Perovskite light emitting diodes(PeLEDs)have attracted considerable research attention because of their external quantum efficiency(EQE)of>20%and have potential scope for further improvement.However,compared to red...Perovskite light emitting diodes(PeLEDs)have attracted considerable research attention because of their external quantum efficiency(EQE)of>20%and have potential scope for further improvement.However,compared to red and green PeLEDs,blue PeLEDs have not been extensively investigated,which limits their commercial applications in the fields of luminance and full-color displays.In this review,blue-PeLED-related research is categorized by the composition of perovskite.The main challenges and corresponding optimization strategies for perovskite films are summarized.Next,the novel strategies for the design of device structures of blue PeLEDs are reviewed from the perspective of transport layers and interfacial layers.Accordingly,future directions for blue PeLEDs are discussed.This review can be a guideline for optimizing perovskite film and device structure of blue PeLEDs,thereby enhancing their development and application scope.展开更多
A high-efficiency green phosphorescent organic light emitting diode with a simplified structure is achieved that is free of a hole transport layer. The design of this kind of device structure not only saves the consum...A high-efficiency green phosphorescent organic light emitting diode with a simplified structure is achieved that is free of a hole transport layer. The design of this kind of device structure not only saves the consumption of organic materials but also greatly reduces the structural heterogeneities and effectively facilitates the charge injection into the emissive layer. The resulting green phosphorescent organic light-emitting diodes (PHOLEDs) exhibit higher electroluminescent efficiency. The maximum external quantum efficiency and current efficiency reach 23.7% and 88 cd/A, respectively. Moreover the device demonstrates satisfactory stability, keeping 23.7% and 88cd/A, 22% and 82cd/A, respectively, at a luminance of 100 and 1000cd/m2. The working mechanism for achieving high efficiency based on such a simple device structure is discussed correspondingly. The improved charge carrier injection and transport balance are proved to prominently contribute to achieve the high efficiency and great stability at high luminance in the green PHOLEDs.展开更多
The central solenoid is an important part of the HT-7U device. In this paper, the computational analysis of the stress and the displacement on the pre-load structures of the central solenoid have been made by the fin...The central solenoid is an important part of the HT-7U device. In this paper, the computational analysis of the stress and the displacement on the pre-load structures of the central solenoid have been made by the finite element analysis system COSMOS/M2.0 under room and/or operating temperature. According to the analytical results, the clip aprons and compression plates are all satisfied with safety design criteria.展开更多
The frequency selective surface (FSS) has been widely applied by means of its spatial frequency-filter characteristic, but it is always designed and used as a device with fixed frequency response. In order to tune the...The frequency selective surface (FSS) has been widely applied by means of its spatial frequency-filter characteristic, but it is always designed and used as a device with fixed frequency response. In order to tune the resonant frequency and switch the frequency channel, a scheme of mechanically tunable FSS is theoretically analyzed by using the method of Floquet's vector modes expansion and fields matching. A double-layer tunable FSS with dipole element can perform a dynamic range of resonant frequency covering whole X-band.展开更多
In order to fully replace the traditional fossil energy supply system, the efficiency of electrochemical energy conversion and storage of new energy technology needs to be continuously improved to enhance its market c...In order to fully replace the traditional fossil energy supply system, the efficiency of electrochemical energy conversion and storage of new energy technology needs to be continuously improved to enhance its market competitiveness. The structural design of energy devices can achieve satisfactory energy conversion and storage performance. To achieve lightweight design, improve mechanical support, enhance electrochemical performance, and adapt to the special shape of the device, the structural energy devices develop very quickly. To help researchers analyze the development and get clear on developing trend,this review is prepared. This review summarizes the latest developments in structural energy devices, including special attention to fuel cells, lithium-ion batteries, lithium metal batteries, and supercapacitors.Finally, the existing problems of structural energy devices are discussed, and the current challenges and future opportunities are summarized and prospected. Structural energy devices can undoubtedly overcome the performance bottlenecks of traditional energy devices, break the limitations of existing materials and structures, and provide a guidance for the development of equipment with high performance,light weight and low cost in the future.展开更多
