Room-temperature synthesis of full-component APbX_(3)perovskite nanocrystal inks for optoelectronic applications

Lead halide perovskite nanocrystals(PNCs)have received great research interests due to their excellent optoelectronic properties.However,high temperature,inert gas protection and insulating long-chain ligands are used during the conventional hot-injection synthesis of PNCs,which limits their practical applications.In this work,we first develop a simple and scalable polar-solvent-free method for the preparation of full-component APbX_(3)(A=Cs,methylammonium(MA),formamidinium(FA),X=Cl,Br,I)PNCs under ambient condition.Through an exothermic reaction between butylamine(BA)and propionic acid(PA)short ligands,the PbX_(2) precursors could be well dissolved without use of any polar solvent.Meanwhile,the relatively lower growth rate of PNCs in our room-temperature reaction enables us to modulate the synthetic procedure to enhance the scalability(40-fold)and achieve large-scale synthesis.The resultant short ligands passivated PNC inks are compatible with varying solution depositing technique like spray coating for large-area film.Finally,we showcase that adopting the as-prepared MAPbI_(3) PNC inks,a self-powered photodetector is fabricated and shows a high photoresponsivity.These results demonstrate that our ambient-condition synthetic approach can accelerate the preparation of tunable and ready-to-use PNCs towards commercial optoelectronic applications.

Atomically dispersed Fe sites on hierarchically porous carbon nanoplates for oxygen reduction reaction

Developing cost-effective,robust and stable non-precious metal catalysts for oxygen reduction reaction(ORR) is of paramount importance for electrochemical energy conversion devices such as fuel cells and metal-air batteries.Although Fe-N-C single atom catalysts(SACs) have been hailed as the most promising candidate due to the optimal binding strength of ORR intermediates on the Fe-N_(4) sites,they suffer from serious mass transport limitations as microporous templates/substrates,i.e.,zeolitic imidazolate frameworks(ZIFs),are usually employed to host the active sites.Motivated by this challenge,we herein develop a hydrogen-bonded organic framework(HOF)-assisted pyrolysis strategy to construct hierarchical micro/mesoporous carbon nanoplates for the deposition of atomically dispersed Fe-N_(4) sites.Such a design is accomplished by employing HOF nanoplates assembled from 2-aminoterephthalic acid(NH_(2)-BDC) and p-phenylenediamine(PDA) as both soft templates and C,N precursors.Benefitting from the structural merits inherited from HOF templates,the optimized catalyst(denoted as Fe-N-C SAC-950) displays outstanding ORR activity with a high half-wave potential of 0.895 V(vs.reversible hydrogen electrode(RHE)) and a small overpotential of 356 mV at 10 mA cm^(-2) for the oxygen evolution reaction(OER).More excitingly,its application potential is further verified by delivering superb rechargeability and cycling stability with a nearly unfading charge-discharge gap of 0.72 V after 160 h.Molecular dynamics(MD) simulations reveal that micro/mesoporous structure is conducive to the rapid mass transfer of O_(2),thus enhancing the ORR performance.In situ Raman results further indicate that the conversion of O_(2) to~*O_(2)-the rate-determining step(RDS) for Fe-N-C SAC-950.This work will provide a versatile strategy to construct single atom catalysts with desirable catalytic properties.

Oxygen-coordinated low-nucleus cluster catalysts for enhanced electrocatalytic water oxidation

The oxygen evolution reaction(OER)activity of single-atom catalysts(SACs)is closely related to the coordination environment of the active site.Oxygencoordinated atomic metal species bring about unique features beyond nitrogen-coordinated atomic metal species due to the fact that the M-O bond is weaker than the M-N bond.Herein,a series of metal-oxygen-carbon structured low-nucleus clusters(LNCs)are successfully anchored on the surface of multiwalled carbon nanotubes(M-MWCNTs,M=Ni,Co,or Fe)through a foolproof low-temperature gas transfer(300℃)method without any further treatment.The morphology and coordination configuration of the LNCs at the atomic level were confirmed by comprehensive characterizations.The synthetic Ni-MWCNTs electrocatalyst features excellent OER activity and stability under alkaline conditions,transcending the performances of Co-MWCNTs,Fe-MWCNTs and RuO_(2).Density functional theory calculations reveal that the moderate oxidation of low-nucleus Ni clusters changes the unoccupied orbital of Ni atoms,thereby lowering the energy barrier of the OER rate-limiting step and making the OER process more energy-efficient.This study demonstrates a novel versatile platform for large-scale manufacturing of oxygen-coordinated LNC catalysts.

