A Thorough Examination of the Variables Affecting the Quantum Efficiency of Radiative Decay of Trichlorotriphenylmethyl Radicals.

Fluorescence quantum efficiency is determined by the competition between radiation and nonradiation processes of the excited states. Understanding the factors affecting the radiation and nonradiative decay rates is of great significance for the design of luminescent materials. The excitation state deactivation mechanisms of singlet and triplet states have been extensively studied, providing a comprehensive understanding of the processes involved in the relaxation of these states. However, research on free radical systems involving doublet states is relatively scarce. Therefore, in this study, radiation and nonradiative decay rates and the mechanism of a series of trichlorotriphenylmethyl-based radicals were investigated theoretically. The results indicate that the relative rotations of electron donor and acceptor, as well as the internal rotations of trichlorotriphenylmethyl moiety, play important roles in energy dissipation through nonradiative channels. The effect of a solid-state environment on the radiation and nonradiative decay rates of radicals was investigated using a combination of quantum mechanics and molecular mechanics methods. The results indicate that the solid-state environment restricts the expansion of the conjugated system in the excited state of radicals, leading to a slight decrease in radiative decay rate. In addition, the solid-state environment reduces the reorganization energy and also affects the adiabatic excitation energy of radicals. The reduction in reorganization energy results in a decrease in nonradiative rate, while the opposite effect is observed for adiabatic excitation energy. The nonradiative rate of radicals in a solid-state environment is thus inflected by a combination of molecular geometric structure relaxation and ground-excited state energy gap.

Superior Superconducting Properties Realized in Quaternary La-Y-Ce Hydrides at Moderate Pressures.

The recent revolution in the superconductivity field stems from hydride superconductors. Multicomponent hydrides provide a crucial platform for tracking high-temperature superconductors. Besides high superconducting transition temperature (Tc), achieving both giant upper critical magnetic field [µ0Hc2(0)] and high critical current density [Jc(0)] is also key to the latent potential of the application for hydride superconductors. In this work, we have successfully synthesized quaternary La-Y-Ce hydrides with excellent properties under moderate pressure by using the concept of "entropy engineering." The obtained temperature dependence of the resistance provides evidence for the superconductivity of Fm3m-(La,Y,Ce)H10, with the maximum Tc ∼ 190 K (at 112 GPa). Notably, Fm3m-(La,Y,Ce)H10 boasts exceptional properties: µ0Hc2(0) reaching 292 T and Jc(0) surpassing 4.61 × 107 A/cm2. Compared with the binary LaH10/YH10, we find that the Fm3m structure in (La,Y,Ce)H10 can be stable at relatively low pressures (112 GPa). These results indicate that multicomponent hydrides can significantly enhance the superconducting properties and regulate stabilizing pressure through the application of "entropy engineering." This work stimulates the experimental exploration of multihydride superconductors and also provides a reference for the search of room-temperature superconductors in more diversified hydride materials in the future.

Theory-Guided Experimental Design of Covalent Triazine Frameworks for Efficient Photocatalytic Hydrogen Production.

The high crystalline covalent triazine framework-1 (CTF-1), composed of alternating triazine and phenylene, has emerged as an efficient photocatalyst for solar-driven hydrogen evolution reaction (HER). However, it is of great challenge to further improve photocatalytic HER performance via increasing crystallinity due to its near-perfect crystallization. Herein, an alternative strategy of scaffold functionalization is employed to optimize the energy band structure of crystalline CTF-1 for boosting hydrogen-evolving activity. Guided by the computational predictions, versatile CTF-based polymer photocatalysts are prepared with different functional groups (OH, NH2, COOH) using binary polymerization for practical hydrogen production. Experiment evidence verifies that the introduction of a limited number of electron-donating groups is sufficient to maintain high crystallinity in CTF, modulate the band structure, broaden visible light absorption, and consequently enhance its photophysical properties. Notably, the functionalization with OH exhibits the most positive effect on CTF-1, delivering a photocatalytic activity with a hydrogen-producing rate exceeding 100 µmol h-1.

MD investigation on the differences in the dynamic interactions between the specific ligand azamulin and two CYP3A isoforms, 3A4 and 3A5.