In this paper, we present the finding that periodic structural defects(PSDs) along a Bragg grating can shift the Bragg wavelength. This effect is theoretically analyzed and confirmed by numerical calculation. We find ...In this paper, we present the finding that periodic structural defects(PSDs) along a Bragg grating can shift the Bragg wavelength. This effect is theoretically analyzed and confirmed by numerical calculation. We find that the Bragg wavelength shift is determined by the defect size and the period of the defects. The Bragg wavelength can be well tuned by properly designing the PSDs, and this may provide an alternative method to fabricate grating-based multiwavelength devices, including optical filter arrays and laser arrays. In regards to wavelength precision, the proposed method has an advantage over the traditional methods, where the Bragg wavelengths are changed directly by changing the grating period. In addition, the proposed method can maintain grating strength when tuning the wavelength since only the period of defects is changed. This will be a benefit for devices such as arrays.展开更多
For the purpose of improving conversion efficiency of solar cells by applying the effect of the wavelength conversion of rare earth ions, photo-luminescence and excitation spectrums of Ce3+-Tb3+ doped phosphate glas...For the purpose of improving conversion efficiency of solar cells by applying the effect of the wavelength conversion of rare earth ions, photo-luminescence and excitation spectrums of Ce3+-Tb3+ doped phosphate glass are investigated. Results show that incorporating Ce3+ ions to Tb3+-doped phosphate glass can greatly increase the absorption coefficient in the range 300-400 nm and then the energy transfer (ET) from Ce3+ to Tb3+ occurs. In addition, increasing Tb3+ concentration in Ce3+/Tb3+ co-doped phosphate glass can greatly enhance the ET efficiency and 545 nm emission intensity. This shows that Ce3+/Tb3+ co-doped phosphate glass would be a promising down-shifting material for enhancing the efficiency of solar cells.展开更多
A triple layer organic light-emitting diode (OLED) with two heterostructure of indium-tin oxide (ITO)/N,N’-diphenyl-N, N’-bis(1-naphthyl) (1,1’-biphenyl)-4,4’-diamine (NPB)/2,9-dimethyl-4,7-diphenyl-1,10-phenanthr...A triple layer organic light-emitting diode (OLED) with two heterostructure of indium-tin oxide (ITO)/N,N’-diphenyl-N, N’-bis(1-naphthyl) (1,1’-biphenyl)-4,4’-diamine (NPB)/2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP)/ 8-Hydrox- yquinoline aluminum (Alq3)/Mg:Ag has been fabricated by using the vacuum deposition method. The influence of different film thickness of BCP layer on the performance of the OLEDs has been investigated. The results show that when the thickness of the BCP layer film gradually ranges from 0.1-4.0 nm, the electroluminescence (EL) spectra of the OLEDs shift from green to greenish-blue to blue, and the BCP layer acts as the role for the recombination region of charge carriers related to EL spectrum, which enhances the brightness and power efficiency. The power efficiency of the OLEDs reaches to as high as 7.3 lm/W.展开更多
Nanomaterials show promising opportunities to address clinical problems (such as insufficient capture of circulating tumor cells; CTCs) via the high surface area-to-volume ratio and high affinity for biological cell...Nanomaterials show promising opportunities to address clinical problems (such as insufficient capture of circulating tumor cells; CTCs) via the high surface area-to-volume ratio and high affinity for biological cells. However, how to apply these nanomaterials as a nano-bio interface in a microfluidic device for efficient CTC capture with high specificity remains a challenge. In the present work, we first found that a titanium dioxide (TiO2) nanorod array that can be conveniently prepared on multiple kinds of substrates has high affinity for tumor cells. Then, the TiO2 nanorod array was vertically grown on the surface of a microchannel with hexagonally patterned Si micropillars via a hydrothermal reaction, forming a new kind of a micro-nano 3D hierarchically structured microfluidic device. The vertically grown TiO2 nanorod array was used as a sensitive nano-bio interface of this 3D hierarchically structured microfluidic device, which showed high efficiency of CTC capture (76.7% ± 7.1%) in an artificial whole-blood sample.展开更多
