Excellent Planarity Research Articles

Intramolecular Hydrogen Bonds Assisted Construction of Planar Tricyclic Structures for Insensitive and Highly Thermostable Energetic Materials.

Safety is fundamental for the practical development and application of energetic materials. Three tricyclic energetic compounds, namely, 1,3-di(1H-tetrazol-5-yl)-1H-1,2,4-triazol-5-amine (ATDT), 5'-nitro-3-(1H-tetrazol-5-yl)-2'H-[1,3'-bi(1,2,4-triazol)]-5-amine (ATNT), and 1-(3,4-dinitro-1H-pyrazol-5-yl)-3-(1H-tetrazol-5-yl)-1H-1,2,4-triazol-5-amine (ATDNP), were effectively synthesized through a simple two-step synthetic route. The introduction of intramolecular hydrogen bonds resulted in excellent molecular planarity for the three new compounds. Additionally, they exhibit regular crystal packing, leading to numerous intermolecular hydrogen bonds and π-π interactions. Benefiting from planar tricyclic structural features, ATDT, ATNT, and ATDNP are insensitive (IS > 60 J, FS = 360 N) when exposed to external stimuli. Furthermore, ATNT (Td = 361.1 °C) and ATDNP (Td = 317.0 °C) exhibit high decomposition temperatures and satisfying detonation performance. The intermolecular hydrogen bonding that produced this planar tricyclic molecular structure serves as a model for the creation of innovative multiple heterocycle energetic materials with excellent stability.

Narrowband emission from fully-bridged triphenylamine derivatives: insights into effects of structure modification and pressure.

Triphenylamine derivatives with narrowband emission have attracted growing attention in purely organic thermally-activated fluorescence (TADF) materials owing to their enhanced color purity and flexible molecular design strategy. Combined time-dependent density functional theory (TD-DFT) and ONIOM (QM/MM) calculations indicate that the excellent planarity of the experimentally developed DQAO could result in gradually decreased intermolecular interactions in the aggregated state at ambient pressure and upon compression, which is unfavorable for suppressing structural relaxation and achieving narrowband emission in its non-doped practical application. Therefore, three structure-modified derivatives, DQAO-Cb, DQAO-Ph, and DQAO-PhCb, were theoretically designed by introducing the spherical o-carborane and dangling phenyl units positioned para to the N atom of the DQAO to provide additional geometrical distortion and steric hindrance. The explorations on the reported DQAO, OQAO, and SQAO found that small structural relaxations, suppressed low-frequency vibrations, and noticeable short-range charge-transfer (SR-CT) natures of DQAO and OQAO are responsible for their much narrower emission spectral full-width at half-maxima (FWHMs) compared to that of SQAO. Introducing the o-carborane unit directly at the para position of the N atom could result in additional scissoring and stretching vibrations of the corresponding DQAO-Cb while the presence of the phenyl unit in DQAO-Ph is beneficial for suppressing the high-frequency vibrations of the pristine DQAO. More importantly, the bridged phenyl unit incorporated in DQAO-PhCb is of particular importance to inhibit the undesired low-frequency scissoring and high-frequency stretching vibrations of the o-carborane unit, which is crucial to reduce the reorganization energy of DQAO-PhCb and achieve narrowband emission. Also, the phenyl unit in DQAO-Ph and DQAO-PhCb helps to shorten charge transfer distances and improve ISC and RISC processes. Since the o-carborane unit is an adopted building block to achieve piezochromic behaviors, the theoretically structure-modified DQAO-PhCb is expected to exhibit narrowband emission, TADF, and piezochromic features all together. Our findings will hopefully provide ideas for designing triphenylamine-based TADF emitters with narrowband emission and piezochromic behaviors.

