Blue multi-resonance thermally activated delayed fluorescence (MR-TADF) materials necessitate high color purity along with visual comfort for their commercialization in organic light-emitting diodes (OLEDs). Given that the slight adjustments in the MR-TADF molecular structure commonly lead to significantly alter the emission spectrum, there is an urgent need to develop strategies for fine-tuning spectral characteristics. Herein, an effective design strategy is proposed to develop blue MR-TADF materials by integrating primary MR skeleton with auxiliary regulation unit, and through modulate the structure of auxiliary regulation unit, three MR-TADF materials are designed and synthesized. The emission wavelengths of these emitters are gradually blue-shifted from 466 to 458 nm accompanied by small full width at half-maximum and negligible shoulder peak. The drastic changes in excited-state dynamics of these emitters are recorded and the underlying mechanisms are systematically investigated and elucidated. High-performance deep-blue OLEDs are achieved based on CBN-P, which provide an electroluminescence peak at 464 nm, Commission Internationale de L'Eclairage coordinates of (0.131, 0.088), a maximum external quantum efficiency (ηext) of 22.4%. Besides, the CBN-A-based blue OLEDs attain a maximum ηext of 30.2%, which is further augmented to 37.4% upon sensitization, representing one of the best blue MR-TADF OLEDs reported so far.

To address the challenges of low product yield and high catalyst cost in lignin hydrogenolysis, this study developed a low-cost, highly efficient bimetallic catalyst system. Using ceiba speciosa biomass as the raw material, a 7%Ni-10.5%Cu/CSFNC bimetallic catalyst was prepared through a simple calcination process, this system in lignin hydrogenolysis was thoroughly investigated. The formation of Ni-Cu alloy significantly enhanced the catalytic activity, achieving a high total yield of 39.36 wt% for phenolic monomers under optimal reaction conditions (250 ℃, 3 MPa H₂). Notably, the catalyst exhibited an impressive 66.74% selectivity toward the target products—4-propylsyringol (S-3) and dihydroconiferyl alcohol (S-3OH), both of which are high-value chemicals widely used in the pharmaceutical and chemical industries. Comprehensive characterization using GC-MS, FT-IR, and 2D HSQC NMR confirmed that this catalytic system effectively cleaves C-O bonds (particularly β-O-4 bonds) in lignin while preserving the aromatic ring structure, thereby preventing deep hydrogenation. Subsequent investigation using model compounds and reaction kinetics elucidated the reaction mechanism, proposing a pathway for the hydrogenolysis of macromolecular lignin into S-type phenolic monomers. This synergistic effect between Ni and Cu in the bimetallic catalyst system offers a promising approach for the high-value utilization of biomass resources, providing a new technical pathway for the sustainable conversion of lignin into valuable chemicals.

ABSTRACT Folded thermally activated delayed fluorescence (TADF) molecules based on through‐space charge transfer (TSCT) have aroused increasing interest, but the electroluminescence (EL) efficiencies of most folded TADF molecules are still inferior, and their application as sensitizers for multi‐resonance TADF (MR‐TADF) emitters remains barely explored. Herein, two novel isomeric folded TADF molecules, f‐ TRZ‐1 and f‐ TRZ‐2, are constructed by using 2,4,6‐triphenyl‐1,3,5‐triazine (TRZ) as acceptor, 9‐phenylcarbazole (PC) as donor, and 11,12‐dihydroindolo[2,3‐a]carbazole (HIC) as bridge. They exhibit regular intramolecular packing structures with effective TSCT and enjoy ultrahigh thermal stability and balanced bipolar charge transport. Moreover, efficient organic light‐emitting diodes (OLEDs) are fabricated using f‐ TRZ‐1 and f‐ TRZ‐2 as emitters, achieving maximum external quantum efficiencies ( η ext,max ) of up to 28.9%. f‐ TRZ‐1 and f‐ TRZ‐2 can perform as efficient sensitizers for the green MR‐TADF emitter tCzphB‐Fl, and the prepared hyperfluorescence OLEDs exhibit outstanding EL performances, with improved η ext,max s of up to 37.8% and reduced efficiency roll‐offs. This work demonstrates the promising potential of these folded TADF molecules as emitters and sensitizers for the fabrication of high‐performance OLEDs.