This paper aimed at extracting optimal structural parameters for Love wave device with structure of multi-waveguides to improve its temperature stability. The theoretical model dealing with the Love wave propagation i...This paper aimed at extracting optimal structural parameters for Love wave device with structure of multi-waveguides to improve its temperature stability. The theoretical model dealing with the Love wave propagation in multi-waveguides was established first, the dispersion characteristic is depicted by the acoustic propagation theory of stratified media and boundary conditions. Combing with the dispersion characteristics and Tomar's method, the optimal structural parameters for the Love wave device with zero temperature coefficient were extracted, and confirmed by the following experimental results. Excellent temperature coefficient of the Love wave device with SU-8/SiO2 on ST-90°X quartz substrate was evaluated experimentally as only 2.16 ppm/℃, which agrees well with the calculated results. The optimized Love wave device is very promising in gas sensing application.展开更多
Stretchable and flexible supercapacitors are highly desired due to their many potential applications in wearable devices. However, it is challenging to fabricate supercapacitors that can withstand large tensile strain...Stretchable and flexible supercapacitors are highly desired due to their many potential applications in wearable devices. However, it is challenging to fabricate supercapacitors that can withstand large tensile strain while maintaining high performance. Herein, we report an ultra-stretchable wire-shaped supercapacitor based on carbon nanotube@graphene@MnO2 fibers wound around a superelastic core fiber. The supercapacitor can sustain tensile strain up to 850%, which is the highest value reported for this type of device to date, while maintaining stable electrochemical performance. The energy density of the supercapacitor is 3.37 mWh·cm^-3 at a power density of 54.0 mW·cm^-3. The results show that 82% of the specific capacitance is retained after 1,000 stretch-release cycles with strains of 700%, demonstrating the superior durability of the elastic supercapacitor and showcasing its potential application in ultra-stretchable flexible electronics.展开更多
基金This work was supported by the National Natural Science Foundation of China(51775199,51735004)Natural Science Foundation of Guangdong Province(2018B030306008)the Fundamental Research Funds for the Central Universities.
文摘Perovskite light emitting diodes(PeLEDs)have attracted considerable research attention because of their external quantum efficiency(EQE)of>20%and have potential scope for further improvement.However,compared to red and green PeLEDs,blue PeLEDs have not been extensively investigated,which limits their commercial applications in the fields of luminance and full-color displays.In this review,blue-PeLED-related research is categorized by the composition of perovskite.The main challenges and corresponding optimization strategies for perovskite films are summarized.Next,the novel strategies for the design of device structures of blue PeLEDs are reviewed from the perspective of transport layers and interfacial layers.Accordingly,future directions for blue PeLEDs are discussed.This review can be a guideline for optimizing perovskite film and device structure of blue PeLEDs,thereby enhancing their development and application scope.
基金Supported by the Nanjing University of Telecommunication and Posts under Grant No NY212010the National Natural Science Foundation of China under Grant Nos 91233117,50973104 and 51333007+2 种基金the Natural Science Fund of Jiangsu Province under Grant No BK2012834the National Basic Research Program of China under Grant No 2015CB932200the Priority Academic Program Development of Jiangsu Higher Education Institutions
文摘A high-efficiency green phosphorescent organic light emitting diode with a simplified structure is achieved that is free of a hole transport layer. The design of this kind of device structure not only saves the consumption of organic materials but also greatly reduces the structural heterogeneities and effectively facilitates the charge injection into the emissive layer. The resulting green phosphorescent organic light-emitting diodes (PHOLEDs) exhibit higher electroluminescent efficiency. The maximum external quantum efficiency and current efficiency reach 23.7% and 88 cd/A, respectively. Moreover the device demonstrates satisfactory stability, keeping 23.7% and 88cd/A, 22% and 82cd/A, respectively, at a luminance of 100 and 1000cd/m2. The working mechanism for achieving high efficiency based on such a simple device structure is discussed correspondingly. The improved charge carrier injection and transport balance are proved to prominently contribute to achieve the high efficiency and great stability at high luminance in the green PHOLEDs.
