도너-어셉터 공중합체의 효과적인 도핑

Molecular doping is effective method for changing the electrical and physical properties of organic semiconductors. However, the mechanism of doping process was not certainly discovered and moreover the doping efficiency of the donor-acceptor copolymer was low. Herein, we synthesized diketopyrrolopyrrole based donor-acceoptor copolymers and investigated the doping efficiency of each polymer by UV-Vis, FT-IR, and EPR spectroscopy. The TBD2F polymer which added thiophene linker with DPP based polymer, could be doped effectively by F4TCNQ molecular dopant. Moreover, the 2D-GIXD was measured to analyze the do-pant position at polymer crystalline phase. From the result we could speculate that by dopant located at alkyl chain region of polymer crystalline matrix, the efficient doping enabled.YⅠ. Introduction 1 1.1 Organic semiconductors 1 1.2 Doping of organic semiconductors 1 1.2.1 Mechanisms of molecular doping 1 1.2.2 Doping of copolymer 2 Ⅱ. Results and discussion 3 2.1 Molecular structures 3 2.2 UV-Visible spectroscopy 3 2.3 Fourier transform infrared spectroscopy 4 2.4 Electron paramagnetic resonance spectroscopy 5 2.5 2-D Gazing incident X-ray diffraction 6 Ⅲ. Conclusion 8MasterdCollectio

Non-Power-Driven Organic Photodiode via Junction Engineering

Here we introduce a junction engineering approach to realize a high performance non-power-driven organic photodiode. To overcome the external power source dependency of conventional photodiodes, in this work, we try not only to implement an inherently large built-in-potential of the junction but also to utilize an inherently low charge carrier concentration of the semiconductor. The strategically designed ITO/plasma-treated ZnO/poly[2-methoxy-5-(2′-ethylhexyloxy)-p-phenylene vinylene] (MEH-PPV)/MoO3/Ag geometry showed near-ideal Schottky junction properties with a high zero-bias built-in potential of 0.54 eV, leading to a zero-bias depletion width of 470 nm. As a result, a green-selective polymeric photodiode with high zero-bias detectivity up to 5 1011 Jones and a low noise equivalent power of 2.98 10-12 W Hz-1/2 are demonstrated, revealing the possibility of a thin film, color-selective and non-power-driven polymeric photodiode for battery-free application. © 2018 IOP Publishing Ltd.1

Facilitating tailored therapeutic strategies for glioblastoma through an orthotopic patient-derived xenograft platform

Despite years of research into its pathobiology and continuing clinical trials for novel therapies, the prognosis for patients with glioblastoma (GBM) remains dismal. An important obstacle against treatment efficacy may be a high degree of intra- and inter-tumoral heterogeneity within GBMs, which may be caused by the presence of self-renewing GBM stem cells (GSCs). Recent advances in multi-omics technology introduce new possibilities for applying personalized strategies to GBM therapy. As drug discovery is accelerating with the transition from non-selective, cytotoxic therapy to a precision, targeted approach, the appropriate in vivo platform for GBM is critical for validating drug targets and prioritizing candidates for clinical studies, for co-development of companion diagnostics and, ultimately, for drug approval. Here we will describe GBM orthotopic patient-derived xenografts (PDXs) as more useful, clinically relevant resources for individually tailored strategies for GBM

Design and Synthesis of a New Non-Fullerene Acceptor for High-Performance Photomultiplication-Type Organic Photodiodes

