This paper provides a teaching concept for control theory education based on Virtual Robot Experimentation Platform(V-REP).A cart inverted pendulum virtual physical model is developed on V-REP.Students must analyze,de...This paper provides a teaching concept for control theory education based on Virtual Robot Experimentation Platform(V-REP).A cart inverted pendulum virtual physical model is developed on V-REP.Students must analyze,design,and implement a suitable controller for the cart inverted pendulum system using their knowledge of the control theory.Different from traditional experiment and numerical simulation,virtual experiment is safe and less constrained.Moreover,the experiment results are more intuitive and obvious.This study can improve students’interest in learning the control theory and help students understand the relevant content better.展开更多
Commercial photodetectors based on silicon are extensively applied in numerous fields. Except for their high performance, their maximum absorption wavelength is not over than 1100 nm and incident light with longer wav...Commercial photodetectors based on silicon are extensively applied in numerous fields. Except for their high performance, their maximum absorption wavelength is not over than 1100 nm and incident light with longer wavelengths cannot be detected; in addition, their cost is high and their manufacturing process is complex. Therefore, it is meaningful and significant to extend absorption wavelength, to decrease cost, and to simplify the manufacturing process while maintaining high performance for photodetectors. Due to the properties of size-dependent bandgap tunability, low cost, facile processing,and substrate compatibility, solution–processed colloidal quantum dots(CQDs) have recently gained significant attention and become one of the most competitive and promising candidates for optoelectronic devices. Among these CQDs, lead chalcogenide CQDs are getting very prominent and are widely investigated. In this paper, the recent progress of infrared(IR) photodetectors based on lead sulfide(PbS), lead selenide(PbSe), and ternary PbS_x Se_(1-x) CQDs, and their underlying concepts, breakthroughs, and remaining challenges are reviewed, thus providing guidance for designing high-performance quantum-dot IR photodetectors.展开更多
Through-space charge transfer(TSCT)is regarded as an effective way to develop thermally activated delayed fluorescence(TADF)emitters.Based on this strategy,many molecular frameworks have been proposed,among which spir...Through-space charge transfer(TSCT)is regarded as an effective way to develop thermally activated delayed fluorescence(TADF)emitters.Based on this strategy,many molecular frameworks have been proposed,among which spirobased scaffolds have been extensively studied due to their unique advantages.In this work,we developed three emitters SPS,SPO,and SPON,which were constructed with the same donor and various acceptors to explore the influence of acceptor modulation at the C9 position of fluorene for spirostructure TSCT emitters.The results show that the acceptor with too weak electronwithdrawing ability will cause the emitter to not have TADF properties,while the acceptor with too much steric hindrance will weaken the face-to-faceπ-πstacking interaction between donor/acceptor(D/A).Since SPO balances the electron-withdrawing strength and steric hindrance of the acceptor,it achieves the highest external quantum efficiency(EQE)of 17.75%.This work shows that appropriate acceptor selection is essential for the TADF properties and high efficiency of the spirobased scaffold TSCT emitter.展开更多
Due to their promising applications in foldable displays,optical communication equipment and environmental monitoring systems,flexible and broadband optoelectronic devices have gained extensive attention in recent yea...Due to their promising applications in foldable displays,optical communication equipment and environmental monitoring systems,flexible and broadband optoelectronic devices have gained extensive attention in recent years.Here,a flexible and broadband photodetector based on CsPbBr_(3)/PbSe quantum dot(QD) heterostructures is firstly presented.The integrated QD heterostructures possess consecutive detection range from ultraviolet(UV) to long-wave length infrared(LW-IR) regions with efficient light absorption and chemical stability,in comparison with the pristine PbSe QDs.Systematic material characterizations reveal the improved exciton dissociation,carrier transport and carrier lifetime of the QD heterostructures.Flexible photodetector Ag/CsPbBr_(3)/PbSe/Ag demonstrate a high responsivity of 7.17 A/W with a specific detectivity of 8.97 × 10^(12) Jones under 25 μW/cm^(2) 365 nm illumination at 5 V.Furthermore,it could maintain 91.2 %(or 94.9 %) of its initial performance even after bending for thousands of times(or exposing in ambient air for 4 weeks).More importantly,its re s ponse time is shortened more than three orders of magnitude as that of pristine PbSe QDs-based photodetectors.Therefore,it provides a feasible and promising method for the next-generation high-performance broadband photodetectors via constructing heterostructures of various QDs.展开更多