Investigation of CMP Process of Silica Substrate by Ceria Abrasive: Insights from Molecular Dynamics Simulation with Neural Network Potential

Chemical mechanical polishing (CMP) is a process of surface planarization by chemical and mechanical driving forces. CMP is expected to solve various problems, including the surface roughness on semiconductor devices. An aqueous slurry, including abrasive grains and chemical components, is used in the CMP process. Development of slurries with high polishing rate, excellent planarity, and superior processability is not only a key challenge, but also a significant opportunity for the future of our industry. In order to achieve the development, it is necessary to understand the detailed mechanism of CMP, which involves complex phenomena accompanied by interfacial chemical reactions and mechanical friction. Computational scientific approaches, such as density functional theory (DFT) and molecular dynamics (MD) simulations, are powerful tools for understanding complex tribochemical phenomena at the atomic scale. However, these methods require much computation time and present difficulties for large-scale simulations. To overcome this limitation, a computational method called Neural Network Potential (NNP) is a powerful tool because it achieves a good balance between accuracy and computational efficiency by constructing potential energy surfaces based on a neural network-based method. We performed NNP-MD simulations of the ceria/silica interface with the development of CMP slurry including ceria abrasive grains, which is typically used on the surfaces of silicon layered devices. As a result, we succeeded in observing polishing phenomena at the interface at the atomic scale, namely Ce-O-Si bond formation between ceria abrasive grains and silica substrate, hydrolysis reaction of Si-O bond, and associated mono-silica dissociation from the substrate. We also performed simulations of systems containing chemical compounds added to the slurry for the purpose of controlling the polishing rate and observed the role of additives on the CMP process. In this presentation, we will show simulation results and discuss the mechanism of CMP of silica substrates with ceria abrasive grains in terms of dependence on surface morphology at the atomic scale and the role of additives. Reference [1] Tran*, R., Lan*, J., Shuaibi*, M., Wood*, B., Goyal*, S., Das, A., Heras-Domingo, J., Kolluru, A., Rizvi, A., Shoghi, N., Sriram, A., Ulissi, Z., & Zitnick, C. (2022). The Open Catalyst 2022 (OC22) Dataset and Challenges for Oxide Electrocatalysis. arXiv preprint arXiv:2206.08917.

Localized Electron Density Regulation Effect for Promoting Solid-Liquid Ion Adsorption to Enhance Areal Capacitance of Micro-Supercapacitors.

The development of flexible microelectronic systems requires the construction of high-energy-output planar micro-supercapacitors (MSCs). Herein, the localized electron density, by introducing graphene quantum dots (GQDs) on the surface of electrodes, is regulated. The enhanced local field intensity promotes ion electrostatic adsorption at the solid-liquid interface, which significantly improves the energy density of MSCs in the confined space. Local electronic structure has been investigated from the perspective of the topological analysis of the electron localization function (ELF) and the electron density. Impressively, the edges of the simulated structure exhibit a higher electron density distribution than the CC skeleton. This finding indicates that the introduced GQDs reinforce the intrinsic electrical double-layer capacitance (EDLC) and the oxygen-bearing functional groups at the edge, further increasing the pseudocapacitance performance. Moreover, the edge electron aggregation effect enables the all-carbon-based symmetric MSCs to exhibit ultra-high areal capacitance (21.78mFcm-2 ) and excellent cycle stability (86.74% retention after 25000 cycles). This novel surface local charge regulation strategy is also applied for intensifying ion electrostatic adsorption on Zn-ion hybrid MSCs (polyvalent metal ions) and ion-gel electrolyte MSCs (non-metallic ions). With excellent planar integration, this device demonstrates excellent flexibility and has potential applications in timing and environmental monitoring.