Thick-layer organic light-emitting diodes(OLEDs) comprising a single thick film to simultaneously transport carriers and emit light offer significant advantages in simplifying the fabrication process and enhancing balanced bipolar carrier transport, strong solid-state emission and high exciton utilization, which impose high requirements on designing luminescent materials. In this work, two representative bipolar aggregation-induced delayed fluorescence(AIDF) emitters are employed to fabricate such thick-layer non-doped devices. Excellent electroluminescence(EL) performances are attained with low turn-on voltages(2.5 V), high external quantum efficiencies(19.8%), and negligible efficiency roll-off at high luminance. Furthermore, the operational lifetime of the thick-layer device increases by more than twofold compared to that of the thin-layer devices. In addition, high-efficiency, high-color-purity simplified thick-layer hyperfluorescence OLEDs are also achieved by using their thick neat films as sensitizers for multi-resonance emitters. These results indicate that the bipolar AIDF emitters are promising candidates for constructing simple thick-layer OLEDs, which provides a feasible strategy for developing highly efficient and stable OLEDs.

With the potential to achieve a theoretical exciton utilization efficiency of 100 %, thermally activated delayed fluorescence (TADF) emitters have garnered considerable attention in the field of organic light-emitting diodes (OLEDs). In particular, TADF emitters based on through-space charge transfer (TSCT) mechanism have emerged as one of the major focuses of recent studies. Herein, three U-shaped folded TADF emitters are successfully constructed with 11,12-dihydroindolo[2,3-a]carbazole as bridging unit to link electron acceptor of xanthone and different electron donors. With the enhancement of the electron-donating strength of donors, the radiative transition characteristic evolves from through-bond charge transfer (TBCT) to TSCT transition, enabling effective modulation of emission wavelengths and efficiencies of the molecule. The face-to-face stacking pattern of the electron donor and acceptor facilitates the formation of TSCT transition. All the emitters exhibit outstanding photoluminescence quantum efficiencies and small singlet-triplet energy gaps, leading to fast reverse intersystem crossing and thus efficient TADF behaviors. Efficient sky-blue and yellow OLEDs are fabricated based on these emitters, which afford high maximum external quantum efficiencies of 21.24 %, and 20.36 % with the emission peaks at 498 and 546 nm, respectively. These results could provide applicable guidance for the design of efficient TSCT-type TADF emitters.

Organometallic phosphorescent materials have been developed as critical luminescent materials for organic light-emitting diodes (OLEDs). However, most purely organic room-temperature phosphorescence (RTP) materials without any heavy metals still lack competitiveness for use in OLEDs. Recently, significant progress has been made regarding purely organic RTP materials, and their electroluminescence (EL) performances have become comparable to those of traditional phosphorescent complexes. In this perspective, advancements and proposed design strategies relating to efficient purely organic RTP materials are summarized. Furthermore, the promising application of these RTP materials as sensitizers for narrow-spectrum multi-resonance emitters is also discussed and an outlook is provided, which is conducive to the development of high-resolution OLEDs. It is expected that this perspective will provide valuable guidelines for advancing robust purely organic RTP sensitizers and further promoting the OLED industry.

The catalytic hydrogenolysis of renewable lignin offers a promising route to produce high-value phenolic monomers, reducing reliance on fossil resources while enhancing biomass utilization efficiency. This study developed a 1 % Pd/CSFNC catalyst through simple calcination of waste Ceiba speciosa flower co-doped with palladium and nitrogen. The catalyst demonstrated high activity and selectivity in the hydrogenolysis of eucalyptus lignin under optimized conditions (280 degrees C, 4 MPa H2, 5 h), achieving 89.09 % lignin conversion and 30.29 % phenolic monomer yield. Notably, 4-propylsyringol (S-3), a high-value compound for pharmaceutical and fine chemical applications, constituted 59.83 % of the monomeric products (18.12 % yield). At the same time, it was found that CSFNC plays a co-catalytic role in the lignin hydrogenolysis process. Furthermore, critical reaction parameters, including catalyst-to-lignin ratio and solid-to-liquid ratio, were systematically optimized. Mechanism insights were gained through hydrogenolysis of 2-phenoxyacetophenone and comprehensive product analysis using FT-IR and 2D HSQC NMR spectroscopy. Based on these studies, the reaction pathway for lignin depolymerization over this catalyst system is proposed.

