Here,this work presents an air-stable ultrabright inverted organic lightemitting device(OLED)by using zinc ionchelated polyethylenimine(PEI)as electron injection layer.The zinc chelation is demonstrated to increase th...Here,this work presents an air-stable ultrabright inverted organic lightemitting device(OLED)by using zinc ionchelated polyethylenimine(PEI)as electron injection layer.The zinc chelation is demonstrated to increase the conductivity of the PEI by three orders of magnitude and passivate the polar amine groups.With these physicochemical properties,the inverted OLED shows a record-high external quantum efficiency of 10.0% at a high brightness of 45,610 cd m^(-2) and can deliver a maximum brightness of 121,865 cd m^(-2).Besides,the inverted OLED is also demonstrated to possess an excellent air stability(humidity,35%)with a half-brightness operating time of 541 h@1000 cd m^(-2) without any protection nor encapsulation.展开更多
Excellent electrical properties and the impact of latest power devices for improving the efficiency of photovohaic（PV） inverters are presented.Power modules using SiC-MOSFET and SBD exhibit the possibility to realiz...Excellent electrical properties and the impact of latest power devices for improving the efficiency of photovohaic（PV） inverters are presented.Power modules using SiC-MOSFET and SBD exhibit the possibility to realize PV inverters with peak efficiency beyond 99%.Si-IGBT modules using reverse-blocking（RB）-IGBT have enabled to massproduce PV inverters with peak efficiency of 98.4%.Si superjunction（SJ）-MOSFET and discrete IGBT have enabled to improve the efficiency of small power PV inverters by 0.5 point.展开更多
Two-dimensional van der Waals(2D vdW)material-based heterostructure devices have been widely studied for high-end electronic applications owing to their heterojunction properties.In this study,we demonstrate graphene(...Two-dimensional van der Waals(2D vdW)material-based heterostructure devices have been widely studied for high-end electronic applications owing to their heterojunction properties.In this study,we demonstrate graphene(Gr)-bridge heterostructure devices consisting of laterally series-connected ambipolar semiconductor/Gr-bridge/n-type molybdenum disulfide as a channel material for field-effect transistors(FET).Unlike conventional FET operation,our Gr-bridge devices exhibit nonclassical transfer characteristics(humped transfer curve),thus possessing a negative differential transconductance.These phenomena are interpreted as the operating behavior in two series-connected FETs,and they result from the gate-tunable contact capacity of the Gr-bridge layer.Multi-value logic inverters and frequency tripler circuits are successfully demonstrated using ambipolar semiconductors with narrow-and wide-bandgap materials as more advanced circuit applications based on non-classical transfer characteristics.Thus,we believe that our innovative and straightforward device structure engineering will be a promising technique for future multi-functional circuit applications of 2D nanoelectronics.展开更多
For electronic piezo gauge used for testing gun chamber pressure, its internal miniature pulse-powered photoelectric invert switch cannot often be powered up normally. To solve this problem, a test system for invert s...For electronic piezo gauge used for testing gun chamber pressure, its internal miniature pulse-powered photoelectric invert switch cannot often be powered up normally. To solve this problem, a test system for invert switch is presented to verify the reliability of the invert switch. The test system uses complex programmable logic device （CPLD） to control data acquisition of A/D converter and data storage of external flash memory, and then transmits the acquired data to a computer for data analysis and processing. The test system can provide the required sampling frequency of the signal in high temperature, normal temperature and low temperature environments, and the reliability of the invert switch can be verified according to the signal parameters. The results show that the test system has high precision and the tested invert switch has low power consumption and high reliability.展开更多
A polyhedral oligomeric silsesquioxane-[60]fullerene (POSS-C60) dyad was designed and used as a novel electron acceptor for bulk heterojunction (BHJ) polymer solar cells (PSCs) with an inverted device configuration. T...A polyhedral oligomeric silsesquioxane-[60]fullerene (POSS-C60) dyad was designed and used as a novel electron acceptor for bulk heterojunction (BHJ) polymer solar cells (PSCs) with an inverted device configuration. The studies of time-resolved photoinduced absorption of the pristine thin film of poly[(4,4'-bis(2-ethylhexyl)dithieno[3,2-b:2',3'-d]silole)-2,6-diyl-alt-(4,7-bis (2-thienyl)-2,1,3-benzothiadiazole)-5,5'-diyl] (SiPCPDTBT) and the composite thin film of SiPCPDTBT:POSS-C60 indicated efficient electron transfer from SiPCPDTBT to POSS-C60 with inhibited back-transfer. BHJ PSCs made by SiPCPDTBT mixed with POSS-C60 yielded the power conversion efficiencies (PCEs) of 1.50%. Under the same operational conditions, PCEs observed from BHJ PSCs made by SiPCPDTBT mixed with [6,6]-phenyl-C61-butyric acid methyl ester were 0.92%. These results demonstrated that POSS-C60 is a potentially good electron acceptor for inverted BHJ PSCs.展开更多