Monolithic three‐dimensional integration of aligned carbon nanotube transistors for high‐performance integrated circuits

AbstractCarbon nanotube field‐effect transistors (CNT FETs) have been demonstrated to exhibit high performance only through low‐temperature fabrication process and require a low thermal budget to construct monolithic three‐dimensional (M3D) integrated circuits (ICs), which have been considered a promising technology to meet the demands of high‐bandwidth computing and fully functional integration. However, the lack of high‐quality CNT materials at the upper layer and a low‐parasitic interlayer dielectric (ILD) makes the reported M3D CNT FETs and ICs unable to provide the predicted high performance. In this work, we demonstrate a multilayer stackable process for M3D integration of high‐performance aligned carbon nanotube (A‐CNT) transistors and ICs. A low‐κ (~3) interlayer SiO2 layer is prepared from spin‐on‐glass (SOG) through processes with a highest temperature of 220°C, presenting low parasitic capacitance between two transistor layers and excellent planarization to offer an ideal surface for the A‐CNT and device fabrication process. A high‐quality A‐CNT film with a carrier mobility of 650 cm2 V–1 s–1 is prepared on the ILD layer through a clean transfer process, enabling the upper CNT FETs fabricated with a low‐temperature process to exhibit high on‐state current (1 mA μm–1) and peak transconductance (0.98 mS μm–1). The bottom A‐CNT FETs maintain pristine high performance after undergoing the ILD growth and upper FET fabrication. As a result, 5‐stage ring oscillators utilizing the M3D architecture show a gate propagation delay of 17 ps and an active region of approximately 100 μm2, representing the fastest and the most compact M3D ICs to date.image

Surface Corrosion Inhibition Effect and Action Mechanism Analysis of 5-Methyl-Benzotriazole on Cobalt-Based Copper Film Chemical Mechanical Polishing for GLSI

With integrated circuit (IC) technology nodes below 20 nm, the chemical mechanical polishing (CMP) of cobalt (Co)-based copper (Cu) interconnection has been gradually changed to one-step polishing, which requires rapid removal rate (RR) of Cu while controlling the height differences of concave and convex areas on the Cu surface, and finally achieving global planarization. Co as the barrier material is also required a lower RR to ensure a high Cu/Co removal rate selection ratio. Therefore, choosing the appropriate inhibitor in the slurry is extremely important. The corrosion inhibitor 5-methyl-benzotriazole (TTA) was thoroughly examined in this study for its ability to prevent corrosion on Cu film as well as its mode of action. The experimental results showed that TTA can effectively inhibit the removal of Cu under both dynamic and static conditions, which was also confirmed by scanning electron microscopy (SEM) and atomic force microscopy (AFM) tests. The corrosion inhibition effect and mechanism of TTA was further revealed by open circuit potential (OCP), polarization curve, adsorption isotherm, quantum chemical calculation, UV–Visible and X-ray photoelectron spectroscopy (XPS) tests. It was found that TTA can inhibit the corrosion of Cu by physical and chemical adsorption on the Cu surface, which is conductive to obtain excellent planarization properties. At the same time, it was also found TTA can also inhibit the corrosion of Co by forming Co-TTA and promoting the conversion of Co(OH)2 to Co3O4, and a Cu/Co removal rate selection ratio of 104 was obtained, which provides a suitable corrosion inhibitor for the polishing of Co-based Cu interconnection CMP and has a broad application prospect.

A Solvent-Free, Thermally Curable Low-Temperature Organic Planarization Layer for Thin Film Encapsulation.

Thin film encapsulation (TFE) is an essential component to ensure reliable operation of environmentally susceptible organic light-emitting diode-based display. In order to integrate defect-free TFE on display with complex surface structures, additional planarization layer is imperative to planarize the surface topography. The thickness of conventional planarization layer is as high as tens of µm, but the thickness must be reduced substantially to minimize the light leakage in smaller devices such as micro light-emitting diodes. In this study, a thin-less than 2 µm-planarization is achieved via solvent-free process, initiated chemical vapor deposition (iCVD). By adapting copolymer from two soft, but curable monomers, glycidyl acrylate (GA) and 2-(dimethylamino)ethyl methacrylate, excellent planarization performance is achieved on various nano-grating patterns. With only 1.5 µm-thick iCVD planarization layer, a 600 nm-deep trench polyurethane acrylate pattern is flattened completely. The TFE fabricated on planarized pattern exhibits excellent barrier property as fabricated on flat glass substrate, which strongly suggests that iCVD planarization layer can serve as a promising planarization layer to fabricate TFE on various types of complicated device surfaces.

