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Through the polymerization of a diphenylacetylene derivative and subsequent post-polymerization modification of the poly(diphenylacetylene), polymers with ionic liquid units of imidazolium as side chains and bromide anions (P2) and bis(trifluoromethylsulfonyl)imide (Tf2N−) anions (P3) as counterions were obtained. P3 exhibited ultra-high sensitivity and an extremely low limit of detection (LOD) for picric acid (PA) detection in the solution state, the Stern–Volmer constant (Ksv) was 108 017 M−1 and the LOD was 0.6 nM. Meanwhile, P3 exhibited good selectivity to PA over 8 other nitro-aromatics. Mechanistic studies confirmed the coexistence of static quenching and dynamic quenching mechanisms, and photo-induced electron transfer (PET) and resonance energy transfer (FRET) processes may also occur during quenching, with electrostatic interactions playing a crucial role. DFT calculation results confirmed that after the exchange of bromide ions with Tf2N− anions, the electron-accepting role of the ionic liquid units is significantly weakened, leading to significantly higher sensitivity of P3 compared to P2. And contact-mode detection of PA was conducted using readily available filter paper strips and spin-coating films to better simulate practical applications. [ABSTRACT FROM AUTHOR]

Organic room-temperature phosphorescence (RTP) materials have emerged as promising candidates for various applications. However, persistent organic RTP materials are still rare and are limited to specific chromophore backbones as most organic molecules possess inefficient intersystem crossing. Herein, a facile molecular engineering strategy is proposed to impart tunable persistent RTP properties to phenanthridone (PTD) derivatives through substituent effects. Notably, by adjusting the electronic effect or position of substituents, an ultralong lifetime of 114.90 ms is achieved in the PTD-BnCl crystal. Single-crystal structure analysis shows that the variation in the electronic effect or position of substituents can significantly affect intermolecular interactions and molecular packing, thus giving rise to a remarkable influence on the RTP properties of PTD derivatives in bulk crystals. Furthermore, theoretical calculations not only reveal the mechanism of persistent RTP emission but also elucidate the impact of substituent effects on RTP properties from the molecular and crystalline perspectives, respectively. These simple PTD derivatives with persistent RTP properties are reported for the first time and will help enrich the diversity of organic RTP chromophores. [ABSTRACT FROM AUTHOR]

Photodynamic therapy (PDT) represents an emerging and noninvasive modality that has gained clinical approval for the treatment of cancers, leveraging photosensitizers for optimal therapeutic efficacy. In this study, we synthesized a photosensitizer (denoted as DTCSPP) exhibiting a donor–π–acceptor (D–π–A) structural motif. The DTCSPP manifests aggregation-induced emission (AIE) characteristics, along with good biocompatibility and mitochondrial targeting capabilities attributed to its intrinsic charge and D–π–A architecture. The excited-state intramolecular charge transfer of DTCSPP was systematically investigated in both solution and aggregate states using femtosecond transient absorption spectroscopy (fs-TA). The fs-TA results revealed that DTCSPP exhibited a more rapid and facile excited-state molecular motion in the solution state compared to the aggregate state, implying the predominance of nonradiative decay in its photophysical processes within the solution. Given its ability to simultaneously generate type I and type II reactive oxygen species and induce ferroptosis and autophagy in cancer cells, DTCSPP demonstrates effectiveness in PDT at both cellular and in vivo levels. This study contributes a comprehensive understanding of the excited-state intramolecular charge transfer dynamics of charged D–π–A type AIE photosensitizers, shedding light on their potential application in PDT. The multifaceted capabilities of DTCSPP underscore its promise in advancing the field of anticancer therapeutics, providing valuable insights for the identification of anticancer targets and the development of novel drugs. [ABSTRACT FROM AUTHOR]

