As eries of donor-acceptor-donor triazine-based molecules with thermally activated delayedf luorescence (TADF) properties were synthesized to obtain highly efficient blue-emitting OLEDs with non-doped emitting layers (EMLs). The targeted molecules use at riazinec ore as the electron acceptor,a nd ab enzene ring as the conjugated linker with different electrond onors to alternate the energy level of the HOMO to further tune the emission color.T he introduction of long alkyl chains on the triazine core inhibits the unwanted intermolecular D-D/A-A-type p-p interactions, resulting in the intermolecularD -A charget ransfer.T he weak aggregation-causedq uenching (ACQ) effectc aused by the sup-pressed intermolecular D-D/A-A-type p-p interaction further enhancest he emission.T he crowded molecular structure allows the electrond onor and acceptort ob en early orthogonal, thereby reducing the energy gap between triplet and singlet excited states (DE ST ). As ar esult, blue-emitting devices with TH-2DMAC and TH-2DPAC non-doped EMLs showed satisfactory efficiencies of 12.8 %a nd 15.8 %, respectively,w hichi so ne of the highest external quantum efficiency (EQEs) reported for blue TADF emitters( l peak < 475 nm), demonstratingt hat our tailored molecular designsare promising strategies to endow OLEDs with excellent electroluminescent performances.

In recent years, owing to the demand for highefficiency phosphorescent organic light-emitting devices (PhOLEDs), many studies have been conducted on the development of bipolar host materials. A series of imidazolylphenylcarbazole-based host materials, i. e., im-CzP, im-CzPCz, im-CzPtBu, and im-OCzP, were synthesized to obtain highefficiency green and red-emitting PhOLEDs. With im-OCzP as the host, satisfactory peak efficiencies of 22.2 (77.0 cd A À 1 and 93.1 lm W À 1 ) and 14.1 % (9.0 cd A À 1 and 10.1 lm W À 1 ) could be obtained, respectively. To further improve the performance of the devices, an electron transport material, bis-4,6-(3,5-di-3pyridylphenyl)-2-methylpyrimidine (B3PyMPM) was selected to construct a co-hosted system. The efficiency of im-OCzP combined with B3PyMPM forming co-hosts could also achieve high values of 23.0 (80.0 cd A À 1 and 98.8 lm W À 1 ) and 16.5 % (10.2 cd A À 1 and 13.4 lm W À 1 ) for green and red PhOLEDs, respectively. These results exhibited that the proposed bipolar hosts have great flexibility in adjusting the carrier balance of EML in OLEDs, demonstrating their ingenious design and high potential.

Recently, the fields of organic light-emitting diodes (OLEDs) and light-emitting electrochemical cells (LECs) have improved tremendously with regard to tunable emission, efficiency, brightness, and thermal stability. Imidazole derivatives are excellent deep blue-green light-emitting layers in the OLED or LEC devices. This Review summarizes the major breakthroughs of various electroluminescence (EL) layers with imidazole-containing organic or organometallic derivatives, the molecular design principles, and their light-emitting performances as effective EL materials. The highly tunable chemical structures and flexible molecular design strategies of imidazole-based compounds are advantages that provide great opportunities for researchers. They can provide a good basis for the design and development of new EL materials with narrower emission and higher efficiency. Moreover, imidazole compounds have demonstrated breakthrough performances in thermally activated delayed fluorescence (TADF) properties where triplet excitons are utilized to inhibit anti-intersystem quenching, showing great promise in breaking the theoretical external quantum efficiencies (EQE) limits in traditional fluorescent devices.

Integrated circuits (IC) are produced by deposition and modification of different dielectric and metal layers on a silicon wafer. Because of the continuing miniaturization of the device dimensions and the requirements of interconnecting an increasing number of devices on a chip, building multilevel interconnections on planarized levels has become an essential part of IC production. Chemical mechanical planarization (CMP) is a process of smoothing the dielectric and metal films in the process of integrated circuit fabrication with the combination of chemical and mechanical forces. For a metal CMP slurry, the key components and steps are as follows: 1. Oxidizing agent is added to the slurry to oxidize the metal surface. 2. Nano-scaled abrasives subsequently remove the dielectric and oxidized metal layer by mechanical force. 3. Inhibitors are added to prevent or minimize undesired corrosion thus controlling the surface quality. A group of surfactant-like inhibitors have been investigated in this study. Their structures differed by the length of their hydrophobic tails (alkyl groups having 4 to 16 carbon atoms). The molecules were absorbed on metal wafer surface through hydrophilic head and the hydrophobic tail wriggled on top and around. Thus, adjusting the length of tail may change the behavior of the adsorbing layer on metal films, which provided a viable route to interrupt the interactions between slurry components and the metal surface. We found that adjusting the length of tail affected the CMP slurry properties (such as suppression of static etching rate, see Figure 1), longer tail lengths led to better etching inhibition, and also caused distinct modification on the surface of abrasive (mean particle size and zeta potential). Polishing performances including removal rates and topography were also affected by the tail length, but the results with various feature sizes were more complex due to the combined net effect of etching inhibition and modified abrasive properties. The tail length demonstrated an important role on slurry stability and polishing performance. Figure 1. The decay of etching rates with inhibitors. The indicate-axis tail numbers designate the carbon atoms in hydrophobic tails. Figure 1

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