Enhanced out-of-plane thermal conductivity of polyimide composite films by adding hollow cube-like boron nitride

Boron nitride nanosheet (BNNS) is widely used in electronic thermal management due to its excellent planar thermal conductivity and insulating properties. However, it is challenging to improve the out-of-plane thermal conductivity of BNNS-doped composites due to the anisotropy of the thermal conductivity of BNNS. Therefore, the BNNS in the matrix must be oriented to obtain composites with high out-of-plane thermal conductivity. In this study, BNNS powders with directional structures were synthesized directly using sodium chloride templates. The as-obtained BNNS powders have a unique hollow cube-like structure with an ultra-low density of 2.67 × 10−2 g/cm3 and nearly 8 times the volume of the same mass of two-dimensional (2D) BNNS, making it easy to form the out-of-plane thermal conductivity paths in the polymer matrix. In addition, the high out-of-plane thermal conductivity of 4.93 W m−1 K−1 at 23.3 wt% loadings was obtained by doping it into a polyimide (PI) matrix. This value is 9.7 times higher than that of 2D BNNS-doped PI at the same loadings, 17.6 times higher than pure PI, and 6.1 times higher than the thermally conductive PI film sold by DuPont. Therefore, the prepared composite film has great potential for application in electronic thermal management.

Fabrication of polymeric vacuum-sealed cavities on a silicon wafer

A method to fabricate low temperature adhesively bonded vacuum-sealed insulated polymeric cavities on a silicon substrate is presented. Multi-purpose use of the same polymer (Benzocyclobutene (BCB)) as the cavity structural material and also as an adhesive bonding agent minimizes process complexity, cost, and dielectric charging. Scanning electron microscopy (SEM) based characterization results show excellent planarity of BCB surfaces and high quality bonding which is indicative of better reliability. The method paves the way to fabricate the package and the sensor in the same process run to enable higher level of integration and minimize the cost further. The technique can be used to realize capacitive micromachined ultrasonic transducers (CMUTs), MEMS pressure sensors, and 3D embedded packaging and integration of heterogeneous dies.

Cyclometalated Platinum(II) Metallomesogens Based on Half-Disc-Shaped β-Diketonate Ligands with Hexacatenar: Crystal Structures, Mesophase Properties, and Semiconductor Devices.

A series of new half-disc-shaped platinum(II) complexes [Pt(ppy)(ALn-6OCnH2n+1)] (Pt-An), [Pt(ppyF)(ALn-6OCnH2n+1)] (Pt-Bn), and [Pt(ppyCF3)(ALn-6OCnH2n+1)] (Pt-Cn) (ALn-6OCnH2n+1 = 1,3-bis(3,4,5-trialkoxyphenyl)propane-1,3-dionato; n = 1, 6, 12) with concise structures have been designed and synthesized, in which 2-phenylpyridine (ppy) derivatives were used as cyclometalated ligands and hexacatenar β-diketonate derivatives ALn-6OCnH2n+1 as auxiliary ligands. The single-crystal data of the methoxy diketonate analogues Pt-A1, Pt-B1, and Pt-C1 indicate that they all display excellent square planarity. These platinum(II) complexes show a certain emission tunability (ranging from λ = 506-535 nm) by the introduction of fluorine or trifluoromethyl into ppy. Thermal studies reveal that the fluorine-substituted complexes are liquid crystals but the trifluoromethyl-substituted complexes are not. The platinum(II) complexes Pt-A12, Pt-B6, and Pt-B12 can form a hexagonal columnar mesophase via intermolecular π-π interactions. In addition, compared to the reported platinum(II) metallomesogens, Pt-A12 and Pt-B12 exhibit improved ambipolar carrier mobility behaviors in semiconductor devices at the liquid crystal states.

