Intrinsically stretchable organic light‐emitting diodes (ISOLEDs) are becoming essential components of wearable electronics. However, the efficiencies of ISOLEDs have been highly inferior compared ...with their rigid counterparts, which is due to the lack of ideal stretchable electrode materials that can overcome the poor charge injection at 1D metallic nanowire/organic interfaces. Herein, highly efficient ISOLEDs that use graphene‐based 2D‐contact stretchable electrodes (TCSEs) that incorporate a graphene layer on top of embedded metallic nanowires are demonstrated. The graphene layer modifies the work function, promotes charge spreading, and impedes inward diffusion of oxygen and moisture. The work function (WF) of 3.57 eV is achieved by forming a strong interfacial dipole after deposition of a newly designed conjugated polyelectrolyte with crown ether and anionic sulfonate groups on TCSE; this is the lowest value ever reported among ISOLEDs, which overcomes the existing problem of very poor electron injection in ISOLEDs. Subsequent pressure‐controlled lamination yields a highly efficient fluorescent ISOLED with an unprecedently high current efficiency of 20.3 cd A−1, which even exceeds that of an otherwise‐identical rigid counterpart. Lastly, a 3 inch five‐by‐five passive matrix ISOLED is demonstrated using convex stretching. This work can provide a rational protocol for designing intrinsically stretchable high‐efficiency optoelectronic devices with favorable interfacial electronic structures.
A protocol to fabricate highly efficient organic light‐emitting diodes that use an intrinsically stretchable 2D‐contact electrode topped with graphene is reported. As a benefit of the fast carrier mobility with complete 2D contact with the organic material and the tunable work function of the 2D‐contact stretchable electro (TCSE), the limited charge injection of the widely used silver‐nanowire‐based stretchable electrode is solved.
Schematics showing Ce-O-Si bonding as well as the mechanisms of (a) physical (megasonic and brush scrubbing) and (b) chemical (SC1, DHF, and SPM) cleaning forces for ceria removal.
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...•Ceria particle removal using different forces were studied during oxide post-CMP cleaning.•Polishing with pH 4 ceria slurry resulted in only electrostatic attraction and easy to remove.•Polishing with pH 8 ceria slurry resulted in stronger Ce-O-Si bonding and difficult to remove.•Physical forces (megasonic and brush scrubbing) unable to break Ce-O-Si bonds.•DHF and SPM could effectively remove chemically bonded (Ce-O-Si) ceria particles.
Ceria removal during the STI post-CMP cleaning process has recently become a serious concern to the semiconductor industries. It is known that ceria forms a strong Ce-O-Si bonding with the oxide surface that causes the difficulty in ceria removal. In this study, the bond formation and their removal were studied by polishing the oxide surface at pH 4 and pH 8 conditions, i.e. the pH of commercially formulated slurries. Ceria removal mechanisms were investigated through the use of different physical cleaning methods (megasonic and brush scrubbing) and chemical cleaning solutions such as standard cleaning solution 1 (SC1, a mixture solution of NH4OH, H2O2 and H2O), sulfuric acid, and hydrogen peroxide mixture (SPM), and diluted HF (DHF). It was found that ceria particles were removed easily at pH 4 polishing conditions as the electrostatic attraction is dominant than Ce-O-Si bond formation. However, at pH 8 conditions, particles were not removed due to strong bond formation. Only DHF and SPM cleaning conditions were able to remove the ceria particles due to the strong undercutting of oxide and dissolution of ceria particles, respectively. SPM could be the better choice as DHF would cause the surface roughness issues.
By considering the qualitative benefits associated with solution rheology and mechanical properties of polymer semiconductors, it is expected that polymer-based electronic devices will soon enter our ...daily lives as indispensable elements in a myriad of flexible and ultra low-cost flat panel displays. Despite more than a decade of research focused on designing and synthesizing state-of-the-art polymer semiconductors for improving charge transport characteristics, the current mobility values are still not sufficient for many practical applications. The confident mobility in excess of ∼10 cm(2)/V·s is the most important requirement for enabling the realization of the aforementioned near-future products. We report on an easily attainable donor-acceptor (D-A) polymer semiconductor: poly(thienoisoindigo-alt-naphthalene) (PTIIG-Np). An unprecedented mobility of 14.4 cm(2)/V·s, by using PTIIG-Np with a high-k gate dielectric poly(vinylidenefluoride-trifluoroethylene) (P(VDF-TrFE)), is achieved from a simple coating processing, which is of a magnitude that is very difficult to obtain with conventional TFTs by means of molecular engineering. This work, therefore, represents a major step toward truly viable plastic electronics.
