How to control the dipole orientation of organic emitters is a challenge in the field of organic light-emitting diodes(OLEDs).Herein,a linear thermally activated delayed fluorescence(TADF)molecule,PhNAI-PMSBA,bearing ...How to control the dipole orientation of organic emitters is a challenge in the field of organic light-emitting diodes(OLEDs).Herein,a linear thermally activated delayed fluorescence(TADF)molecule,PhNAI-PMSBA,bearing a 1,8-naphthalimide-acridine framework was designed by a doublesite long-axis extension strategy to actively control the dipole orientation.The horizontal ratio of emitting dipole orientation of PhNAI-PMSBA reaches 95%,substantially higher than that of isotropic emitters(67%).This unique feature is associated with the intrinsically horizontal molecular orientation of PhNAI-PMSBA and the good agreement between its transition dipole moment direction and molecular long axis.The PhNAI-PMSBA-based OLED achieves an ultrahigh optical outcoupling efficiency of 43.2%and thus affords one of the highest red electroluminescence with an external quantum efficiency of 22.3%and the Commission International de l’Eclairage 1931 coordinates at around(0.60,0.40).展开更多
Tomography is an informative imaging modality that is usually implemented by mechanical scanning,owing to the limited depth-of-field(DOF)in conventional systems.However,recent imaging systems are working towards more ...Tomography is an informative imaging modality that is usually implemented by mechanical scanning,owing to the limited depth-of-field(DOF)in conventional systems.However,recent imaging systems are working towards more compact and stable architectures;therefore,developing nonmotion tomography is highly desirable.Here,we propose a metalens-based spectral imaging system with an aplanatic GaN metalens(NA=0.78),in which large chromatic dispersion is used to access spectral focus tuning and optical zooming in the visible spectrum.After the function of wavelength-switched tomography was confirmed on cascaded samples,this aplanatic metalens is utilized to image microscopic frog egg cells and shows excellent tomographic images with distinct DOF features of the cell membrane and nucleus.Our approach makes good use of the large diffractive dispersion of the metalens and develops a new imaging technique that advances recent informative optical devices.展开更多
An approach of phase-locking control for piezoelectric backlight inverter for cold cathode fluorescent lamp (CCFL) is presented. According to the characteristic of piezoelectric transformer (PZT) and CCFL a frequency-...An approach of phase-locking control for piezoelectric backlight inverter for cold cathode fluorescent lamp (CCFL) is presented. According to the characteristic of piezoelectric transformer (PZT) and CCFL a frequency-sweep control is applied for ignition. Then a phase locking loop is used to control the driving frequency to maintain the optimum operating point of the inverter system.展开更多
基金the National Natural Science Foundation of China(51873158,51573141,91833304 and 91433201)the National Key R&D Program of China(2016YFB0401002)+4 种基金Shenzhen Science and Technolgy Program(KQTD20170330110107046 and JCYJ20190808151209557)the Key Technological Innovation Program of Hubei Province(2018AAA013)the Natural Science Foundation for Distinguished Young Scholars of Hubei Province(2017CFA033)the support from the Ministry of Science and Technology of Taiwan(MOST 107-2221-E-002-160-MY3 and 108-2221-E-002-148-MY3)the post-doctoral fellowship from the Ministry of Education(MOE)of Taiwan。
文摘How to control the dipole orientation of organic emitters is a challenge in the field of organic light-emitting diodes(OLEDs).Herein,a linear thermally activated delayed fluorescence(TADF)molecule,PhNAI-PMSBA,bearing a 1,8-naphthalimide-acridine framework was designed by a doublesite long-axis extension strategy to actively control the dipole orientation.The horizontal ratio of emitting dipole orientation of PhNAI-PMSBA reaches 95%,substantially higher than that of isotropic emitters(67%).This unique feature is associated with the intrinsically horizontal molecular orientation of PhNAI-PMSBA and the good agreement between its transition dipole moment direction and molecular long axis.The PhNAI-PMSBA-based OLED achieves an ultrahigh optical outcoupling efficiency of 43.2%and thus affords one of the highest red electroluminescence with an external quantum efficiency of 22.3%and the Commission International de l’Eclairage 1931 coordinates at around(0.60,0.40).
基金the financial support from The National Key R&D Program of China(2016YFA0202103,2017YFA0303700)the National Natural Science Foundation of China(Nos.91850204,11674167,11621091,11774164)the Department of Science and Technology,Taiwan,China(Grant No.MOST-107-2112-M-001-042-MY3,MOST-107-2911-I-001-508,MOST-107-2911-I-001-510,MOST-107-2923-M-001-010-MY3).
文摘Tomography is an informative imaging modality that is usually implemented by mechanical scanning,owing to the limited depth-of-field(DOF)in conventional systems.However,recent imaging systems are working towards more compact and stable architectures;therefore,developing nonmotion tomography is highly desirable.Here,we propose a metalens-based spectral imaging system with an aplanatic GaN metalens(NA=0.78),in which large chromatic dispersion is used to access spectral focus tuning and optical zooming in the visible spectrum.After the function of wavelength-switched tomography was confirmed on cascaded samples,this aplanatic metalens is utilized to image microscopic frog egg cells and shows excellent tomographic images with distinct DOF features of the cell membrane and nucleus.Our approach makes good use of the large diffractive dispersion of the metalens and develops a new imaging technique that advances recent informative optical devices.
文摘An approach of phase-locking control for piezoelectric backlight inverter for cold cathode fluorescent lamp (CCFL) is presented. According to the characteristic of piezoelectric transformer (PZT) and CCFL a frequency-sweep control is applied for ignition. Then a phase locking loop is used to control the driving frequency to maintain the optimum operating point of the inverter system.