The search for deep-blue dyes with high luminescence efficiency in the aggregate state and high brightness is particularly important in optoelectronic application. Herein, based on a typical aggregation-induced emission (AIE) unit of tetraphenylpyrazine (TPP), four dyes were prepared by connecting it with chiral binaphthyl units via an acetylenic bond. The use of the TPP unit is critical to aggregation-enhanced emission (AEE) and deep-blue emission, whereas the merging of the binaphthyl unit is beneficial for molecular conjugation to remarkably improve absorption, photoluminescence (PL) quantum efficiency and brightness. Besides, the binaphthyl unit can serve as an axially chiral source to endow the deep-blue dyes with chirality. It was revealed that attaching a longer alkoxy chain to the dyes facilitates the formation of helical self-assemblies determined by chiral transfer but leads to an aggregation-caused emission (ACQ) effect. Moreover, using these deep-blue dyes as energy donors for energy delivery, other emissions and pure white light emission can be generated effectively via an energy transfer process based on a rational mixture of donors and acceptors in PMMA films. The device fabricated by coating this film onto a blue LED also emitted distinct and stable white light. This work provides a flexible way to design high-performance blue materials for potential applications. [ABSTRACT FROM AUTHOR]

Charge transfer (CT) could endow organic luminescent materials with many outstanding properties, particularly triplet harvesting for room-temperature phosphorescence (RTP), which has attracted extensive attention from scientists in recent years. Among them, through-space charge transfer (TSCT) was extensively investigated as a hot topic. However, detecting the existence of TSCT and adjusting it through rational methods are still huge challenges. Herein, we demonstrate a new strategy combining donor (PtzO) and accepter (BP) by a non-conjugated alkyl chain to obtain compound PtzO–3C–BP, successfully realizing TSCT-based RTP in the crystal state. In return, the RTP effect could act as a direct signal to indicate the strength of TSCT. Furthermore, compounds PtzO–nC–BP (n = 4–6) with changed alkyl chains are synthesized, to explore the semi-quantitative relation between TSCT-based phosphorescence performance and donor–accepter distance in the crystal state for a deeper understanding of TSCT. [ABSTRACT FROM AUTHOR]

Aggregation-induced emission (AIE) materials can be well utilized to fabricate high-efficiency blue fluorescence organic light-emitting diodes (OLEDs) due to their fast reverse intersystem crossing (hRISC) from the high-lying triplet state (Tn ≥ 2) to low-lying singlet state (S1) and high photoluminescence (PL) quantum efficiency in the solid film, which should be conducive to the preparation of high-efficiency white OLEDs (WOLEDs). In this study, we fabricated high-efficiency two-color and four-color hybrid WOLEDs based on an AIEgen of 4′-(4-(diphenylamino)phenyl)-5′phenyl-[1,1′:2′,1′′-terphenyl]-4-carbonitrile (TPB-AC) as the blue emitter and host of yellow phosphor, and the efficiency and efficiency roll-off were greatly improved by incorporating a triplet–triplet fusion (TTF) layer in the TPB-AC blue emitter. Finally, the two-color WOLED exhibited a low turn-on voltage of 2.6 V, and the maximum EQE, CE, and PE of 23.2%, 73.2 cd A−1, and 78.7 lm W−1, respectively. The CE, PE, and EQE were maintained at 21.1%, 63.2 cd A−1, and 58.3 lm W−1, respectively, at the luminance of 1000 cd m−2, achieving an extremely low-efficiency roll-off. The optimized four-color hybrid WOLED also showed the maximum EQE, CE, and PE of 24.9%, 49.6 cd A−1, and 51.9 lm W−1, respectively, with low-efficiency roll-off and CRI was over 85. Our results fully demonstrate the potential application value of AIEgens in the preparation of high-performance WOLEDs. [ABSTRACT FROM AUTHOR]

Fluorescent imaging probes are crucial for exploring nucleus-related cellular events in live cells. Ideal probes should be photostable, small-sized, highly contrasted, and low in background. Here, we discovered that malachite green is a water-soluble near-infrared luminogen with aggregation-induced emission properties. Importantly, it can be used for living cell nucleus staining in a wash-free manner. [ABSTRACT FROM AUTHOR]