Recently, indoor organic photovoltaics (OPVs) has attracted substantial research attention, due to the emergence of self‐powered electronic devices for Internet‐of‐Things (IoT) applications. This ...progress report discusses recent developments in indoor OPVs, focusing on the strategic role of synergistic parasitic resistance in suppressing the leakage current to achieve high indoor efficiencies. Moreover, an underexplored area is presented, namely the impact of optical modulation on enhancing light absorption in indoor OPVs. First, the main advances in material design for indoor OPVs are briefly presented. This is followed by detailed discussions of the crucial strategies, including interfacial engineering, the effect of photoactive layer thickness, and the effectiveness of transparent conducting electrodes for improving the OPV performance. Overall, this review highlights that understanding the indispensable role of parasitic resistance under dim light conditions may provide new opportunities for developing efficient indoor OPVs for practical applications. Finally, after summarizing recent progress in indoor OPVs, a critical perspective is provided.
Research on indoor organic photovoltaics (OPVs) over the last five years is discussed. Focusing on the indoor environment (much lower luminance, diverse emission spectra, etc.), reported photoactive layer materials are discussed. Then, the efforts to improve indoor OPV performance by utilizing synergistic parasitic resistance and optical modulation are described. Finally, a description of the relevant optical simulation methods is provided.
A robust hydrogel with a reliable deformation region in an aqueous environment is proposed. The gel has a homogeneous network where hydrophilic/hydrophobic components are uniformly distributed. In an ...aqueous environment, aggregated hydrophobic segments serve as “mechanical fuse links,” inhibiting sudden macroscopic fracture. The gel endures threefold stretching for more than 100 cycles in water without mechanical hysteresis.
Although Asian people are believed to be more susceptible to bleeding on currently recommended dose of ticagrelor, there is limited evidence supporting low-dose ticagrelor. We prospectively ...randomized patients receiving dual antiplatelet therapy with aspirin and clopidogrel into 3 groups; aspirin plus clopidogrel 75 mg versus aspirin plus ticagrelor 90 mg once daily versus aspirin plus ticagrelor 45 mg twice daily. Platelet function assessments were conducted using VerifyNow P2Y12 assay at baseline and 28 days after randomization. No differences in baseline P2Y12 reaction unit (PRU) values were observed among the 3 groups. PRU values at the end of the treatment periods were significantly lower in low-dose ticagrelor (90 mg QD group, 98.6 ± 73.4 and 45 mg BID group, 65.5 ± 58.8) compared with clopidogrel (221.2 ± 50.1, both p <0.001). There was no significant difference in PRU values between 2 groups of low-dose ticagrelor (p = 0.208). The rates of high on-treatment platelet reactivity were significantly lower in low-dose ticagrelor compared with clopidogrel, whereas clopidogrel showed higher rate of optimal on-treatment platelet reactivity than ticagrelor 45 mg BID. However, similar rate of optimal on-treatment platelet reactivity was observed in clopidogrel and ticagrelor 90 mg QD. In conclusion, low-dose ticagrelor treatment, either with 90 mg QD or 45 mg BID, was associated with a more potent antiplatelet effect compared with clopidogrel treatment and once daily dose provided similar antiplatelet effect but favorable effect on optimal platelet inhibition compared with twice daily dose.
