Intermediate Connector Research Articles

69‐4: Distinguished Paper: High‐luminance and Highly Reliable Tandem OLED Display Including New Intermediate Connector Designed for Photolithography Applications

We achieved a high‐luminance and highly reliable tandem organic light‐emitting diode (OLED) designed for photolithography applications by developing a new intermediate connector with resistance to water and atmospheric elements. We succeeded in fabricating a side‐by‐side (SBS) tandem OLED display by our SBS pixel‐patterning method involving organic layer etching via photolithography.

High‐luminance and Highly Reliable Tandem OLED Display Including New Intermediate Connector Designed for Photolithography Applications

AbstractWe achieved a high‐luminance and highly reliable tandem organic light‐emitting diode (OLED) designed for photolithography applications by developing a new intermediate connector with high resistance to water and atmospheric elements. We succeeded in fabricating a red, green, and blue (RGB) side‐by‐side (SBS) tandem OLED display without a fine metal mask using our SBS pixel‐patterning method involving organic layer etching via photolithography.

Exploring the preparation of YbBa2Cu3O7-y superconductor in flowing oxygen atmosphere.

REBCO has been used extensively as coated conductors applied to superconducting magnets due to its exceptional superconducting properties. As a REBCO superconductor, YbBa2Cu3O7-y (Yb123) has a low melting temperature, making it suitable for use as an intermediate medium connector while preparing the superconducting joint. However, there is still uncertainty about the formation mechanism of Yb123 and the synthesis of this superconductor has not been fully understood. Therefore, this study systematically investigated the phase transformation process of Yb123 during heat treatment in flowing oxygen. The results indicated that Yb123 sample with the highest phase purity could be obtained by annealing at 927°C or 937°C but not in between, respectively. Furthermore, a quantitative phase analysis revealed that the sample annealed at 937°C had a phase purity greater than 80 wt%. Additionally, a strong c-axis texture was observed in the bulk Yb123 superconductor prepared at 937°C. Meanwhile, the superconducting results revealed that the bulk sample's Tc was 89.9 K, and its self-field critical current densities at 4.2 K and 77 K were 1.3 × 105 A/cm2 and 5.0 × 103 A/cm2, respectively. Based on the results mentioned above, the phase transformation process and formation mechanism of Yb123 in flowing oxygen were elaborated.

Analyzing Gas Station Visits during Hurricane Ida: Implications for Future Fuel Supply

Fuel demand surges and supply shortages during hurricanes are problematic. However, fuel consumption and refueling behavior are not well discussed in disaster scenarios compared with the extant literature on these topics during normal conditions. This study used an emerging data source to report when fuel demand (indicated by gas station visits) deviated from a normal variation range during Hurricane Ida (a Category 4 Atlantic hurricane in 2021), how long the deviation lasted, and which area(s) experienced greater deviations. Gas station visits are likely to surge within 2 days before storm landfall, while evacuation destinations and intermediate trip connectors had longer surges. Using univariate linear regression, this study also statistically explored what factors might affect the fuel demand deviation at an aggregate level. The testing results revealed that zones of higher vehicle ownership, more daily commuters driving alone, lower residential stability, more mobile homes, and less storm impacts tended to have more gas station visits (i.e., greater fuel demand). Then, this study analyzed data at a more disaggregate level to identify the characteristics of gas stations that are more likely to have more visitors. Gas stations near interstates/highways attracted more visits, especially within 2 days before storm landfall. Gas stations farther away from interstates/highways attracted more visits after storm landfall. Overall, this study contributes to our knowledge about fuel consumption and refueling location preferences during hurricanes. These findings could help public agencies and private companies in their fuel supply planning (e.g., fuel distribution) and response (e.g., providing power generators to focal locations).

Strength of Composite Columns Consists of Welded Double CF Sigma-Sections Filled with Concrete—An Experimental Study

In-filled tubes section is a very successful configuration for axially loaded members such as columns and struts. Steel shell tube filled with concrete has many advantages, such as eliminating the need for shuttering, reinforcement bars or ties besides increasing both flexural and axial capacities and enhancing the ductility. The main disadvantage of in-filled tubes is the need for a shell thick enough to prevent the local buckling and hence the local decomposition. Previous studies tried to solve this problem using intermediate stiffeners or shear connectors. This research presents another approach to solve this problem using double cold-formed sigma-sections (face to face) as steel shell tubes. Sixteen specimens with different lengths, cross section dimensions and shell thicknesses were tested under both concentric and eccentric compression loads. Ultimate capacities, lateral deformations and normal strains were recorded. The theoretical capacities were calculated using AISC-LRDF-94, EN-1994-04 and CSI-COL software considering full composite action, and the deviations from the experimental results were 24%, 24% and 13%, respectively.