Sulfur-containing polymers have gained much attention in polymer science due to their unique properties. However, their preparation has posed considerable challenges, particularly in diversifying their structures and achieving highly efficient polymerizations. This is especially true for polymers derived from CS2, a readily available one-carbon (C1) feedstock, as their synthesis often requires the use of harsh conditions or results in unexpected by-products. In this work, we established a regio-selective and atom-economical spontaneous multicomponent polymerization based on carbonyl or ester group-activated internal alkynes, commercially available amines, and CS2. Similar to the angled half lap joint of two plates in a scarf joint of ancient Chinese "mortise and tenon" architecture, internal ethynyl and amino groups cannot be readily linked at room temperature, whereas added CS2 acts as a "wedge" to make the monomers spontaneously expand into tight linkages of polymer chains with satisfactory molecular weights (up to 31 600) in high yields (up to 97%). The polymers exhibited exceptional optical characteristics (refractive indices of up to 1.7471 at 632.8 nm) and good film-forming capabilities. This polymerization opens up a new avenue for the green and efficient synthesis of functional sulfur-containing polymers with low energy consumption, minimized waste generation and efficient use of CS2 resources. [ABSTRACT FROM AUTHOR]

For the first time, we report novel aggregation-induced electrochemiluminescence (AIECL) of organic dots in aqueous media, with near-infrared II (NIR-II) luminescence peaked at 906 nm. Furthermore, a hybrid mechanism of ECL generation is revealed by various experiments in conjunction with theoretical calculations. This work opens a window for exploring efficient organic dye-based NIR-II AIECL emitters. [ABSTRACT FROM AUTHOR]

A novel metal–organic framework (MOF) Zn-PBC (H2PBC = pyridine-3,5-bis(phenyl-4-carboxylic acid)) was designed and synthesized via a solvothermal reaction with the H2PBC ligand, and produced a strong fluorescence. The material exhibited good stability and an ideal luminescent property in water. In addition, it was found that Zn-PBC displayed a different fluorescent response to different types of amino acids, and the mechanism was investigated. This research might give insight to the interaction between MOFs and amino acids, which would provide a strategy to fabricate MOF-based sensors for biomolecules in future. [ABSTRACT FROM AUTHOR]

Cancer is a mortal disease that can invade other parts of the body and cause severe complications. Despite their continuous progress, conventional cancer therapies including surgery, chemotherapy, and radiation therapy have their inherent limitations. To improve the precision of cancer treatment, maximize the therapeutic effect and minimize mortality, synergistic therapies combining imaging guiding technologies, phototherapy, and other therapies have emerged due to the mutually strengthening therapeutic efficacy. However, traditional organic phototherapeutic agents are limited since their aggregation in aqueous media usually affects both their luminescence behavior and therapeutic effect. In contrast, aggregate-induced emission luminogens (AIEgens) provide an ideal solution to develop phototherapy with bright fluorescence and a significant treatment effect in the aggregate state. Combining AIE-based phototherapy and conventional therapies benefits from synergistic effects and extends the potential of developing accurate cancer therapy. AIE-based synergistic therapy has been popularly discussed with such unexplored potential in recent years. This review will introduce the most recent progress of AIE-based synergistic cancer therapy. [ABSTRACT FROM AUTHOR]