Unfolding the structure-property relationships of Li_(2)S anchoring on two-dimensional materials with high-throughput calculations and machine learning

Lithium-sulfur(Li-S)batteries are notable for their high theoretical energy density,but the‘shuttle effect’and the limited conversion kinetics of Li-S species can downgrade their actual performance.An essential strategy is to design anchoring materials(AMs)to appropriately adsorb Li-S species.Herein,we propose a new three-procedure protocol,named InfoAd(Informative Adsorption)to evaluate the anchoring of Li_(2)S on two-dimensional(2D)materials and disclose the underlying importance of material features by combining high-throughput calculation workflow and machine learning(ML).In this paradigm,we calculate the anchoring of Li_(2)S on 12552D A_(x)B_(y)(B in the VIA/VIIA group)materials and pick out 44(un)reported nontoxic 2D binary A_(x)B_(y)AMs,in which the importance of the geometric features on the anchoring effect is revealed by ML for the first time.We develop a new Infograph model for crystals to accurately predict whether a material has a moderate binding with Li_(2)S and extend it to all 2D materials.Our InfoAd protocol elucidates the underlying structure-property relationship of Li_(2)S adsorption on 2D materials and provides a general research framework of adsorption-related materials for catalysis and energy/substance storage.

Deep-red and near-infrared organic lasers based on centrosymmetric molecules with excited-state intramolecular double proton transfer activity

Organic lasers that emit light in the deep-red and near-infrared(NIR)region are of essential importance in laser communication,night vision,bioimaging,and information-secured displays but are still challenging because of the lack of proper gain materials.Herein,a new molecular design strategy that operates by merging two excited-state intramolecular proton transfer-active molecules into one excited-state double proton transfer(ESDPT)-active molecule was demonstrated.Based on this new strategy,three new materials were designed and synthesized with two groups of intramolecular resonance-assisted hydrogen bonds,in which the ESDPT process was proven to proceed smoothly based on theoretical calculations and experimental results of steady-state and transient spectra.Benefiting from the effective six-level system constructed by the ESDPT process,all newly designed materials showed low threshold laser emissions at approximately 720 nm when doped in PS microspheres,which in turn proved the existence of the second proton transfer process.More importantly,our well-developed NIR organic lasers showed high laser stability,which can maintain high laser intensity after 12000 pulse lasing,which is essential in practical applications.This work provides a simple and effective method for the development of NIR organic gain materials and demonstrates the ESDPT mechanism for NIR lasing.

Fluorescent Silicon Nanorods-Based Nanotheranostic Agents for Multimodal Imaging-Guided Photothermal Therapy

The utilization of diagnosis to guide/aid therapy procedures has shown great prospects in the era of personalized medicine along with the recognition of tumor heterogeneity and complexity.Herein,a kind of multifunctional silicon-based nanostructure,i.e.,gold nanoparticles-decorated fluorescent silicon nanorods(Au@SiNRs),is fabricated and exploited for tumor-targeted multimodal imaging-guided photothermal therapy.In particular,the prepared Au@SiNRs feature high photothermal conversion efficiency(~43.9%)and strong photothermal stability(photothermal performance stays constant after five-cycle NIR laser irradiation),making them high-performance agents for simultaneously photoacoustic and infrared thermal imaging.The Au@SiNRs are readily modified with targeting peptide ligands,enabling an enhanced tumor accumulation with a high value of^8.74%ID g?1.Taking advantages of these unique merits,the Au@SiNRs are superbly suitable for specifically ablating tumors in vivo without appreciable toxicity under the guidance of multimodal imaging.Typically,all the mice treated with the Au@SiNRs remain alive,and no distinct tumor recurrence is observed during 60-day investigation.