It is urgently needed to have antibacterial treatments that offer a controlled release of therapeutic agents, effectively targeting the breadth and universality of pathogens while ensuring sustained efficacy. Herein, we demonstrated the fabrication of a temperature and pH dual-sensitive hydrogel, prepared by cross-linking Nisopropyl acrylamide-co-acrylic acid (NIPAM-co-AA) networks with tannic acid (TA) and loaded with curcumin (Cur) (termed as NIPAM-co-AA/TA@Cur), providing the on-demand release of Cur triggered by changes in the wound microenvironment (MET). The prepared hydrogel exhibited excellent tensile property (50-fold the length of the original), superior self-healing ability, and high adhesion performance (6.2 kPa). We further confirmed that this dual-sensitive hydrogel can respond to typical wound pH and temperature changes, promoting Cur release (>90 % release) at alkaline pH (>= 8.0) while achieving up to 92 % Cur release at 37 degrees C. The in vitro antibacterial efficacy tests displayed that a high potency to kill E.coli and S.aureus while significantly enhancing antibacterial ability under simulated wound MET with high temperature and alkaline conditions. This versatile hydrogel presents a promising approach for targeted drug delivery by responding to specific pathological regions, thereby minimizing potential side effects and bolstering antimicrobial efficacy.

Multiresonance thermally activated delayed fluorescence (MR-TADF) emitters are promising candidates for organic light-emitting diodes (OLEDs) with high color quality. However, in most cases, noble metal-containing phosphors are required as sensitizers for MR-TADF emitters to improve their electroluminescence (EL) performances, which may lead to high cost and environmental pollution. Herein, an efficient purely organic room-temperature phosphorescence (RTP) material, 3,2-PIC-TXT, with fast phosphorescence radiation is developed. It not only exhibits impressive EL performances as an emitter with an outstanding external quantum efficiency (EQE) of 33.2%, higher than that of Ir(ppy)3 (25.2%), but also functions remarkably as a sensitizer for green MR-TADF emitters (BN2, tCzphB-Ph, and tCzphB-Fl). The hyperfluorescence OLEDs using 3,2-PIC-TXT as a sensitizer provide ultrahigh EQEs of 40.9 to 43.8%, superior to those based on an Ir(ppy)3 sensitizer (37.0 to 38.0%), along with superb color purity and excellent operational stability. These OLEDs are the best devices based on RTP materials reported so far.

Reverse intersystem crossing (RISC) process is critical for thermally activated delayed fluorescence (TADF) materials to realize spin–flip of triplet excitons in organic light-emitting diodes (OLEDs), but the RISC processes of most TADF materials are not fast enough, undermining electroluminescence (EL) efficiency stability and operational lifetime. Herein, a symmetry breaking strategy to accelerate RISC processes is proposed. By designing asymmetric electron-withdrawing backbone consisting of benzonitrile and xanthone/thioxanthone groups, two new asymmetric TADF molecules, 4 t CzCN- p XT and 4 t CzCN- p TXT, with multiple 3,6-di- tert -butylcarbazole donors are successfully developed. They own increased molecular vibrations, which promote intrinsic RISC process and enable multi-channel transitions via vibronic coupling of high-lying triplet states. Consequently, they exhibit fast RISC rates of up to 1.24 × 10 7 s −1 , being one order of magnitude higher than that of the symmetric control molecule. They can perform as luminescent materials in OLEDs, providing outstanding external quantum efficiencies (EQEs) of up to 31.2% and 35.8% in non-doped and doped devices, respectively, with very small roll-offs. The OLEDs using them as sensitizers for multi-resonance emitters achieve remarkable EQEs over 40%, and extraordinary operational stability with LT 90 of 24974 h at 1000 cd m −2 , demonstrating their great potentials in OLEDs.

