While heteroatom doping serves as a powerful strategy for devising novel polycyclic aromatic hydrocarbons(PAHs), the further fine-tuning of optoelectronic properties via the precisely altering of doping patterns remai...While heteroatom doping serves as a powerful strategy for devising novel polycyclic aromatic hydrocarbons(PAHs), the further fine-tuning of optoelectronic properties via the precisely altering of doping patterns remains a challenge. Herein, by changing the doping positions of heteroatoms in a diindenopyrene skeleton, we report two isomeric boron, sulfur-embedded PAHs, named Anti-B_(2)S_(2) and Syn-B_(2)S_(2), as electron transporting semiconductors. Detailed structure-property relationship studies revealed that the varied heteroatom positions not only change their physicochemical properties, but also largely affect their solid-state packing modes and Lewis base-triggered photophysical responses. With their low-lying frontier molecular orbital levels, n-type characteristics with electron mobilities up to 1.5 × 10^(-3)cm^(2)V^(-1)s^(-1)were achieved in solution-processed organic field-effect transistors. Our work revealed the critical role of controlling heteroatom doping patterns for designing advanced PAHs.展开更多
Boron(B)-and sulfur(S)-doped polycyclic aromatic hydrocarbons(PAHs)are developed as a novel kind of multiple resonance emitters for ultrapure blue thermally activated delayed fluorescence(TADF)polymers with narrowband...Boron(B)-and sulfur(S)-doped polycyclic aromatic hydrocarbons(PAHs)are developed as a novel kind of multiple resonance emitters for ultrapure blue thermally activated delayed fluorescence(TADF)polymers with narrowband electroluminescence.The combination of electron-deficient B atom and electron-rich S atom in PAH can form an intramolecular push-pull electronic system in a rigid aromatic framework,leading to reduced singlet-triplet energy splitting and limited structure relaxation of excited states.The critical roles of S atom in determining emission properties with respect to the oxygen analogues are in two aspects:(i)reducing energy bandgap to shift emission from human-eye-insensitive ultraviolet zone to blue region,and(ii)promoting reverse intersystem crossing process by heavy-atom effect to activate TADF effect.The resulting polymer containing B,S-doped PAH as emitter and acridan as host exhibits efficient blue electroluminescence at 458 nm with small full-width at halfmaximum of 31 nm,representing the first example for ultrapure TADF polymer with narrowband electroluminescence.展开更多
Doping heteroatoms into polycyclic aromatic hydrocarbons(PAHs)is an efficient strategy to achieve fascinating electronic structures and materials.However,nanoscale B-doped PAHs remain very challenging because of the i...Doping heteroatoms into polycyclic aromatic hydrocarbons(PAHs)is an efficient strategy to achieve fascinating electronic structures and materials.However,nanoscale B-doped PAHs remain very challenging because of the intrinsic instability of the boron atom and the lack of suitable precursors.In this study,we report a C_(54)B_(2) polycyclicπ-system with one embedded 1,4-diboron-substituted benzene subunit,which was successfully synthesized from doubly B-doped heptazethrene.Thismolecule represents not only the largest B-doped PAH by far but also an unprecedented B-doped nanographene.The fully zigzag-armchair-edged structure creates a planar conformation,thus leading to its unique bilayer assembly behavior.More importantly,it possesses intriguing electronic structure and optoelectronic properties,such as very broad light absorption that covers 350–750 nm,sharp near-infrared fluorescence with a band width of only 26 nm,and reversible five-step redox capability,all of which are rarely observed for other B-doped PAHs.In addition,this molecule displays distinctive local aromaticity that cannot be reproduced via the reductive manipulation of an allcarbon congener.展开更多
The RTS technology can produce ultra-low sulfur diesel at lower costs using available hydrogenation catalyst and device.However,with the increase of the mixing proportion of secondary processed diesel fuel in the feed...The RTS technology can produce ultra-low sulfur diesel at lower costs using available hydrogenation catalyst and device.However,with the increase of the mixing proportion of secondary processed diesel fuel in the feed,the content of nitrogen compounds and polycyclic aromatic hydrocarbons in the feed increased,leading to the acceleration of the deactivation rate of the primary catalyst and the shortening of the service cycle.In order to fully understand the reason of catalyst deactivation,the effect of mixing secondary processed diesel fuel oil on the operating stability of the catalyst in the first reactor was investigated in a medium-sized fixed-bed hydrogenation unit.The results showed that the nitrogen compounds mainly affected the initial activity of the catalyst,but had little effect on the stability of the catalyst.The PAHs had little effect on the initial activity of the catalyst,but could significantly accelerate the deactivation of the catalyst.Combined with the analysis of the reason of catalyst deactivation and the study of RTS technology,the direction of RTS technology process optimization was put forward,and the stability of catalyst was improved obviously after process optimization.展开更多
