Search

Abstract Anti-Kasha’s process in organic luminogens has attracted many attentions since its discovery. However, only limited examples of anti-Kasha’s rule have been reported and anti-Kasha triplet energy transfer (ET) is even less-touched. Benefiting from anti-Kasha’s rule, this work provided an efficient strategy to realize excitation wavelength dependent (Ex-De) afterglow in a host-guest system. The host has almost imperceptible RTP upon 365 nm excitation and guest is totally RTP inactive, while the doping host-guest system exhibits Ex-De afterglow with improved quantum yields. Anti-Kasha triplet ET process is realized from the higher excited triplet state T2 of host to the lowest excited singlet state S1 of the aggregated/unimolecular guest. ET efficiency in the doping system could be tuned by simply changing its processing methods to guide host and guest to adopt denser or looser intermolecular packing. The strategy of anti-Kasha triplet ET endows the host-guest doping system with multiple stimuli-responsive properties, including Ex-De afterglow, mechano-, and thermal-triggered afterglow behaviors. The corresponding applications of these properties are also realized in multiple information anti-counterfeiting and display.

Recently, purely organic room-temperature phosphorescence (RTP) from guest-host-doped systems has grown exponentially due to their high modulation flexibility. Benzophenone has been found as a preferred host matrix thanks to its low melting point, minimal biological toxicity, remarkable stability, and cost-effectiveness. However, the precise role of benzophenone remains elusive and has been debated within the scientific community concerning mechanistic elucidations. Here, five indole derivatives were designed and synthesized as guest molecules while retaining benzophenone as the host to construct doped materials exhibiting outstanding RTP properties. Our experimental findings unequivocally establish that the host benzophenone initially absorbs excitation energy, subsequently intersystem crossing into triplet exciton, facilitating the exciton transfer to guest molecule through the triplet energy transfer and culminating in guest RTP emission. Mechanistic investigation corroborates the superiority of benzophenone in possessing a large spin-orbit coupling constant and quantitatively triplet energy transfer. Collectively, this work provides compelling evidence deciphering energy transfer between host and guest entities for the manifestation of phosphorescence performance in benzophenone-hosted doped materials.

The development of non-invasive, rapid responsive phosphorescence is highly desirable but has rarely been described. Herein, the authors designed and prepare a series of molecular rotors containing a room temperature phosphorescence active triazine core and three bromobiphenyl units acting as rotors and demonstrate light stimulus triggered phosphorescence.

Switchable hydrogen-bonded frameworks have potential applications in the development of smart materials. Herein, the authors report eleven hydrogen-bonded organic frameworks and two non-porous structures that can undergo reversible structural and fluorescence switching; white-light emission is enabled.

The potential of organic materials with persistent room-temperature phosphorescence for high-tech application is limited by their low efficiency. Here, the authors report a strategy to enhance persistent room-temperature phosphorescence efficiency via intramolecular triplet-triplet energy transfer.

The development of intelligent materials, in particular those showing the highly sensitive mechanoresponsive luminescence (MRL), remains challenging. Here the authors report a strategy for constructing high performance On-Off MRL materials by introducing nitrophenyl groups to molecules with aggregation-induced emission characteristic.

The development of single molecule white light-emitters is extremely challenging for pure phosphorescent metal-free systems at room temperature. Here the authors show a single pure organic room temperature phosphor, 4-chlorobenzoyldibenzothiophene, utilizing the emission from both T1 and T2 states.

Organic fluorophores with reversibleemission switching behaviorare promising materials for applications in sensors, optical recording,security inks, and optoelectronics. A variety of aggregation-inducedemission (AIE) luminogens with mechanochromic luminescence has beenprepared, and the transformation of efficient bluer-emitting crystalsto amorphous powders with redder and weaker emission is proposed tobe the cause for such behavior. However, detailed mechanistic understandingfrom experimental to theoretical is lacking. In this work, we presentthe design and synthesis of a group of bis(diarylmethylene)dihydroanthraceneswith butterfly-like shapes. These molecules exhibit aggregation-inducedemission characteristics due to the restriction of intramolecularmotion in the aggregated state. They show mechanochromism, becauseof the transformation between crystal and amorphous states with differentcolors and efficiencies aided by grinding/heating or solvent fumingprocesses. By investigation of their single-crystal structures andtheoretical calculations, the loose molecular packing with noncovalentintermolecular interactions, the extent of conformational twisting,and the packing density of the luminogens, as well as freedom of intermolecularmotion in the excited state, are stemmed for their reversible polymorphism-dependentemission behaviors. [ABSTRACT FROM AUTHOR]

The article presents a study which explores about the dual organelle-targeting mechanosensitive probe. It mentions that study also introduces a unique tool for mapping the membrane tension in the plasma membrane and mitochondria together, providing us great opportunities to study organelle's interactions in mechanobiology.