A high-effective bottom anode is essential for high-performance top-emitting organic light-emitting devices (OLEDs). In this paper, Ag-based top-emitting OLEDs are investigated. Ag has the highest reflectivity for vis...A high-effective bottom anode is essential for high-performance top-emitting organic light-emitting devices (OLEDs). In this paper, Ag-based top-emitting OLEDs are investigated. Ag has the highest reflectivity for visible light among all metals, yet its hole-injection properties are not ideal for anodes of top-emitting OLED. The performance of the devices is significantly improved using the molybdenum oxide as anode buffer layer at the surface of Ag. By introducing the molybdenum oxide, the hole injection from Ag anodes into top-emitting OLED is largely enhanced with rather high reflectivity retained.展开更多
The film cooling performance of a trunk-branch hole is investigated by numerical simulation in this paper. The geometry of the hole is a novel cooling concept, which controls the vortices-pair existing at the mink hol...The film cooling performance of a trunk-branch hole is investigated by numerical simulation in this paper. The geometry of the hole is a novel cooling concept, which controls the vortices-pair existing at the mink hole outlet using the injection of the branch hole. The trunk-branch holes require easily machinable round hole as compared to the shaped holes. The flow cases were considered at the blowing ratios of 0.5, 0.75, 1.0, 1.5 and 2.0. At the low blowing ratio of 0.5, the vortices-pair at the outlet of the trunk hole is reduced and the laterally coverage of the film is improved. At the high blowing ratio of 2.0, the vortices-pair is killed by the vortex which is produced by the injection of the branch hole. The flow rate of the two outlets becomes more significantly different when the blowing ratio increases from 0.75 to 2.0. The discharge coefficients increase 0.15 and the laterally averaged film effectiveness improve 0.2 as compared to the cylindrical holes. The optimal blowing ratios occur at M=1.0 or M= 1.5 according to the various locations downstream of the holes.展开更多
Organic light-emitting diodes(OLEDs)have drawn tremendous attention due to their widespread applications in flat-panel displays and solid-state lightings over the years[1-4].The charge injection is crucial for the per...Organic light-emitting diodes(OLEDs)have drawn tremendous attention due to their widespread applications in flat-panel displays and solid-state lightings over the years[1-4].The charge injection is crucial for the performance of OLEDs featuring sandwiched p-i-n structures[5-9].For OLEDs,an indium tin oxide(ITO)electrode with a work function of 4.7 eV,and most holetransporting materials(HTMs)with the highest occupied molecular orbitals(HOMOs)close to-5.5 eV.展开更多
A key requirement for well performing devices based onorganic semiconductors is to ensure ohmic contacts, where anefficient hole and electron injection and extraction can beachieved at the electrode/semiconductor inte...A key requirement for well performing devices based onorganic semiconductors is to ensure ohmic contacts, where anefficient hole and electron injection and extraction can beachieved at the electrode/semiconductor interfaces. The usualway to obtain ohmic contacts involves fine tuning of the energet-ics at the interfaces by using dopants (p- type and n-type) to con-trol the Fermi level of the semiconductor [1,2], or using suitablemetals or metal oxides as electrodes [3].展开更多
A dual-blue light-emitting diode(LED) with asymmetric AlGaN composition-graded barriers but without an AlGaN electron blocking layer(EBL) is analyzed numerically. Its spectral stability and efficiency droop are improv...A dual-blue light-emitting diode(LED) with asymmetric AlGaN composition-graded barriers but without an AlGaN electron blocking layer(EBL) is analyzed numerically. Its spectral stability and efficiency droop are improved compared with those of the conventional InGaN/GaN quantum well(QW) dual-blue LEDs based on stacking structure of two In0.18Ga0.82N/GaN QWs and two In0.12Ga0.88N/GaN QWs on the same sapphire substrate. The improvement can be attributed to the markedly enhanced injection of holes into the dual-blue active regions and effective reduction of leakage current.展开更多
基金supported by the National Natural Science Foundation of China (No.60425101)the Young Excellence Project of University of Electronic Science and Technology of China (No.UESTC-060206)the Fundamental Research Funds for the Central Universities of China (Nos.ZYGX2010Z004 and ZYGX2009J054)
文摘A high-effective bottom anode is essential for high-performance top-emitting organic light-emitting devices (OLEDs). In this paper, Ag-based top-emitting OLEDs are investigated. Ag has the highest reflectivity for visible light among all metals, yet its hole-injection properties are not ideal for anodes of top-emitting OLED. The performance of the devices is significantly improved using the molybdenum oxide as anode buffer layer at the surface of Ag. By introducing the molybdenum oxide, the hole injection from Ag anodes into top-emitting OLED is largely enhanced with rather high reflectivity retained.