Improving electron and ion transport by constructing 3D graphene nanosheets sandwiched between porous carbon nanolayers produced from resorcinol-formaldehyde resin for high-performance supercapacitor electrodes

An ideal supercapacitor electrode should contain three-dimensional (3D) interpenetrating electron and ion pathways with a short transport distance. Graphene-based carbon materials offer new and fascinating opportunities for high performance supercapacitor electrodes due to their excellent planar conductivity and large surface area. 3D graphene nanosheets coated with carbon nanolayers of controllable thickness from resorcinol-formaldehyde (RF) resin are constructed and activated by KOH to develop pores. Such a sandwich structure provides abundant transport channels for ions with short paths. The porous carbon nanolayers accelerate ion transport, while the graphene networks improve the conductivity, boosting electron transport. As expected, the prepared porous carbon has a high surface area of 690 m2 g−1 and a high specific capacitance of up to 324 F g−1 in a 6 mol L−1 KOH aqueous electrolyte at a current density of 0.2 A g−1. More than 99% of the capacitance is retained after 8000 charge–discharge cycles at a high current density of 5 A g−1, indicating good cycling stability. This research provides an effective strategy for the development of outstanding electrode materials for the enhanced transport of both electrons and ions.

N-Vinyl pyrrolidone and undecylenic acid copolymerized on silica surface as mixed-mode stationary phases for reversed-phase and hydrophilic interaction chromatography

In this work, three new mixed-mode stationary phases were prepared, based on different ratio of N-vinyl pyrrolidone (NVP) copolymerized together with undecylenic acid (UA) on silica microspheres surface without silanization, which named Sil@NVPUA series. The combination of NVP and UA rendered the Sil@NVPUA suitable for reversed-phase liquid chromatography (RPLC) and hydrophilic interaction liquid chromatography (HILIC), and shown excellent methyl, planar, isomers and ion selectivity. Five types of model analytes including eight polycyclic aromatic hydrocarbons, six alkylbenzenes, eight nucleosides and nucleobases, seven ginsenosides and five oxazolidinones can be well separated on this stationary phase. The preparation method of NVP and UA modified silica-based stationary phase is simple, and it also provides a new idea for the design of synthetic polymers to develop mixed-mode chromatography.

Recent Advances in Molecular Design of Organic Thermoelectric Materials

Recent Advances in Molecular Design of Organic Thermoelectric Materials

Superior galvanostatic electrochemical deposition of platinum nanograss provides high performance planar microelectrodes for in vitro neural recording

Objective. Platinum nanograss (Ptng) has been demonstrated as an excellent coating to increase the electrode roughness and reduce the impedance of microelectrodes for neural recording. However, the optimisation of the original potentiostatic electrochemical deposition (PSED) method has been performed by the original group only and no in vitro validation of functionality was reported. Approach. This study firstly reinvestigates the use of the PSED method for Ptng coating at different charge densities which highlights non-uniformities in the edges of the microelectrodes for increasing deposition charge densities, leading to a decreased impedance which is in fact an artefact. We then introduce a novel Ptng fabrication method of galvanostatic electrochemical deposition (GSED). Main results. We demonstrate that the GSED deposition method also significantly reduces the electrode impedance, raises the charge storage capacity and provides a significantly more planar electrode surface in comparison to the PSED method with negligible edge effects. In addition, we demonstrate how high-quality neural recordings were performed, for the first time, using the Ptng GSED deposition microelectrodes from human hNT neurons and how spiking and bursting were observed. Significance. Thus, the GSED Ptng deposition method presented here provides an alternative method of microelectrode fabrication for neural applications with excellent impedance and planarity of surface.