Photomultiplication-type organic photodiodes (PM-OPDs) rely on acceptor molecules for both charge separation and efficient gain generation. Herein, a new non-fullerene acceptor is designed and synthesized by introducing thienylenevinylene (TV) groups into the conventional 2,2MODIFIER LETTER PRIME-[[6,6,12,12-tetrakis(4-hexylphenyl)-6,12-dihydrodithieno[2,3-d:2MODIFIER LETTER PRIME,3MODIFIER LETTER PRIME-dMODIFIER LETTER PRIME]-s-indaceno[1,2-b:5,6-bMODIFIER LETTER PRIME]dithiophene-2,8-diyl]bis[methylidyne(3-oxo-1H-indene-2,1(3H)-diylidene)]]bis[propanedinitrile] (ITIC) structure. The resulting TV-ITIC acceptor possesses not only extended pi-conjugation length, which leads to lower energy bandgap as well as deeper lowest unoccupied molecular orbital (LUMO) level, but also enhanced hydrophobic characteristics, owing to the increased volumetric portion of the aliphatic chain, which improves the miscibility with the donor polymer semiconductor, poly(3-hexylthiophene-2,5-diyl) (P3HT). Moreover, pristine TV-ITIC films consist of intrinsically well-ordered anisotropic crystallites, which are confirmed by 2D grazing incidence X-ray diffraction (2D-GIXD) analysis. All of these photophysical properties are beneficial for efficient exciton separation, electron trapping, and charge injection abilities of PM-OPDs compared to those obtained with conventional ITIC. Because of such synergetic contributions of TV-ITIC to the photomultiplication mechanism, the resulting optimized PM-OPD exhibits a high external quantum efficiency (>74,000%) and a large specific detectivity (>10(12) Jones). © 2020 Wiley-VCH GmbH1

Boosting the Performance of Photomultiplication‐Type Organic Photodiodes by Embedding CsPbBr3 Perovskite Nanocrystals

Abstract In this study, it is demonstrated that CsPbBr3 perovskite nanocrystals (NCs) can enhance the overall performances of photomultiplication‐type organic photodiodes (PM‐OPDs). The proposed approach enables the ionic‐polarizable CsPbBr3 NCs to be evenly distributed throughout the depletion region of Schottky junction interface, allowing the entire trapped electrons within the depletion region to be stabilized, in contrast to previously reported interface‐limited strategies. The optimized CsPbBr3‐NC‐embedded poly(3‐hexylthiophene‐diyl)‐based PM‐OPDs exhibit exceptionally high external quantum efficiency, specific detectivity, and gain–bandwidth product of 2,840,000%, 3.97 × 1015 Jones, and 2.14 × 107 Hz, respectively. 2D grazing‐incidence X–ray diffraction analyses and drift–diffusion simulations combined with temperature‐dependent J–V characteristic analyses are conducted to investigate the physics behind the success of CsPbBr3‐NC‐embedded PM‐OPDs. The results show that the electrostatic interactions generated by the ionic polarization of NCs effectively stabilize the trapped electrons throughout the entire volume of the photoactive layer, thereby successfully increasing the effective energy depth of the trap states and allowing efficient PM mechanisms. This study demonstrates how a hybrid‐photoactive‐layer approach can further enhance PM‐OPD when the functionality of inorganic inclusions meets the requirements of the target device

Differential Localization of Pain-Related and Pain-Unrelated Neural Responses for Acupuncture at BL60 Using BOLD fMRI

The objective of this study was to differentiate between pain-related and pain-unrelated neural responses of acupuncture at BL60 to investigate the specific effects of acupuncture. A total of 19 healthy volunteers were evaluated. fMRI was performed with sham or verum acupuncture stimulation at the left BL60 before and after local anesthesia. To investigate the relative BOLD signal effect for each session, a one-sample t-test was performed for individual contrast maps, and a paired t-test to investigate the differences between the pre- and post-anesthetic signal effects. Regarding verum acupuncture, areas that were more activated before local anesthesia included the superior, middle, and medial frontal gyri, inferior parietal lobule, superior temporal gyrus, thalamus, middle temporal gyrus, cingulate gyrus, culmen, and cerebellar tonsil. The postcentral gyrus was more deactivated before local anesthesia. After local anesthesia, the middle occipital gyrus, inferior temporal gyrus, postcentral gyrus, precuneus, superior parietal lobule, and declive were deactivated. Pre-anesthetic verum acupuncture at BL60 activated areas of vision and pain transmission. Post-anesthetic verum acupuncture deactivated brain areas of visual function, which is considered to be a pain-unrelated acupuncture response. It indicates that specific effects of acupoint BL60 are to control vision sense as used in the clinical setting

Laser Scanning Confocal Thermoreflectance Microscope for the Backside Thermal Imaging of Microelectronic Devices

In this paper, we report on a confocal thermoreflectance imaging system that can examine the thermal characteristics of microelectronic devices by penetrating the backside of a device through the substrate. In this system, the local reflectivity variations due to heat generation in the device are measured point by point by a laser scanning confocal microscope capable of eliminating out-of-focus reflections and the thermoreflectance is extracted via Fourier-domain signal processing. In comparison to the conventional widefield thermoreflectance microscope, the proposed laser scanning confocal thermoreflectance microscope improves the thermoreflectance sensitivity by ~23 times and the spatial resolution by ~25% in backside thermoreflectance measurements