Boosting polysulfide redox conversion of Li-S batteries by one-step-synthesized Co-Mo bimetallic nitride

Lithium-sulfur(Li-S)batteries are considered as one of the most promising next generation energy storage systems due to the high theoretical specific capacity,low cost,and environmental benignity.However,the notorious shuttle effect of polysulfides hinders the practical application of Li-S batteries.Herein,we have rationally designed and synthesized sea urchin-like Co-Mo bimetallic nitride(Co_(3) MO_(3) N)in the absence of additional nitrogen sources with only one step,which was applied as the sulfur host materials for Li-S batteries.The results indicate that Co_(3) Mo_(3) N can efficiently anchor and catalyze the conversion of polysulfides,thus accelerating the electrochemical reaction kinetics and enabling prominent electrochemical properties.As a consequence,the S@Co_(3) Mo_(3) N cathode exhibits a high rate performance of 705 mAh g^(-1) at 3 C rate and an excellent cycling stability with a low capacity fading rate of 0.08%per cycle at 1 C over 600 cycles.Even at a high sulfur loading of 5.4 cmg cm^(-2),it delivers a high initial areal capacity of 4.50 mAh cm^(-2) which is still retained at 3.64 mAh cm^(-2) after 120 cycles.Furthermore,the catalytic mechanism and structural stability of Co_(3) Mo_(3) N during cycling were elucidated by a combination of X-ray photoelectron spectroscopy and X-ray absorption fine structure.This work highlights the strategy of structure-catalysis engineering of bimetallic nitride,which is expected to have a wide application in Li-S batteries.

One-step growth of large-area silicon nanowire fabrics for high-performance multifunctional wearable sensors

Silicon nanowire(SiNW)fabrics are of great interest for fabricating high-performance multifunctional wearable sensors.However,it remains a big challenge to fabricate high-quality SiNW fabrics in a simple and efficient manner.Here we report,for the first time,one-step growth of large-area SiNW fabrics for multifunctional wearable sensors,by using a massive metal-assisted chemical vapor deposition(CVD)method.With bulk Sn as a catalyst source,numerous millimeter-long SiNWs grow and naturally interweave with each other,forming SiNw fabrics over 80 cm2 in one experiment.In addition to intrinsic electronic properties of Si materials,the SiNw fabrics also feature high flxibility,good tailorability and light weight,rendering them ideal for fabricating multifunctional wearable sensors.The prototype sensors based on the SiNW fabrics could efectively detect various stimuli including temperature,light,strain and pressure,with outstanding performance among reported multifunctional sensors.We further demonstrate the integration of the prototype sensors onto the body of a robot,enabling its perception to various environmental stimuli.The ability to prepare high-quality SiNW fabrics in a simple and eficient manner will stimulate the development of wearable devices for applications in portable electronics,Internet of Things,health care and robotics.

Unraveling Passivation Mechanism of Imidazolium-Based Ionic Liquids on Inorganic Perovskite to Achieve Near-Record-Efficiency CsPbI_(2)Br Solar Cells

The application of ionic liquids in perovskite has attracted wide-spread attention for its astounding performance improvement of perovskite solar cells(PSCs).However,the detailed mechanisms behind the improvement remain mysterious.Herein,a series of imidazolium-based ionic liquids(IILs)with different cations and anions is systematically investigated to elucidate the passivation mechanism of IILs on inorganic perovskites.It is found that IILs display the following advantages:(1)They form ionic bonds with Cs^(+)and Pb^(2+)cations on the surface and at the grain boundaries of perovskite films,which could effectively heal/reduce the Cs^(+)/I−vacancies and Pb-related defects;(2)They serve as a bridge between the perovskite and the hole-transport-layer for effective charge extraction and transfer;and(3)They increase the hydrophobicity of the perovskite surface to further improve the stability of the CsPbI_(2)Br PSCs.The combination of the above effects results in suppressed non-radiative recombination loss in CsPbI_(2)Br PSCs and an impressive power conversion efficiency of 17.02%.Additionally,the CsPbI_(2)Br PSCs with IILs surface modification exhibited improved ambient and light illumination stability.Our results provide guidance for an indepth understanding of the passivation mechanism of IILs in inorganic perovskites.

Carbon dots regulate the interface electron transfer and catalytic kinetics of Pt-based alloys catalyst for highly efficient hydrogen oxidation

The regulation of interface electron-transfer and catalytic kinetics is very important to design the efficient electrocatalyst for alkaline hydrogen oxidation reaction(HOR).Here,we show the Pt-Ni alloy nanoparticles(PtNi_(2))have an enhanced HOR activity compared with single component Pt catalyst.While,the interface electron-transfer kinetics of PtNi_(2)catalyst exhibits a very wide electron-transfer speed distribution.When combined with carbon dots(CDs),the interface charge transfer of PtNi_(2)-CDs composite is optimized,and then the PtNi_(2)-5 mg CDs exhibits about 2.67 times and 4.04 times higher mass and specific activity in 0.1 M KOH than that of 20%commercial Pt/C.In this system,CDs also contribute to trapping H^(+)and H_(2)O generated during HOR,tuning hydrogen binding energy(HBE),and regulating interface electron transfer.This work provides a deep understanding of the interface catalytic kinetics of Pt-based alloys towards highly efficient HOR catalysts design.