The unmarked potential drug molecule azamulin has been found to be a specific inhibitor of CYP3A4 and CYP3A5 in recent years, but this molecule also shows different binding ability and affinity to the two CYP3A isoforms. In order to explore the microscopic mechanism, conventional molecular dynamics (MD) simulation methods were performed to study the dynamic interactions between two isoforms and azamulin. The simulation results show that the binding of the ligand leads to different structural properties of two CYP3A proteins. First of all, compared with apo-CYP3A4, the binding of the ligand azamulin can lead to changes in the structural flexibility of CYP3A4, i.e., holo-CYP3A4 is more flexible than apo-CYP3A4. The structural changes of CYP3A5 are just the opposite. The ligand binding increases the rigidity of CYP3A5. Furthermore, the representative structures of the production phase in the MD simulation were in details analyzed to obtain the microscopic interactions between the ligand azamulin and two CYP3A isoforms at the atomic level. It is speculated that the difference of composition and interaction of the active sites is the fundamental cause of the change of structural properties of the two proteins.Communicated by Ramaswamy H. Sarma.

Piezofluorochromism in Hierarchical Porous π-stacked Supermolecular Spring Frameworks from Aromatic Chiral Cages.

Piezochromic materials that exhibit pressure-dependent luminescence variations are attracting interest with wide potential applications in mechanical sensors, anticounterfeiting and storage devices. Crystalline porous materials (CPMs) have been widely studied in piezochromism for highly tunable luminescence. Nevertheless, reversible and high-contrast emission response with a wide pressure range is still challenging. Herein, the first example of hierarchical porous cage-based πOF (Cage-πOF-1) with spring structure was synthesized by using aromatic chiral cages as building blocks. Its elastic properties evaluated based on the bulk modulus (9.5 GPa) is softer than most reported CPMs and the collapse point (20.0 GPa) significantly exceeds ever reported CPMs. As smart materials, Cage-πOF-1 displays linear pressure-dependent emission and achieves a high-contrast emission difference up to 154 nm. Pressure-responsive limit is up to 16 GPa, outperforming the CPMs reported so far. Dedicated experiments and density functional theory (DFT) calculations illustrate that π-π interactions-dominated controllable structural shrinkage and porous-spring-structure-mediated elasticity is responsible for the outstanding piezofluorochromism.

Density Functional Calculation and Evaluation of the Spectroscopic Properties and Luminescent Material Application Potential of the N-Heterocyclic Platinum(II) Tetracarbene Complexes.

A series of reported Pt(II) carbene complexes possibly have the ability to serve as the new generation of blue emitters in luminescent devices because of their narrow emission spectra, high photoluminescence quantum yields (PLQYs), and rigid molecular skeleton. However, the combination of all carbene ligands with different multidentate structures will affect the overall planarity and horizontal dipole ratio to varying degrees, but the specific extent of this effect has not previously been analyzed in detail. In this work, density functional computation is used to study a class of platinum tetracarbene bidentate complexes with similar absorption and emission band characteristics, which is the main reason for the remarkable difference in quantum efficiency due to subtle differences in electronic states caused by different ligands. From the calculation results, the major reason, which results in significantly decrease in quantum efficiency for [Pt(cyim)2]2+, is that [Pt(cyim)2]2+ can reach the non-radiative deactivation metal-centered d-d excited state through an easier pathway compared with [Pt(meim)2]2+. The result, based on changes in the dihedral angle between ligands, can achieve the goal of improving and designing materials by adjusting the degree of the dihedral angle. (meim: bis(1,1'-dimethyl-3,3'-methylene-diimidazoline-2,2'-diylidene); cyim: bis(1,1'-dicyclohexyl-3,3'-methylene-diimidazoline-2,2'-diylidene).

Solvent-Promoted Catalyst-Free Recycling of Waste Polyester and Polycarbonate Materials.

Polymeric materials are indispensable in our daily lives. However, the generation of vast amounts of waste polymers poses significant environmental and ecological challenges. Instead of resorting to landfilling or incineration, strategies for polymer recycling offer a promising approach to mitigate environmental pollution. Pioneering studies have demonstrated the alcoholysis of waste polyesters and polycarbonates; however, these processes typically require the use of catalysts. Moreover, the development of strategies for catalyst removal and recycling is crucial, particularly in some industrial applications. In contrast, we present a catalyst-free method for the alcoholysis of common polyester and polycarbonate materials into small organic molecules. Certain polar organic solvents exhibit remarkable efficiency in polymer degradation under catalyst-free conditions. Employing these polar solvents, both polymer resins and commercially available products could be effectively degraded via alcoholysis. Our design contributes a straightforward route for recycling waste polymeric materials.