Highly efficient polymer light-emitting diodes using graphene oxide-modified flexible single-walled carbon nanotube electrodes

We present flexible polymer light-emitting diodes (FPLEDs) using graphene oxide-modified single-walled carbon nanotube (GO-SWCNT) films as an anode on polyethylene terephthalate (PET) substrates. The electrode of GO-SWCNTs used in this study shows quite a low sheet resistance of similar to 75 Omega per square at 65% (at 550 nm) optical transparency with resistance to bending fatigue. The small-sized GO nanosheets onto the SWCNT network films are significantly effective in reducing the sheet resistance and the surface porosity of the SWCNT network films without sacrificing the transmittance. Moreover, the top layer of the large-sized GO nanosheets are crucial for high device efficiency to reduce the roughness of the SWCNT surface and enhance the wettability with PEDOT:PSS. The optimized FPLED using a GO-SWCNT electrode shows a maximum luminous efficiency of 5.0 cd A(-1) (at 9.2 V), power efficiency of 2.4 lm W-1 (at 5.6 V), external quantum efficiency 1.9% (at 9.0 V) and turn-on voltage (2.0 V), which is comparable to conventional PLEDs using an indium-tin-oxide (ITO) electrode (a maximum luminous efficiency of 6.2 cd A(-1) (at 9.4 V), power efficiency of 2.6 lm W-1 (at 5.8 V), external quantum efficiency 2.3% (at 9.0 V) and turn-on voltage (2.0 V)). This result confirms that a GO-SWCNT electrode can be efficiently used to replace ITO for flexible optoelectronic devices.close3

Stoichiometric Engineering of Cs2AgBiBr6 for Photomultiplication- Type Photodetectors

Photomultiplication (PM)-type photodetectors with a high external quantum efficiency (EQE) can be realized through adequately engineered trap states and trap-assisted charge injection. By strategically introducing slightly rich Bi and highly rich Br stoichiometric conditions, efficient trap states are realized for holes in lead-free Cs1.98AgBi1.15Br7.9 double perovskite (DP). With the diode structure of ITO/SnO2/Cs1.98AgBi1.15Br7.9/poly(3-hexylthiophene) (P3HT)/MoOx/Ag, where SnO2 and P3HT layers are used as the hole-and electron-blocking layers, respectively, successful realization of the selective hole trap and the resulting band bending/electron injection at the anode interface is demonstrated. As a result, a high EQE of similar to 16,000%, responsivity of similar to 50 A W-1, and specific detectivity of over 1012 Jones at -3 V are demonstrated. The origin of the suggested PM mechanism is discussed using photophysical and optoelectronic measurements and theoretical studies. This work ensures the successful demonstration of PM-type photodetectors using lead-free Cs2AgBiBr6 DP through strategic trap engineering

3D Defect Localization on Exothermic Faults within Multi-Layered Structures Using Lock-In Thermography: An Experimental and Numerical Approach

Micro-electronic devices are increasingly incorporating miniature multi-layered integrated architectures. However, the localization of faults in three-dimensional structure remains challenging. This study involved the experimental and numerical estimation of the depth of a thermally active heating source buried in multi-layered silicon wafer architecture by using both phase information from an infrared microscopy and finite element simulation. Infrared images were acquired and real-time processed by a lock-in method. It is well known that the lock-in method can increasingly improve detection performance by enhancing the spatial and thermal resolution of measurements. Operational principle of the lock-in method is discussed, and it is represented that phase shift of the thermal emission from a silicon wafer stacked heat source chip (SSHSC) specimen can provide good metrics for the depth of the heat source buried in SSHSCs. Depth was also estimated by analyzing the transient thermal responses using the coupled electro-thermal simulations. Furthermore, the effects of the volumetric heat source configuration mimicking the 3D through silicon via integration package were investigated. Both the infrared microscopic imaging with the lock-in method and FE simulation were potentially useful for 3D isolation of exothermic faults and their depth estimation for multi-layered structures, especially in packaged semiconductors