To achieve fabrication and cost competitiveness in organic optoelectronic devices that include organic solar cells(OSCs)and organic light-emitting diodes(OLEDs),it is desirable to have one type of material that can si...To achieve fabrication and cost competitiveness in organic optoelectronic devices that include organic solar cells(OSCs)and organic light-emitting diodes(OLEDs),it is desirable to have one type of material that can simultaneously function as both the electron and hole transport layers(ETLs and HTLs)of the organic devices in all device architectures(i.e.,normal and inverted architectures).We address this issue by proposing and demonstrating Cs-intercalated metal oxides(with various Cs mole ratios)as both the ETL and HTL of an organic optoelectronic device with normal and inverted device architectures.Our results demonstrate that the new approach works well for widely used transition metal oxides of molybdenum oxide(MoOx)and vanadium oxide(V_(2)O_(x)).Moreover,the Cs-intercalated metaloxide-based ETL and HTL can be easily formed under the conditions of a room temperature,water-free and solution-based process.These conditions favor practical applications of OSCs and OLEDs.Notably,with the analyses of the Kelvin Probe System,our approach of Cs-intercalated metal oxides with a wide mole ratio range of transition metals(Mo or V)/Cs from 1:0 to 1:0.75 can offer significant and continuous work function tuning as large as 1.31 eV for functioning as both an ETL and HTL.Consequently,our method of intercalated metal oxides can contribute to the emerging large-scale and low-cost organic optoelectronic devices.展开更多
100-W class power storage systems were developed, which comprised spherical Si solar cells, a maximum power point tracking charge control-ler, a lithium-ion battery, and one of two different types of direct current (D...100-W class power storage systems were developed, which comprised spherical Si solar cells, a maximum power point tracking charge control-ler, a lithium-ion battery, and one of two different types of direct current (DC)-alter- nating current (AC) converters. One inverter used SiC met-al-oxide-semicon-ductor field-effect transistors (MOSFETs) as switching devices while the other used Si MOSFETs. In these 100-W class inverters, the ON resistance was considered to have little influence on the efficiency. Nevertheless, the SiC-based inverter exhibited an approximately 3% higher DC-AC conversion efficiency than the Si-based inverter. Power loss analysis indicated that the higher efficiency resulted predominantly from lower switching and reverse recovery losses in the SiC MOSFETs compared with in the Si MOSFETs.展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.61905086,62174067,62175085)Science and Technology Development Planning of Jilin Province(Project Nos.20190101024JH,20200201296JC)+1 种基金the Hong Kong Scholars Program(Project No.XJ2020028)grants from the Research Grants Council of the Hong Kong Special Administrative Region,China(Project Nos.11300418 and 11300419).
文摘Here,this work presents an air-stable ultrabright inverted organic lightemitting device(OLED)by using zinc ionchelated polyethylenimine(PEI)as electron injection layer.The zinc chelation is demonstrated to increase the conductivity of the PEI by three orders of magnitude and passivate the polar amine groups.With these physicochemical properties,the inverted OLED shows a record-high external quantum efficiency of 10.0% at a high brightness of 45,610 cd m^(-2) and can deliver a maximum brightness of 121,865 cd m^(-2).Besides,the inverted OLED is also demonstrated to possess an excellent air stability(humidity,35%)with a half-brightness operating time of 541 h@1000 cd m^(-2) without any protection nor encapsulation.
文摘Excellent electrical properties and the impact of latest power devices for improving the efficiency of photovohaic（PV） inverters are presented.Power modules using SiC-MOSFET and SBD exhibit the possibility to realize PV inverters with peak efficiency beyond 99%.Si-IGBT modules using reverse-blocking（RB）-IGBT have enabled to massproduce PV inverters with peak efficiency of 98.4%.Si superjunction（SJ）-MOSFET and discrete IGBT have enabled to improve the efficiency of small power PV inverters by 0.5 point.
基金Y.T.L.acknowledges the financial support from the National Research Foundation of Korea(NRF)(No.NRF-2021R1C1C1005235)D.K.H.acknowledges the financial support from the Korea Institute of Science and Technology(KIST)Institution Program(No.2E31532).
