Light-emitting diodes(LEDs)based on perovskite semiconductor materials with tunable emission wavelength in visible light range as well as narrow linewidth are potential competitors among current light-emitting display...
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Light-emitting diodes(LEDs)based on perovskite semiconductor materials with tunable emission wavelength in visible light range as well as narrow linewidth are potential competitors among current light-emitting display technologies,but still suffer from severe instability driven by electric ***,we develop a stable,efficient and highcolor purity hybrid LED with a tandem structure by combining the perovskite LED and the commercial organic LED technologies to accelerate the practical application of *** LED and organic LED with close photoluminescence peak are selected to maximize photon emission without photon reabsorption and to achieve the narrowed emission *** designing an efficient interconnecting layer with p-type interface doping that provides good opto-electric coupling and reduces Joule heating,the resulting green emitting hybrid LED shows a narrow linewidth of around 30 nm,a peak luminance of over 176,000 cd m^(−2),a maximum external quantum efficiency of over 40%,and an operational half-lifetime of over 42,000 h.
P-GaN gate AlGaN/GaN high electron mobility transistor (HEMT) is currently the mainstream solution to realize enhancement mode GaN-based power electronic devices, but the influence of Schottky contact or ohmic contact...
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P-GaN gate AlGaN/GaN high electron mobility transistor (HEMT) is currently the mainstream solution to realize enhancement mode GaN-based power electronic devices, but the influence of Schottky contact or ohmic contact on the device characteristics is still an issue to be further comparatively studied. In this paper, the impacts of Schottky and ohmic-type gate contacts on device performances such as transfer characteristics, transconductance and breakdown voltage of p-GaN gate AlGaN/GaN HEMT devices were studied by TCAD simulation. In Schottky-gate devices, the gate leakage is lower, and a larger threshold voltage (>6V) can be obtained by adjusting the parameters of the p-GaN cap layer, but as the threshold voltage increases, the drain current density will be correspondingly suppressed. In contrast, the threshold voltage of ohmic-gate devices is relatively stable and the drain current density is larger. In addition, ohmic-gate devices exhibit superior voltage withstand capability, but ohmic-type gate devices suffer serious gate leakage problem. Then the influence of Schottky- and ohmic- gate contacts on the stability of p-GaN gate AlGaN/GaN HEMT is studied. It is found that the threshold voltage of both devices is unstable.
Organic memristors with low power consumption,fast write/erasure speed,and complementary metal-oxide-semiconductor(CMOS)compatibility have attracted tremendous attention to mimic biological synapses to realize neuromo...
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Organic memristors with low power consumption,fast write/erasure speed,and complementary metal-oxide-semiconductor(CMOS)compatibility have attracted tremendous attention to mimic biological synapses to realize neuromorphic computation in recent *** this paper,organic resistive switching memory(ORSM)based on(Z)-3-(naphthalen-2-yl)-2-(4-nitrophenyl)acrylonitrile(NNA)and polymer poly(N-vinylcarbazole)(PVK)composite film was prepared by spin-coating *** performance based on NNA:PVK composite films with different mass fractions of NNA were systematically *** ORSM based on PVK:40%(mass fraction)NNA composite film exhibited non-volatile and bipolar memory properties with a switching ratio(Ion/Ioff)of 24.1,endurance of 68 times and retention time of 104 s,a“SET”voltage(Vset)of−0.55 V and a“RESET”voltage(Vreset)of 2.35 *** resistive switching was ascribed to the filling and vacant process of the charge traps induced by NNA and the inherent traps in PVK *** holes trapping and de-trapping process occurred when the device was applied with a negative or positive bias,which caused the transforming of the conductive way of charges,that is the resistive behaviors in the *** study provides a promising platform for the fabrication of ORSM with high performance.
Although doped hole-transport materials(HTMs)off er an effi ciency benefi t for perovskite solar cells(PSCs),they inevi-tably diminish the ***,we describe the use of various chlorinated small molecules,specifi cally f...
