Thermally activated delayed fluorescence(TADF)materials driven by a through-space charge transfer(TSCT)mechanism have garnered wide interest.However,access of TSCT-TADF molecules with longwavelength emission remains a...Thermally activated delayed fluorescence(TADF)materials driven by a through-space charge transfer(TSCT)mechanism have garnered wide interest.However,access of TSCT-TADF molecules with longwavelength emission remains a formidable challenge.In this study,we introduce a novel V-type DA-D-A’emitter,Trz-mCzCbCz,by using a carborane scaffold.This design strategically incorporates carbazole(Cz)and 2,4,6-triphenyl-1,3,5-triazine(Trz)as donor and acceptor moieties,respectively.Theoretical calculations alongside experimental validations affirm the typical TSCT-TADF characteristics of this luminogen.Owing to the unique structural and electronic attributes of carboranes,Trz-mCzCbCz exhibits an orange-red emission,markedly diverging from the traditional blue-to-green emissions observed in classical Cz and Trz-based TADF molecules.Moreover,bright emission in aggregates was observed for Trz-mCzCbCz with absolute photoluminescence quantum yield(PLQY)of up to 88.8%.As such,we have successfully fabricated five organic light-emitting diodes(OLEDs)by utilizing Trz-mCzCbCz as the emitting layer.It is important to note that both the reverse intersystem crossing process and the TADF properties are profoundly influenced by host materials.The fabricated OLED devices reached a maximum external quantum efficiency(EQE)of 12.7%,with an emission peak at 592 nm.This represents the highest recorded efficiency for TSCT-TADF OLEDs employing carborane derivatives as emitting layers.展开更多
Au is considered as one of the most promising catalysts for nitrogen reduction reaction(NRR),however maximizing the activity utilization rate of Au and understanding the synergistic effects between Au and carriers pos...Au is considered as one of the most promising catalysts for nitrogen reduction reaction(NRR),however maximizing the activity utilization rate of Au and understanding the synergistic effects between Au and carriers pose ongoing challenges.Herein,we systematically explore the synergistic catalytic effect of incorporating Au with boron clusters for accelerating NRR kinetics.An in-situ abinitio strategy is employed to construct B-doped Au nanoparticles(2-6 nm in diameter)loaded on BO_(x) substrates(AuBO_(x)),in which B not only modulates the surface electronic structure of Au but also forms strong coupling interactions to stabilize the nanoparticles.The electrochemical results show that Au-BO_(x) possesses excellent NRR activity(NH_(3) yield of 48.52μg h^(-1)mg_(cat)^(-1),Faraday efficiency of 56.18%),and exhibits high stability and reproducibility throughout the electrocatalytic NRR process.Theoretical calculations reveal that the introduction of B induces the formation of both Au dangling bond and Au-B coupling bond.which considerably facilitates the hydrogenation of~*N_(2)^(-)~*NH_(3).The present work provides a new avenue for the preparation of metal-boron materials achieved by one-step reduction and doping process,utilizing boron clusters as reducing and stabilizing agents.展开更多
The thermal stability and bonding characteristics of the larger boron clusters B n and their corresponding boranes with T d , O h or I h symmetries were studied by means of ab initio...The thermal stability and bonding characteristics of the larger boron clusters B n and their corresponding boranes with T d , O h or I h symmetries were studied by means of ab initio method. The results obtained from the calculation show that the clusters and boranes are all thermally stable to a different extent. The number of the skeletal bonding orbitals of B n H 2- n satisfies the Wades rule, but this kind of clusters need not be a complete triangular face polyhedron. The results also indicate that the larger neutral boranes B n H n may exist.展开更多
Four isomers of the three-dimensionally connected bare boron cationic cluster B were investigated by using ab initio molecular orbital theory at the HF/6-31G level. The results show that the D5h symmetric isomer of B ...Four isomers of the three-dimensionally connected bare boron cationic cluster B were investigated by using ab initio molecular orbital theory at the HF/6-31G level. The results show that the D5h symmetric isomer of B is a possible isomer candidate of its stable geometries with closed structure.展开更多
