Multiresonant thermally activated delayedfluorescence(MR-TADF)emitters have been the focus of extensive design efforts as they are recognized to show bright,narrowband emission,which makes them very appealing for displ...Multiresonant thermally activated delayedfluorescence(MR-TADF)emitters have been the focus of extensive design efforts as they are recognized to show bright,narrowband emission,which makes them very appealing for display applications.However,the planar geometry and relatively large singlet–triplet energy gap lead to,respectively,severe aggregation-caused quenching(ACQ)and slow reverse intersys-tem crossing(RISC).Here,a design strategy is proposed to address both issues.Two MR-TADF emitters triphenylphosphine oxide(TPPO)-tBu-DiKTa and tripheny-lamine(TPA)-tBu-DiKTa have been synthesized.Twisted ortho-substituted groups help increase the intermolecular distance and largely suppress the ACQ.In addition,the contributions from intermolecular charge transfer states in the case of TPA-tBu-DiKTa help to accelerate RISC.The organic light-emitting diodes(OLEDs)with TPPO-tBu-DiKTa and TPA-tBu-DiKTa exhibit high maximum external quan-tum efficiencies(EQEmax)of 24.4%and 31.0%,respectively.Notably,the device with 25 wt%TPA-tBu-DiKTa showed both high EQEmax of 28.0%and reduced efficiency roll-off(19.9%EQE at 1000 cd m^(-2))compared to the device with 5 wt%emitter(31.0%EQEmax and 11.0%EQE at 1000 cd m^(-2)).The new emitters were also introduced into single-layer light-emitting electrochemical cells(LECs),equipped with air-stable electrodes.The LEC containing TPA-tBu-DiKTa dispersed at 0.5 wt%in a matrix comprising a mobility-balanced blend-host and an ionic liq-uid electrolyte delivered blue luminance with an EQEmax of 2.6%at 425 cd m^(-2).The high efficiencies of the OLEDs and LECs with TPA-tBu-DiKTa illustrate the potential for improving device performance when the DiKTa core is decorated with twisted bulky donors.展开更多
The rapid pace of change in the wide band gap(WBG)power semiconductor area has led to an explosion in potential uses for WBG devices in a huge variety of applications.The applications include automotive,aerospace and ...The rapid pace of change in the wide band gap(WBG)power semiconductor area has led to an explosion in potential uses for WBG devices in a huge variety of applications.The applications include automotive,aerospace and traction applications,as well as grid related or charging systems,with the potential to provide paradigm shifts in performance and efficiency over Silicon devices in current use today.Despite these exciting developments,however,there are still many outstanding challenges for both researchers and industry to solve before WBG technology becomes pervasive.In this paper we will explore some of these challenges and highlight the strengths of WBG devices,some of the specific issues for machine drives and develop some potential solutions for future developments in power electronics.展开更多
A functionalized silicon nanowire field-effect transistor （SiNW FET） was fabricated to detect single molecules in the pM range to detect disease at the early stage with a sensitive, robust, and inexpensive method wi...A functionalized silicon nanowire field-effect transistor （SiNW FET） was fabricated to detect single molecules in the pM range to detect disease at the early stage with a sensitive, robust, and inexpensive method with the ability to provide specific and reliable data. The device was designed and fabricated by indented ash trimming via shallow anisotropic etching. The approach is a simple and low-cost technique that is compatible with the current commercial semiconductor standard CMOS process without an expensive deep reactive ion etcher. Specific electric changes were observed for DNA sensing when the nanowire surface was modified with a complementary captured DNA probe and target DNA through an organic linker （--OCH2CH3） using organofunctional alkoxysilanes （3-aminopropyl） triethoxysilane （APTES）. With this surface modification, a single specific target molecule can be detected. The simplicity of the sensing domain makes it feasible to miniaturize it for the development of a cancer detection kit, facilitating its use in both clinical and non-clinical environments to allow non-expert interpretation. With its novel electric response and potential for mass commercial fabrication, this biosensor can be developed to become a portable/point of care biosensor for both field and diagnostic applications.展开更多