In this paper, a simple design for a triple-band circularly polarized (CP) antenna with the capability of switching its polarization between dual-sense CPs is presented. The proposed antenna is ...comprised of a monopole loop antenna as a primary radiator. By placing a parasitic loop around the primary radiator, an additional CP band is achieved. Reconfigurability of the polarization between right-hand CP (RHCP) and left-hand CP (LHCP) at three different frequencies of 2.5, 3.3, and 3.8 GHz was realized by controlling the ON/OFF states of two PIN diodes. For validation, the fabricated antenna yielded an impedance bandwidth of 52.6% (2.34-4.01 GHz), while the axial ratio bandwidths for both the RHCP and LHCP states were 3.5% (2.47-2.56 GHz), 6.6% (3.20-3.42 GHz), and 2.4% (3.74-3.83 GHz). The measured broadside gains within the axial ratio bandwidth were 1.2, 2.7, and 1.4 dBi, respectively. Compared to other reconfigurable multi-band CP antennas, the proposed design is the first work to achieve a reconfigurable polarization at three distinct bands at a low fabrication cost by using only two diodes. The proposed antenna is suitable for WLAN and WiMAX applications.
Despite recent improvements in their power‐conversion efficiency (PCE), organic photovoltaics (OPVs) cannot yet be guaranteed stable in an indoor environment. In this study, the destabilizing effects ...of morphological evolution and molecular‐ordering variation on photoactive layers containing two to four photoactive components are investigated under realistic indoor photothermal (>55 °C for 1000 h) and mechanical (10% strain and 1000 cycles) deformation conditions. Layers with more stable morphologies are obtained by increasing the number of photoactive components; consequently, the quaternary OPVs show the best PCE retention (over 90% and 82% of the initial values after the photothermal and mechanical stresses, respectively). The increase in entropy caused by the additional components in the quaternary blend leads to a more balanced molecular arrangement and excellent photothermal stability. Stronger intermolecular bonding and less variation of molecular ordering likewise occur in the quaternary OPVs, enhancing their mechanical endurance.
In this study, performance degradation factors of organic photovoltaics (OPVs) under indoor stress are unveiled. Morphological evolution and molecular packing variation are deeply investigated. Indoor stability enhancement is achieved with increasing photoactive components. The quaternary OPVs show great performance retention under viable indoor stresses.
Major Depressive Disorder (MDD) imposes a substantial burden within the healthcare domain, impacting millions of individuals worldwide. Functional Magnetic Resonance Imaging (fMRI) has emerged as a ...promising tool for the objective diagnosis of MDD, enabling the investigation of functional connectivity patterns in the brain associated with this disorder. However, most existing methods focus on a single brain atlas, which limits their ability to capture the complex, multi-scale nature of functional brain networks. To address these limitations, we propose a novel multi-atlas fusion method that incorporates early and late fusion in a unified framework. Our method introduces the concept of the holistic Functional Connectivity Network (FCN), which captures both intra-atlas relationships within individual atlases and inter-regional relationships between atlases with different brain parcellation scales. This comprehensive representation enables the identification of potential disease-related patterns associated with MDD in the early stage of our framework. Moreover, by decoding the holistic FCN from various perspectives through multiple spectral Graph Convolutional Neural Networks and fusing their results with decision-level ensembles, we further improve the performance of MDD diagnosis. Our approach is easily implemented with minimal modifications to existing model structures and demonstrates a robust performance across different baseline models. Our method, evaluated on public resting-state fMRI datasets, surpasses the current multi-atlas fusion methods, enhancing the accuracy of MDD diagnosis. The proposed novel multi-atlas fusion framework provides a more reliable MDD diagnostic technique. Experimental results show our approach outperforms both single- and multi-atlas-based methods, demonstrating its effectiveness in advancing MDD diagnosis.
We investigate the influence of a matching load resistance on frequency responses of a lumped-electro-absorption modulator-integrated lasers (EMLs) whose modulation band-widths are extended by LC ...resonance effect. An equivalent circuit modeling is performed to determine the optimal values of a matching load resistance enabling 112-Gbaud PAM4 operation for a lumped-EML chip with an electro-absorption modulator (EAM) length of 150 um. To verify the simulation results, we package a lumped-EML submodule and measure its high-frequency charac-teristics. Then, we experimentally demonstrate that the 3-dB bandwidth of the lumped-EML submodule can be enhanced to 55 GHz and beyond by optimizing the matching load resistance value as well as lengths of the bondwires, although the EAM length is as long as 150 um. The fabricated lumped-EML submodule exhibits clear optical eye patterns under 112-Gbaud PAM4 operation.
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