Recent advances of dithienobenzodithiophene-based organic semiconductors for organic electronics

In recent years, fused aromatic dithienobenzodithiophene (DTBDT)-based functional semiconductors have been potential candidates for organic electronics. Due to the favorable features of excellent planarity, strong crystallinity, high mobility, and so on, DTBDT-based semiconductors have demonstrated remarkable performance in organic electronic devices, such as organic feld-effect transistor (OFET), organic photovoltaic (OPV), organic photodetectors (OPDs). Driven by this success, recent developments in the area of DTBDT-based semiconductors for applications in electronic devices are reviewed, focusing on OFET, OPV, perovskite solar cells (PSCs), and other organic electronic devices with a discussion of the relationship between molecular structure and device performance. Finally, the remaining challenges, and the key research direction in the near future are proposed, which provide a useful guidance for the design of DTBDT-based materials.

Evaluation of ATTR-cardiac amyloidosis employing Tc-99m pyrophosphate scintigraphy using planar, SPECT and gated SPECT imaging on dedicated cardiac CZT camera

Abstract Background/Introduction Recent recognition that ATTR cardiac amyloidosis (ATTR-CA) is not uncommon and the emergence of novel therapeutic opportunities resulted in the publication of “Expert Consensus Recommendations for Multimodality Imaging in Cardiac Amyloidosis”. However, almost all data were derived from general purpose NaI cameras, while new cardiac dedicated CZT cameras are becoming more widespread. Purpose To evaluate Tc-99m pyrophosphate (PYP) scintigraphy on D-SPECT cardio dedicated CZT camera (Spectrum Dynamics) in suspected ATTR-CA patients. Methods Seventy three consecutive patients suspected for ATTR-CA underwent planar (5 min), SPECT and gated SPECT (10 min, 8 bins) scintigraphy 89±26 min after injection of Tc99m-PYP 740 MBq, followed by late scintigraphy after 92±36 min in 65 consecutive patients. Perguini visual score, planar H/CL and SPECT derived H/CL ratio were evaluated by two blinded independent experienced readers. Diagnosis was based on visual interpretation after blood pool and monoclonal gammopathy were excluded. Results Very good to excellent planar and SPECT image quality was observed in almost all patients. PYP scintigraphy was positive in 6/73 patients, with left ventricular wall uptake clearly evident in the planar images of most patients. There was perfect agreement between readers regarding positive/negative interpretation. There was also substantial inter-observer agreement regarding the Perguini scoring (Cohen's k with linear weighting 0.819, 95% CI 0.701–0.937). Inter-observer agreement for H/CL ratio was also good (Pearson's correlation coefficient r(71)=0.873). SPECT and gated SPECT images were helpful only in one positive patient, and did not have an added value in any of the negative studies. Slightly better images were observed during late scintigraphy, but there was no change in interpretation, and H/CL ratio was not significantly changed (median difference −0.01, IQR 0.09). Alas, Inter-observer agreement of H/CL ratio was lower (Pearson's correlation coefficient r(64)=0.633). We also evaluated H/CL ratio derived from SPECT based application of the camera manufacturer. Agreement between early planar and early SPECT based H/CL ratio was good for both readers (r(69)=0.778 and r(66)=0.747), but inter-observer agreement was lower (r(66)=0.697). Conclusions ATTR PYP scintigraphy using cardiac dedicated CZT camera yielded excellent images in almost all patients, and uptake in the left ventricular wall could be easily identified in positive patients. Inter-observer agreement was excellent for both visual scoring and planar H/CL ratio. Early planar images were high quality, and limited additional diagnostic value was observed for both SPECT and gated SPECT scintigraphy and from later acquisition. Funding Acknowledgement Type of funding source: None