文摘The central solenoid is an important part of the HT-7U device. In this paper, the computational analysis of the stress and the displacement on the pre-load structures of the central solenoid have been made by the finite element analysis system COSMOS/M2.0 under room and/or operating temperature. According to the analytical results, the clip aprons and compression plates are all satisfied with safety design criteria.
文摘The frequency selective surface (FSS) has been widely applied by means of its spatial frequency-filter characteristic, but it is always designed and used as a device with fixed frequency response. In order to tune the resonant frequency and switch the frequency channel, a scheme of mechanically tunable FSS is theoretically analyzed by using the method of Floquet's vector modes expansion and fields matching. A double-layer tunable FSS with dipole element can perform a dynamic range of resonant frequency covering whole X-band.
基金supported in part by the National key R&D Program of China (No. 2018YFB0105200)National Natural Science Foundation of China (No. U1864213)。
文摘In order to fully replace the traditional fossil energy supply system, the efficiency of electrochemical energy conversion and storage of new energy technology needs to be continuously improved to enhance its market competitiveness. The structural design of energy devices can achieve satisfactory energy conversion and storage performance. To achieve lightweight design, improve mechanical support, enhance electrochemical performance, and adapt to the special shape of the device, the structural energy devices develop very quickly. To help researchers analyze the development and get clear on developing trend,this review is prepared. This review summarizes the latest developments in structural energy devices, including special attention to fuel cells, lithium-ion batteries, lithium metal batteries, and supercapacitors.Finally, the existing problems of structural energy devices are discussed, and the current challenges and future opportunities are summarized and prospected. Structural energy devices can undoubtedly overcome the performance bottlenecks of traditional energy devices, break the limitations of existing materials and structures, and provide a guidance for the development of equipment with high performance,light weight and low cost in the future.
基金supported by the National Natural Science Foundation of China(Youth)(61306068)the Natural Science Foundation of Jiangsu Province of China(BK20130585,BK20140414)+1 种基金the National Natural Science Foundation of China(61435014,61504170,61504058)the National 863 Program(2015AA016902)
文摘In this paper, we present the finding that periodic structural defects(PSDs) along a Bragg grating can shift the Bragg wavelength. This effect is theoretically analyzed and confirmed by numerical calculation. We find that the Bragg wavelength shift is determined by the defect size and the period of the defects. The Bragg wavelength can be well tuned by properly designing the PSDs, and this may provide an alternative method to fabricate grating-based multiwavelength devices, including optical filter arrays and laser arrays. In regards to wavelength precision, the proposed method has an advantage over the traditional methods, where the Bragg wavelengths are changed directly by changing the grating period. In addition, the proposed method can maintain grating strength when tuning the wavelength since only the period of defects is changed. This will be a benefit for devices such as arrays.
基金Supported by the National Natural Science Foundation of China under Grant Nos 50902137 and 60937003.
文摘For the purpose of improving conversion efficiency of solar cells by applying the effect of the wavelength conversion of rare earth ions, photo-luminescence and excitation spectrums of Ce3+-Tb3+ doped phosphate glass are investigated. Results show that incorporating Ce3+ ions to Tb3+-doped phosphate glass can greatly increase the absorption coefficient in the range 300-400 nm and then the energy transfer (ET) from Ce3+ to Tb3+ occurs. In addition, increasing Tb3+ concentration in Ce3+/Tb3+ co-doped phosphate glass can greatly enhance the ET efficiency and 545 nm emission intensity. This shows that Ce3+/Tb3+ co-doped phosphate glass would be a promising down-shifting material for enhancing the efficiency of solar cells.
基金supported by National Science Foun-dation of China (Grant No. 60425101)Program for New CenturyExcellent Talents in University of Education Ministry of China(Grant No. NCET-06-0812)the Young Excellence Project ofUESTC (Grant No.060206.)