High-Efficiency Tandem White Perovskite Light-Emitting Diodes by Using an Organic/Inorganic Intermediate Connector

The performance of monochromatic perovskite light-emitting diodes (PeLEDs) has undergone rapid development in recent years, while white PeLEDs are still in their infancy. The tandem devices prepared by connecting light-emitting units of different colors with intermediate connectors comprise one of the promising approaches for realizing white light emission. The intermediate connector plays a crucial role in determining the effectiveness of the light-emitting units. In this work, all-perovskite-based white LEDs are assembled by employing sky-blue (490 nm) and red (690 nm) perovskite emitters as active layers. With mixed p-type and n-type organic charge transport materials as the intermediate connector, the highest external quantum efficiency (EQE) of the device was 1.4%, the electroluminescence (EL) peak position of the blue light part was shifted to 512 nm, and the red light part was shifted to 673 nm. In contrast, with organic and inorganic charge transport materials as the intermediate connector, the devices exhibited better charge generation/injection capabilities and a record EQE of 8.5%. The EL peak position of the device prepared from the stored film was not shifted, implying that the organic/inorganic layer effectively suppresses halide migration. Our work paves the way for highly efficient tandem white PeLEDs.

Research of a new hot-rolled connector connection to composite walls

The composite members in steel residential buildings often possess small sections and have high restrictions on the indoor space extrusion of structural components, and then traditional diaphragm type and internal or exterior stiffener connections are hardly applied. A new hot-rolled connector connection was proposed, which used the flange-to-web arch transition of hot-rolled steel beams as the intermediate connector. The smooth section transition of the connector at the column face junction can reduce the stress concentrations and premature fracture potentials of connections between H-shaped beams and small-size composite walls or CFST columns in steel residential buildings. Four hot-rolled connector connections with different connector designs and beam sizes were tested under cyclic loads, and the seismic performances and working mechanisms were investigated. Refined finite element simulations were performed to indicate the load transfer path and load sharing mode in the connection. Results indicated that the proposed connection displayed plump hysteretic relations and satisfactory energy dissipation ability. The strengthened connectors succeeded in inducing the high plasticity away from the wall or column face. The bottom beam flange to connector butt weld was prone to fracture. The HTC connection with a long HTC connecting beam and the two bolt-row construction as the web connection was suggested.

Efficient tandem organic light-emitting diode with fluorinated hexaazatrinaphthylene charge generation layer

ABSTRACT We present the fluorinated hexaazatrinaphthylene derivative, 1,2,3,4,7,8,9,10,13,14,15,16-dodecafluoro-5,6,11,12,17,18-hexaazatrinaphthylene (HATNA-F12), as a new material to replace another hexaazatrinaphthylene molecule, 1,4,5,8,9,11-hexaazatriphenylene-hexacarbonitrile (HAT-CN), which is widely used as an intermediate connector and charge generation layer (CGL) in tandem organic light-emitting diodes (OLEDs). Upon comparison with the reference single emitting layer unit OLED, the tandem device with HATNA-F12 CGL had improved current efficiency and external quantum efficiency of 42.1% and 41.7%, respectively. Our results show that HATNA-F12 is an excellent substitute for HAT-CN and has more promising characteristics as a CGL material for applications in tandem OLEDs. When compared to devices with HAT-CN CGL, the green tandem OLEDs with CGL consisting of HATNA-F12 demonstrated improved current efficiency, power efficacy, and external quantum efficiency values, while the change of the CGL material had almost no effect on the operating voltage, current density, and color coordinates of the OLEDs. We confirm that using the newly suggested HATNA-F12 molecule as a CGL in these OLEDs can enhance device efficiency.

Interfacial charge transfer study of hexacarbonitrile-based intermediate connecter in blue tandem organic light-emitting diodes

The charge generation process of hexaazatriphenylene hexacarbonitrile-based intermediate connectors (ICs) in blue tandem organic light-emitting diodes (OLEDs) is investigated via photoelectron spectroscopic and device studies. Though 1,4,5,8,9,11-hexaazatriphenylene hexacarbonitrile (HATCN) is well-known to be a p-type hole-injection layer, our photoelectron spectroscopic results indicate that HATCN becomes the n-type when it is sandwiched between Li-doped 4,7-diphenyl-1,10-phenanthroline (BPhen) and N,N″-diphenyl-N,N″-bis(1-naphthyl)-(1,1′-biphenyl)-4,4′-diamine (NPB) layers, and the charge generation and separation at the Li:BPhen/HATCN/NPB interfaces become energetically favorable, as depicted by their energy level alignments. This explains the superior device performance when Li:BPhen/HATCN/NPB is used as a connecting unit in tandem devices.