SYNTHESIS OF MONOMERS BASED ON 6-HYDROXYAURONE AND INVESTIGATION ITS PHOTOCHEMICAL PROPERTIES

In particular, as an important class of organic heterocyclic dyes, aurones exhibit unique photochemical and photophysical properties, which render them useful in a variety of applications, such as fluorescent labels and probes in biology and medicine. Despite of the wide range of applications, the photochemical properties of the aurone class remain less well known. The backbone of aurone molecule has excellent planarity and from the viewpoint of molecular engineering, molecular planarity plays an important role in tuning nonlinear optical properties of materials. Therefore, this work is aimed to the synthesis of new derivatives based on 6-hydroxyaurone and study their photochemical properties. Novel monomers based on (2Z)-2-benzylidene)-6-hydroxy-1-benzofuran-3 (2H)-one with different withdrawing substituents in the benzylidene moiety were synthesized by acylation of the hydroxy group by methacryloil chloride. The polymerization was carried out in 10% solutions of the monomers in dimethylformamide, 2,2ˊ-azobisisobutyronitrile was used as the initiator The structure of the synthesized compounds was proved by 1H NMR spectroscopy. The study of the photochemical properties of synthesized polymers was performed by UV VIS spectroscopy. New polymers with auron moiety have been shown ability to photoinduced Z-E-isomerization. The rate constants of Z-E-photoisomerization were determined by slope angle tangent of dependence ln(D/D0) on the irradiation time. The half-reaction periods for E-isomers of auronecontaining polymers were calculated.

Multilayer Fabrication of Micromolding and Electroforming with the Planarization of Grinding for High-Aspect-Ratio Microelectrodes in Electro-conjugate Fluid (ECF) Micropumps

Previously, we described a single layer fabrication combining thick photoresist (KMPR) micromolding and electroforming to fabricate ECF micropumps with triangular prism and slit electrode pairs (TPSEs). However, the fabricated TPSEs have a height limitation due to the limitation of KMPR’s aspect ratio caused by serious swelling and deformation of KMPR micromolds. To solve this problem and realize high-aspect-ratio TPSEs, we propose to utilize the multilayer fabrication instead of the single layer one. After each prior micromolding layer fabrication, the precision surface grinding technique is introduced to achieve the excellent planarization of the KMPR micromolds and electroplated TPSEs between the first layer and the second one. We apply this method to successfully fabricate the 3D-integration ECF micropump (3D-EMP) with TPSEs of 880 µm in height. Also, we validate this method by experimentally investigating and comparing the output performance of ECF micropumps composed of double layer TPSEs and previous single layer ones. The novel MEMS fabrication method combining multilayer micromolding and electroforming with the planarization is promising and applicable to a broad range of high-aspect-ratio metallic microstructures.

Uncommon Intramolecular Charge Transfer Effect and Its Potential Application in OLED Emitters

Planarized intramolecular charge transfer(PLICT) state can facilitate the fluorescence process thanks to the relative excellent planarity. Recently, we have discovered that the excited state quinone-conformation induced planarization(ESQIP) occurring on tetraphenylpyrazine(TPP) based derivatives could furnish them with PLICT feature. Unlike to the well-known intramolecular charge transfer, strengthening the electron-donating nature on the donor(D) moiety did not impair the PLICT. The calculation results showed that planarization of the TPP based compounds scarcely accompanied with energy wastage while amount of energy was required for the torsion on geometries. In the polar solvents, the energy consumption for planarization could further decrease, but that for twisting structure would increase. To take advantage of the transformation of the frontier orbitals’ distribution, the PLICT type materials would perform a potential application on organic light-emitting diodes(OLEDs).

Developments of Diketopyrrolopyrrole‐Dye‐Based Organic Semiconductors for a Wide Range of Applications in Electronics

In recent times, fused aromatic diketopyrrolopyrrole (DPP)-based functional semiconductors have attracted considerable attention in the developing field of organic electronics. Over the past few years, DPP-based semiconductors have demonstrated remarkable improvements in the performance of both organic field-effect transistor (OFET) and organic photovoltaic (OPV) devices due to the favorable features of the DPP unit, such as excellent planarity and better electron-withdrawing ability. Driven by this success, DPP-based materials are now being exploited in various other electronic devices including complementary circuits, memory devices, chemical sensors, photodetectors, perovskite solar cells, organic light-emitting diodes, and more. Recent developments in the use of DPP-based materials for a wide range of electronic devices are summarized, focusing on OFET, OPV, and newly developed devices with a discussion of device performance in terms of molecular engineering. Useful guidance for the design of future DPP-based materials and the exploration of more advanced applications is provided.