Thermally activated delayed fluorescence (TADF) materials are regarded as the most promising next-generation emitters in organic light-emitting diodes (OLEDs). In this work, three TADF compounds were designed and synthesized based on 1,2,3,4-tetrahydrophenazine as acceptor and 9,9-dimethyl-9,10-dihydroacridine (DMAC-TTPZ), phenoxazine (PXZ-TTPZ), and phenothiazine (PTZ-TTPZ) as donors. Wherein, cyclohexane was introduced to the acceptor segment to improve solubility and weaken the conjugate degree to realize blue-shifted emission. Due to the twisted conformation, the frontier molecular orbital (FMO) overlap was largely minimized, resulting in small singlet-triplet energy splitting (ΔEST) of 0.15, 0.09, and 0.07 eV for DMAC-TTPZ, PXZ-TTPZ, and PTZ-TTPZ, respectively. Taking these compounds as emitters for OLEDs, maximum brightness, power efficiency (PE), and external quantum efficiency (EQE) of up to 36 480 cd m−2, 41.0 lm W−1, and 15.3% were achieved, demonstrating their potential in OLEDs. [ABSTRACT FROM AUTHOR]

The pursuit of phototheranostic agents with near-infrared II (NIR-II) emission, high photothermal conversion efficiency (PCE) and the robust generation of reactive oxygen species (ROS) in the aggregated state is always in high demand but remains a big challenge. Herein, we report a simple strategy to endow molecules with NIR-II imaging and photothermal therapy (PTT)/photodynamic therapy (PDT) abilities by equipping NIR-II aggregation-induced emission luminogens (AIEgens) with the cationic trimethylammonium unit, named as TDTN+. The resultant TDTN+ species can self-assemble into nanoparticles, which exhibit a maximum emission at ∼1052 nm, a high PCE (66.7%), type I and type II ROS generation and a mitochondria-targeting ability, simultaneously. The TDTN+ can realize brain imaging with bright fluorescence and an effective tumor killing effect. Overall, this work presents an innovative design strategy to develop multimodality phototheranostic agents. [ABSTRACT FROM AUTHOR]

The intramolecular charge transfer (ICT) process exists widely in lasing molecules which contain electron donors and acceptors. These types of polar molecules are advantageous for securing the charge carrier transport balance that is significant for achieving electrically pumped organic semiconductor lasers (EPOSLs). Therefore, a good understanding of how the ICT process affects the stimulated emission is helpful to develop efficient organic gain materials for applications in EPOSLs. Here, the amplified spontaneous emission (ASE) properties of two donor–π–acceptor type aggregation-enhanced emission (AEE) luminogens (2PB-AC and TPB-AC) were investigated using both steady-state and transient photoluminescence spectroscopy as well as femtosecond transient absorption spectra analysis. The ICT process for polar molecules is sensitive to the distance of the adjacent molecule, which induced the properties of spontaneous emission and stimulated emission to show a concentration dependence. With the enhancement of the ICT process, the overlap between the emission and excited state absorption spectra is enlarged, and the ASE threshold also increases. It is shown that the physical doping or introducing steric groups into molecules can effectively guarantee mirror symmetry between the stimulated emission and emission spectra and reduce the ASE threshold, providing a new idea for the design of efficient lasing organic molecules. [ABSTRACT FROM AUTHOR]

A near-infrared (NIR) luminogen TST was designed and used to efficiently trigger HSP90α protein knockdown through photo-thermal conversion based on a gene interference strategy, by which in vitro and in vivo tumor ablation were significantly acquired at low-temperature. [ABSTRACT FROM AUTHOR]

In this work, a series of butterfly-like isomers named oxacalix[2]naphthalene[2]pyrazine (ONP) were conveniently synthesized by a one-step catalyst-free reaction in a facile manner, and they exhibit typical characteristics of aggregation-induced emission (AIE). The mechanism study shows that restriction of intramolecular vibration (RIV) is the reason for their AIE properties. The pyrazine groups endow ONP molecules with good coordination ability, which makes them ideal ligands for constructing metal–organic frameworks (MOFs). Thus, three ONP-based luminescent MOFs were constructed, and they exhibit intense emission with lifetimes in the order of microseconds. More importantly, different ONP isomers have different binding capacities, and thus only one kind of MOF can be obtained even when using an isomer mixture of ONP ligands. This result suggested that the conformation of ONPs is an important determining factor for their application as bridging ligands. This work not only reports a series of new RIV-type AIEgens, but also offers a new platform for the construction of luminescent MOFs. [ABSTRACT FROM AUTHOR]

