Unsaturated magnetoresistance (MR) has been reported in type-II Weyl semimetal WTe2, manifested as a perfect compensation of opposite carriers. We report linear MR (LMR) in WTe2 crystals, the onset of which was id...Unsaturated magnetoresistance (MR) has been reported in type-II Weyl semimetal WTe2, manifested as a perfect compensation of opposite carriers. We report linear MR (LMR) in WTe2 crystals, the onset of which was identified by constructing the MR mobility spectra for weak fields. The LMR further increased and became dominant for fields stronger than 20 T, while the parabolic MR gradually decayed. The LMR was also observed in high-pressure conditions.展开更多
As one of the core parts of two-terminal(2 T) monolithic tandem photovoltaics, the interconnecting layers(ICLs) play a critical role in modulating the carrier transport and recombination between the sub-cells,and thus...As one of the core parts of two-terminal(2 T) monolithic tandem photovoltaics, the interconnecting layers(ICLs) play a critical role in modulating the carrier transport and recombination between the sub-cells,and thus influencing the tandem device performance. Here, for the first time, the relationship between ICLs architecture and 2 T monolithic perovskite/organic tandem device performance has been studied by investigating the change of ICLs composition layer thickness on the ICLs optical and electrical properties, sub-cells EQE properties, and tandem device J-V properties. It is revealed that the ability of ICLs on modulating the sub-cells carrier balance properties is strongly associated with its composited layers thickness, and the tandem device carrier balance properties can be reflected by the relative EQE intensity between the sub-cells. Finally, with a deep understanding of the mechanisms, rational design of ICLs can be made to benefit the tandem device development. Based on the optimized ICL a high PCE of 20.03% is achieved.展开更多
Tandem cell with structure of indium tin oxide(ITO)/molybdenum oxide(MoO_(3))/fullerene(C60)/copper phthalocyanine(CuPc)/C60/tris-8-hydroxy-quinolinato aluminum(Alq_(3))/Al was fabricated to study the effect of net ca...Tandem cell with structure of indium tin oxide(ITO)/molybdenum oxide(MoO_(3))/fullerene(C60)/copper phthalocyanine(CuPc)/C60/tris-8-hydroxy-quinolinato aluminum(Alq_(3))/Al was fabricated to study the effect of net carriers at the interconnection layer. The open circuit voltage and short circuit current were found to be 1.15 V and 0.56 mA/cm^(2),respectively. Almost the same performance(1.05 V, 0.58 mA/cm^(2)) of tandem cell with additional recombination layer(ITO/MoO_(3)/C60/Alq_(3)/Al/Ag/MoO_(3)/CuPc/C60/Alq_(3)/Al) demonstrates that the carrier balance is more crucial than carrier recombination. The net holes at the interconnection layer caused by more carrier generation from the back cell on one hand would enhance the recombination with electrons from the front cell and on the other hand would quench the excitons produced in CuPc of the back cell.展开更多
Since polymer-based light-emitting diodes(PLEDs)arewellsuited building blocks for large-area and low-cost flexible display equipment,state-of-the-art thermally activated delayed fluorescence(TADF)PLEDs are in high dem...Since polymer-based light-emitting diodes(PLEDs)arewellsuited building blocks for large-area and low-cost flexible display equipment,state-of-the-art thermally activated delayed fluorescence(TADF)PLEDs are in high demand.To respond to this demand,light-emitting TADF units have initially been modified with electron-transporting units to balance the carrier transport of regiorandom TADF polymers,and simultaneously,an intramolecular sensitizing strategy has also been employed by covalently incorporating TADF sensitizers with light-emitting TADF units and hosts in conjugated polymers to accelerate the spin-flip of triplet excitons.Superior photophysical properties have been achieved by a rational regulation of the proportions of each component,achieving a photoluminescence quantumyield of 90%,an extremely high rate of reverse intersystem crossing of 3×106 s−1,and a relatively low nonradiative decay rate of around 105 s−1.As a result,the solutionprocessed PLEDs can attain an external quantum efficiency(EQE)value of 25.4%with emission peaks of around 550 nm,representing record-high performance for PLEDs.The efficiency roll-off can also be significantly suppressed,maintaining an EQE value of 24.2%at 1000 cd/m2 with ideal efficiency roll-off of lower than 5%.Encouragingly,this work provides a valid strategy to tackle the imperative need for PLEDs with high EQE and low efficiency roll-off.展开更多
文摘Unsaturated magnetoresistance (MR) has been reported in type-II Weyl semimetal WTe2, manifested as a perfect compensation of opposite carriers. We report linear MR (LMR) in WTe2 crystals, the onset of which was identified by constructing the MR mobility spectra for weak fields. The LMR further increased and became dominant for fields stronger than 20 T, while the parabolic MR gradually decayed. The LMR was also observed in high-pressure conditions.