Designing multi-resonant (MR) materials that integrate narrowband emission and efficient exciton utilization remains challenging, especially for indolocarbazole (ICz) cores. To address this, two novel ICz-derived MR emitters, 4CzmICz and 4CzpICz, were developed by strategically extending π-conjugation via peripheral carbazole units. This modulates charge-transfer (CT) states while retaining MR character, endowing both molecules with hybridized local and charge transfer (HLCT) properties. The meta-isomer 4CzmICz exhibits exceptional deep-blue emission (430 nm, FWHM = 14 nm in hexane). The para-isomer 4CzpICz achieves record HLCT-OLED performance: a narrowband device (FWHM = 29 nm) with 19.5% external quantum efficiency (EQE). In an exciplex-sensitized configuration, EQE reaches 25.0% without emission broadening. This work pioneers MR-HLCT integration and establishes a roadmap for next-generation OLED materials.

Catalytic hydrogenolysis of lignin to produce high-value monophenols has emerged as a pivotal strategy in modern biorefineries. In this study, we synthesized spherical nitrogen-doped porous carbon (SNCB) materials by using Al/Co-BTC as a precursor, introducing melamine as a supplementary carbon and nitrogen source, and activating the material with NaOH solution. The SNCB framework was decorated with Cu-Pd bimetallic nanoparticles, exhibiting outstanding catalytic activity in the hydrogenolytic depolymerization of organosolv lignin. The Cu-Pd@SNCB catalyst exhibited remarkable activity, attributed to the hierarchical porous structure of SNCB that facilitated metal nanoparticle dispersion and reactant accessibility. The synergistic effect between Cu as the reactive site for reactant adsorption and Pd as the reactive site for H2 adsorption enhanced the catalytic activity of the catalyst. Systematically optimized conditions (2 MPa H2, 270 °C, 3 h) yielded 43.02 wt% phenolic monomers, with 4-(3-hydroxypropyl)-2,6-dimethoxyphenol dominating the product profile at 46.3% selectivity. The catalyst and its reaction products were analyzed using advanced characterization techniques, including XPS, XRD, TEM, SEM, BET, GC-MS, GPC, 2D HSQC NMR, and FT-IR, to elucidate the reaction mechanism. The mechanism proceeds through: (1) nucleophilic substitution of the β-O-4 hydroxyl group by MeOH, followed by (2) simultaneous hydrogenolytic cleavage of Cβ-O and Cα-O bonds mediated by Cu-Pd@SNCB under H2 atmosphere, which selectively produces 4-(3-hydroxypropyl)-2,6-dimethoxyphenol and 4-propyl-2,6-dimethoxyphenol. This study proposes a bimetallic synergistic mechanism, offering a general blueprint for developing selective lignin valorization catalysts.

Lignin valorization is critical to the advancement of economically competitive lignocellulosic biorefinery processes. Catalytic hydrogenolysis is a promising pathway for converting lignin into valuable products. In this study, we investigated the economic viability as well as the environmental sustainability of catalytic hydrogenolysis of lignin for producing the value-added product 4-hydroxy-3,5-dimethoxyphenylacetic acid (HDMPA). The estimated minimum product selling price (MPSP) is $74.25/kg ($64.62-86.13/kg, 5th-95th percentiles range), which is economically competitive with the market price. The global sensitivity analysis identified the lignin hydrogenolysis section as the key influencing factor on the MPSP and environmental impacts. Therefore, the effects of hydrogenolysis temperature and solid/liquid ratio on these two aspects were investigated. The results show that increasing the solid loading is more efficient in reducing the GWP than lowering the reaction temperature, resulting in 12.63 kg CO2-eq/kg at a solid/liquid ratio of 5%. In conclusion, this study found that producing bio-based HDMPA from lignin is feasible and emphasized the potential for lignin valorization within a sustainable bioeconomy.