Modulating eg orbitals through ligand engineering to boost the electrocatalytic activity of NiSe for advanced lithium-sulfur batteries

Accelerating the sluggish redox kinetics of lithium polysulfides(LiPSs)by electrocatalysis is essential to achieve high performance lithium-sulfur(Li-S)batteries.However,the issue of insufficient catalytic activity remains to be addressed.Herein,a strategy of modulating e_(g) orbitals through ligand engineering has been proposed to boost the catalytic activity of NiSe for rapid LiPSs redox conversion.The X-ray spectroscopic measurements and theoretical calculations reveal that partial substitution of Se with N disrupts the octahedral coordination of Ni atoms in NiSe,leading to the reduced degeneracy and upward shift of e_(g) orbitals of Ni 3 d states.As a consequence,the bonding strength of N-substituted NiSe(N-NiSe)with LiPSs is enhanced,which facilitates the interfacial charge transfer kinetics and accelerates the LiPSs redox kinetics.Therefore,the Li-S batteries assembled with N-NiSe present a high capacity of 682.6 mAh g^(-1) at a high rate of 5 C and a high areal capacity of 6.5 mAh cm^(-2)at a high sulfur loading of 6 mg cm^(-2).This work provides a promising strategy to develop efficient transition-metal based electrocatalysts for Li-S batteries through e_(g) orbital modulation.

Bidirectionally catalytic polysulfide conversion by high-conductive metal carbides for lithium-sulfur batteries

Utilizing catalysts to accelerate the redox kinetics of lithium polysulfides (LiPSs) is a promising strategy to alleviate the shuttle effect of lithium–sulfur (Li–S) batteries.Nevertheless,most of the reported catalysts are only effective for LiPSs reduction,resulting in the devitalization of catalysts over extended cycles as a consequence of the continuous accumulation of Li_(2)S passivation layer.The situation gets even worse when employing mono-directional catalyst with poor electron conductivity because the charge transfer for the decomposition of solid Li_(2)S is severely hampered.Herein,a high-conductive and dualdirectional catalyst Co_(3)C decorated on porous nitrogen-doped graphene-like structure and carbon nanotube (Co_(3)C@PNGr-CNT) is fabricated as sulfur host,which not only promotes the precipitation of Li_(2)S from Li PSs during discharge but also facilitates the decomposition of Li;S during subsequent charge,as evidenced by the reduced activation energies for both reduction and oxidation processes.Furthermore,the long-term catalytic stability of Co_(3)C is corroborated by the reversible evolution of Co–C bond length over extended cycles as observed from X-ray absorption fine structure results.As a consequence,the fabricated Co_(3)C@PNGr-CNT/S cathode delivers a low capacity decay of 0.043%per cycle over 1000 cycles at 2C.Even at high sulfur loading (15.6 mg cm^(-2)) and low electrolyte/sulfur (E/S) ratio (~8μL mg^(-1))conditions,the battery still delivers an outstanding areal capacity of 11.05 m Ah cm^(-2) after 40 cycles.This work provides a rational strategy for designing high-efficient bidirectional catalyst with single component for high-performance Li-S batteries.

Unraveling the role of Ti3C2 MXene underlayer for enhanced photoelectrochemical water oxidation of hematite photoanodes

Hematite is regarded as a promising photoanode for photoelectrochemical(PEC) water splitting.However,the charge recombination occurred at the interface of FTO/hematite strictly limits the PEC performance of hematite.Herein,we reported a Ti3C2 MXene underlayer modified hematite(Ti-Fe2O3) photoanode via a simple drop-casting followed by hydrothermal and annealing processes.Owing to the bifunctional role of Ti3C2 MXene underlayer in improving the interfacial properties of FTO/hematite and providing Ti source for the construction of Fe2 TiO5/Fe2O3 heterostructure in hematite nanostructure,the bulk and interfacial charge transfer dynamics of hematite are significantly enhanced,and consequently enhancing the PEC performance.Compared with the pristine hematite,the as-prepared Ti-Fe2O3 photoanode shows an increased photocurrent density from 0.80 mA/cm^(2) to 1.30 mA/cm^(2) at 1.23 V vs.RHE.Moreover,a further promoted PEC performance including a dramatically increased photocurrent density of 2.49 mA/cm^(2) at1.23 V vs.RHE and an obviously lowered onset potential is achieved for the Ti-Fe2O3 sample after the subsequent surface F-treatment and the loading of FeNiOOH cocatalyst.Such results suggest that the introduction of Ti3C2 MXene underlayer is a facile but effective approach to improve the PEC water splitting activity of hematite.

