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• Understand public perception of AVs by analyzing social media data in China; • Introduce text network analysis to the research on public perception of AVs as a supplement to existing research methods; • Analyze the gender differences in public perception of AVs using social media; • The public's insufficient knowledge of AVs is related to the publicity of automobile companies and the media; • The public expresses more blame for vehicles with L2 driving automation than human drivers after the NIO crash. In China, vehicles with L2 driving automation are already widespread, while L3-L5 automated vehicles (AVs) are not allowed on the road. Surprisingly, crashes involving vehicles with L2 driving automation contributed to the public's discussion of L3-L5 AVs. Understanding the variations in public perception of AVs is imperative, which could significantly affect the future evolution of AVs. Respondents have few opportunities to express their views freely in survey-based studies relying on structured questionnaires (e.g., Likert scale). We collected 42,111 comments from Chinese mainstream social media platforms (Sina Weibo and Tik Tok) in August 2021 and applied advanced text mining technology (Latent Dirichlet Allocation topic model, text network analysis, and sentiment analysis) to understand variations in public perception of AVs before and after the crashes. The results show that the public expresses more blame for vehicles with L2 driving automation than human drivers and has misunderstandings about the current development of L3-L5 AVs, which is closely connected with publicity from automobile companies and media. Women were more negative than men both before and after the crash, and the sentiment difference was most significant in the first three days of the crash. This research provides new ideas for a timely understanding of the public perception of AVs. Findings contribute to specific policy recommendations to help in the technological change and wider adoption of AVs. [ABSTRACT FROM AUTHOR]

Abstract π-Bridges play a crucially important role in determining the optical absorption, bandgap and energy levels of donor-π-acceptor-π type conjugated polymers. In this contribution, a new polymer donor named PBT1-C-2Cl is synthesized by inserting the chlorine atoms onto π-bridges of the polymer PBT1-C. The introduction of chlorine atoms enables PBT1-C-2Cl with a lower highest occupied molecular orbital energy level and enhanced crystallinity than those of PBT1-C due to the high electronegativity and big atomic radius of chloride atom. When PBT1-C-2Cl is blended with the non-fullerene acceptor IT-4F, a high power conversion efficiency (PCE) of 12.7%, an open-circuit voltage (V oc) of 0.85 V and an impressive fill factor (FF) of 76.0% are achieved, which are all higher than those of PBT1-C:IT-4F based devices (PCE = 10.9%, V oc = 0.79 V and FF = 70.5%). The enhanced charge dissociation, efficient charge transport and reduced charge recombination account for the improved photovoltaic performance of PBT1-C-2Cl: IT-4F devices. The results indicate that inserting chlorine atoms onto π-bridges is a rational strategy for the synthesis of high-performance donor-π-acceptor-π type conjugated polymer donors. Graphical abstract fx1 Highlights • A novel polymer donor named PBT1-C-2Cl with chlorinated thiophene π-bridges was synthesized with high yield. • The incorporation of chlorine atom enables PBT1-C-2Cl of tight molecular packing and thereby the high hole mobility. • PBT1-C-2Cl-based solar cells exhibit a high efficiency of 12.7% with an impressivehigh fill factor of 76.0%. • The introduction of chlorine atoms onto thiophene π-bridge is a useful strategy to improve the photovoltaic performance of D-A type polymer donors. [ABSTRACT FROM AUTHOR]