While rare-earth borides represent a class of important materials in modern industries,there are few fundamental researches on their electronic structures and physicochemical properties.Recently,we have performed comb...While rare-earth borides represent a class of important materials in modern industries,there are few fundamental researches on their electronic structures and physicochemical properties.Recently,we have performed combined experimental and theoretical studies on rare-earth boron clusters and their cluster-assembled complexes,revealing a series of rare-earth inverse sandwich clusters with fascinating electronic structures and chemical bonding patterns.In this overview article,we summarize recent progresses in this area and provide a perspective view on the future development of rare-earth boride clusters.Understanding the electronic structures of these clusters helps to design materials of f-element(lanthanide and actinide)borides with critical physiochemical properties.展开更多
A density functional theory （DFT） investigation has been performed in this work on the cage-like boron-rich boron oxide clus-ters Bn（BO）n^2-,CBn-1（BO）n^-,and C2Bn-2（BO）n （n = 5–12） which are boronyl analogu...A density functional theory （DFT） investigation has been performed in this work on the cage-like boron-rich boron oxide clus-ters Bn（BO）n^2-,CBn-1（BO）n^-,and C2Bn-2（BO）n （n = 5–12） which are boronyl analogues of the closo-boranes BnHn2-,monocarbo-ranes CBn-1H-n,and dicarboranes C2Bn-2Hn. These boron oxide clusters possess similar geometrical and electronic structures with the corresponding boranes and carboranes and prove to be three-dimensional （3D） aromatic compounds,consistent with the previously proposed BO/H isolobal analogy. Neutral C2Bn-2（BO）n species possess considerably high ionization potentials in the range 12.0–12.7 eV and CBn-1H-n monoanions have the vertical electron detachment energies in the range 6.6–9.4 eV at the DFT level. BO terminals singly bonded to the skeletal vertexes through a B atom possess the characteristic stretching vi-brational frequencies at about 2000 cm-1,clearly indicating the existence of B-O triple bonds in these clusters. Experimental syntheses and characterizations of these interesting clusters may expand the structural concepts of boron oxides and bring im-portant applications for boron oxide clusters as molecular devices in chemistry and new materials in boron neutron capture therapy.展开更多
Structures, energies and vibrational frequencies have been calculated for hollow cage clusters N28, B4N24, B12N16, and B16N12 with Td symmetry using ab initio quantum mechanical methods at the RHF/3-21G level. Each sp...Structures, energies and vibrational frequencies have been calculated for hollow cage clusters N28, B4N24, B12N16, and B16N12 with Td symmetry using ab initio quantum mechanical methods at the RHF/3-21G level. Each species is predicted to be both chemically and kinetically stable. Skeletal polyhedrons of all considered boron nitride hollow cage clusters are constructed from 5- and 6-membered rings.展开更多
基金supported by the Natural Science Foundation of Jiangsu Province(No.BZ2022007)the National Natural Science Foundation of China(No.92261202)+1 种基金the Ministry of Science and Technology of the People’s Republic of China(No.2021YFE0114800)the Ministry of Science and Higher Education of the Russian Federation(No.075-15-2021-1027).
文摘Thermally activated delayed fluorescence(TADF)materials driven by a through-space charge transfer(TSCT)mechanism have garnered wide interest.However,access of TSCT-TADF molecules with longwavelength emission remains a formidable challenge.In this study,we introduce a novel V-type DA-D-A’emitter,Trz-mCzCbCz,by using a carborane scaffold.This design strategically incorporates carbazole(Cz)and 2,4,6-triphenyl-1,3,5-triazine(Trz)as donor and acceptor moieties,respectively.Theoretical calculations alongside experimental validations affirm the typical TSCT-TADF characteristics of this luminogen.Owing to the unique structural and electronic attributes of carboranes,Trz-mCzCbCz exhibits an orange-red emission,markedly diverging from the traditional blue-to-green emissions observed in classical Cz and Trz-based TADF molecules.Moreover,bright emission in aggregates was observed for Trz-mCzCbCz with absolute photoluminescence quantum yield(PLQY)of up to 88.8%.As such,we have successfully fabricated five organic light-emitting diodes(OLEDs)by utilizing Trz-mCzCbCz as the emitting layer.It is important to note that both the reverse intersystem crossing process and the TADF properties are profoundly influenced by host materials.The fabricated OLED devices reached a maximum external quantum efficiency(EQE)of 12.7%,with an emission peak at 592 nm.This represents the highest recorded efficiency for TSCT-TADF OLEDs employing carborane derivatives as emitting layers.