The electroluminescence (EL) of bilayer devices (ITO/Polymer/Alqa/AI) made from two PPV derivatives (MN-PPV and MEH-PPV), respectively, and the influence of the organic layers’ thickness on the characteristics of the...The electroluminescence (EL) of bilayer devices (ITO/Polymer/Alqa/AI) made from two PPV derivatives (MN-PPV and MEH-PPV), respectively, and the influence of the organic layers’ thickness on the characteristics of the device are investigated. Different spectra and variations are observed for different thicknesses of Alq3 layer in this bilayer organic light-emitting diodes (LEDs) as increasing applied bias. Based on the energy level and field-assisted tunneling at the interface, we attributed these phenomena to electric field redistribution in the device and field-assisted charges being transported and tunneling through energy barrier at high electric field.展开更多
A novel inverted telephoto four mirror zoom system with large field of view (FOV) was designed over a wide specWal bandwidth. The initial configuration of the zoom system was obtained by applying the aberration equa...A novel inverted telephoto four mirror zoom system with large field of view (FOV) was designed over a wide specWal bandwidth. The initial configuration of the zoom system was obtained by applying the aberration equations under certain constraints. Then, a method was presented to correlate the aspheric coefficients with the aberrations of this system. By using this method, the required image quality could be achieved after optimiza- tion using the ZEMAX Optical Design Code. Besides good image quality, another benefits of using this system is the potential for using cheap optics.展开更多
基金supported by the 2021 Higher Education Teaching Reform Research Project of SEAC(No.221057)2021 Ministry of Education Collaborative Education Project(No.202102646007)2022 Guizhou Province Gold Course Construction Project.
文摘This paper provides a teaching concept for control theory education based on Virtual Robot Experimentation Platform(V-REP).A cart inverted pendulum virtual physical model is developed on V-REP.Students must analyze,design,and implement a suitable controller for the cart inverted pendulum system using their knowledge of the control theory.Different from traditional experiment and numerical simulation,virtual experiment is safe and less constrained.Moreover,the experiment results are more intuitive and obvious.This study can improve students’interest in learning the control theory and help students understand the relevant content better.
基金Project supported by the Fund from the State Key Laboratory of Transducer Technology,China(Grant No.SKT1404)the Fund from the Key Laboratory of Photoelectronic Imaging Technology and System(Grant No.2017OEIOF02)at Beijing Institute of Technology,Ministry of Education of China
文摘Commercial photodetectors based on silicon are extensively applied in numerous fields. Except for their high performance, their maximum absorption wavelength is not over than 1100 nm and incident light with longer wavelengths cannot be detected; in addition, their cost is high and their manufacturing process is complex. Therefore, it is meaningful and significant to extend absorption wavelength, to decrease cost, and to simplify the manufacturing process while maintaining high performance for photodetectors. Due to the properties of size-dependent bandgap tunability, low cost, facile processing,and substrate compatibility, solution–processed colloidal quantum dots(CQDs) have recently gained significant attention and become one of the most competitive and promising candidates for optoelectronic devices. Among these CQDs, lead chalcogenide CQDs are getting very prominent and are widely investigated. In this paper, the recent progress of infrared(IR) photodetectors based on lead sulfide(PbS), lead selenide(PbSe), and ternary PbS_x Se_(1-x) CQDs, and their underlying concepts, breakthroughs, and remaining challenges are reviewed, thus providing guidance for designing high-performance quantum-dot IR photodetectors.