Noncancerous diseases include a wide plethora of medical conditions beyond cancer and are a major cause of mortality around the world. Despite progresses in clinical research, many puzzles about these diseases remain unanswered, and new therapies are continuously being sought. The evolution of bio-nanomedicine has enabled huge advancements in biosensing, diagnosis, bioimaging, and therapeutics. The recent development of aggregation-induced emission luminogens (AIEgens) has provided an impetus to the field of molecular bionanomaterials. Following aggregation, AIEgens show strong emission, overcoming the problems associated with the aggregation-caused quenching (ACQ) effect. They also have other unique properties, including low background interferences, high signal-to-noise ratios, photostability, and excellent biocompatibility, along with activatable aggregation-enhanced theranostic effects, which help them achieve excellent therapeutic effects as an one-for-all multimodal theranostic platform. This review provides a comprehensive overview of the overall progresses in AIEgen-based nanoplatforms for the detection, diagnosis, bioimaging, and bioimaging-guided treatment of noncancerous diseases. In addition, it details future perspectives and the potential clinical applications of these AIEgens in noncancerous diseases are also proposed. This review hopes to motivate further interest in this topic and promote ideation for the further exploration of more advanced AIEgens in a broad range of biomedical and clinical applications in patients with noncancerous diseases. [ABSTRACT FROM AUTHOR]

A novel spiro-type donor 5H-spiro[benzo[b]acridine-12,9′-fluorene] (SPBAC) and a thermally activated delayed fluorescence (TADF) emitter bis(4-(5H-spiro[benzo[b]acridine-12,9′-fluoren]-5-yl)phenyl)methanone (2SPBAC-BP) were synthesized for a high efficiency organic light-emitting diode (OLED). The naphthalene moiety can introduce the local excited triplet (3LED) state into the 2SPBAC-BP molecule. 3LED can enhance the spin–orbit coupling (SOC) between the lowest triplet excited state (T1) and the lowest singlet excited state (S1), working as an intermediate between the two charge transfer states (3CT and 1CT) for efficient triplet exciton utilization. Using this strategy, a doped film of 20 wt% 2SPBAC-BP in the PPF host exhibits a high photoluminescence quantum yield of 72%, and the organic light-emitting diode (OLED) based on 2SPBAC-BP displays a high EQE of 26.4%, a current efficiency (CE) of 86.8 cd A−1, and a power efficiency (PE) of 85.2 lm W−1. [ABSTRACT FROM AUTHOR]

Correction for 'Malachite green: a long-buried water-soluble AIEgen with near-infrared fluorescence for living cell nucleus staining' by Yuan Luo et al., Chem. Commun., 2024, 60, 1452–1455, https://doi.org/10.1039/D3CC05535C. [ABSTRACT FROM AUTHOR]

Self-luminescence, which eliminates the real-time external optical excitation, can effectively avoid background autofluorescence in photoluminescence, endowing with ultrahigh signal-to-noise ratio and sensitivity in bioassay. Furthermore, in situ generated and emitted photons have been applied to develop excitation-free diagnostics and therapeutic agents against deeply seated diseases. "Enhanced" self-luminescence, referring to the aggregation-induced emission (AIE)-integrated self-luminescence systems, is endowed with not only the above merits but also other superiorities including stronger luminous brightness and longer half-life compared with "traditional" self-luminescence platforms. As an emerging and booming hotspot, the "enhanced" self-luminescence facilitated by the win–win cooperation of the aggregation-induced emission and self-luminescent techniques has become a powerful tool for interdisciplinary research. This tutorial review summarizes the advancements of AIE-assisted self-luminescence including chemiluminescence and afterglow imaging, starting from the discussion on the design and working principles, luminescent mechanisms of self-luminescence fuels, versatile integrated approaches and advantages, and a broad range of representative examples in biosensors and oncotherapy. Finally, the current challenges and perspectives are discussed to further actuate the development of "enhanced" self-luminescence agents for biomedical diagnosis and treatment. [ABSTRACT FROM AUTHOR]