基金financially supported by the Guangdong Major Project of Basic and Applied Basic Research(2019B030302007)the Ministry of Science and Technology(2017YFA0206600,2019YFA0705900)+6 种基金the Natural Science Foundation of China(51973063,91733302 and 51803060)Guangdong Basic and Applied Basic Research Foundation for Distinguished Young Scholar(2021B1515020028)the Fund of Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates(South China University of Technology)(2019B030301003)the Science and Technology Program of Guangzhou,China(201904010147)the funding by State Key Lab of Luminescent Materials and Devices,South China University of Technologythe Fellowship of China Postdoctoral Science Foundation(2020M682703)the National Natural Science Foundation of China(52003090)。
文摘As one of the core parts of two-terminal(2 T) monolithic tandem photovoltaics, the interconnecting layers(ICLs) play a critical role in modulating the carrier transport and recombination between the sub-cells,and thus influencing the tandem device performance. Here, for the first time, the relationship between ICLs architecture and 2 T monolithic perovskite/organic tandem device performance has been studied by investigating the change of ICLs composition layer thickness on the ICLs optical and electrical properties, sub-cells EQE properties, and tandem device J-V properties. It is revealed that the ability of ICLs on modulating the sub-cells carrier balance properties is strongly associated with its composited layers thickness, and the tandem device carrier balance properties can be reflected by the relative EQE intensity between the sub-cells. Finally, with a deep understanding of the mechanisms, rational design of ICLs can be made to benefit the tandem device development. Based on the optimized ICL a high PCE of 20.03% is achieved.
基金supported by the National Natural Science Foundation of China (Grant Nos. 11774293, 1207432, and 61874016)。
文摘Tandem cell with structure of indium tin oxide(ITO)/molybdenum oxide(MoO_(3))/fullerene(C60)/copper phthalocyanine(CuPc)/C60/tris-8-hydroxy-quinolinato aluminum(Alq_(3))/Al was fabricated to study the effect of net carriers at the interconnection layer. The open circuit voltage and short circuit current were found to be 1.15 V and 0.56 mA/cm^(2),respectively. Almost the same performance(1.05 V, 0.58 mA/cm^(2)) of tandem cell with additional recombination layer(ITO/MoO_(3)/C60/Alq_(3)/Al/Ag/MoO_(3)/CuPc/C60/Alq_(3)/Al) demonstrates that the carrier balance is more crucial than carrier recombination. The net holes at the interconnection layer caused by more carrier generation from the back cell on one hand would enhance the recombination with electrons from the front cell and on the other hand would quench the excitons produced in CuPc of the back cell.
基金the National Natural Science Foundation of China(nos.51922021 and 52103220)the Shandong Provincial Natural Science Foundation(no.ZR2019ZD50).
文摘Since polymer-based light-emitting diodes(PLEDs)arewellsuited building blocks for large-area and low-cost flexible display equipment,state-of-the-art thermally activated delayed fluorescence(TADF)PLEDs are in high demand.To respond to this demand,light-emitting TADF units have initially been modified with electron-transporting units to balance the carrier transport of regiorandom TADF polymers,and simultaneously,an intramolecular sensitizing strategy has also been employed by covalently incorporating TADF sensitizers with light-emitting TADF units and hosts in conjugated polymers to accelerate the spin-flip of triplet excitons.Superior photophysical properties have been achieved by a rational regulation of the proportions of each component,achieving a photoluminescence quantumyield of 90%,an extremely high rate of reverse intersystem crossing of 3×106 s−1,and a relatively low nonradiative decay rate of around 105 s−1.As a result,the solutionprocessed PLEDs can attain an external quantum efficiency(EQE)value of 25.4%with emission peaks of around 550 nm,representing record-high performance for PLEDs.The efficiency roll-off can also be significantly suppressed,maintaining an EQE value of 24.2%at 1000 cd/m2 with ideal efficiency roll-off of lower than 5%.Encouragingly,this work provides a valid strategy to tackle the imperative need for PLEDs with high EQE and low efficiency roll-off.