基金financial support from the National Natural Science Foundation of China(Nos.51773141,51873139,61961160731,62175171 and 22175124)funded by the Suzhou Science and Technology Plan Project(No.SYG202010)+2 种基金supported by Suzhou Key Laboratory of Functional Nano&Soft Materials,Collaborative Innovation Center of Suzhou Nano Science&Technologythe 111 ProjectJoint International Research Laboratory of Carbon-Based Functional Materials and Devices。
文摘Through-space charge transfer(TSCT)is regarded as an effective way to develop thermally activated delayed fluorescence(TADF)emitters.Based on this strategy,many molecular frameworks have been proposed,among which spirobased scaffolds have been extensively studied due to their unique advantages.In this work,we developed three emitters SPS,SPO,and SPON,which were constructed with the same donor and various acceptors to explore the influence of acceptor modulation at the C9 position of fluorene for spirostructure TSCT emitters.The results show that the acceptor with too weak electronwithdrawing ability will cause the emitter to not have TADF properties,while the acceptor with too much steric hindrance will weaken the face-to-faceπ-πstacking interaction between donor/acceptor(D/A).Since SPO balances the electron-withdrawing strength and steric hindrance of the acceptor,it achieves the highest external quantum efficiency(EQE)of 17.75%.This work shows that appropriate acceptor selection is essential for the TADF properties and high efficiency of the spirobased scaffold TSCT emitter.
基金partially funded by the Project of State Key Laboratory of Transducer Technology (No. SKT1404)the Fundamental Research Funds for the Central Universities (No. 2020CX02002 and BITBLR2020013)the Key R&D Projects of the Ministry of Science and Technology (No. SQ2019YFB220038)。
文摘Due to their promising applications in foldable displays,optical communication equipment and environmental monitoring systems,flexible and broadband optoelectronic devices have gained extensive attention in recent years.Here,a flexible and broadband photodetector based on CsPbBr_(3)/PbSe quantum dot(QD) heterostructures is firstly presented.The integrated QD heterostructures possess consecutive detection range from ultraviolet(UV) to long-wave length infrared(LW-IR) regions with efficient light absorption and chemical stability,in comparison with the pristine PbSe QDs.Systematic material characterizations reveal the improved exciton dissociation,carrier transport and carrier lifetime of the QD heterostructures.Flexible photodetector Ag/CsPbBr_(3)/PbSe/Ag demonstrate a high responsivity of 7.17 A/W with a specific detectivity of 8.97 × 10^(12) Jones under 25 μW/cm^(2) 365 nm illumination at 5 V.Furthermore,it could maintain 91.2 %(or 94.9 %) of its initial performance even after bending for thousands of times(or exposing in ambient air for 4 weeks).More importantly,its re s ponse time is shortened more than three orders of magnitude as that of pristine PbSe QDs-based photodetectors.Therefore,it provides a feasible and promising method for the next-generation high-performance broadband photodetectors via constructing heterostructures of various QDs.
文摘The electroluminescence (EL) of bilayer devices (ITO/Polymer/Alqa/AI) made from two PPV derivatives (MN-PPV and MEH-PPV), respectively, and the influence of the organic layers’ thickness on the characteristics of the device are investigated. Different spectra and variations are observed for different thicknesses of Alq3 layer in this bilayer organic light-emitting diodes (LEDs) as increasing applied bias. Based on the energy level and field-assisted tunneling at the interface, we attributed these phenomena to electric field redistribution in the device and field-assisted charges being transported and tunneling through energy barrier at high electric field.
文摘A novel inverted telephoto four mirror zoom system with large field of view (FOV) was designed over a wide specWal bandwidth. The initial configuration of the zoom system was obtained by applying the aberration equations under certain constraints. Then, a method was presented to correlate the aspheric coefficients with the aberrations of this system. By using this method, the required image quality could be achieved after optimiza- tion using the ZEMAX Optical Design Code. Besides good image quality, another benefits of using this system is the potential for using cheap optics.