To characterize how the speed and load of a medium-duty diesel engine affected the organic compounds in diesel particle matter（PM） below 1 μm, four driving conditions were examined. At all four driving conditions, ...To characterize how the speed and load of a medium-duty diesel engine affected the organic compounds in diesel particle matter（PM） below 1 μm, four driving conditions were examined. At all four driving conditions, concentration of identifiable organic compounds in PM ultrafine（34–94 nm） and accumulation（94–1000 nm） modes ranged from 2.9 to 5.7 μg/m3 and 9.5 to 16.4 μg/m3, respectively. As a function of driving conditions, the non-oxygencontaining organics exhibited a reversed concentration trend to the oxygen-containing organics. The identified organic compounds were classified into eleven classes： alkanes,alkenes, alkynes, aromatic hydrocarbons, carboxylic acids, esters, ketones, alcohols, ethers,nitrogen-containing compounds, and sulfur-containing compounds. At all driving conditions,alkane class consistently showed the highest concentration（8.3 to 18.0 μg/m3） followed by carboxylic acid, esters, ketones and alcohols. Twelve polycyclic aromatic hydrocarbons（PAHs）were identified with a total concentration ranging from 37.9 to 174.8 ng/m3. In addition, nine nitrogen-containing polycyclic aromatic compounds（NPACs） were identified with a total concentration ranging from 7.0 to 10.3 ng/m3. The most abundant PAH（phenanthrene）and NPACs（7,8-benzoquinoline and 3-nitrophenanthrene） comprise a similar molecular（3 aromatic-ring） structure under the highest engine speed and engine load.展开更多
基金the National Natural Science Foundation of China (Nos.22375059, 22005133, 51922039 and52273174)Shenzhen Science and Technology Program (No.RCJC20200714114434015)+1 种基金Science and Technology Innovation Program of Hunan Province (No.2020RC5033)National Key Research and Development Program of China (No.2020YFC1807302) for financial support。
文摘While heteroatom doping serves as a powerful strategy for devising novel polycyclic aromatic hydrocarbons(PAHs), the further fine-tuning of optoelectronic properties via the precisely altering of doping patterns remains a challenge. Herein, by changing the doping positions of heteroatoms in a diindenopyrene skeleton, we report two isomeric boron, sulfur-embedded PAHs, named Anti-B_(2)S_(2) and Syn-B_(2)S_(2), as electron transporting semiconductors. Detailed structure-property relationship studies revealed that the varied heteroatom positions not only change their physicochemical properties, but also largely affect their solid-state packing modes and Lewis base-triggered photophysical responses. With their low-lying frontier molecular orbital levels, n-type characteristics with electron mobilities up to 1.5 × 10^(-3)cm^(2)V^(-1)s^(-1)were achieved in solution-processed organic field-effect transistors. Our work revealed the critical role of controlling heteroatom doping patterns for designing advanced PAHs.
基金supported by the National Natural Science Foundation of China(52073282,51833009,21975247)the National Basic Research Program of China(2015CB655000)the Youth Innovation Promotion Association of Chinese Academy of Sciences(2015180)。
文摘Boron(B)-and sulfur(S)-doped polycyclic aromatic hydrocarbons(PAHs)are developed as a novel kind of multiple resonance emitters for ultrapure blue thermally activated delayed fluorescence(TADF)polymers with narrowband electroluminescence.The combination of electron-deficient B atom and electron-rich S atom in PAH can form an intramolecular push-pull electronic system in a rigid aromatic framework,leading to reduced singlet-triplet energy splitting and limited structure relaxation of excited states.The critical roles of S atom in determining emission properties with respect to the oxygen analogues are in two aspects:(i)reducing energy bandgap to shift emission from human-eye-insensitive ultraviolet zone to blue region,and(ii)promoting reverse intersystem crossing process by heavy-atom effect to activate TADF effect.The resulting polymer containing B,S-doped PAH as emitter and acridan as host exhibits efficient blue electroluminescence at 458 nm with small full-width at halfmaximum of 31 nm,representing the first example for ultrapure TADF polymer with narrowband electroluminescence.