Objective： This study aimed to evaluate of the accuracy and efficiency of the in-vivo dosimetry systems for routine cancer patient dose verification. Methods： In vivo dosimetry, using diodes and thermoluminescent do...Objective： This study aimed to evaluate of the accuracy and efficiency of the in-vivo dosimetry systems for routine cancer patient dose verification. Methods： In vivo dosimetry, using diodes and thermoluminescent dosimeters （TLD） is performed in many radiotherapy departments to verify the dose delivered during treatment. A total of 40 TLD divided into two batches （one of 20 and other of 20 TLD） were used. Different doses of Co6~ beam were delivered to the TLD chips at different depths. Diodes were irradiated at different depths in a （30 x 30 x 30） cm3 water slab phantom with various conditions of Field sizes, monitor units and SSDs. Results： The limitation of the in-vivo dosimetry technique is that dose can only be in system readout difficulty and type of readout （TLD system and diode） as the patient dose is directly measured. Several authors have investigated the measurements was 1.3%, with a standard deviation of 2.6%. Results were normally distributed around a mean as -0.39 and 0.34 respectively. After the evaluation of in vivo dosimetry brain case as an example, the mean doses for both eyes were 1.8%, with a standard deviation of 2.7%. These results are similar to studies conducted with diodes and TLD＇s. Conclusion： The diode is superior to TLD, since the diode measurements can be obtained on line and allows an immediate check. Other advantages of diodes include high sensitivity, good spatial resolution, and small size, simplicity of used.展开更多
Themass production and the practical number of cryogenic quantum devices producible in a single chip are limited to the number of electrical contact pads and wiring of the cryostat or dilution refrigerator.It is,there...Themass production and the practical number of cryogenic quantum devices producible in a single chip are limited to the number of electrical contact pads and wiring of the cryostat or dilution refrigerator.It is,therefore,beneficial to contrast themeasurements of hundreds of devices fabricated in a single chip in one cooldown process to promote the scalability,integrability,reliability,and reproducibility of quantum devices and to save evaluation time,cost and energy.Here,we used a cryogenic on-chip multiplexer architecture and investigated the statistics of the 0.7 anomaly observed on the first three plateaus of the quantized conductance of semiconductor quantum point contact(QPC)transistors.Our single chips contain 256 split gate field-effect QPC transistors(QFET)each,with two 16-branch multiplexed source-drain and gate pads,allowing individual transistors to be selected,addressed and controlled through an electrostatic gate voltage process.A total of 1280 quantum transistors with nano-scale dimensions are patterned in 5 different chips of GaAs heterostructures.From the measurements of 571 functioning QFETs taken at temperatures T[1.4 K and T[40 mK,it is found that the spontaneous polarisation model and Kondo effect do not fit our results.Furthermore,some of the features in our data largely agreed with van Hove model with short-range interactions.Our approach provides further insight into the quantum mechanical properties and microscopic origin of the 0.7 anomaly in QFETs,paving the way for the development of semiconducting quantum circuits and integrated cryogenic electronics,for scalable quantum logic control,readout,synthesis,and processing applications.展开更多
基金Engineering and Physical Sciences Research Council,Grant/Award Numbers:EP/R035164/1,EP/W007517/1,EP/W015137/1China Scholarship Council,Grant/Award Number:202006250026+3 种基金Swedish Energy Agency,Grant/Award Numbers:50779-1,P2021-00032Swedish Research Council,Grant/Award Numbers:2019-02345,2021-04778European Research Council,Grant/Award Number:101096650Knut och Alice Wallenbergs Stiftelse,Grant/Award Number:WISE-AP01-D02。
文摘Multiresonant thermally activated delayedfluorescence(MR-TADF)emitters have been the focus of extensive design efforts as they are recognized to show bright,narrowband emission,which makes them very appealing for display applications.However,the planar geometry and relatively large singlet–triplet energy gap lead to,respectively,severe aggregation-caused quenching(ACQ)and slow reverse intersys-tem crossing(RISC).Here,a design strategy is proposed to address both issues.Two MR-TADF emitters triphenylphosphine oxide(TPPO)-tBu-DiKTa and tripheny-lamine(TPA)-tBu-DiKTa have been synthesized.Twisted ortho-substituted groups help increase the intermolecular distance and largely suppress the ACQ.In addition,the contributions from intermolecular charge transfer states in the case of TPA-tBu-DiKTa help to accelerate RISC.The organic light-emitting diodes(OLEDs)with TPPO-tBu-DiKTa and TPA-tBu-DiKTa exhibit high maximum external quan-tum efficiencies(EQEmax)of 24.4%and 31.0%,respectively.Notably,the device with 25 wt%TPA-tBu-DiKTa showed both high EQEmax of 28.0%and reduced efficiency roll-off(19.9%EQE at 1000 cd m^(-2))compared to the device with 5 wt%emitter(31.0%EQEmax and 11.0%EQE at 1000 cd m^(-2)).The new emitters were also introduced into single-layer light-emitting electrochemical cells(LECs),equipped with air-stable electrodes.The LEC containing TPA-tBu-DiKTa dispersed at 0.5 wt%in a matrix comprising a mobility-balanced blend-host and an ionic liq-uid electrolyte delivered blue luminance with an EQEmax of 2.6%at 425 cd m^(-2).The high efficiencies of the OLEDs and LECs with TPA-tBu-DiKTa illustrate the potential for improving device performance when the DiKTa core is decorated with twisted bulky donors.