Synergistic Integration of Amorphous Cobalt Phosphide with a Conductive Channel for Highly Efficient Electrocatalytic Nitrate Reduction to Ammonia.

Electrocatalytic nitrate reduction to ammonia (NO3 RR) is regarded as a viable alternative reaction to "Haber Bosch" process. Nevertheless, it remains a major challenge to explore economical and efficient electrocatalysts that deliver high NH3 yield rates and Faraday efficiencies (FE). Here, it demonstrates the fabrication of a 3D core-shell structured Co-carbon nanofibers (CNF)/ZIF-CoP for NO3 RR application. Benefitting from the distinct electron transport property of Co-CNF and desirable mass transfer ability from amorphous CoP framework, the as-prepared Co-CNF/ZIF-CoP exhibits large NH3 FE (96.8 ± 3.4% at -0.1 V vs reversible hydrogen electrode (RHE)) and high yield rate (38.44 ± 0.65 mg cm-2 h-1 at -0.6 V vs RHE), which are better than Co-CNF/ZIF-crystal CoP. Density functional theory (DFT) calculations further reveal that amorphous CoP presents a lower energy barrier in the rate determination step of the protonation of *NO to produce *NOH intermediates compared with crystal CoP, resulting in a superior NO3 RR performance. Eventually, an aqueous galvanic Zn-NO3 - battery is assembled by using Co-CNF/ZIF-CoP as cathode material to achieve efficient production of NH3 whilst simultaneously supplying electrical power. This work offers a reliable strategy to construct amorphous metal phosphide framework on conducting CNF as efficient electrocatalyst and enriches its promising application for NO3 RR.

Differences of Atomic-Level Interactions between Midazolam and Two CYP Isoforms 3A4 and 3A5.

CYP 3A4 and CYP 3A5 are two important members of the human cytochrome P450 family. Although their overall structures are similar, the local structures of the active site are different, which directly leads to obvious individual differences in drug metabolic efficacy and toxicity. In this work, midazolam (MDZ) was selected as the probe substrate, and its interaction with two proteins, CYP 3A4 and CYP 3A5, was studied by molecular dynamics simulation (MD) along with the calculation of the binding free energy. The results show that two protein-substrate complexes have some similarities in enzyme-substrate binding; that is, in both complexes, Ser119 forms a high occupancy hydrogen bond with MDZ, which plays a key role in the stability of the interaction between MDZ and the enzymes. However, the complex formed by CYP 3A4 and MDZ is more stable, which may be attributed to the sandwich structure formed by the fluorophenyl group of the substrate with Leu216 and Leu482. Our study interprets the binding differences between two isoform-substrate complexes and reveals a structure-function relationship from the atomic perspective, which is expected to provide a theoretical basis for accurately measuring the effectiveness and toxicity of drugs for individuals in the era of precision medicine.

Investigating the influence of substituent groups in TTM based radicals for the excitation process: a theoretical study.

Tri-(2,4,6-trichlorophenyl)methyl (TTM) based radicals can be promising in providing relatively high fluorescence quantum efficiency. In this study, we have evaluated the photoluminescence properties of a series of TTM-based radicals by means of DFT and TD-DFT methods. The optimized structures of the ground states (D0) and the first excited states (D1) of all the radicals are calculated and the computed emission bands are comparable with previous experimental results. knr is determined from transition dipole moments (µ12) and the energy gaps between D0 and D1 (ΔE), both of which can be regulated by the conjugated structures from the substituent groups. knr was derived from the mode-averaging method and is consistent with the experimental results. Factors influencing kr and knr, including the potential energy differences (ΔG0), the vibrational reorganization energies (λ) and the electron coupling term (Hab), are discussed. By comparing kr and knr in solvents with different polarities (cyclohexane, toluene, and chloroform), TTM based radicals in cyclohexane exhibit the most promising fluorescence efficiencies. Besides, two substituted radicals, namely 2Br-TTM-3PCz and 2F-TTM-3PCz, have been fabricated. The results show that fluorine atoms are able to increase ΔG0 and a considerably small knr has been predicted. We expect that our calculation can benefit the design of light-emitting molecules in further experiments.

Dynamic Metastable Characteristics of Carbon Cages Embedded with Er2C2.