The utilization of biomass for producing porous carbon presents significant promise for supercapacitor electrode materials. This work introduces an efficient and environmentally friendly two-step synthesis method for preparing Ceiba speciosa flowers derived porous carbon (CSDC). The findings highlight the tubular porous character of the resulting carbon material. Notably, the sample (CS-700-T2) using thiosemicarbazide as a dopant results in a pore volume of 0.949 cm3 & sdot;g- 1 and an exceptionally high SSA of up to 2090 m2 & sdot;g- 1. CS-700-T2 exhibits outstanding electrochemical performance, achieving a capacitance of 355.3 F & sdot;g- 1 at 0.5 A & sdot;g- 1. Its exceptional rate capability is evidenced by maintaining 83.1 % capacitance at 20 A & sdot;g- 1. In a symmetric CS-700-T2||CS-700T2 electrode system, the capacitance remains at 97.3 % after 10,000 cycles at 5 A & sdot;g- 1. Furthermore, to enhance the energy density, Na2SO4 was used as the electrolyte, successfully expanding the operating voltage to 0-1.6 V. This adjustment significantly increases energy density, reaching 26.2 Wh & sdot;kg- 1. Therefore, the synthesized CS700-T2 material, with its exceptional electrochemical performance, stands out as a powerful contender for future SC electrode materials.

Spin-flip process involving multiple excited states plays a key role for the function and application of many organic molecules. However, it remains extremely challenging to experimentally identify and investigate intermediate states in spin-flip transition due to its rapid inactivation via various electronic transitions. Herein, we report the deciphering of intermediate states involved in the spin-flip transition in a tailor-made carbonyl-nitrogen multi-resonance molecule (anti-DIQAO) designed with high symmetry. The transitions among different electronic states of anti-DIQAO are slowed by high molecular symmetry and distinguished using steady-state and transient spectroscopies. The second excited triplet (T2) state is identified as the intermediate state in the spin-flip transition, whose transition to higher energy levels and phosphorescence radiation are recorded. It is demonstrated that, in reverse intersystem crossing, intramolecular vibration drives the rate-dominant reverse internal conversion from the lowest excited triplet (T1) state to the T2 state, and thermal activation triggers transition from mixed T2 and T1 states to the lowest excited singlet (S1) state. Additionally, anti-DIQAO exhibits narrow-bandwidth electroluminescence with an outstanding external quantum efficiency of up to 32.6%. This research provides an effective molecular design to tune the populations of excited states, which is of high significance for exploring efficient luminescent materials.

Two tailor-made new aggregation-induced delayed fluorescence luminogens are constructed. The effect of methyl substitution sites on the luminescence behaviors is systematically evaluated. Efficient blue non-doped and doped organic light-emitting diodes are fabricated based on these emitters, furnishing high external quantum efficiencies of 14.3% and 30.4%, respectively.

Purely organic molecules with room‐temperature phosphorescence (RTP) are potential luminescent materials with high exciton utilization for organic light‐emitting diodes (OLEDs), but those exhibiting superb electroluminescence (EL) performances are rarely explored, mainly due to their long phosphorescence lifetimes. Herein, a robust purely organic RTP molecule, 3,6‐bis(5‐phenylindolo[3,2‐a]carbazol‐12(5H)‐yl)‐xanthen‐9‐one (3,2‐PIC‐XT), is developed. The neat film of 3,2‐PIC‐XT shows strong green RTP with a very short lifetime (2.9 μs) and a high photoluminescence quantum yield (72%), and behaviors balanced bipolar charge transport. The RTP nature of 3,2‐PIC‐XT is validated by steady‐state and transient absorption and emission spectroscopies, and the working mechanism is deciphered by theoretical simulation. Non‐doped multilayer OLEDs using thin neat films of 3,2‐PIC‐XT furnish an outstanding external quantum efficiency (EQE) of 24.91% with an extremely low roll‐off (1.6%) at 1000 cd m‒2. High‐performance non‐doped top‐emitting and tandem OLEDs are also achieved, providing remarkable EQEs of 24.53% and 42.50%, respectively. Delightfully, non‐doped simplified OLEDs employing thick neat films of 3,2‐PIC‐XT are also realized, furnishing an excellent EQE of 17.79% and greatly enhanced operational lifetime. The temperature‐dependent and transient EL spectroscopies demonstrate the electrophosphorescence attribute of 3,2‐PIC‐XT. These non‐doped OLEDs are the best devices based on purely organic RTP materials reported so far.