Elastic compressive buckling resistance for back-to-back double angle assemblies

The present study investigates the elastic buckling resistance of compression members consisting of non-slender hot-rolled double angles connected back-to-back with discrete interconnectors. Towards this goal, the study (a) formulates a thin-walled beam finite element buckling solution that treats both angles as independent members away from the intermediate connector locations while constraining the displacements for both angles at interconnector locations, and (b) develops an extension of the Vlasov thin-walled beam theory, originally intended for monolithic members, to determine the effective torsional/warping sectional properties for back-to-back double angle members. The validity of the thin-walled beam finite element model is then verified against experimental results and shell finite element models and its predictions are shown to asymptotically converge to the Vlasov theory extension developed in the present study as the number of interconnectors is increased. A systematic parametric study consisting of 1250 finite element runs is then conducted and the database of results generated is used to propose a simple equation to predict the elastic compressive buckling resistance of double angle compression members.

Improved corrosion resistance of AZ31 Mg alloy coated with MXenes/MgAl-LDHs composite layer modified with yttrium

MXenes, a novel two-dimensional (2D) material of Ti3C2, present wide applications in energy-related fields. However, a mass of sedimentary multilayer Ti3C2 was discarded and non-recyclable due to incomplete exfoliation in the preparation of single layer Ti3C2. In this work, a composite structure, mixing MXenes/magnesium aluminum-layered double hydroxides (MXenes/MgAl-LDHs) with Y(OH)3, was synthesized in-situ as a smart coating on Mg alloy AZ31 via (i) exfoliating those multilayer Ti3C2 to few-layer MXenes (FLMs), and (ii) adding Y(NO3)3 to FLMs solution for a one-step hydrothermal treatment. Results show the electronegative mainboard of MXenes can effectively absorb cations in the reaction solution, and promote growth of MgAl-LDHs and Y(OH)3 on its surface. Moreover, MgAl-LDHs being the intermediate connector facilitate growth of MXenes upon the surface of Mg alloy AZ31. The corrosion tests indicated that the composite coating modified with yttrium had an excellent anticorrosion performance (Ecorr = −0.36 VSCE, Icorr = 9.12 × 10−9 A cm−2) and self-healing ability. Further, the formation and corrosion mechanism of composite coatings were finally proposed.

Aorto-pulmonary bypass shunt for intraoperative right ventricular support during LVAD implantation.

We describe a simple modification of the cardiopulmonary bypass (CPB) circuit that allows selective intraoperative circulatory support of the right ventricle during left ventricular assist device (LVAD) implantation. The addition of a side branch to the arterial line and an intermediate line connector allows selective venting and perfusion through a cannula inserted in the main pulmonary artery. This modification of the CPB circuit allows for selective evaluation of right ventricular function, titration of inotropic support, and early identification of patients that require right ventricular assist device (RVAD) support.

Efficient blue fluorescence tandem organic light emitting device with a novel intermediate connector

A novel intermediate connector (IC) was formed which was composed of aluminum (Al, 3 nm)/1,4,5,8,9,11-hexaazatriphenylene-hexacarbonitrile (HAT-CN). The 3-nm-thick Al in the IC is certified to efficiently generate intrinsic charge carriers, and the HAT-CN is proved to work as the holes injection layer (HIL) for the corresponding electroluminescent (EL) unit simultaneously. This simply IC comprehensively takes advantage of the features of the HAT-CN so as to stack two single EL units without introducing extra material. In addition to a significant enhancement in luminance and current efficiency, a current efficiency (CE) of 10.2 cd/A and a luminance of 2 042 cd/m2 under the current density 20 mA/cm2 of this tandem organic light emitting device (TOLED) are yielded, which are notably almost the sum of that of the two single-unit devices.

High performance hybrid tandem white organic light-emitting diodes by using a novel intermediate connector

Using Liq/Ca/HAT-CN as an intermediate connector, high-performance hybrid tandem WOLEDs with EQE of 39.57% and CRI of 93 were developed.

Silver ethynide clusters constructed with fluorinated β-diketonate ligands

Phosphonate can act as the intermediate connector to link two silver ethynide clusters functionalized by hfac ligands together to enlarge the silver cluster.