Novel endohedral metallofullerenes (EMFs), namely, Er2C2@C2v(5)-C80, Er2C2@Cs(6)-C82, Er2C2@Cs(15)-C84, Er2C2@C2v(9)-C86, Er2C2@Cs(15)-C86, and Er2C2@Cs(32)-C88, had been experimentally synthesized, and the unique structures and many fascinating properties had also been widely explored. Nevertheless, the position of the Er atoms inside the cage shows a severe disorder within the stable EMF monomer, which is difficult to understand and explain from the experimental point of view. In this work, based on the density functional theoretical calculations, the Er2C2@Cs(6)-C82 has 73 directional isomers and 2 Er atoms that are far beyond from Er-Er single bonding and tend to be close to the cage side (marked as "shell"), and the core (Er2C2 units) takes on a butterfly shape as generally revealed. The energy difference between any two of the isomers is in the range of 0.05 to 25.6 kcal/mol, indicating a relatively easy thermodynamic transition between the isomers. The other five Er carbide cluster EMFs (Er2C2@C2v(5)-C80, Er2C2@Cs(15)-C84, Er2C2@C2v(9)-C86, Er2C2@Cs(15)-C86, and Er2C2@Cs(32)-C88) are also studied in the same way, and 30, 37, 39, and 43 most stable Er-oriented sites inside the cage, respectively, are obtained. In addition, the shape of the Er2C2 gradually changed from butterfly to linear. Moreover, the electronic structure and molecular orbital analyses show that it is easy for Er2C2@C80-88 to form a charge transfer state of [Er2C2]4+@[C80-88]4- via the dynamic core-shell coordination equilibrium. Er2C2 with a steep drop in chemical stability is restricted to forming varying degrees of metastable states in the shell, determined by the shell size, to ensure the overall stability. The lowest unoccupied molecular orbital energy level of these EMFs is increased by 0.5-1.1 eV compared with fullerenes C80-88, potentially providing favorable conditions for suitable energy level matching with EMF as an electron acceptor used in organic solar cell devices.

Mo Single-Atom Nanozyme Anchored to the 2D N-Doped Carbon Film: Catalytic Mechanism, Visual Monitoring of Choline, and Evaluation of Intracellular ROS Generation.

Single-atom nanozymes (SANs) have attracted great attention in constructing devices for instant biosensing due to their excellent stability and atom utilization. Here, Mo atoms were immobilized in 2D nitrogen-doped carbon films by cascade-anchored one-pot pyrolysis to obtain Mo single-atom nanozyme (Mo-SAN) with high atomic loading (4.79 wt %) and peroxidase-like activity. The coordination environment and enzyme-like activity mechanism of Mo-SAN were studied by combining synchrotron radiation and density functional theory. The strong oxophilicity of single-atom Mo makes the catalytic center more capable of transferring electrons to free radicals to selectively generate •OH in the presence of H2O2. Choline oxidase and Mo-SAN were used as signal opening unit and signal amplification unit, respectively. Combining the portability and visualization functions of smartphone and test strips, a paper-based visual sensing platform was constructed, which can accurately identify choline at a concentration of 0.5-35 µM with a limit of detection as low as 0.12 µM. The recovery of human serum samples was 96.4-102.2%, with an error of less than 5%. Furthermore, the potential of Mo-SAN to efficiently generate toxic •OH in tumor cells was intuitively confirmed. This work provides a technical and theoretical basis for designing highly active SANs and detecting neurological markers.

A Z-Scheme Heterojunctional Photocatalyst Engineered with Spatially Separated Dual Redox Sites for Selective CO2 Reduction with Water: Insight by In Situ µs-Transient Absorption Spectra.

Solar-driven CO2 reduction by water with a Z-scheme heterojunction affords an avenue to access energy storage and to alleviate greenhouse gas (GHG) emissions, yet the separation of charge carriers and the integrative regulation of water oxidation and CO2 activation sites remain challenging. Here, a BiVO4 /g-C3 N4 (BVO/CN) Z-scheme heterojunction as such a prototype is constructed by spatially separated dual sites with CoOx clusters and imidazolium ionic liquids (IL) toward CO2 photoreduction. The optimized CoOx -BVO/CN-IL delivers an ≈80-fold CO production rate without H2 evolution compared with urea-C3 N4 counterpart, together with nearly stoichiometric O2 gas produced. Experimental results and DFT calculations unveil the cascade Z-scheme charge transfer and subsequently the prominent redox co-catalysis by CoOx and IL for holes-H2 O oxidation and electrons-CO2 reduction, respectively. Moreover, in situ µs-transient absorption spectra clearly show the function of each cocatalyst and quantitatively reveal that the resulting CoOx -BVO/CN-IL reaches up to the electron transfer efficiency of 36.4% for CO2 reduction, far beyond those for BVO/CN (4.0%) and urea-CN (0.8%), underlining an exceptional synergy of dual reaction sites engineering. This work provides deep insights and guidelines for the rational design of highly efficient Z-scheme heterojunctions with precise redox catalytic sites toward solar fuel production.