PTDF is prepared by a convenient ionic reaction of phytic acid, terephthalic dihydrazide and iron salts in water. It is a new type of high efficiency flame retardant. PTDF has high phosphorus and nitrogen content and good thermal stability, which can effectively improve the flame retardancy of PLA. PTFE is an anti-drip agent and is often used to improve the flame retardancy of PLA together with flame retardants. The addition of 4 wt% PTDF and 0.1 wt% PTFE made PLA reach V-0 flame retardant grade from non-flame retardant, and the oxygen index increased from 19.5 % to 24.5 %. With the increase of PTDF content, the performance of PLA improved significantly. The peak heat release rate (PHRR) and THR of PLA/6PTDF composites decrease by 27.4 % and 16.2 %, respectively, and the flame retardant index FRI increase by 232 %, showing excellent flame retardant efficiency. 6 wt% PTDF can increase the crystallinity of PLA by 25.9 %, tensile strength, maximum force required for impact fracture and notch impact strength by 12 %, 37 % and 129 %, respectively, and effectively improve the mechanical properties and toughness of the composite. The bio-based flame-retardant PLA/PTDF composites reported in this paper can be applied to office equipment.

Sodium-alginate-based aerogels possess wide prospects in the fields of packaging, aerospace, industrial construction and transportation because of their environmental compatibility and thermal insulation, but it is still a challenge to obtain a sodium alginate-based aerogel with high flame retardancy and good thermal insulation. Herein, a sodium-alginate-based aerogel with high flame retardancy, thermal insulation and good hydrophobic properties was prepared by two-step crosslinking strategy of phytic acid and metal ions and liquid phase deposition of trans-cinnamic acid. As a result, the prepared SA/PA Mn+ aerogels obtained excellent flame retardancy (UL-94 V-0, LOI 50.1%) and rapid self-extinguishing, and SA/PA Mn+ aerogels obtained good hydrophobic ability (CA = 134.2 degrees). In addition, the mechanical properties of SA/PA Mn+ aerogels have also been improved, the compressive modulus increased from 0.66 to 6.37 MPa, and the specific modulus increased from 15.7 to 140.2 MPa cm (-3) g(-1). This research broadens the application of bio-based flame-retardant aerogels in the fields of packaging, aerospace, industrial construction and transportation.

Achieving strong solid-state photoluminescence and fast charge transport simultaneously for organic molecules is of significant importance but challenging because of the trade-off between these properties. Herein, two tailored blue luminescent molecules constructed with ring-fused carbonyl-containing electron acceptors and spiro-acridine electron donors are developed. Owing to ordered long-range molecular alignment with proper interaction energies, their neat films exhibit ultrafast bipolar charge transport and strong delayed fluorescence with high quantum yields and short lifetimes. In doped organic light-emitting diodes (OLEDs), both molecules display eminent electroluminescence performances with excellent external quantum efficiencies (EQEs) of 40.6%. They also exhibit brilliant blue lights with record-beating EQEs of 30.2% in non-doped thin-layer OLEDs, and more importantly, high-performance simplified non-doped thick-layer OLEDs are achieved, rendering lowered driving voltages, and the best EQEs of 23.0% with tiny efficiency roll-offs. In addition, using them as sensitizers, remarkable EQEs of 40.1% and 23.2% with ultrasmall efficiency roll-offs are realized in blue hyperfluorescence thin-layer and thick-layer OLEDs, respectively. The operational lifetimes are obviously elongated matter in non-doped thick-layer devices or hyperfluorescence thick-layer devices. This work provides promising candidates for efficient simplified thick-layer OLEDs and opens a new avenue toward organic molecules with strong delayed fluorescence and fast charge transport simultaneously. Ultrafast bipolar charge transport and strong blue delayed fluorescence are realized in neat films of novel organic molecules constructed with ring-fused carbonyl-containing electron acceptors and spiro-acridine electron donors, and high-performance non-doped thin-layer OLEDs and simplified non-doped thick-layer OLEDs with record-beating EQEs of 30.2% and 23.0% and tiny roll-offs are achieved. image