Self-assembled CoOOH on TiO_(2) for enhanced photoelectrochemical water oxidation

Providing efficient charge transfer through the interface between the semiconductor and co-catalyst is greatly desired in photoelectrocatalytic (PEC) energy conversion.Herein,we excogitate a novel and facile means,via electrochemical activation,to successfully load the amorphous CoOOH layer architecture onto the surface of TiO_(2).Intriguingly,the as-obtained 6%CoOOH-TiO_(2)photoelectrode manifests optimal PEC performance with a high photocurrent density of 1.3 mA/cm~2,3.5 times higher than that of pristine TiO_(2).Electrochemical impedance spectroscopy (EIS),Tafel analysis and cyclic voltammetry (CV) methods show that the carrier transfer barrier within the electrode and the transition of Co^(3+)OOH to Co^(4+)OOH have the dominating effects on the PEC performance.Theoretical calculation reveals that the interface between the CoOOH and TiO_(2)improves the homogeneity of effective d-orbital electronic-transfer ability among Co sites.This research sheds light on the water oxidation reaction and the design of more favorable PEC cocatalysts.

Carbon nanotube supported PtOx nanoparticles with hybrid chemical states for efficient hydrogen evolution

Efficient electrocatalysts for hydrogen evolution reaction(HER) in alkaline solution are highly required for water splitting.Here we design an ultra-small PtOx nanoparticle with hybrid Pt chemical states on carbon nanotubes as highly efficient alkaline HER catalyst,which shows a low overpotential of 19.4 mV at 10 mA cm^(-2),a high mass activity of 5.56 A mg_(Pt)^(-1) at 0.1 V, and a stable durability for at least 20 h.The HER performance is better than that of the benchmark 20 wt% Pt/C while the Pt content in the catalyst is only about one tenth of that in Pt/C.It also represents one of the best catalysts ever reported for HER in alkaline solution.Synchrotron radiation X-ray absorption spectroscopy reveals that the efficient and stable alkaline HER performance can be attributed to the favorable design of hybrid chemical states of Pt with carbon nanotubes,which exhibits abundant surface Pt-O as active catalytic sites and forms stable Pt-C interfacial interaction to both anchor the NPs and improve the synergistic effect between catalyst and substrate.

FeF_(x) and Fe_(2)ZrO_(5) Co-modified hematite for highly efficient solar water splitting

Hematite is an excellent catalyst for photoelectrochemical (PEC) water splitting but its performance has been highly limited by poor conductivity and high charge recombination.Here by a Zr-based treatment to create bulk Fe_(2)ZrO_(5) in hematite and a F-based treatment to form an ultrathin surface FeF_(x) layer,the charge transfer can be highly improved and the charge recombination can be significantly suppressed.As a result,the FeF_(x) /Zr-Fe_(2)O_(3) photoanode presents an enhanced PEC performance with a photocurrent density of 2.43 m A/cm^(2)at 1.23 V vs.RHE,which is around 3 times higher than that of the pristine Fe_(2)O_(3) .The FeF_(x) /Zr-Fe_(2)O_(3) photoanode also shows a low onset potential of 0.77 V vs.RHE (100 mV lower than the pristine hematite).The performance is much higher than that of the sample treated by Zr or F alone,suggesting the synergistic effect between bulk Fe_(2)ZrO_(5) and surface FeF_(x) .By coupling with the FeNiOOH co-catalyst,the final photoanode can achieve a high photocurrent density of 2.81 mA/cm^(2) at 1.23 V vs.RHE.The novel design of Zr and F co-modified hematite can be used as a promising way to prepare efficient catalysts for solar water splitting.