Improving CO2 photoconversion with ionic liquid and Co single atoms.

Photocatalytic CO2 conversion promises an ideal route to store solar energy into chemical bonds. However, sluggish electron kinetics and unfavorable product selectivity remain unresolved challenges. Here, an ionic liquid, 1-ethyl-3-methylimidazolium tetrafluoroborate, and borate-anchored Co single atoms were separately loaded on ultrathin g-C3N4 nanosheets. The optimized nanocomposite photocatalyst produces CO and CH4 from CO2 and water under UV-vis light irradiation, exhibiting a 42-fold photoactivity enhancement compared with g-C3N4 and nearly 100% selectivity towards CO2 reduction. Experimental and theoretical results reveal that the ionic liquid extracts electrons and facilitates CO2 reduction, whereas Co single atoms trap holes and catalyze water oxidation. More importantly, the maximum electron transfer efficiency for CO2 photoreduction, as measured with in-situ µs-transient absorption spectroscopy, is found to be 35.3%, owing to the combined effect of the ionic liquid and Co single atoms. This work offers a feasible strategy for efficiently converting CO2 to valuable chemicals.

Solvent stimuli-responsive off-on fluorescence induced by synergistic effect of doping and phase transformation for Te4+ doped indium halide perovskite: Giving printable and colorless ink for information encryption and decryption.

Since traditional fluorescent materials are too easily observed by the eyes just under the UV light, off-on fluorescent materials are explored as the new generation of fluorescent labels. In the "off" state, such off-on fluorescent labels cannot be observed by naked eyes under either natural light or UV light. Only after a specific decryption treatment to make the fluorescent materials turning into the "on" state, the fluorescent labels can be observed under the UV light. Up to now, it is still a challenge to prepare fluorescent inks with aforementioned ideal properties by using halide perovskite materials. Herein, we reported the first example of Te4+ doped indium halide perovskite inks with both off-on fluorescence under solvent stimuli and invisible ink color by the naked eyes. The synergistic effect of doping/undoping of Te4+ together with the reversible phase transformation between Cs2InCl5(H2O) and Cs3InCl6 under solvent stimuli is key for the off-on fluorescence of crystals. Under acid solvent, the substitutional doping of Te4+ during the process of phase transformation from Cs3InCl6 to Cs2InCl5(H2O):Te4+ gives rise to "turning-on" orange emission from Te-induced self-trap emission (STE). Under the stimuli of methanol, the dissolution of Te4+ from the crystals destroys the structure of Te4+ in ligand-field and results in "turning-off" Te-induced emission during the process of phase transformation from Cs2InCl5(H2O):Te4+ to Cs3InCl6. On the basis of the Te4+ doped indium halide perovskite, printable and colorless ink can be prepared for the confidential information encryption and decryption. Since the mixture of Cs3InCl6 crystals and TeCl4 have no absorption in visible light scope, the printed encrypted information by such off-state fluorescent ink is colorless and invisible by the naked eyes under either ambient light or UV light. After decryption by acid solvent stimuli, the resulted Cs2InCl5(H2O):Te4+ doping crystals have a large Stokes shift with absorption below 450 nm from the excitation of Te4+ in ligand-field and emission around 570 nm from Te-induced STE. It makes the decryption information still colorless and invisible by the naked eyes under the ambient light but visible and readable under the UV light. In comparison to traditional undoped CsPbBr3/CsPb2Br5 perovskites with small Stokes shift and eye-visible ink color, the current colorless Te4+doped indium halide perovskites are no doubt providing better security level for both encrypted and decrypted information.

Interface Reversible Electric Field Regulated by Amphoteric Charged Protein-Based Coating Toward High-Rate and Robust Zn Anode.