基金supported by National Natural Science Foundation of China(grant nos.22175074 and 21822507).
文摘Doping heteroatoms into polycyclic aromatic hydrocarbons(PAHs)is an efficient strategy to achieve fascinating electronic structures and materials.However,nanoscale B-doped PAHs remain very challenging because of the intrinsic instability of the boron atom and the lack of suitable precursors.In this study,we report a C_(54)B_(2) polycyclicπ-system with one embedded 1,4-diboron-substituted benzene subunit,which was successfully synthesized from doubly B-doped heptazethrene.Thismolecule represents not only the largest B-doped PAH by far but also an unprecedented B-doped nanographene.The fully zigzag-armchair-edged structure creates a planar conformation,thus leading to its unique bilayer assembly behavior.More importantly,it possesses intriguing electronic structure and optoelectronic properties,such as very broad light absorption that covers 350–750 nm,sharp near-infrared fluorescence with a band width of only 26 nm,and reversible five-step redox capability,all of which are rarely observed for other B-doped PAHs.In addition,this molecule displays distinctive local aromaticity that cannot be reproduced via the reductive manipulation of an allcarbon congener.
基金This work was financially supported by the Technology Development Project of SINOPEC(121025)All of the staff in our laboratory had provided a lot of support in the analysis of oil samples and catalyst characterization.
文摘The RTS technology can produce ultra-low sulfur diesel at lower costs using available hydrogenation catalyst and device.However,with the increase of the mixing proportion of secondary processed diesel fuel in the feed,the content of nitrogen compounds and polycyclic aromatic hydrocarbons in the feed increased,leading to the acceleration of the deactivation rate of the primary catalyst and the shortening of the service cycle.In order to fully understand the reason of catalyst deactivation,the effect of mixing secondary processed diesel fuel oil on the operating stability of the catalyst in the first reactor was investigated in a medium-sized fixed-bed hydrogenation unit.The results showed that the nitrogen compounds mainly affected the initial activity of the catalyst,but had little effect on the stability of the catalyst.The PAHs had little effect on the initial activity of the catalyst,but could significantly accelerate the deactivation of the catalyst.Combined with the analysis of the reason of catalyst deactivation and the study of RTS technology,the direction of RTS technology process optimization was put forward,and the stability of catalyst was improved obviously after process optimization.
基金supported by the Transportation Pollution Research Center, National Institute of Environmental Research in the Republic of Korea and the Korean government overseas study fellowship (Program: 2003-S-20)
文摘To characterize how the speed and load of a medium-duty diesel engine affected the organic compounds in diesel particle matter（PM） below 1 μm, four driving conditions were examined. At all four driving conditions, concentration of identifiable organic compounds in PM ultrafine（34–94 nm） and accumulation（94–1000 nm） modes ranged from 2.9 to 5.7 μg/m3 and 9.5 to 16.4 μg/m3, respectively. As a function of driving conditions, the non-oxygencontaining organics exhibited a reversed concentration trend to the oxygen-containing organics. The identified organic compounds were classified into eleven classes： alkanes,alkenes, alkynes, aromatic hydrocarbons, carboxylic acids, esters, ketones, alcohols, ethers,nitrogen-containing compounds, and sulfur-containing compounds. At all driving conditions,alkane class consistently showed the highest concentration（8.3 to 18.0 μg/m3） followed by carboxylic acid, esters, ketones and alcohols. Twelve polycyclic aromatic hydrocarbons（PAHs）were identified with a total concentration ranging from 37.9 to 174.8 ng/m3. In addition, nine nitrogen-containing polycyclic aromatic compounds（NPACs） were identified with a total concentration ranging from 7.0 to 10.3 ng/m3. The most abundant PAH（phenanthrene）and NPACs（7,8-benzoquinoline and 3-nitrophenanthrene） comprise a similar molecular（3 aromatic-ring） structure under the highest engine speed and engine load.