文摘The film cooling performance of a trunk-branch hole is investigated by numerical simulation in this paper. The geometry of the hole is a novel cooling concept, which controls the vortices-pair existing at the mink hole outlet using the injection of the branch hole. The trunk-branch holes require easily machinable round hole as compared to the shaped holes. The flow cases were considered at the blowing ratios of 0.5, 0.75, 1.0, 1.5 and 2.0. At the low blowing ratio of 0.5, the vortices-pair at the outlet of the trunk hole is reduced and the laterally coverage of the film is improved. At the high blowing ratio of 2.0, the vortices-pair is killed by the vortex which is produced by the injection of the branch hole. The flow rate of the two outlets becomes more significantly different when the blowing ratio increases from 0.75 to 2.0. The discharge coefficients increase 0.15 and the laterally averaged film effectiveness improve 0.2 as compared to the cylindrical holes. The optimal blowing ratios occur at M=1.0 or M= 1.5 according to the various locations downstream of the holes.
基金supported by the National Natural Science Foundation of China(51203138,51273179)National Key Basic Research Program of China(973)(2011CBA00700)International S&T Cooperation Program,China(2012DFA51210)~~
基金supported by the National Key Basic Research and Development Program of China (2017YFA0204501 and 2020YFA0715000)the National Natural Science Foundation of China (51903137 and 61890942)+1 种基金Foshan Xianhu Laboratory of the Advanced Energy Science and Technology Guangdong Laboratory (XHT2020-005)financial support from the Young Elite Scientist Sponsorship Program (2019QNRC001) by China Association for Science and Technology。
文摘Organic light-emitting diodes(OLEDs)have drawn tremendous attention due to their widespread applications in flat-panel displays and solid-state lightings over the years[1-4].The charge injection is crucial for the performance of OLEDs featuring sandwiched p-i-n structures[5-9].For OLEDs,an indium tin oxide(ITO)electrode with a work function of 4.7 eV,and most holetransporting materials(HTMs)with the highest occupied molecular orbitals(HOMOs)close to-5.5 eV.
基金supported by the Knut and Alice Wallenberg Foundation(KAW)through a Wallenberg Scholar grant to Olle Ingans。
文摘A key requirement for well performing devices based onorganic semiconductors is to ensure ohmic contacts, where anefficient hole and electron injection and extraction can beachieved at the electrode/semiconductor interfaces. The usualway to obtain ohmic contacts involves fine tuning of the energet-ics at the interfaces by using dopants (p- type and n-type) to con-trol the Fermi level of the semiconductor [1,2], or using suitablemetals or metal oxides as electrodes [3].
文摘A dual-blue light-emitting diode(LED) with asymmetric AlGaN composition-graded barriers but without an AlGaN electron blocking layer(EBL) is analyzed numerically. Its spectral stability and efficiency droop are improved compared with those of the conventional InGaN/GaN quantum well(QW) dual-blue LEDs based on stacking structure of two In0.18Ga0.82N/GaN QWs and two In0.12Ga0.88N/GaN QWs on the same sapphire substrate. The improvement can be attributed to the markedly enhanced injection of holes into the dual-blue active regions and effective reduction of leakage current.