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Although doped hole-transport materials(HTMs)off er an effi ciency benefi t for perovskite solar cells(PSCs),they inevi-tably diminish the ***,we describe the use of various chlorinated small molecules,specifi cally fl uorenone-triphenylamine(FO-TPA)-x-Cl[x=para,meta,and ortho(p,m,and o)],with diff erent chlorine-substituent positions,as dopant-free HTMs for *** chlorinated molecules feature a symmetrical donor-acceptor-donor structure and ideal intramolecular charge transfer properties,allowing for self-doping and the establishment of built-in potentials for improving charge *** effi cient hole-transfer interfaces are constructed between perovskites and these HTMs by strategi-cally modifying the chlorine ***,the chlorinated HTM-derived inverted PSCs exhibited superior effi ciencies and air ***,the dopant-free HTM FO-TPA-o-Cl not only attains a power conversion effi ciency of 20.82% but also demonstrates exceptional stability,retaining 93.8%of its initial effi ciency even after a 30-day aging test conducted under ambient air conditions in PSCs without *** fi ndings underscore the critical role of chlorine-substituent regulation in HTMs in ensuring the formation and maintenance of effi cient and stable PSCs.
Colloidal quantum dots/perovskites based light-emitting diodes (QLEDs/PeLEDs) have attracted extensive attention for lighting and displayapplications because of their excellent advantages, such as narrow emission ban...
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Micro-LED has attracted more attention due to its unique photoelectric properties, such as high brightness, high energy efficiency, high stability and other characteristics, which facilitate its widespread application...
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ISBN:
(数字)9798331541149
ISBN:
(纸本)9798331541156
Micro-LED has attracted more attention due to its unique photoelectric properties, such as high brightness, high energy efficiency, high stability and other characteristics, which facilitate its widespread application. Bumps can be used for electrical connections and heat transfer paths as well as structural supports that affect the reliability of Micro-LED devices. Hybrid bonding enhances the reliability and longevity of electronic devices while also ensuring the compatibility of bonding process. Currently, there is limited finite element simulation research on Micro-LEDs, particularly regarding electrothermal and mechanical multi-physical field simulations. Herein, the electrothermal and mechanical coupling of a quarter of a 6×6 Micro-LED array model was analyzed using COMSOL Multiphysics simulation software and the finite element method. The analysis primarily focused on the stress and displacement of bumps in the hybrid bonding model. The optimal combinations of different bump materials (indium-In, tin-Sn) and filling materials (epoxy resin-EP and benzocyclobutene-BCB) were obtained. The results indicate that BCB is a more suitable filling material, while In is preferable as a bump material. Furthermore, variations in thermal stress and displacement of cylindrical and circular-truncated cone bumps of different aspect ratios were analyzed. This paper provides an idea for optimizing the fabrication of Micro-LED bumps and bonding processes.
Micro-LED displays have garnered widespread attention due to their high resolution, high brightness, and long lifespan. However, the heterogeneous integration and the reliability of Micro-LEDs pose significant challen...
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ISBN:
(数字)9798331541149
ISBN:
(纸本)9798331541156
Micro-LED displays have garnered widespread attention due to their high resolution, high brightness, and long lifespan. However, the heterogeneous integration and the reliability of Micro-LEDs pose significant challenges for their commercialization. As Micro-LED products develop towards larger sizes and narrower pitches, the Au/In bonding process has become a prevalent strategy for achieving high-resolution interconnections. To address the issue of the life span being affected by the plastic deformation of indium bumps, which ultimately fail in the form of yielding, an Au/In-resin hybrid bonding technique to improve the reliability of high-resolution Micro-LEDs was proposed in this paper. The reliability of the flip-chip bonding structure of a $4\times 4$ Micro-LED array was analyzed using ANSYS simulation software and finite element methods. The Anand unified viscoplastic constitutive model was employed for both indium bumps and the encapsulating resin. The model was subjected to temperature cycling loads ranging from $-55^{\circ}\mathrm{C}$ to $125^{\circ}\mathrm{C}$ in accordance with the JEDEC temperature cycling standard. The Coffin-Manson fatigue life prediction model, which accounts for plastic strain in materials, was introduced to estimate the thermal cycling fatigue life of the Micro-LED interconnection structures. The equivalent plastic strain range of hybrid bonding device was $6.708\times 10^{-3}$ , surpassing the $7.59\times 10^{-3}$ observed in device with conventional bump bonding. The hybrid bonding device exhibited a thermal cycling life of 12747 cycles, which was about 36% longer than that of the bump bonding device. It suggests that resin helps to extend the thermal cycling life of the device and enhance its reliability.