• Study conducted a randomized controlled trial and applied Double Machine Learning. • The causality between "over-hype" and public misconceptions about AVs was identified. • Participants believed AVs are already available but not safer than human drivers. • The sociodemographic factors have little impact on the susceptibility to "over-hype." • It is necessary to regulate public communication about AVs. Traffic accidents caused by drivers' over-reliance on SAE L2 advanced driver assistance systems (ADAS) have become a new type of accident worthy of attention. There is growing concern that the "over-hype" about automation technology produced by manufacturers or the media might affect the formation of public misconceptions about autonomous vehicles (AVs), further influencing their unsafe interaction behaviors with the system. The purpose of our study was to explore whether and how "over-hype" in various contexts affects public misconceptions about AVs from the view of causality. We conducted a randomized controlled trial with a control group of 396 participants and a treatment group of 545 participants drawn from Zhenjiang, China. We applied Double Machine Learning (DML), ordered logit models, and significant difference tests to estimate the impact of "over-hype" in various contexts. The results found that the statement that "over-hype" caused public misconceptions was less rigorous. Significant causality varies among contexts of "over-hype" and aspects of misconceptions. Specifically, "over-hype" in fatal accident reports will lead to availability misconception about AVs, but not safety misconception, suggesting that participants believed AVs were available nowadays but not safe as human drivers. "Over-hype" that exaggerates ADAS capabilities has the greatest average treatment effect on public misconceptions, especially the safety misconception. We found that the young and the more educated are more likely to have safety and availability misconceptions under the "over-hype" of some contexts. However, the effects of "over-hype" varied less among groups with different socio-economic factors on the whole, which revealed the universality of the influence of "over-hype." The results provided empirical evidence for regulating propaganda about AV technology and provided practical insights on how to introduce AV technology to the general public properly. [ABSTRACT FROM AUTHOR]

A pair of linear two-dimensional conjugated non-fullerene acceptors, named as TVIDTPDI and TVIDTzPDI , which have the same perylene diimide end-capping groups, but different in two-dimensional conjugated central core (the dithienyl vinylene-fused indacenodithiophene or dithienyl vinylene-fused indacenodithiazole), were successfully synthesized and evaluated as acceptor materials in organic solar cells (OSCs). Such core units in these small acceptors play a decisive role in the formation of the nanoscale separation of the blend films, which were systematically investigated through absorption spectra, electrochemical properties, density functional theory calculations, AFM images, and charge mobility measurement by space-charge-limited current SCLC method. By incorporation of the dithienyl vinylene-fused indacenodithiazole-based core, TVIDTzPDI showed better planarity in the core unit with a dihedral 45.4° and 49.6° angle of between central core and the PDI. Moreover, the TVIDTzPDI blend with PTB7-Th displays higher and more balanced mobilities ( μ h = 4.56 × 10 −4 and μ e = 6.12 × 10 −4 cm 2 V −1 s −1 ) in comparison with those of TVIDTPDI blend with PTB7-Th . Therefore, the TVIDTzPDI/PTB7-Th based OSCs showed a higher PCE of 2.09% than that of the TVIDTPDI/ PTB7-Th devices (1.50%). The purpose of this study is to provide a facile strategy to design PDI-based two-dimensional conjugated small molecular acceptors and understand the impact of installing the two dimensional core and more electron-deficient thiazole unit in such small molecular acceptors. [ABSTRACT FROM AUTHOR]

Autonomous vehicles (AVs) will bring considerable benefits to individuals and society, while the process of AVs' popularity may not always be smooth. Sometimes crashes are unavoidable, which could hinder the widespread acceptance of AVs. Although previous studies have investigated factors that affect AV acceptance, few of them pay attention to the impact of accidents and not to mention quantitative analysis. This study aims to explore what the public is really concerned about the AV crash and whether it significantly affects the public's behavioral intention to use AVs utilizing a multi-method analytical approach, including latent Dirichlet allocation, structural equation model, and Bayesian network. We employed a qualitative exploratory analysis to identify the topics of social media data about AV crashes and proposed an integrated framework using variables originating from topics. We introduced perceived severity in AV acceptance research to cater to the context of AV crashes. The findings reveal how trust, attitude, knowledge, perceived risk, media exposure, and perceived severity affect the public acceptance of AVs and how differences exist between full automation and driver assistance. This research helps to provide theoretical contributions and practical implications to reduce the negative effect of AV crashes and improve public acceptance of AVs. • This paper investigates public perceptions of autonomous vehicles (AVs) after an accident. • A hybrid method combining social media and a questionnaire survey aims to get the real public concern about AV crashes. • We proposed an integrated framework using variables originating from social media data. • This study reveals the mechanism of consumers' adoption of AV technology. [ABSTRACT FROM AUTHOR]