文摘A triple layer organic light-emitting diode (OLED) with two heterostructure of indium-tin oxide (ITO)/N,N’-diphenyl-N, N’-bis(1-naphthyl) (1,1’-biphenyl)-4,4’-diamine (NPB)/2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP)/ 8-Hydrox- yquinoline aluminum (Alq3)/Mg:Ag has been fabricated by using the vacuum deposition method. The influence of different film thickness of BCP layer on the performance of the OLEDs has been investigated. The results show that when the thickness of the BCP layer film gradually ranges from 0.1-4.0 nm, the electroluminescence (EL) spectra of the OLEDs shift from green to greenish-blue to blue, and the BCP layer acts as the role for the recombination region of charge carriers related to EL spectrum, which enhances the brightness and power efficiency. The power efficiency of the OLEDs reaches to as high as 7.3 lm/W.
基金The authors are thankful for funding from the National Natural Science Foundation of China (Nos. 51402063, 51432005, 61405040, 61505010, 51502018, 31270022, and 81471784), the "100 Talents Program" of the Chinese Academy of Sciences, Beijing City Committee of science and technology (No. Z151100003315010), Beijing Natural Science Foundation (Nos. 2164077 and 2164076), the Fundamental Research Funds of Shandong University (No. 2014QY003), and the Youth Innovation Promotion Association of the Chinese Academy of Sciences (No. 2015023). The authors also acknowledge the support from the"thousands talents" program for pioneer researchers and his innovation team, and support from the President Funding of the Chinese Academy of Sciences.
文摘Nanomaterials show promising opportunities to address clinical problems (such as insufficient capture of circulating tumor cells; CTCs) via the high surface area-to-volume ratio and high affinity for biological cells. However, how to apply these nanomaterials as a nano-bio interface in a microfluidic device for efficient CTC capture with high specificity remains a challenge. In the present work, we first found that a titanium dioxide (TiO2) nanorod array that can be conveniently prepared on multiple kinds of substrates has high affinity for tumor cells. Then, the TiO2 nanorod array was vertically grown on the surface of a microchannel with hexagonally patterned Si micropillars via a hydrothermal reaction, forming a new kind of a micro-nano 3D hierarchically structured microfluidic device. The vertically grown TiO2 nanorod array was used as a sensitive nano-bio interface of this 3D hierarchically structured microfluidic device, which showed high efficiency of CTC capture (76.7% ± 7.1%) in an artificial whole-blood sample.
基金supported by the National Nature Science Foundation of China(11074268,10834010)
文摘This paper aimed at extracting optimal structural parameters for Love wave device with structure of multi-waveguides to improve its temperature stability. The theoretical model dealing with the Love wave propagation in multi-waveguides was established first, the dispersion characteristic is depicted by the acoustic propagation theory of stratified media and boundary conditions. Combing with the dispersion characteristics and Tomar's method, the optimal structural parameters for the Love wave device with zero temperature coefficient were extracted, and confirmed by the following experimental results. Excellent temperature coefficient of the Love wave device with SU-8/SiO2 on ST-90°X quartz substrate was evaluated experimentally as only 2.16 ppm/℃, which agrees well with the calculated results. The optimized Love wave device is very promising in gas sensing application.
基金This work was supported by the National Natural Science Foundation of China (Nos. 51422204, 51372132, and 51672153) and the National Basic Research Program of China (Nos. 2016YFA0200103 and 2013CB228506).
文摘Stretchable and flexible supercapacitors are highly desired due to their many potential applications in wearable devices. However, it is challenging to fabricate supercapacitors that can withstand large tensile strain while maintaining high performance. Herein, we report an ultra-stretchable wire-shaped supercapacitor based on carbon nanotube@graphene@MnO2 fibers wound around a superelastic core fiber. The supercapacitor can sustain tensile strain up to 850%, which is the highest value reported for this type of device to date, while maintaining stable electrochemical performance. The energy density of the supercapacitor is 3.37 mWh·cm^-3 at a power density of 54.0 mW·cm^-3. The results show that 82% of the specific capacitance is retained after 1,000 stretch-release cycles with strains of 700%, demonstrating the superior durability of the elastic supercapacitor and showcasing its potential application in ultra-stretchable flexible electronics.