Video-text retrieval is one of the most popular branches in the cross-modal research area facing the exponential growth of multimedia services. Present methods typically mea-sure cross-modal similarities only by the c...
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Quasi-two-dimensional (quasi-2D) perovskite-based light-emitting diodes (PeLEDs) have attracted intensive attention due to their high quantum yields, tunable emission wavelengths, and solution-processing capability, s...
Quasi-two-dimensional (quasi-2D) perovskite-based light-emitting diodes (PeLEDs) have attracted intensive attention due to their high quantum yields, tunable emission wavelengths, and solution-processing capability, showing great potential in next-generation display and lighting applications. However, further performance enhancement in PeLEDs is severely limited by the uncontrolled transfer of charge carriers under bias, leading to crowding of interfacial carriers and severe efficiency roll-off. Herein, we insert an ultra-thin dielectric buffer layer of lithium fluoride (LiF) into the electron transport layer (ETL) to regulate the transfer dynamics of electrons and passivate the interfacial defects simultaneously. The dielectric LiF interlayer can effectively reduce the efficiency roll-off in PeLEDs by improving the charge balance through preventing the overwhelming injection of electrons. Moreover, the fluoride anions from LiF can passivate the surface defects of the perovskite film, enhancing the radiative recombination. As a result, the LiF interlayer-assisted quasi-2D PeLED presents an outstanding external quantum efficiency (EQE) of 24.03% and a maximum brightness of 30 845 cd m−2. The operational stability of the device is also extended, with a half-lifetime (T50) of 71.28 min (at an initial luminance of 1 000 cd m−2), which is 7.4-fold longer than that for the control device.
To investigate the stratosphere-troposphere exchange(STE)process induced by the gravity waves(GWs)caused by Typhoon Molave(2020)in the upper troposphere and lower stratosphere,we analyzed the ERA5 reanalysis data prov...
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To investigate the stratosphere-troposphere exchange(STE)process induced by the gravity waves(GWs)caused by Typhoon Molave(2020)in the upper troposphere and lower stratosphere,we analyzed the ERA5 reanalysis data provided by the European Centre for Medium-Range Weather Forecasts and the CMA Tropical Cyclone Best Track *** also adopted the mesoscale forecast model Weather Research and Forecasting model V4.3 for numerical *** of the previous studies were about typhoon-induced STE and typhoon-induced GWs,while our research focused on the STE caused by typhoon-induced gravity *** analysis shows that most of the time,the gravity wave signal of Typhoon Molave appeared below the *** was stronger on the east side of the typhoon center(10°-20°N,110°-120°E)than on the west side,suggesting an eastward tilted structure with height *** the GWs in the upper troposphere and lower stratosphere region on the west side of the typhoon center broke up,it produced strong turbulence,resulting in stratosphere-troposphere *** this time,the average potential vorticity vertical flux increased with the average ozone mass mixing *** gravity wave events and STE process simulated by the WRF model were basically consistent with the results of ERA5 reanalysis data,but the time of gravity wave breaking was *** study indicates that after the breaking of the GWs induced by typhoons,turbulent mixing will also be generated,and thus the STE.
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