基金supported by the National Natural Science Foundation of China(22075133,62288102,22375091,21971114,and 21701086)the Jiangsu Provincial Funds(BX2022013)。
文摘Au is considered as one of the most promising catalysts for nitrogen reduction reaction(NRR),however maximizing the activity utilization rate of Au and understanding the synergistic effects between Au and carriers pose ongoing challenges.Herein,we systematically explore the synergistic catalytic effect of incorporating Au with boron clusters for accelerating NRR kinetics.An in-situ abinitio strategy is employed to construct B-doped Au nanoparticles(2-6 nm in diameter)loaded on BO_(x) substrates(AuBO_(x)),in which B not only modulates the surface electronic structure of Au but also forms strong coupling interactions to stabilize the nanoparticles.The electrochemical results show that Au-BO_(x) possesses excellent NRR activity(NH_(3) yield of 48.52μg h^(-1)mg_(cat)^(-1),Faraday efficiency of 56.18%),and exhibits high stability and reproducibility throughout the electrocatalytic NRR process.Theoretical calculations reveal that the introduction of B induces the formation of both Au dangling bond and Au-B coupling bond.which considerably facilitates the hydrogenation of~*N_(2)^(-)~*NH_(3).The present work provides a new avenue for the preparation of metal-boron materials achieved by one-step reduction and doping process,utilizing boron clusters as reducing and stabilizing agents.
文摘The thermal stability and bonding characteristics of the larger boron clusters B n and their corresponding boranes with T d , O h or I h symmetries were studied by means of ab initio method. The results obtained from the calculation show that the clusters and boranes are all thermally stable to a different extent. The number of the skeletal bonding orbitals of B n H 2- n satisfies the Wades rule, but this kind of clusters need not be a complete triangular face polyhedron. The results also indicate that the larger neutral boranes B n H n may exist.
文摘Four isomers of the three-dimensionally connected bare boron cationic cluster B were investigated by using ab initio molecular orbital theory at the HF/6-31G level. The results show that the D5h symmetric isomer of B is a possible isomer candidate of its stable geometries with closed structure.
基金financially supported by the National Natural Science Foundation of China (No. 9164520321433005 and 21590792)Brown University was supported by the U.S. National Science Foundation (CHE-1763380)The support of Guangdong Provincial Key Laboratory of Catalysis (No. 2020B121201002) is also acknowledged。
文摘While rare-earth borides represent a class of important materials in modern industries,there are few fundamental researches on their electronic structures and physicochemical properties.Recently,we have performed combined experimental and theoretical studies on rare-earth boron clusters and their cluster-assembled complexes,revealing a series of rare-earth inverse sandwich clusters with fascinating electronic structures and chemical bonding patterns.In this overview article,we summarize recent progresses in this area and provide a perspective view on the future development of rare-earth boride clusters.Understanding the electronic structures of these clusters helps to design materials of f-element(lanthanide and actinide)borides with critical physiochemical properties.
基金supported by the National Natural Science Founda-tion of China (20873117)the Shanxi Natural Science Foundation (2010011012-3)
文摘A density functional theory （DFT） investigation has been performed in this work on the cage-like boron-rich boron oxide clus-ters Bn（BO）n^2-,CBn-1（BO）n^-,and C2Bn-2（BO）n （n = 5–12） which are boronyl analogues of the closo-boranes BnHn2-,monocarbo-ranes CBn-1H-n,and dicarboranes C2Bn-2Hn. These boron oxide clusters possess similar geometrical and electronic structures with the corresponding boranes and carboranes and prove to be three-dimensional （3D） aromatic compounds,consistent with the previously proposed BO/H isolobal analogy. Neutral C2Bn-2（BO）n species possess considerably high ionization potentials in the range 12.0–12.7 eV and CBn-1H-n monoanions have the vertical electron detachment energies in the range 6.6–9.4 eV at the DFT level. BO terminals singly bonded to the skeletal vertexes through a B atom possess the characteristic stretching vi-brational frequencies at about 2000 cm-1,clearly indicating the existence of B-O triple bonds in these clusters. Experimental syntheses and characterizations of these interesting clusters may expand the structural concepts of boron oxides and bring im-portant applications for boron oxide clusters as molecular devices in chemistry and new materials in boron neutron capture therapy.
基金Project supported by the National Natural Science Foundation of China.
文摘Structures, energies and vibrational frequencies have been calculated for hollow cage clusters N28, B4N24, B12N16, and B16N12 with Td symmetry using ab initio quantum mechanical methods at the RHF/3-21G level. Each species is predicted to be both chemically and kinetically stable. Skeletal polyhedrons of all considered boron nitride hollow cage clusters are constructed from 5- and 6-membered rings.