Side-chain engineering is one of the most promising ways to develop non-fullerene acceptors (NFAs) for organic solar cells. In this work, we designed and synthesized a novel acceptor IT-BnC6-4F by introducing methylene group between the phenyl group and the sp3 hybrid carbon atoms of central conjugated cores to form benzyl side chains. IT-BnC6-4F shows broader absorption spectrum and higher crystallinity than those of its analogue, IT-4F. When blended with PT2, the IT-BnC6-4F based device achieved a high power conversion efficiency (PCE) of 13.36 %, with an open-circuit voltage (V oc) of 0.87 V and a short-circuit current density (J sc) of 20.99 mA cm−2. [Display omitted] • Benzyl side chains functionalized non-fullerene acceptor was synthesized. • Substitution effects of the benzyl side chains on photovoltaic performance of the non-fullerene acceptor were investigated. • Benzyl side chains could endure the non-fullerene acceptor with broader absorption spectrum and higher crystallinity. [ABSTRACT FROM AUTHOR]

Perylenediimide (PDI)-based small molecules have significantly contributed to the development of non-fullerene acceptors, whereas the development of PDI-based polymer acceptors is relatively lagging behind. In this study, we designed and synthesized two PDI-based n-type polymers named as PF-PDI and PBDT-PDI, in which PDI was used as electron-deficient unit and fluorene (F) or benzodithiophene (BDT) were used as electronrich components. The density functional theory (DFT) calculations and grazing incidence wide-angle X-ray scattering (GIWAXS) results indicate that the PF-PDI shows larger steric hindrance and relatively weaker lamellar packing than that of PBDT-PDI. Comparing with PBDT-PDI, PF-PDI shows red-shift absorption and lower-lying HOMO level, which agrees well with the DFT results. A well-known wide bandgap polymer donor, PDBT-T1 was employed to fabricate polymer solar cells (PSCs) with the two acceptors. The all polymer solar cells (all-PSCs) based on PDBT-T1:PF-PDI showed a high power conversion efficiency (PCE) of 4.47%, which is approximately 2-fold larger than that of devices with PDBT-T1:PBDT-PDI (PCE = 2.70%). [ABSTRACT FROM AUTHOR]

Fluorination exhibits multiple effects on the photophysical properties of conjugated copolymers and has attracted enormous attention in organic solar cells (OSCs). Herein, a series of structurally identical benzo[1,2-c:4,5-c′]dithiophene-4,8-dione (T1) based polymers (named PPhF0-T1 to PPhF4-T1) with different numbers of fluorine substitutions have been designed and synthesized. With the number of fluorine substitution increases, the energy levels of the polymers decrease gradually. ITPTC non-fullerene acceptor was employed to fabricate OSCs with these polymers. We found that the introduction of fluorine can effectively improve the open-circuit voltage of the device. Upon one or two fluorine atoms are appended to the polymer, the corresponding short-circuit currents (J sc s) are obviously promoted. However, due to the excessive phase separation and hence suppressed charge carrier mobility, the J sc decreases when there are four fluorine atoms in the polymer. Consequently, without any additives, the PPhF2-T1 based device gives the highest power conversion efficiency of 10.61%, which is much higher than that of nonfluorinated polymer based OSC (3.97%). This work presents a systematic study upon the effect of different numbers of fluorine atoms on the photovoltaic performance of OSCs, which may serve as a useful guideline in the design of efficient conjugated polymers. To investigated the effect of fluorination on the performance of T1 copolymers. We designed and synthesized four copolymers by altering the numbers of fluorine atoms on the benzene group (named PPhF0-T1 to PPhF4-T1). When one or two F atoms are introduced to the polymers, the PCEs of OSCs are significantly improved. PPhF2-T1:ITCPTC based device delivers a highest PCE of 10.61%, while PPhF4-T1 based OSC yields a relatively lower PCE of 6.28%. Image 1 • Different numbers of fluorine substitutions controllable conjugated polymers were synthesized. • Substitution effects of amount of fluorine atoms on the photovoltaic performance were systematically investigated. • Multiple understanding the fluorination would be better for development of high-performance polymer donor materials. [ABSTRACT FROM AUTHOR]