Metallic interface engineering is a promising strategy to stabilize Zn anode via promoting Zn2+ uniform deposition. However, strong interactions between the coating and Zn2+ and sluggish transport of Zn2+ lead to high anodic polarization. Here, we present a bio-inspired silk fibroin (SF) coating with amphoteric charges to construct an interface reversible electric field, which manipulates the transfer kinetics of Zn2+ and reduces anodic polarization. The alternating positively and negatively charged surface as a build-in driving force can expedite and homogenize Zn2+ flux via the interplay between the charged coating and adsorbed ions, endowing the Zn-SF anode with low polarization voltage and stable plating/stripping. Experimental analyses with theoretical calculations suggest that SF can facilitate the desolvation of [Zn(H2O)6]2+ and provide nucleation sites for uniform deposition. Consequently, the Zn-SF anode delivers a high-rate performance with low voltage polarization (83 mV at 20 mA cm-2) and excellent stability (1500 h at 1 mA cm-2; 500 h at 10 mA cm-2), realizing exceptional cumulative capacity of 2.5 Ah cm-2. The full cell coupled with ZnxV2O5·nH2O (ZnVO) cathode achieves specific energy of ~ 270.5/150.6 Wh kg-1 (at 0.5/10 A g-1) with ~ 99.8% Coulombic efficiency and retains ~ 80.3% (at 5.0 A g-1) after 3000 cycles.

Novel quadrilateral-pore 2D-COFs as visible-light driven catalysts evaluated by the descriptor of integrated pz-orbital population.

In the past few decades, strategies for designing new two-dimensional covalent organic framework (2D-COF) structures have been limited to the shape of positive hexagonal pores, and the underlying relationship between their structure and electronic properties still remains unclear. Herein, novel 2D-COFs with C, N and H elements confined to the quadrilateral-pore skeleton based on first-principles calculations and the topological assembly of different benzene-based building blocks were designed and studied. These 2D-COFs enriched the topology types and can offer an ideal platform for band engineering aimed at spontaneously driving the hydrogen evolution reaction (HER) under visible light irradiation. The approach for regulating pore structures on nodes, linkers and linkages can effectively tune band gaps, and thus the 2D-COF, consisting of benzene building blocks and imine linkages, has the optimal activity for the photocatalytic HER under common visible light conditions. Furthermore, the integrated pz-orbital population was found to evaluate the photocatalytic activity efficiently. We demonstrate that the pz-orbital population is in linear relationship with the intensity of H+ adsorption, indicating that the total contribution of the pz-orbital electrons can be an efficient descriptor for screening suitable 2D-COF structures for use as photocatalysts for the HER. Therefore, this work presents a new strategy for designing novel quadrilateral-pore 2D-COFs as visible-light photocatalysts and provides an important insight into the relationship between catalytic activity and the population of activated electrons.

Maximized Green Photoluminescence in Tb-Based Metal-Organic Framework via Pressure-Treated Engineering.

Lanthanide metal-organic frameworks are of great interest in the development of photoluminescence (PL) materials owing to their structural tunability and intrinsic features of lanthanide elements. However, there exists some limitations arising from poor matching with metal ions, thereby exhibiting a weak ligand-to-metal energy transfer (LMET) process. Here we demonstrate a pressure-treated strategy for achieving high PL performance in green-emitting Tb(BTC)(H2 O)6 . The PL quantum yield of pressure-treated sample increased from 50.6 % to 90.4 %. We found that the enhanced hydrogen bonds locked the conjugated configuration formed by two planes of carboxyl group and benzene ring, enabling the promoted intersystem crossing to effectively drive LMET. Moreover, the optimized singlet and triplet states also validated the facilitated LMET process. This work opens the opportunity of structure optimization to improve PL performance in MOFs by pressure-treated engineering.

Pressure-Induced Restricting Intermolecular Vibration of a Herringbone Dimer for Significantly Enhanced Multicolor Emission in Rotor-Free Truxene Crystals.

Organic solid-state luminescent materials exhibit numerous exciting photoelectric properties that are central to emergent organic light-emitting diodes, smart sensors, and data encryption. However, the luminescence of pure organic rotor-free materials has been afflicted with strong intermolecular π-π stacking interactions. Herein, an unprecedented pressure-induced emission enhancement (PIEE) is realized in a system of rigid planar pure polycyclic aromatics, i.e., truxene crystals. The emission intensity is enhanced 7-fold below 3.0 GPa with a photoluminescence quantum yield increased to 10.17% compared with the initial value of 1.78%, and the emission colors change from green (520 nm) to red (640 nm) within 11.8 GPa. Spectral characterizations and first-principles calculations reveal that the PIEE and piezochromism can mainly be attributed to the restricted intermolecular vibration and the decreased energy gap. Our findings enrich the PIEE mechanism and provide a new guideline for designing pressure-responsive luminescent materials in advancing their photoelectric applications.