文摘The rapid pace of change in the wide band gap(WBG)power semiconductor area has led to an explosion in potential uses for WBG devices in a huge variety of applications.The applications include automotive,aerospace and traction applications,as well as grid related or charging systems,with the potential to provide paradigm shifts in performance and efficiency over Silicon devices in current use today.Despite these exciting developments,however,there are still many outstanding challenges for both researchers and industry to solve before WBG technology becomes pervasive.In this paper we will explore some of these challenges and highlight the strengths of WBG devices,some of the specific issues for machine drives and develop some potential solutions for future developments in power electronics.
文摘A functionalized silicon nanowire field-effect transistor （SiNW FET） was fabricated to detect single molecules in the pM range to detect disease at the early stage with a sensitive, robust, and inexpensive method with the ability to provide specific and reliable data. The device was designed and fabricated by indented ash trimming via shallow anisotropic etching. The approach is a simple and low-cost technique that is compatible with the current commercial semiconductor standard CMOS process without an expensive deep reactive ion etcher. Specific electric changes were observed for DNA sensing when the nanowire surface was modified with a complementary captured DNA probe and target DNA through an organic linker （--OCH2CH3） using organofunctional alkoxysilanes （3-aminopropyl） triethoxysilane （APTES）. With this surface modification, a single specific target molecule can be detected. The simplicity of the sensing domain makes it feasible to miniaturize it for the development of a cancer detection kit, facilitating its use in both clinical and non-clinical environments to allow non-expert interpretation. With its novel electric response and potential for mass commercial fabrication, this biosensor can be developed to become a portable/point of care biosensor for both field and diagnostic applications.
基金Supported by grants from the Al-Hosain Hospital, Faculty of Medicine, Al Azhar University and Tanta University
文摘Objective： This study aimed to evaluate of the accuracy and efficiency of the in-vivo dosimetry systems for routine cancer patient dose verification. Methods： In vivo dosimetry, using diodes and thermoluminescent dosimeters （TLD） is performed in many radiotherapy departments to verify the dose delivered during treatment. A total of 40 TLD divided into two batches （one of 20 and other of 20 TLD） were used. Different doses of Co6~ beam were delivered to the TLD chips at different depths. Diodes were irradiated at different depths in a （30 x 30 x 30） cm3 water slab phantom with various conditions of Field sizes, monitor units and SSDs. Results： The limitation of the in-vivo dosimetry technique is that dose can only be in system readout difficulty and type of readout （TLD system and diode） as the patient dose is directly measured. Several authors have investigated the measurements was 1.3%, with a standard deviation of 2.6%. Results were normally distributed around a mean as -0.39 and 0.34 respectively. After the evaluation of in vivo dosimetry brain case as an example, the mean doses for both eyes were 1.8%, with a standard deviation of 2.7%. These results are similar to studies conducted with diodes and TLD＇s. Conclusion： The diode is superior to TLD, since the diode measurements can be obtained on line and allows an immediate check. Other advantages of diodes include high sensitivity, good spatial resolution, and small size, simplicity of used.
基金financial support from EPSRC,UK.the China Scholarship Council(CSC)for its financial support.
文摘Themass production and the practical number of cryogenic quantum devices producible in a single chip are limited to the number of electrical contact pads and wiring of the cryostat or dilution refrigerator.It is,therefore,beneficial to contrast themeasurements of hundreds of devices fabricated in a single chip in one cooldown process to promote the scalability,integrability,reliability,and reproducibility of quantum devices and to save evaluation time,cost and energy.Here,we used a cryogenic on-chip multiplexer architecture and investigated the statistics of the 0.7 anomaly observed on the first three plateaus of the quantized conductance of semiconductor quantum point contact(QPC)transistors.Our single chips contain 256 split gate field-effect QPC transistors(QFET)each,with two 16-branch multiplexed source-drain and gate pads,allowing individual transistors to be selected,addressed and controlled through an electrostatic gate voltage process.A total of 1280 quantum transistors with nano-scale dimensions are patterned in 5 different chips of GaAs heterostructures.From the measurements of 571 functioning QFETs taken at temperatures T[1.4 K and T[40 mK,it is found that the spontaneous polarisation model and Kondo effect do not fit our results.Furthermore,some of the features in our data largely agreed with van Hove model with short-range interactions.Our approach provides further insight into the quantum mechanical properties and microscopic origin of the 0.7 anomaly in QFETs,paving the way for the development of semiconducting quantum circuits and integrated cryogenic electronics,for scalable quantum logic control,readout,synthesis,and processing applications.