文摘Two-dimensional van der Waals(2D vdW)material-based heterostructure devices have been widely studied for high-end electronic applications owing to their heterojunction properties.In this study,we demonstrate graphene(Gr)-bridge heterostructure devices consisting of laterally series-connected ambipolar semiconductor/Gr-bridge/n-type molybdenum disulfide as a channel material for field-effect transistors(FET).Unlike conventional FET operation,our Gr-bridge devices exhibit nonclassical transfer characteristics(humped transfer curve),thus possessing a negative differential transconductance.These phenomena are interpreted as the operating behavior in two series-connected FETs,and they result from the gate-tunable contact capacity of the Gr-bridge layer.Multi-value logic inverters and frequency tripler circuits are successfully demonstrated using ambipolar semiconductors with narrow-and wide-bandgap materials as more advanced circuit applications based on non-classical transfer characteristics.Thus,we believe that our innovative and straightforward device structure engineering will be a promising technique for future multi-functional circuit applications of 2D nanoelectronics.
文摘For electronic piezo gauge used for testing gun chamber pressure, its internal miniature pulse-powered photoelectric invert switch cannot often be powered up normally. To solve this problem, a test system for invert switch is presented to verify the reliability of the invert switch. The test system uses complex programmable logic device （CPLD） to control data acquisition of A/D converter and data storage of external flash memory, and then transmits the acquired data to a computer for data analysis and processing. The test system can provide the required sampling frequency of the signal in high temperature, normal temperature and low temperature environments, and the reliability of the invert switch can be verified according to the signal parameters. The results show that the test system has high precision and the tested invert switch has low power consumption and high reliability.
基金supported by the US NSF (DMR-0906898)the Joint Research Fund for Overseas Chinese Scholars, the National Natural Science Foundation of China (5082830)
文摘A polyhedral oligomeric silsesquioxane-[60]fullerene (POSS-C60) dyad was designed and used as a novel electron acceptor for bulk heterojunction (BHJ) polymer solar cells (PSCs) with an inverted device configuration. The studies of time-resolved photoinduced absorption of the pristine thin film of poly[(4,4'-bis(2-ethylhexyl)dithieno[3,2-b:2',3'-d]silole)-2,6-diyl-alt-(4,7-bis (2-thienyl)-2,1,3-benzothiadiazole)-5,5'-diyl] (SiPCPDTBT) and the composite thin film of SiPCPDTBT:POSS-C60 indicated efficient electron transfer from SiPCPDTBT to POSS-C60 with inhibited back-transfer. BHJ PSCs made by SiPCPDTBT mixed with POSS-C60 yielded the power conversion efficiencies (PCEs) of 1.50%. Under the same operational conditions, PCEs observed from BHJ PSCs made by SiPCPDTBT mixed with [6,6]-phenyl-C61-butyric acid methyl ester were 0.92%. These results demonstrated that POSS-C60 is a potentially good electron acceptor for inverted BHJ PSCs.
基金This study was supported by the University Grant Council of the University of Hong Kong(Grant Nos.10401466 and 201111159062)the General Research Fund(Grant Nos.HKU711813 and HKU711612E)+1 种基金an RGC-NSFC grant(N_HKU709/12)grant CAS14601 from the CAS-Croucher Funding Scheme for Joint Laboratories.
文摘To achieve fabrication and cost competitiveness in organic optoelectronic devices that include organic solar cells(OSCs)and organic light-emitting diodes(OLEDs),it is desirable to have one type of material that can simultaneously function as both the electron and hole transport layers(ETLs and HTLs)of the organic devices in all device architectures(i.e.,normal and inverted architectures).We address this issue by proposing and demonstrating Cs-intercalated metal oxides(with various Cs mole ratios)as both the ETL and HTL of an organic optoelectronic device with normal and inverted device architectures.Our results demonstrate that the new approach works well for widely used transition metal oxides of molybdenum oxide(MoOx)and vanadium oxide(V_(2)O_(x)).Moreover,the Cs-intercalated metaloxide-based ETL and HTL can be easily formed under the conditions of a room temperature,water-free and solution-based process.These conditions favor practical applications of OSCs and OLEDs.Notably,with the analyses of the Kelvin Probe System,our approach of Cs-intercalated metal oxides with a wide mole ratio range of transition metals(Mo or V)/Cs from 1:0 to 1:0.75 can offer significant and continuous work function tuning as large as 1.31 eV for functioning as both an ETL and HTL.Consequently,our method of intercalated metal oxides can contribute to the emerging large-scale and low-cost organic optoelectronic devices.
文摘100-W class power storage systems were developed, which comprised spherical Si solar cells, a maximum power point tracking charge control-ler, a lithium-ion battery, and one of two different types of direct current (DC)-alter- nating current (AC) converters. One inverter used SiC met-al-oxide-semicon-ductor field-effect transistors (MOSFETs) as switching devices while the other used Si MOSFETs. In these 100-W class inverters, the ON resistance was considered to have little influence on the efficiency. Nevertheless, the SiC-based inverter exhibited an approximately 3% higher DC-AC conversion efficiency than the Si-based inverter. Power loss analysis indicated that the higher efficiency resulted predominantly from lower switching and reverse recovery losses in the SiC MOSFETs compared with in the Si MOSFETs.
