Nanomorphology dependence of the environmental stability of organic solar cells

Previous studies have reported contradictory effects of small-molecule acceptors on the environmental stability of polymer:small-molecule blends, with one showing that a small-molecule acceptor stabilizes and another showing that it destabilizes the polymer donor. In this work, to investigate the origin of these contradictory results, the effects of the nanomorphologies of small-molecule acceptors on the environmental stability of polymer:small-molecule blends are demonstrated. Investigations on the environmental stabilities of polymer:fullerene blends of poly[[4, 8-bis[(2-ethylhexyl)oxy]benzo[1, 2-b:4, 5-b′]dithiophene-2, 6-diyl][3-fluoro-2-[(2-ethylhexyl)carbonyl]thieno[3, 4-b]thiophenediyl]] (PTB7):phenyl-C₆₁-butyric acid methyl ester (PCBM) with contrasting nanomorphologies of PCBM reveal that dispersed PCBM in a mixed phase is the critical factor that causes triplet-mediated singlet oxygen generation and, hence, the severe photooxidation of PTB7, whereas an aggregated PCBM phase stabilizes PTB7 by reducing the formation of PTB7 triplet excitons. In addition, the photooxidation of PTB7 substantially degrades hole transport in the PTB7:PCBM blends by destroying the crystalline PTB7 phases within the films; this effect is strongly correlated with the efficiency losses of the PTB7:PCBM organic solar cells. These conclusions are also extended to polymer:nonfullerene blends of PTB7:ITIC and PTB7:Y6, thereby confirming the generality of this phenomenon for polymer:small-molecule organic solar cells

Preoperative 18F-Fdg Pet/CT and CT Radiomics for Identifying Aggressive Histopathological Subtypes in Early Stage Lung Adenocarcinoma

Lung adenocarcinoma (ADC) is the most common non-small cell lung cancer. Surgical resection is the primary treatment for early-stage lung ADC while lung-sparing surgery is an alternative for non-aggressive cases. Identifying histopathologic subtypes before surgery helps determine the optimal surgical approach. Predominantly solid or micropapillary (MIP) subtypes are aggressive and associated with a higher likelihood of recurrence and metastasis and lower survival rates. This study aims to non-invasively identify these aggressive subtypes using preoperative 18F-FDG PET/CT and diagnostic CT radiomics analysis. We retrospectively studied 119 patients with stage I lung ADC and tumors ≤ 2 cm, where 23 had aggressive subtypes (18 solid and 5 MIPs). Out of 214 radiomic features from the PET/CT and CT scans and 14 clinical parameters, 78 significant features (3 CT and 75 PET features) were identified through univariate analysis and hierarchical clustering with minimized feature collinearity. A combination of Support Vector Machine classifier and Least Absolute Shrinkage and Selection Operator built predictive models. Ten iterations of 10-fold cross-validation (10 ×10-fold CV) evaluated the model. A pair of texture feature (PET GLCM Correlation) and shape feature (CT Sphericity) emerged as the best predictor. The radiomics model significantly outperformed the conventional predictor SUVmax (accuracy: 83.5% vs. 74.7%, p = 9e-9) and identified aggressive subtypes by evaluating FDG uptake in the tumor and tumor shape. It also demonstrated a high negative predictive value of 95.6% compared to SUVmax (88.2%, p = 2e-10). The proposed radiomics approach could reduce unnecessary extensive surgeries for non-aggressive subtype patients, improving surgical decision-making for early-stage lung ADC patients

２次元上の電荷輸送およびトラップを評価するための複素誘電率解析法の開発

京都大学0048新制・課程博士博士(工学)甲第20815号工博第4419号新制||工||1687(附属図書館)京都大学大学院工学研究科分子工学専攻(主査)教授 関 修平, 教授 佐藤 啓文, 教授 梶 弘典学位規則第4条第1項該当Doctor of Philosophy (Engineering)Kyoto UniversityDGA

The 3D Position Estimation and Tracking of a Surface Vehicle Using a Mono-Camera and Machine Learning

The ability to obtain the 3D position of target vehicles is essential to managing and coordinating a multi-robot operation. We investigate an ML-backed object localization and tracking system to estimate the target’s 3D position based on a mono-camera input. The passive vision-only technique provides a robust field awareness in challenging conditions such as GPS-denied or radio-silent environments. Our processing pipeline utilizes a YOLOv5 neural network as the back-end detection module and a temporal filtering technique to improve detection and tracking accuracy. The filtering process effectively removes false positive labels to improve tracking accuracy. We propose a piecewise projection model to predict the target 3D position from the estimated 2D bounding box. Our projection model utilizes the co-plane property of ground vehicles to calculate 2D–3D mapping. Experimental results show that the piecewise model is more accurate than existing methods when the training dataset is not evenly distributed in the sampling space. Our piecewise model outperforms the singular RANSAC-based and the 6DPose methods by 28% in location errors. A less than 10-m error is observed for most near-to-mid-range cases

Repurposing DNA-binding agents as H-bonded organic semiconductors

DNA結合剤の電子材料としての新しい機能を開拓 --抗がん剤が有機半導体材料になる--. 京都大学プレスリリース. 2019-09-25.Organic semiconductors are usually polycyclic aromatic hydrocarbons and their analogs containing heteroatom substitution. Bioinspired materials chemistry of organic electronics promises new charge transport mechanism and specific molecular recognition with biomolecules. We discover organic semiconductors from deoxyribonucleic acid topoisomerase inhibitors, featuring conjugated backbone decorated with hydrogen-bonding moieties distinct from common organic semiconductors. Using ellipticine as a model compound, we find that hydrogen bonds not only guide polymorph assembly, but are also critical to forming efficient charge transport pathways along π−conjugated planes when at a low dihedral angle by shortening the end-to-end distance of adjacent π planes. In the π−π stacking and hydrogen-bonding directions, the intrinsic, short-range hole mobilities reach as high as 6.5 cm2V−1s−1 and 4.2 cm2V−1s−1 measured by microwave conductivity, and the long-range apparent hole mobilities are up to 1.3 × 10–3 cm2V−1s−1 and 0.4 × 10–3 cm2V−1s−1 measured in field-effect transistors. We further demonstrate printed transistor devices and chemical sensors as potential applications

Photomultiplication-type Organic Photodetectors with Fast Response Time Enabled by the Controlled Charge Trapping Dynamics of Quantum Dot Interlayer

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In Situ Neutron Diffraction Study of Phase Transformation of High Mn Steel with Different Carbon Content

In situ neutron diffraction was employed to examine the phase transformation behavior of high-Mn steels with different carbon contents (0.1, 0.3, and 0.5 wt.%C). With increasing carbon contents from 0.1 C to 0.5 C, the austenite phase fraction among the constituent phases increased from ~66% to ~98%, and stacking fault energy (SFE) increased from ~0.65 to ~16.5 mJ/m2. The 0.1 C and 0.3 C steels underwent phase transformation from γ-austenite to ε-martensite or α’-martensite during tensile deformation. On the other hand, the 0.5 C steel underwent phase transformation only from γ-austenite to ε-martensite. The 0.3 C steel exhibited a low yield strength, a high strain hardening rate, and the smallest elongation. The high strain hardening of the 0.3 C alloy was due to a rapid phase transformation rate from γ-austenite to ε-martensite. The austenite of 0.5 C steel was strengthened by mechanical twinning during loading process, and the twinning-induced plasticity (TWIP) effect resulted in a large ductility. The 0.5 wt.% carbon addition stabilized the austenite phase by delaying the onset of the ε-martensite phase transformation