Cobalt coordination with pyridines in sulfurized polyacrylonitrile cathodes to form conductive pathways and catalytic M-N4S sites for accelerated Li-S kinetics

Sulfurized polyacrylonitrile(SPAN)represents a unique class of cathode material for lithium sulfur(Li-S)batteries as it eradicates the polysulfides shuttling issue in carbonate-based electrolyte.However,due to the essential chemical S-linking and organic nature of SPAN,the active mass percentage and rate capability are two bottleneck issues preventing its ultimate deployment outside of laboratories.In the current work,aiming to endow both the charge conductivity and catalytic activity to SPAN for maximizing the redox kinetics of S conversion,a freestanding nanofibrous SPAN cathode embedding conductive CNTs and atomically dispersed Co centers is fabricated via multivariate electrospinning.While the CNTs enable dramatically enhancing the fiber conductivity and generating mesoscopic porosity for facilitating charge and mass transportation,the cross-linking of SPAN by Co-N_(4) S motifs creates extra charge conduction pathways and further serves as the catalytic active sites for expediting redox S conversion.As a result,an extraordinary Li-SPAN performance is achieved with a high specific capacity up to 1856 mAh g^(-1)@0.2 C,a superb rate capability up to 10 C,and an ultra-long battery life up to 1500 cycles@1 C.Consequently,our study here provides insights into the adoption of coordination chemistry to maximize the sulfur utilization by ensuring a more complete redox conversion from SPAN to Li2 S,and vice versa.

用于含能分子性质预测的分子描述符增强图神经网络

含能分子在军事和民用应用中都发挥着重要作用.传统上,确定含能分子的物理化学参数需要实验工作量且具有风险,而新兴的机器学习方法有望解决这一问题.在这项工作中,我们报道了一种分子描述符增强的图神经网络(MD增强的GNN)模型,该模型可以准确快速地预测含能分子的三个爆轰参数.该模型集成了基于序列的分子描述符和基于结构的图向量,提供了一个不需要自定义描述符的全面框架.因此,我们构建了一个包含18,991个CHNO含能分子的含能分子数据集,并将我们的模型与单一的分子指纹/描述符和GNN方法进行了比较.研究发现,我们提出的MD增强的GNN集成方法通过结合两个不同的互补特征,实现了卓越的精度,R2超过0.93,学习速度提高了20%以上,这突出了我们的模型在重塑含能分子设计格局方面的潜力,并有望在这一关键领域内大幅提高效率和有效性.

可见光到近红外Ⅱ区内宽领域可调发射的芘基共晶

有机材料的可变发光在波导和显示应用方面具有广泛的潜力.然而,基于单一有机分子体系实现从可见光到近红外区域的大范围发光调节仍然是一项挑战.本文介绍了一系列基于芘的同构共晶体,可提供从可见光到近红外Ⅱ区的可调发射.它们的能级是通过引入电荷转移和无氟芳烃-全氟芳烃相互作用而定制的.令人印象深刻的是,这项工作中的有机微晶可以成功地应用于微观层面的多色波导以及宏观层面的二维码显示,为先进的光子学开辟了新的道路.这项工作为获得400至1100 nm的有机晶体提供了一种简单而有效的方法,从而为制造多种光电子学的核心材料提供了可能性.

Narrowband blue emitter based on fused nitrogen/carbonyl combination with external quantum efficiency approaching 30%

Multi-resonance thermally activated delayed fluorescence(MR-TADF)emitters can enable narrowband emission with high color purity and electroluminescence efficiency.Nitrogen/carbonyl(N/C=O)system is receiving increasing attention while the nitrogen/boron(N/B)system has been widely studied.Donor decoration is an effective approach for N/B type MR-TADF system but always leads to broadening and red-shifting of the emission band in N/C=O MR-TADF system.We attribute these unfavorable phenomena to the formation of intramolecular charge transfer between the MR-core and peripheral donors.To address this issue,we have developed a new strategy by decorating DMQAO(a fused N/C=O MR-core)with a triazine acceptor and a neutral terphenyl group to construct MTDMQAO and MBDMQAO,respectively.The introduction of the triazine acceptor not only realizes efficient narrowband emission in MTDMQAO,but also accelerates the reverse intersystem crossing process through enhanced spin-orbital coupling.As a result,MTDMQAO exhibits a significantly higher external quantum efficiency of 29.4%compared to the referent emitters,validating the rationality of our derivation strategy.This study highlights the potential of the N/C=O system for MR-TADF emitters and provides important insights for understanding the difference between N/B and N/C=O systems.