The exploitation of ultralong organic room temperature phosphorescence (UORTP) materials lags far behind the need because of the lack of general design strategies. Here we proposed a facile design strategy based on the structural control of intramolecular hydrogen bonding (IHB) and push–pull electron effects (PPEEs) to construct highly efficient UORTP materials. Two series of carbazole derivatives with different IHBs and PPEEs were designed accordingly. By enhancing the IHB interactions of the luminophores, the molecular planarity, intermolecular interactions and packing mode were effectively tuned, facilitating the intermolecular electron coupling. PPEEs, enhanced by introducing heteroatoms and heavy atoms, strengthened the intramolecular charge transfer states, which changed the orbital transition configuration of excited states, thus boosting the intersystem crossing (ISC) and spin–orbit coupling (SOC). Consequently, CzPM and CzPMBr with dual IHBs and the strongest PPEEs exhibited ultralong lifetimes (τP) of 1.31 s and 233 ms with the highest phosphorescence quantum yields (ΦP) of 1.7% and 48.6% in their series, respectively. Theoretical investigations revealed that the high-lying intersystem crossing (HISC) between excited singlet states (Sm, m > 1) and triplet states (Tn, n > 1) occurred and played a vital role in enhancing the ΦP values of UORTP materials. Significantly, the SOC matrix elements between S3 and T7 (ξ(S3,T7)) of CzPMBr reached up to 39.95 cm−1. Finally, CzPMBr was successfully used as an anti-counterfeiting ink in calligraphy and painting due to its excellent RTP properties. The design strategy based on the structural control of IHBs and PPEEs will greatly widen the design platform of UORTP materials. Meanwhile, the discovery of the HISC process will also provide a new insight for the design of UORTP materials. [ABSTRACT FROM AUTHOR]

"Hot-exciton" emitters featuring high-lying reverse intersystem crossing (hRISC) have served as promising candidates due to their improved exciton utilization efficiency and efficiency roll-off in organic light-emitting diodes (OLEDs). Generally, optimal and expected hRISC processes should take place from T2 to S1, which could be achieved by fabricating a larger energy gap between T2 and T1 (ΔET2T1) and a small energy difference between T2 and S1 (ΔET2S1). The accurate and controlled regulation of the distribution of excited-state energy levels showed the special importance of activating hRISC but, regrettably, work has rarely been reported on how to regulate the position of high-lying triplet levels. In this work, two similar emitters (2NpNMZ and 2AnNMZ) were designed to attempt to tune the T2 state based on a new "hot-exciton" core of naphtho[2,3-d][1,2,3]triazole (NMZ). An interesting discovery was that the T2 levels of the two emitters were contributed by the T1 levels of the corresponding substituent group, which was ascribed to the orbital electrons on the T2 state being concentrated in substituent units (naphthalene and anthracene). Their T1 energy levels were similar because the orbital electrons of the T1 state were both contributed by the NMZ core. 2NpNMZ possessed larger ΔET2T1 than 2AnNMZ because of the higher T1 level of Np than that of an An unit, which might suppress the internal conversion of a T2 exciton to a T1 platform (T2 → T1). In addition, the higher PLQY in neat film and smaller ΔET2S1 mean 2NpNMZ enjoys better efficiency than 2AnNMZ when they are used as the emitting layers of non-doped OLEDs. [ABSTRACT FROM AUTHOR]