Sensitivity analysis of cable oscillating wave test system on multi-source defects diagnostics

By using OWTS, the existence of partial discharge defects simultaneously among the three intermediate cabling connectors was discovered. Statistics to the relationship among discharge frequency characteristic and test voltage for the three positions, respectively, found that the discharge pulse number presented terraced rising trend with the increase of test voltage, which is exactly the characteristics of typical discharge. To reveal the cause of concentrated discharge, a variety of advanced state detection technology were applied on the second defective intermediate joint. Partial discharge type identification with pulse current method suggested that: when phase A was at U0, recognition showed two discharge types, surface discharge and internal discharge. However, when the voltage came to 1.73U0, surface discharge gradually disappeared, left surface discharge only. These two discharge types always existed in phase B. The signal in phase C was weak, with intermittent and 180° phase characteristics. The subsequent disintegration of the second defective joint revealed that: the existence of the defect inside the joint partial discharge risks, and this is due to the obvious result of making bad process. At the same time, this case also shows that the oscillation detection technology effectively, as well as field testers judged entirely correct.

The electro-optic performance and photovoltaic effect of organic devices based on cesium carbonate/Al/molybdenum trioxide intermediate connector

Abstract An intermediate connector of Cs 2 CO 3 /Al/MoO 3 used in tandem organic light-emitting diodes (OLEDs) was investigated in this work. Here, an ultrathin Cs 2 CO 3 /Al was used as an electron-injection layer (EIL) from MoO 3 to the adjacent electron transporting layer (ETL). To verify the function of this intermediate connector, the device performances were evaluated through current density-voltage-luminance characteristics, current density-efficiency curves, and EL spectra. Additionally, the effect of photon energy on carriers behavior in the Cs 2 CO 3 /Al/MoO 3 connector is also estimated. The electrical properties and EL spectra of tandem OLEDs show that the Cs 2 CO 3 /Al/MoO 3 can function well for charge generation and transport, and the current density-voltage curves of Cs 2 CO 3 /Al/MoO 3 based special multilayer device shows the photovoltaic effect as a photovoltaic cell.

The effect of illumination and electrode adjustment on the carrier behavior in special multilayer devices

Intermediate connectors play an important role in semiconductor devices, especially in tandem devices. In this paper, four types of different intermediate connectors (e.g. Mg:Alq3/MoO3, MoO3, Mg:Alq3, and none) and two kinds of modified electrode materials (LiF and MoO3) integrated into the special multilayer devices are proposed, with the aim of studying the impact of light illumination and electrode adjustment on the carrier behavior of intermediate connectors through the current density–voltage characteristics, interfacial electronic structures, and capacitance–voltage characteristics. The results show that the illumination enhances the charge generation and separation in intermediate connectors, and further electrode interface modifications enhance the functionality of intermediate connectors. In addition, the device with an efficient intermediate connector structure shows a photoelectric effect, which paves the way for organic photovoltaic devices to realize optical-electrical integration transformation.

Dynamic processes of charges generation in intermediate connectors for tandem organic light emitting diodes

The role of transition metal oxides (TMOs) based intermediate connectors in tandem organic light emitting diodes (OLEDs) has been studied via capacitance-voltage and current-voltage characteristics, in order to elucidate the dynamic processes of charges generation and transport within externally applied voltages. The TMO-based intermediate connectors are composed of molybdenum trioxide (MoO3) and cesium azide (CsN3)-doped-4, 7–diphenyl-1, 10-phenanthroline (BPhen) layers, where MoO3 and CsN3 are used due to low deposition temperatures. From the obtained results of capacitance and current density, charges generation in CsN3:BPhen/MoO3/NPB is proposed to the defect states in thermally evaporated MoO3, which offers a minimal energy offset for charges generation. Moreover, our results clearly indicate that charges generation efficiency is not only relying on the MoO3-NPB interface, but also influenced by CsN3:BPhen-MoO3 interface. CsN3 doped BPhen layer further improves charges separation efficiency, which finally results in favorable charges transport into the adjacent layers and ensure to function efficiently for tandem OLEDs.

Tandem Organic Light-Emitting Diodes.

A tandem organic light-emitting diode (OLED) is an organic optoelectronic device that has two or more electroluminescence (EL) units connected electrically in series with unique intermediate connectors within the device. Researchers have studied this new OLED architecture with growing interest and have found that the current efficiency of a tandem OLED containing N EL units (N > 1) should be N times that of a conventional OLED containing only a single EL unit. Therefore, this new architecture is potentially useful for constructing high-efficiency, high-luminance, and long-lifetime OLED displays and organic solid-state lighting sources. In a tandem OLED, the intermediate connector plays a crucial role in determining the effectiveness of the stacked EL units. The interfaces in the connector control the inner charge generation and charge injection into the adjacent EL units. Meanwhile, the transparency and the thickness of the connector affect the light output of the device. Therefore, the intermediate connector should be made to meet both the electrical and optical requirements for achieving optimal performance. Here, recent advances in the research of the tandem OLEDs is discussed, with the main focus on material selection and interface studies in the intermediate connectors, as well as the optical design of the tandem OLEDs.