. The maximum RTP wavelength of doping materials can reach 635 nm with a lifetime of 9.35 ms. Water‐disperse nanoparticles are successfully prepared for in vivo time‐resolved bioimaging, which eliminates the background fluorescence interference from biological tissues. These reveal a delicate design strategy for the construction of long‐wavelength emissive RTP materials for high‐resolution bioimaging. [ABSTRACT FROM AUTHOR]

Monotonous luminescence has always been a major factor limiting the application of organic room‐temperature phosphorescence (RTP) materials. Enhancing and regulating the intermolecular interactions between the host and guest is an effective strategy to achieve excellent phosphorescence performance. In this study, intermolecular halogen bonding (CN⋅⋅⋅Br) was introduced into the host–guest RTP system. The interaction promoted intersystem crossing and stabilized the triplet excitons, thus helping to achieve strong phosphorescence emission. In addition, the weak intermolecular interaction of halogen bonding is sensitive to external stimuli such as heat, mechanical force, and X‐rays. Therefore, the triplet excitons were easily quenched and colorimetric multi‐stimuli responsive behaviors were realized, which greatly enriched the luminescence functionality of the RTP materials. This method provides a new platform for the future design of responsive RTP materials based on weak intermolecular interactions between the host and guest molecules. [ABSTRACT FROM AUTHOR]

Organic materials with long‐lived, color‐tunable phosphorescence are potentially useful for optical recording, anti‐counterfeiting, and bioimaging. Herein, we develop a series of novel host–guest organic phosphors allowing dynamic color tuning from the cyan (502 nm) to orange red (608 nm). Guest materials are employed to tune the phosphorescent color, while the host materials interact with the guest to activate the phosphorescence emission. These organic phosphors have an ultra‐long lifetime of 0.7 s and a maximum phosphorescence efficiency of 18.2 %. Although color‐tunable inks have already been developed using visible dyes, solution‐processed security inks that are temperature dependent and display time‐resolved printed images are unprecedented. This strategy can provide a crucial step towards the next‐generation of security technologies for information handling. [ABSTRACT FROM AUTHOR]

Halogen Bonding, Host-Guest Systems, Multi-Stimuli-Responsive Luminescence, Radioluminescence, Room-Temperature Phosphorescence, Weak Intermolecular Interactions Rücktitelbild: Halogen Bonding: A New Platform for Achieving Multi-Stimuli-Responsive Persistent Phosphorescence (Angew. Keywords: Halogen Bonding; Host-Guest Systems; Multi-Stimuli-Responsive Luminescence; Radioluminescence; Room-Temperature Phosphorescence; Weak Intermolecular Interactions EN Halogen Bonding Host-Guest Systems Multi-Stimuli-Responsive Luminescence Radioluminescence Room-Temperature Phosphorescence Weak Intermolecular Interactions 1 1 1 03/16/22 20220321 NES 220321 B Die Halogenbindung b ist ein wirksames Mittel in der supramolekularen Festkörperchemie, um Kristallstrukturen zu stabilisieren. [Extracted from the article]

Back Cover: Halogen Bonding: A New Platform for Achieving Multi-Stimuli-Responsive Persistent Phosphorescence (Angew. Halogen Bonding, Host-Guest Systems, Multi-Stimuli-Responsive Luminescence, Radioluminescence, Room-Temperature Phosphorescence, Weak Intermolecular Interactions Keywords: Halogen Bonding; Host-Guest Systems; Multi-Stimuli-Responsive Luminescence; Radioluminescence; Room-Temperature Phosphorescence; Weak Intermolecular Interactions EN Halogen Bonding Host-Guest Systems Multi-Stimuli-Responsive Luminescence Radioluminescence Room-Temperature Phosphorescence Weak Intermolecular Interactions 1 1 1 03/16/22 20220321 NES 220321 B Halogen bonding b is an effective tool in solid-state supramolecular chemistry to stabilize crystal structures. [Extracted from the article]

Comprehensive Summary: Organic room‐temperature phosphorescence (RTP) materials have attracted immense attention in bioimaging due to their long emission lifetime and large Stokes shift. RTP materials with long emission wavelength can improve the penetration depth for bioimaging. However, the design of red persistent RTP materials is still challenging. In this study, a fused‐ring structure has been proposed to effectively decrease the triplet energy level, thus extending the emission wavelength of phosphorescence. In addition, the fused‐ring structure exhibits a high molar extinction coefficient (ɛ) and high luminescence efficiency due to the rigid structure. A new class of crystalline hosts (iminodibenzyl, IDB) are developed to stabilize the triplet excitons that are generated from the fused‐ring molecules. The maximum RTP wavelength of doping materials can reach 635 nm with a lifetime of 9.35 ms. Water‐disperse nanoparticles are successfully prepared for in vivo time‐resolved bioimaging, which eliminates the background fluorescence interference from biological tissues. These reveal a delicate design strategy for the construction of long‐wavelength emissive RTP materials for high‐resolution bioimaging. [ABSTRACT FROM AUTHOR]