The sensitive detection and dynamic monitoring of the structural health of polymers are crucial to increase their quality, reliability, and durability. Although a lot of effort has been devoted to the indication of static damaged and/or healed states of polymers, the simple, sensitive, and real-time monitoring of dynamic damaging–healing processes still remains challenging. In this work, a facile design strategy for multifunctional polymer coatings that can sensitively show their damaging–healing processes in an on-site, real-time, and full-field manner is demonstrated. By embedding UV-blocking microcapsules containing the diisocyanate solution of an aggregation-induced emission luminogen (AIEgen) into a polymer matrix, immediate turn-on fluorescence is observed upon damage, and dual-signal variations in both the fluorescence intensity and color can be clearly visualized during the dynamic healing process. These changes can also be readily and semi-quantitatively detected by using a fluorescence spectrometer and digital image correlation analysis. Such a high-contrast fluorescence change is achieved due to the collective effects of AIE and twisted intramolecular charge transfer of the luminogen. Benefiting from the multifunctional microcapsules, the composite polymeric coatings exhibit excellent photo-protective and water-proof performances in addition to the autonomous damaging–healing visualization capability, which are appealing to various practical applications. [ABSTRACT FROM AUTHOR]

Organic emitters with multiple emissions such as aggregation-induced emission (AIE), thermally activated delayed fluorescence (TADF), room-temperature phosphorescence (RTP), and mechanoluminescence (ML) are promising candidates for various high-tech applications but are still very rare. Here, for the first time, an effective strategy of positional isomerism is applied to obtain simple organic isomers featuring diversified emissive behaviors of AIE, TADF, RTP, dual-RTP, and ML. In particular, AIE, TADF, and ML are successfully realized simultaneously in the ortho-isomer o-ClTPA while typical AIE and unique dual-RTP coexist in the para-isomer p-ClTPA. Crystal structure analysis shows that the subtle variation in the substitution position can significantly alter intermolecular interactions and molecular packings, which in turn exerts remarkable effects on the crystal-state emissive properties. Therefore, diversified emissive behaviors of TADF, RTP, dual-RTP, and ML are consequently observed from these positional isomers. Furthermore, theoretical calculations not only afford deep insight into the mechanism of different luminescence properties but also elaborate the relationship between positional isomers and luminescence properties from molecular and crystalline perspectives. These simple isomers featuring diversified emissive behaviors of AIE, TADF, RTP, dual-RTP, and ML are reported for the first time, which will deepen the understanding of the relationship between molecule structures and multiple emissions. [ABSTRACT FROM AUTHOR]

With the development of microelectronics technology, personalized intelligent lighting and lighting control systems have been widely utilized in smart buildings to save energy, facilitate people's lives, and decorate our community environment. This article presents four bipolar molecules (1–4) with bright color-tunable emission from blue (446 nm) to red (637 nm) light, which were designed and synthesized via constructing a pull–push system. Moreover, these highly thermally stable molecules with tunable fluorescence emission were used as highly efficient emitters for fabricating stable RGB LED devices with a considerable color rendering index (CRI). Furthermore, we designed an electrocircuit system to control green, red and yellow LED devices using an "ON" and "OFF" switch via voice-activated microelectronics technology. Thus, this study not only provides a molecular strategy to construct tunable-emission materials for multi-color LED device applications, but also offers an efficient example for combining organic synthesis with electronic devices to realize a personalized intelligent lighting and light control system via microelectronics technology. [ABSTRACT FROM AUTHOR]

Strong polarity usually causes emission quenching; however, the polarity induced emission enhancement with great importance for applications in some polar environments is rarely reported. A structural and theoretical proof-of-concept to realize polarity enhanced emission materials is necessary. In this research, we have achieved polarity enhanced emission by studying the intramolecular charge transfer mechanism: (1) the weak emission in non-polar solvents is attributed to the obvious hole–electron overlap on the flexible tetraphenylpyrazine unit; (2) the planarized intramolecular charge transfer could increase the hole–electron population gradually and reduce the overlap degree on tetraphenylpyrazine to achieve emission enhancement in highly polar solvents; (3) twisted conformation with excessive charge separation (twisted intramolecular charge transfer) could cause fluorescence quenching in highly polar solvents. In addition, these findings can offer guidelines for the design of new molecular systems with polarity enhanced emission behavior. [ABSTRACT FROM AUTHOR]