Coinage bonds, a type of non-covalent interaction, occur between group 11 elements (Au, Ag and Cu) with electron donor groups. Despite theoretical validation, empirical evidence remains limited. In this study, an aggregation-induced emission (AIE)-active Au(I) complex, ITCPAu, which exhibits Au···I coinage bonds, was revealed based on the single-crystal X-ray diffraction and theoretical calculations. Further examination of the luminescence properties of the ITCPAu revealed multi-switchable behavior, including mechanochromism and thermochromism. Nearly pure white-light emission was achieved with Commission Internationale de L’Eclairage (CIE) 1931 chromaticity coordinates of (0.30, 0.31) by grinding the green-emissive ITCPAu monomer crystals. Moreover, visualization and manipulation of solid-state molecular motion (SSMM) in the yellow-emissive ITCPAu dimer crystals, driven by the robust Au···I coinage bonds, were revealed through a combination of crystal engineering and luminescent properties. Furthermore, to support the robust Au···I coinage bonds, a versatile carrier for small solvent molecules in crystal lattices was developed for uptake and release. Our findings provide experimental and theoretical evidence for Au···I coinage bonds, highlighting their ability to boost photoluminescence quantum yield (PLQY) and trigger SSMM, emphasizing their potential in developing smart materials with stimuli-responsive properties.

Organic light-emitting diodes (OLEDs) based on purely organic room-temperature phosphorescence (RTP) materials often encounter issues of relatively low efficiency and spectral instability. To overcome this limitation, three (arylthio)benzene derivatives (4S, 5S, and 6S) with gradually increased RTP component are designed and compared. Theoretical calculation and photophysical investigation reveal that the fully-substituted arylthio effect could enhance the aggregation-induced phosphorescence, enlarge the spin orbital coupling, and reduce the energy gap between S 1 and T 1 as much as possible. As a result, 6S can exhibit single spectra in films with a high phosphorescence efficiency up to 76.7%, and its doped RTP-OLED furnishes a high maximum external quantum efficiency (EQE) of 15.3% and ultra-stable spectra with the brightness raised from 30 cd m -2 to 2000 cd m -2. Furthermore, serving 6S as the sensitizer, the RTP-sensitized-fluorescent OLEDs based on fluorescence dopant TBRb and multiple resonance TADF dopant BN3 show three times improvement in electroluminescence performance, with EQE values of 11.3% and 25.6%, respectively. These results demonstrate the feasibility of fully-substituted arylthio effect in designing RTP materials and could advance the development of high-performance RTP OLEDs.

Solar-driven interfacial evaporation is a promising technology for desalination. The photothermal conversion materials are at the core and play a key role in this field. Design of photothermal conversion materials based on organic dyes for desalination is still a challenge due to lack of efficient guiding strategy. Herein, a new D (donor)-A (acceptor) type conjugated tetraphenylpyrazine (TPP) luminophore (namely TPP-2IND) was prepared as a photothermal conversion molecule. It exhibited a broad absorption spectrum and strong π– π stacking in the solid state, resulting in efficient sunlight harvesting and boosting nonradiative decay. TPP-2IND powder exhibited high photothermal efficiency upon 660 nm laser irradiation (0.9 Wcm -2), and the surface temperature can reach to 200 oC. Then, an interfacial heating system based on TPP-2IND is established successfully. The water evaporation rate and the solar-driven water evaporation efficiency were evaluated up to 1.04 kgm -2h -1 and 65.8% under 1 sunlight, respectively. Thus, this novel solar-driven heating system shows high potential for desalination and stimulates the development of advanced photothermal conversion materials.

Fluorescence imaging, a key technique in life science research, frequently utilizes fluorogenic probes for precise imaging in living systems. Tetrazine is an effective emission quencher in the design of fluorogenic probes, which can be selectively damaged upon bioorthogonal click reactions, leading to considerable emission enhancement. Despite significant efforts to increase the emission enhancement ratio upon click reaction (IAC/IBC) of tetrazine-functionalized fluorogenic probes, the influence of molecular aggregation on the emission properties has been largely overlooked in the design of these probes. In this study, we reveal that an ultrahigh IAC/IBC can be realized in the aggregate system when tetrazine is paired with aggregation-induced emission (AIE) luminogens. Tetrazine can increase its quenching efficiency upon aggregation and drastically reduce background emissions. Subsequent click reactions damage tetrazine and trigger significant AIE, leading to considerably enhanced IAC/IBC. We further showcase the capability of these ultra-fluorogenic systems in selective imaging of multiple organelles in living cells. We propose the term “Matthew Effect” in Aggregate Emission to describe the unique fluorogenicity of these probes, potentially providing a universal approach to attain ultrahigh emission enhancements in diverse fluorogenic aggregate systems.

The study of luminescence phenomena in non-conjugated systems, namely clusteroluminescence, has gained significant attention for the development of advanced luminescent materials. While conventional strategies to manipulate the luminescent performances are based on complicated chemical reactions. In contrast, nature employs complexation to modulate luminescence, inspiring researchers to adopt an engineering approach for the construction of efficient clusteroluminogens. In this work, we explore the complexation-induced clusteroluminescence of carbonyl-based polymers with nitrogen-containing organic bases, exemplified by polyamide, polyester, polycarbonate, and poly(monothiocarbonate). The results demonstrate an increase in the intrinsic 440 nm emission of carbonyl groups and the emergence of new emission peaks upon complexation. The study proposes a through-space n‧‧‧π complex mechanism, highlighting the potential of complexation as a strategy for modulating the clusteroluminescent properties of non-conjugated systems. Further research is necessary to unravel underlying mechanisms, optimize cluster structures, and explore new materials for complexation, thereby advancing optoelectronics and photonics fields and enabling practical applications of clusteroluminescent materials.

Room-temperature phosphorescence (RTP) of purely organic materials is easily quenched with unexpected purposes because the excited triplet state is extremely susceptible to external stimuli. How to stabilize the RTP property of purely organic luminogens is still challenging and considered as the bottleneck in the further advancement of the bottom-up approach. Here, we describe a gated strategy that can effectively harness RTP by employing complexation/dissociation with proton. Due to the order-disorder transition orientation of intermolecular packing, the RTP of triazine derivative Br-TRZ will easily vanish upon mechanical force. Impressively, by enhancing its intramolecular charge transfer effect, the protonated Br-TRZ stubbornly possesses an obvious RTP under external grinding, whatever in the ordered or disordered intermolecular arrangement state. Consequently, the “Lock” gate of RTP was achieved in the protonated Br-TRZ molecule. Combined with theoretical calculation analysis, the enhanced charge transfer effect can narrow the singlet−triplet energy gap significantly, and stabilize the RTP property of triazine derivative sequentially. Furthermore, the locked RTP can be tuned via proton and counterions repeatedly and show excellent reversibility. This gated RTP concept provide an effective strategy for stabilizing the RTP emission of purely organic systems.